Living Near Agriculture Increases Rates of Serious Health Problems
Compilation of the Scientific Research
- by Chem-Tox.com - January, 2016
View Spanish Version
Time to Move?
Families living near farming areas experience greatly increased rates of health disorders. This is the conclusion from the following report summarizing more than 25 peer reviewed scientific studies on this topic over the past 30 years. Illnesses found to occur at higher rates for people living close to agriculture include birth defects, brain cancer, autism, infertility, miscarriage, Parkinson's Disease, immune system damage, leukemia, developmental brain damage in children, higher rates of child cancers, non-Hodgkin's lymphoma, autoimmune disorders, arthritis, lupus and diabetes. Of great concern (because of the rapid rise of diabetes, over the past 20 years), 21 studies presented at the 2015 European Association for the Study of Diabetes show pesticides increase the risk of diabetes by 61%. While our current report focuses on health disorders resulting from living near farming areas, it brings attention to the potential for elevated health problems to occur in neighborhoods using airplanes and trucks to apply mosquito control pesticides. This situation may be further amplified in poorer communities in Africa and South America that receive highly concentrated levels of pesticides from backpack spray techniques - Homes here typically do not have "close-able" windows, thereby dramatically increasing exposure to family members. This entire report has been translated to Spanish which can be viewed HERE.

Pesticides in the Air Weeks After Application
The cause of these health problems is believed to result from low level pesticide vapors that are present in the air days and sometimes weeks after application on food crops. Some pesticides react with sunlight (in a process known as photolysis) to form new chemicals that are more toxic than the original. Adults and children inhale these chemicals at far greater concentrations than people living farther away. Of great concern, health effects were seen not just for those just living directly next to the fields, but some studies showed effects up to 1 mile away! Continuous breathing of low levels of nerve poisons is suspected of accelerating the aging process by suppressing or damaging genes involved in maintaining health. Some people experience more harm than others as they have lower levels of the protective liver detoxification enzyme cytochrome P-450. Of significant concern, it has been shown that children experience greater harm from pesticides because of their size and less efficient detoxification pathways. While this report emphasizes the dangers of residential homes close to agriculture, similar health effects could be expected for those working in offices or schools within one mile from agriculture as well. It is important to remember, that pesticides are designed with the specific intent to damage biological processes within an organism, which is why even very low levels would be able to cause harm over time.

  Body's Defense Weakened
Everyone is protected from pesticide harm by a liver enzyme known as cytochrome P-450. Its job it to break-down pesticides in the blood into a less-toxic form. Some people, however, have only 1/3rd the normal levels of these important enzymes, and therefore, would have higher levels of pesticides in their blood for longer periods of time, thereby resulting in more harm from the chemical.

Brain's Defense Weakened
The human brain also has a defense known as the blood brain barrier. Its major role is to keep toxic molecules out of the brain cell network. The blood brain barrier is composed of tight junctions between cells that line the interior blood vessels that feed the brain. These tight-junctions (when working properly) prevent larger toxic molecules from squeezing-through and entering the brain cell network. There is also a metabolic blood brain barrier that helps to remove toxic chemicals getting past these tight junctions. As seen in two studies below, the blood brain barrier defense can be weakened or damaged by pesticides. When this occurs, elevated levels of poisons enter the brain resulting in accelerated decline of brain function. This situation takes on new meaning as research over the past 5-10 years has shown that people with Epilepsy, Psychosis, Parkinson's, Multiple Sclerosis and Alzheimer's, do in fact, have a weakened blood brain barrier. These new findings raise the next logical question - Would removing someone with a neurological condition from an agricultural pesticide environment result in restored blood brain barrier function, and thereby, experience improvement in mental function that naturally occurs with a properly functioning blood brain barrier? These are critical studies that must be conducted by sources without a conflict of interest.

Health Disorders Occurring at Higher Rates in Agricultural Settings
Click link to view study or scroll down to view all research - VIEW SPANISH VERSION

Asthma Higher Parkinson's Disease #2
Non-Hodgkin's Lymphoma Autism - Depression - Alzheimer's
Birth Defects Higher Pesticide Vapors Present
Weeks after Application
Autoimmune Disorders Obesity & Pesticides
Severe Birth Defects & Death Immune System Damage #1 Arthritis & Lupus Hyperactivity Higher in Children
Brain Cancer #1 Brain Development Damage Neuroblastoma Lower IQ Scores
Autism Study #1 Higher Child Leukemia #1 Immune System Damage #2 Hemochromatosis - High Iron
Developmental Delays
Brain & Lung Cancer Hydrocephaly & Cleft Palet Microcephaly & Pesticides
Miscarriage Wilm's Tumors Intestinal Disorders in Children Diabetes Higher in Pesticide Sprayers
Brain's Defense Damaged #1 Prostate Cancer Higher Trouble on the Farm
(Article NRDC)
Higher Blood Pesticides = Diabetes
Parkinson's Disease #1 Pesticides 7x's higher on children
living near agriculture
Major study on Cancer Rates
in High Agriculture areas
Guillain Barre Syndrome Higher
  Link to Epilepsy & Alzheimer's
Brain Defense Damaged #2
2nd Generation Health Problems Organic Foods Lower Blood Pesticides

Asthma 4x Higher if Pesticide Exposure in 1st Year of Life
18x's Higher Today than in the 1940's

SOURCE: Environmental Health Perspectives
Vol. 112(6): 760-765, May 2004
View Journal Summary
- View Full Text PDF

Childhood asthma has increased dramatically in the United States over the past 50+ years, affecting less than 1% of children before 1960 and increasing to nearly 9% in 2010. For comparison, historical studies of child asthma show it was even lower prior to 1950, affecting only about one-half of 1% of the population. This shows the percentage of children with asthma in 2010 is 18 times higher than it was in the 1930's & 40's. These studies can be seen in the April 2006 journal THORAX.

In a 2010 CDC report, asthma was reported to affect nearly 8% of white children and 12% of black children. These dramatic increases in asthma strongly suggests environmental factors are responsible and stresses the importance of conducting research investigating how asthma relates to exposure to different environmental factors.

To address this question, researchers at the Department of Preventive Medicine at University of Southern California, investigated environmental exposures among 4,000 children previously diagnosed with asthma before age 5 and compared their environmental exposures to asthma-free children. Most of the children were white and male with middle income status. Below are the results of their study.

Weed Killers increase Asthma Rate 4.5 times
Children exposed to herbicides (weed killers) in the first year of life were over than 4 times more likely to develop asthma than children not exposed to these chemicals. The increase occurred in both farm and non-farm settings. (Herbicides are chemicals used to kill weeds and include such chemicals as 2,4-D and glyphosate). Researchers said these findings are consistent with a previous study that reported a 3-fold increase in asthma in 7-10 year old children who had the chemical DDE in their blood (Karmaus et al. 2001b). Children receive exposure to DDT/DDE from eating conventional non-organic food crops, older homes where DDT was used indoors, farms using the pesticide kelthatne (which contains DDT) and in countries using DDT for malaria control.

Farm Crops Doubles Risk of Asthma
The study also found that children exposed to farm crops/dust had twice the risk of developing asthma as children not exposed.

Department of Preventive Medicine
University of Southern California
Los Angeles, CA, USA


Asthma Higher for Children Living in Agriculture Community

SOURCE: Environmental Health Perspectives
Vol. 114(12): 1916-1922, Dec 2006
View Journal Summary
- View Full Text PDF

To understand this next study, it is important to first understand the latest research on why asthma occurs. Researchers state that asthma is characterized by chronic inflammation in the airways and is accompanied by high numbers of compounds called interleukins, produced by T helper 2 immune system cells. These interleukins bring about an asthma attack by attracting other immune system cells called eosinophils and mast cells to the airwarys, causing inflammation and making it difficult to breathe. On the opposite side, the immune system also has what is called T helper 1 cells. These are believed to be the "good guys" and protect against asthma by producing interferon. Studies of patients with allergies and asthma show they have higher levels of the "bad" T helper 2 compounds known as interleukin-4 and interleukin-5 and abnormally low levels of interferon and tumor necrosis factor produced by the "good" T helper 1 cells. This brings into question on whether pesticides can have an immunotoxic effect and "change" the natural balance of these critical "good" and "bad" asthma regulating compounds in the immune system.

To answer this question, researchers studied 239 children living in one of the largest agricultural settings in California in Salinas Valley. Children had blood samples taken at 24 months of age and measured for the "good" and "bad" asthma related immune system compounds. Researchers also had mothers complete questionnaires on whether they worked in agriculture - used pesticides in the home - and other environmental exposures. Of the 239 children in the study, nearly 10% had been diagnosed with asthma by 24 months of age. Results showed that children with asthma had significantly higher levels of the "bad" T helper 2 compounds than children without asthma. If the a mother worked in agriculture fields, her child had 26% more of these "bad" T helper 2 interleukin compounds. As a side note, gas stoves were also associated with increasing levels of the bad T helper 2 compounds.

Center for Children's Environmental Health
Dept. of Epidemiology & Biostatistics
University of California, Berkeley, California


Birth Defects Higher in Babies Born Near Agriculture

SOURCE: Environmental Health Perspectives, Vol. 111(9):1259-1264, July, 2003
View Journal Online -
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Babies born to families living near wheat growing farms using pesticides were 65% more likely to have have birth defects related to the circulatory and respiratory system. Researchers also found a 50% increase in birth defects affecting the muscle and skeletal systems (see picture at left). The pesticide category believed to be the culprit is known as chlorophenoxy herbicides that contain the chemical 2,4-D. Chlorophenoxy herbicides are used to kill a variety of weeds and are also commonly used by city and county maintenance departments for grass and weed control along roads, canals etc. Scientists also found that infants conceived from April-June (the time of primary pesticide application) had a 75% increased risk of being diagnosed with birth defects - compared to birth defect rates for conception during other times of the year. In conclusion, the scientists stated:

"These results are especially of concern because
of widespread use of chlorophenoxy herbicides."

Dina M. Schreinemachers
National Health and Environmental effects Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency, Research Triangle Park, North Carolina


Severe Birth Defects Ending in Death: 1 Mile from Agriculture

SOURCE: Epidemiology, Vol.12(2):148-156, March, 2001
View Journal Online

Living within 1 mile of agriculture resulted in increased risk of fetal death due to major birth defects, according to a study conducted by the School of Public Health, University of North Carolina. The most important factor increasing fetal death rate was the timing of pesticide exposure. If pesticide exposure occurred between the 3rd and 8th week of pregnancy, there was a 40% increase in major birth defects ending in fetal death.

If pesticide exposure was from the soil fumigant pesticides used typically for nematodes, during the 3rd and 8th week of pregnancy, there was more than double the rate of death from birth defects. Organ and limb formation occurs in the developing child between weeks 3 and 8, and therefore, would be more vulnerable to harm.

Department of Epidemiology
School of Public Health,
University of North Carolina, Chapel Hill, NC


Living in Farming Areas = Higher Child Cancer Rates
Conclusive Study of over 25 million Children

SOURCE: Environmental Health Perspectives, Vol. 116(4): 559-565, April 2008
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In this very large scale study, funded by the National Cancer Institute, scientists wanted to determine if rates of child cancer were higher in U.S. counties that contain a higher percentage of agriculture cropland. For example, in the state of Arizona - approximately 1.8% of the land area is covered in cropland whereas Iowa devotes about 74.7% of its land to agriculture. Therefore, if pesticides used in agriculture were causing an increase in child cancers, then we should see higher rates in Iowa than Arizona.

The study included analysis of cancer rates for over 25 million children (age 0 - 14) living in more than 1000 counties across the U.S. For comparing cancer rates, counties were divided into 3 categories depending on the percent of farmland in the county: Counties with less than 20% farmland were called the referent category (total 515 counties) - counties with 20% to 59% farmland were labeled as "medium exposure" and counties with 60% or more farmland were labeled as "high exposure."

To identify increases in child cancer - researchers first calculated cancer rates in the "referent" counties with 20% or less cropland and then compared these to cancer rates in the medium and high exposure counties.

After completing the analysis, researchers found that counties having 60% or more of land area devoted to farming had two or more times the risk for childhood cancer than cancer rates in the low exposure "referrant" category.

Examples of specific cancer increases included the following: Liver cancer occurred 3 times more often among children in high cropland counties than low cropland counties - Hodgkin and non-Hodking lymphomas were two times more likely to appear in the higher exposure counties - bone tumors more than twice as likely - malignant melanoma nearly 5 times more likely - Wilms' tumor more than twice as likely and neuroblastoma was found to be 70% higher in counties with the most agricluture cropland.

In conclusion the researchers stated:

Our study results indicate an increased risk for many types of childhood cancers associated with residence at diagnosis in counties having a moderate to high level of agricultural activity, with a remarkably consistent dose–response effect seen for counties having ≥ 60% of the total county acreage devoted to farming. Further, the finding that patterns of risk for individual cancers varied by crop type suggests that the development of different childhood cancers is likely to be related to specific pesticides.

Department of Epidemiology and Biostatistics, School of Rural Public Health,
Texas A&M Health Science Center, College Station, Texas, USA
National Center for Atmospheric Research, Boulder, Colorado, USA
Department of Community and Environmental Health,
Boise State University, Boise, Idaho, USA
Centers for Health Promotion and Prevention Research,
School of Public Health,
University of Texas Health Science Center at Houston, Houston, Texas, USA


Brain Cancer Doubles if Living 1/2 Mile from Agriculture

SOURCE: American Journal of Public Health, Vol. 86(9):1289-96, 1996
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High brain cancer rates were found for people living near a cranberry agricultural growing area in Cape Cod, Massachusetts.  Researchers from the Boston University School of Public Health compared the home locations of approximately 1000 cancer patients to the home locations of 1000 patients dying of illnesses not related to cancer. Results showed that living within 2600 feet of the cranberry growing area resulted in twice the risk for all brain cancers and nearly a 7-fold increased risk for a type of brain cancer known as astrocytoma. (Astrocytomas are in the family of "glioma" cancers which begin in the glial tissue (glial tissue are the cells which hold the other brain cells together).

For more information on brain cancer and neuroblastoma see:
www.chem-tox.com/cancerchildren - brain cancer research summaries
www.chem-tox.com/neuroblastoma - neuroblastoma research summaries

Drs. A. Aschengrau, D. Ozonoff, P.Coogan, R. Vezina, T. Heeren
Department of Epidemiology and Biostatistics
Boston University School of Public Health


Prostate Cancer 50% Higher Living 1/3rd Mile from Agriculture

SOURCE: American Journal of Epidemiology, Vol.173(11): 1280-1288, Jan 2011
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Prostate cancer is the third leading cause of cancer deaths among men. The incidence of prostate cancer has shown a gradual increase since the 1960's with large increases in the late 1980's and 1990's in the United States (BJU Int, 2002). In this study, researchers at the University of Southern California investigated pesticide exposure amoung 173 men with prostate cancer between 60-74 years old. All men lived in agricultural areas in California's Central Valley. Conclusions from the study showed that exposure to the pesticide methyl bromide increased prostate cancer by 62% - exposure to a group of organochlorine pesticides more than doubled the risk of prostate cancer and living in homes within 500 meters (1/3rd mile) of farms using organochlorine pesticides increased prostate cancer for family members by about 50%.

Drs. Myles Cockburn, Paul Mills, Xinbo Zhang, John Zadnick, Dan Goldberg
Department of Preventive Medicine
University of Southern California


Autism (ASD) 7x Higher in Children Living Near Agriculture

SOURCE: Environmental Health Perspectives, 115(10): 1482-1489, 2007
View Original Article in Environmental Health Perspectives
View Video of this Study

Rates for Autism Spectrum Disorder (ASD) were more than 6 times higher for children whose mothers were exposed to certain pesticides during a specific time-window in pregnancy. 465 children were identified with ASD in the Sacramento River Valley and San Joaquin River Valley air basin of California. Residences were identified and proximity to pesticide sprayed farms was determined through state mandated agriculture pesticide use reporting files. Results showed that the risk of having a child with Autism Spectrum Disorder was 7.6 times higher than normal if certain conditions were present. This included:

1. Homes were located within 500 meters (< 1/3 mile) from pesticide treated fields
2. Crops were treated using the pesticides dicofol and endosulfan
3. Pesticides applied between week 1 and week 8 after conception

Further support for these findings is shown by the fact that the risk of ASD increased with the pounds of pesticide used and decreased with distance from the treated fields.

CHEM-TOX COMMENT: Also of significance, the human brain begins growing at over 4,000 cells per second beginning in the 4th week of pregnancy, thereby suggesting this would be a highly vulnerable time period.

Eric Roberts, Paul English, Judith Grether, Galye Windham,
Lucia Somberg, Craig Wolff
Public Health Institute, Oakland, CA, USA
California Department of Health Services, Richmond, CA
School of Public Health, University of California, Berkeley, CA


Autism and Developmental Delays Higher in Children
Living Near Agriculture

SOURCE: Environmental Health Perspectives, 122(10), October 2014
Study funded by National Institutes of Environmental Health Sciences & U.S. EPA
View Journal Online
Read Summary of Article in Environmental Health News

Living within 1 mile of food crops grown using pesticides was shown to result in a higher rate of autism and developmental disorders in children. The background statement of this research states exposure to several common agricultural pesticides during pregnancy can induce developmental neurotoxicity in humans, and has been associated with developmental delay and autism. The researchers involved in this study evaluated whether residential proximity to agricultural pesticides during pregnancy was associated with autism spectrum disorders (ASD) or developmental delay (DD) in the Childhood Autism Risks from Genetics and Environment (CHARGE) study.

The study included 970 participants, commercial pesticide application data from the California Pesticide Use Report (1997–2008) were linked to the addresses during pregnancy. Pounds of active ingredient applied for organophophates, organochlorines, pyrethroids, and carbamates were aggregated within 1.25-km, 1.5-km, and 1.75-km buffer distances from the home. Multinomial logistic regression was used to estimate the odds ratio (OR) of exposure comparing confirmed cases of ASD (n = 486) or DD (n = 168) with typically developing referents (n = 316).

Results: Approximately one-third of CHARGE study mothers lived, during pregnancy, within 1.5 km (just under 1 mile) of an agricultural area treated with pesticides. Proximity to organophosphates at some point during gestation was associated with a 60% higher risk for ASD, higher for third-trimester exposures (OR = 2.0; 95% CI: 1.1, 3.6), and second-trimester chlorpyrifos applications (OR = 3.3; 95% CI: 1.5, 7.4). Children of mothers residing near pyrethroid insecticide applications just before conception or during third trimester were at greater risk for both ASD and DD, with ORs ranging from 1.7 to 2.3. Risk for DD was increased in those near carbamate applications, but no specific vulnerable period was identified.

Conclusions: This study of ASD strengthens the evidence linking neurodevelopmental disorders with gestational pesticide exposures, particularly organophosphates, and provides novel results of ASD and DD associations with, respectively, pyrethroids and carbamates.

Department of Public Heatlh Sciences (University of Calfornia, Davis)
Division of General Medicine, Department of Pediatrics,
School of Medicine, Univ. California
Department of Neurology, University of California, Los Angeles, CA


Children Living Near Farms have Higher Levels of Pesticides
in Urine/Blood - Evidence for Increased Health Risk

SOURCE: Environmental Research, Volume 84(3):290-302, May, 2000
View Study Online or Download PDF

Children living near fruit orchard farms were found to have 5x higher levels of organophosphate pesticides in their bodies than other children. The study was conducted by the Department of Environmental Health, University of Washington.

109 children (ages 9 months to 6 years) from 75 families were tested for their exposure to pesticides. Children lived in areas with small family orchards that typically grow apples, cherries, pears and peaches. To determine pesticide exposure, samples were taken from urine, hand wipes and household dust.

The study consisted of 35 families who lived within 50 feet from a pesticide treated orchard - 12 families who lived between 50 and 200 feet and 4 families who lived between 200 feet and 1/4 mile from pesticide treated orchards. For comparison, pesticide levels were measure in 14 reference families who lived more than 1/4 mile from the pesticide treated orchard.

Results showed that families living within 1/4 mile from the orchards had house dust concentrations 7 times higher than found in the reference homes. Pesticide levels in urine were 5 times higher than in children living more than 1/4 mile away. Children living within 200 feet of pesticide sprayed groves had the highest blood levels of pesticides and contaminated house dust.

The researchers concluded by stating:

These findings indicate that children living with parents who work with agricultural pesticides, or who live in proximity to pesticide-treated farmland, have higher exposures than do other children living in the same community

Department of Environmental Health
School of Public Health & Community Medicine
University of Washington, Seattle, Washington


Miscarriage Rates Higher Near Agriculture

SOURCE: Epidemiology, March 2001
View Article Summary in "SCIENCE"

The risk of fetal death from birth defects is higher for those living near farming areas. This was the conclusion of a study conducted at the University of North Carolina at Chapel Hill. The study, which involved almost 700 women in 10 California counties, showed that pregnant mothers who lived near food crops where certain pesticides were sprayed faced significantly increased rates of miscarriage due to birth defects.

To break this down further - Women who lived within 2 miles of a place where halogenenated pesticides were used during the first 2 months of pregnancy (when fetal organs are formed), were more than twice as likely to have a miscarriage caused by fetal defects. Other common pesticides (organophosphates and carbamates), raised the risk of miscarriage by 40%.

According to the scientists,

Our study showed a consistent pattern with respect to timing of exposure," said Dr. Erin Bell, who earned her doctorate with the research at the University of North Carolina (UNC) School of Public Health. "The largest risks for fetal death due to birth defects were from pesticide exposure during the third week to the eighth week of pregnancy.

"The risks appeared to be strongest among pregnant women who lived in the same square mile where pesticides were used," she said.

"This is the first study to our knowledge of pesticides and pregnancy in which exposures were in close proximity to the subjects and the verification of pesticide use was objective, not relying on people's memories of what they might have been exposed to," Hertz-Picciotto said.

Erin Bell (Ph.D.)
University of North Carolina
School of Public Health


Brain Defense Damaged by all 3 Classes of Pesticides
Links to Epilepsy, Psychosis, Alzheimers & Parkinsons

SOURCE:  Human Experimental Toxicology, Vol. 18(3):174-9, March, 1999
View Journal Online

The human brain is protected from harm by a defense system known as the blood brain barrier. The first stage of the blood brain barrier is made from exceptionally "tight-junctions" between cells that line the blood vessels supplying nutrients to the brain. These tight-junctions prevent larger toxic molecules from squeezing-through and entering the brain cell network. Unfortunately, the tight-junctions can become "lose" after exposure to some chemicals in the environment - thereby, allowing toxic chemicals into the brain cell network resulting in elevated damage to the brain. Chemicals now being found to damage the blood brain barrier take on new interest as research over the past decade has found defects in blood brain barrier function in people with Psychosis(1), Epilepsy(2), Alzheimers(3) and Parkinson's Disease(4).

In this 1999 research, scientists exposed 10 day old rat pups to three separate pesticides. This included quinalphos (an organophosphate pesticide) - cypermethrin (a pyrethoid pesticide) and the chemical Lindane (an organochlorine pesticide). Exposure levels were 1/50th the amount that would kill 50% of the animals. To determine if the pesticides were damaging the blood brain barrier, animals were injected with a radioactive tracer. Normally, the tracer would be blocked by the blood brain barrier and not enter the brain. However, 2 hours after exposure to the pesticides, the tracer had entered the brain, thereby demonstrating blood brain barrier dysfunction. The three pesticides had disrupted blood brain barrier permeability by 130, 80, and 50% respectively. Defects in blood brain barrier function was also seen at exposure levels of only 1/100th the amount needed to kill 50% of the animals. Of significant interest, 15 day old rat pups had less barrier damage than the 10 day old rat pups. Adult rats showed no evidence of blood brain barrier damage whatsoever. Extrapolating these results to humans, we would then expect younger children to receive far more harm from pesticide exposure than adolescents or adults. Unfortunately, allowable levels of pesticide exposure are currently set from research done with healthy adult animals.

1. British Journal of Psychiatry Volume 141(3):273-281, September, 1982
2. Epilepsia, Volume 47(11):1761-1774, November, 2006
3. Neurobiology of Aging, Volume 28(7):977-986, July, 2007

4. Annals of Neurology, Volume 57:176–179, 2005

Predictive Toxicology Research Group
Industrial Toxicology Research Center
Lucknow, India


Parkinson's Disease Higher in Agricultural Areas

SOURCE: Biochem Soc Trans, 29(2):81-4, 2000
View Journal Online

BACKGROUND: In the last two decades reports from different countries emerged associating pesticide and herbicide use with Parkinson's disease (PD). California growers use approximately 250 million pounds of pesticides annually, about a quarter of all pesticides used in the US.

METHODS: The scientists in this study employed a proportional odds mortality design to compare all cases of PD recorded as underlying causes of death (1984-1994) or associated causes of death (1984-1993) occurring in California with all deaths from ischaemic heart disease (ICD-9 410-414) during the same period. Based on pesticide use report data, scientists divided California counties into several pesticide use categories. Agricultural census data allowed them to create measures of percentage of land per county treated with pesticides. Employing logistic regression models, the scientists estimated the effect of pesticide use controlling for age, gender, race, birthplace, year of deaths, and education. RESULTS: Mortality from PD as the underlying cause of death was higher in agricultural pesticide-use counties than in non-use counties. A dose response was observed for insecticide use per county land treated when using 1982 agricultural census data, but not for amounts of restricted pesticides used or length of residency in a country prior to death.
CONCLUSIONS: Data shows an increased Parkinson's Disease mortality in California counties using agricultural pesticides.

Ritz B, Yu F
Department of Epidemiology
Center for Occupational and Environmental Health
School of Public Health, UCLA, Los Angeles, CA 90095-1772, USA.


Parkinson's Disease Linked to Pesticide Combination

SOURCE: Journal of Neuroscience, 20(24):9207, December 15, 2000
View Journal Online

A combination of two commonly used agricultural pesticides, are showing the ability to cause the same pattern of brain damage seen in Parkinson's disease. Mice exposed to the weed killer paraquat and the fungicide maneb showed clear signs of Parkinson's, a progressive and incurable brain illness, according to Deborah Cory-Slechta and colleagues at the University of Rochester School of Medicine and Dentistry. What is interesting about this study is that neither chemical alone works to create the distinctive pattern of brain damage. The findings add to a growing body of evidence that exposure to chemicals such as pesticides may at least contribute to the brain damage seen in Parkinson's.

"No one has looked at the effects of studying together some of these compounds that, taken by themselves, have little effect. This has enormous implications," Cory-Slechta said in a statement. Dr. Eric Richfield, a neurologist who worked on the study, said it may mean that no one will ever be able to predict who is at risk of Parkinson's based on exposure to chemicals.

Parkinson's disease, which affects an estimated 500,000 people in the United States alone, is a progressive and incurable disease that involves the destruction of brain cells that produce dopamine, an important message-carrying chemical linked with movement. Patients start out with tremors and can become paralyzed and die. There is no cure and treatments can delay the disease for a while but eventually stop working. Perhaps the best-known patient is Pope John Paul II, whose doctor admitted on Wednesday the pontiff had the disease. Actor Michael J. Fox also has Parkinson's, and boxer Muhammad Ali has symptoms of the disease. Researchers suspect that a combination of genetic vulnerability and exposure to something in the environment may be responsible. One major suspect is organophosphate pesticides, which are known to affect the nervous system.

Writing in the Dec. 15 issue of the Journal of Neuroscience, Cory-Slechta's team said they studied the effects of a mixture of paraquat and maneb. Both are used on millions of acres of crops such as potatoes, tomatoes, lettuce, corn, soybeans, cotton and fruit.

Mice exposed to one or the other alone showed no ill effects, but when the combination was given they showed clear patterns of brain damage. The mice moved around much less than normal and had lower levels of an enzyme known as tyrosine hydroxylase that is used as a measure of the health of the dopamine system. The mice had nearly four times as many "reactive astrocytes,'' brain cells that suggest they are damaged, they had about 15 percent fewer dopamine neurons, and they produced 15 percent less dopamine than normal mice.

University of Rochester School of Medicine

 


Pesticide Vapors Present Days/Weeks after Application

Source: Pest Control Technology Magazine, pg. 44, August 1987

In research to determine the amount of air contamination following application of pesticides, it was found that the levels of the pesticide Dursban drop to one-sixth of its original 1 hour level four days after application. Dursban was previously used as a common indoor and lawn pesticide but because of research finding damage to the immune system, it was banned and is now only allowed in agriculture (under the name Lorsban). Unfortunately, families living near agriculture could receive significantly higher exposure levels depending on size of farming areas and wind direction.


Immune System Damage from Agriculture Pesticide Mix

SOURCE: Aquatic Toxicology, 67(1):33-43, March 30, 2004
View Journal Online

The dangers of pesticides are typically calculated by looking at only one pesticide at a time. However, this is not what occurs in real life situations for people working around pesticides or families living in homes within 1/2 to 1 mile of farming areas. For example, On one day, pesticide "A" can be applied - and the next day pesticide "B." Some pesticides emit vapors for weeks after application. Others have been found to react with sunlight, and through a process known as photolysis, form even more toxic compounds.

In this study, researchers investigated the effects of a combination of six common pesticides used in agriculture. This included atrazine, metribuzine, endosulfan, lindane, aldicarb and dieldren. The concentrations of these chemicals were equal to what is typically found in the enviroment of the southwest region of the province of Quebec. The purpose of the study was to determine how the pesticide combination affected the immune systems of two amphibian frog species. Results showed that the combination caused a reduction in the ability of certain immune system cells to "engulf" (consume) pathogens (bacteria, viruses, fungi) and slowed the immune system's ability to multiply cells needed for removing pathogens. In conclusion, the researchers stated,

Taken together, these results indicate that agricultural pesticides can alter some aspects of the immune response in frogs and could contribute to their global decline by rendering them more susceptible to certain infections.

Department of Biology, Concordia University, Montreal, Conada
Vanderbilt University Medical Center, Nashville, TN


Landmark BEFORE and AFTER Pesticide Exposure Study
Common Weed Killer Dramatically Weakens Immune System

SOURCE: Occupational and Environmental Medicine, Volume 53:583-585, 1996
View Journal Online 

Normally, because of ethics considerations, humans cannot intentionally be exposed to pesticides in health effects research. This is why animals are the chosen alternative. However, scientists were able to get around this by studying farmers in their place of work.

While this study was done on farmers, it is being included here because it shows a dramatic lowering in human immune system quality immediately following the use of pesticides. This reduction in quality occurred after a single pesticide application and raises a red flag as it suggests this could be happening to people living in an agricultural area who receive many repeated "lower" exposures to pesticides.

In this study, scientists measured immune system quality in 10 farmers before applying the weed killer 2,4-D to their fields and again after 12 days and again after 2 months.

In the first test before spraying began, farmers had their blood drawn and tested for the total numer of white blood cells, total lymphocytes, T-Cells, Natural Killer cells and Natural Killer activity. Tests were also conducted to measure how fast their lymphocytes would attack a foreign substance (called the PHA and ConA test). The same test was given again at 12 days and at two months.

RESULTS: While their total white blood count remained basically the same before and after spraying (around 6,000 cells per cubic millimeter of blood), the farmers showed a significant 30% decrease in the number of natural killer cells. (Natural killer cells are an extremely important first-line defense against viruses entering the body). Along with this lowering in number, the ability of natural killer cells to "do their job" and attack other cells also decreased by 50%. Another significant finding was that the ability of their lymphocytes (also a type of white blood cell) to multiply (as needed when mounting an attack against a virus) was decreased by more than 50% during the 12 day period after spraying and was still decreased by about 25% two months after spraying. As no other types of pesticides were used by the farmers during the study, this provides important documentation on how 2,4-D can seriously weaken the immune system after just one exposure.

WHY THIS IS IMPORTANT: Your immune system protects you from bacteria as well as from viruses that cause the flu - pneumonia and even the common cold. It kills cancer cells and cancer patients with higher numbers of natural killer cells have been found to have increased likelihood of remission (see study). With this information in mind, it is certainly understandable that everyone should do whatever possible to have a stronger immune system.

While this study was conducted on farmers who applied the chemical once during the season, exposure to the same chemical also occurs to people living in an agricultural setting.

STOP SPRAYING COMMENT: Also, as the weakening of immune systems was found among people with normal immune systems at onset, we could expect to see more serious consequences among people who already have weak immune systems to begin with (such as the elderly and children). For example, a 50% reduction in natural killer cell function could be tolerated by someone with a healthy immune system, but could cause severe illness and infection in someone who already has low natural killer cell function. Also of concern, current EPA testing guidelines do not require chemical manufacturers to report detailed immune system effects such as those found here with natural killer cells.

Department of Occupational and Environmental Medicine, Linkoping, Sweden
Epidemiology Unit, Lazio Regional Health Authority, Rome, Italy
Local Health Unit, Tarquinia, Italy

 


Child Brain Development Harmed by Agriculture Pesticide Chlorpyrifos (Lorsban)

SOURCE: Toxicology and Applied Pharmacology, 134(1):53-62, 1995
View Original Journal Summary
View Journal Online (PDF)

Chem-Tox Comment: While the pesticide chlorpyrifos was banned for indoor use in 2000 (under the name Dursban), it is still used in agriculture under the name Lorsban. This results in high exposure for families living near agriculture. Lorsban is used frequently in citrus agriculture in Florida and California.

The following research was conducted at the Department of Pharmacology, Duke University Medical Center, Durham, North Carolina. The first paragraph below is the abstract taken from the original research article:

Researchers administered chlorpyrifos to neonatal rats in apparently subtoxic doses that caused no mortality and little or no weight deficits and examined developing brain regions (cerebellum, forebrain, brainstem) for signs of interference with cell development. One day old rats given 2 mg/kg of chlorpyrifos showed significant inhibition of DNA synthesis in all brain regions within 4 hours of treatment; equivalent results were obtained when a small dose (0.6 ug) was introduced directly into the brain via intracisternal injection, indicating that the actions were not secondary to systemic toxicity. Inhibition of DNA synthesis was also seen at 8 days of age; however, at this point, there was regional selectivity, with sparing of the cerebellum... These results indicate that low doses of chlorpyrifos target the developing brain during the critical period in which cell division is occurring, effects which may produce eventual cellular, synaptic, and behavioral aberrations after repeated or prolonged subtoxic exposures."

In summary the researchers stated,

In extrapolating findings in the developing rat brain to man, it is important to note that the first 10 days of postnatal life in the rat represent stages of neurodevelopment corresponding to the last trimester of gestation in man; thus, our finding of a much greater sensitivity to chlorpyrifos in the neonate, in terms of both systemic toxicity and targeting of DNA and protein synthesis within the brain, emphasize the need for caution in assigning safety standards. Further study of acute and chronic exposure to chlorpyrifos should be undertaken to evaluate the cellular, synaptic, and behavioral consequences of low-level exposures.

K. D. Whitney, F. J. Seidler, T.A. Slotin
Department of Pharmacology
Duke University Medical Center
Durham, North Carolina


Pesticide Inhalation Associated with Brain and Lung Cancer

SOURCE: Journal of the National Cancer Institute, 71(1), July 1983
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A study of 3,827 Florida pesticide applicators employed for 20 or more years found they had nearly 3 times the risk for developing lung cancer. The same study also showed the pesticide applicators had twice the risk for brain cancer. There was not any increased cancer risk when applicators were studied for only 5 years implying it takes over 5 years to accumulate enough damage to the genetic structure to develop the cancers.


Kidney Cancer (Wilms' Tumor) Higher for Children

SOURCE: British Journal of Cancer, 77(5):825-829, March 1998
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A type of kidney cancer known as Wilms' tumor occured nearly 60% higher than expected in children whose fathers worked around pesticides. Job occupations included farmers, agricultural workers, agricultural machinery drivers, gardeners and foresters. Wilms' tumor is a type of kidney cancer that is the fourth most common childhood cancer, accounting for approximately 6% of all malignancies diagnosed before 15 years of age). Child exposure can occur from pesticides on the father being inhaled and transferred to the child.

Cancer Epidemiology Unit, Imperial Cancer Research Fund, Oxford
Leukaemia Research Fund, Center for Clinical Epidemiology, University of Leeds


Brain's Defense Damaged from Agriculture Weed Killer
Link to Epilepsy, Psychosis, Parkinson's & Alzheimer's

SOURCE: Toxicology & Applied Pharmacology, Vol. 65(1), Aug. 1982, Pg. 23-31
View Journal Online

The human brain is protected from harm by a defense system known as the blood brain barrier. The first stage of the blood brain barrier is made from exceptionally "tight-junctions" between cells that line the blood vessels supplying nutrients to the brain. These tight-junctions prevent larger toxic molecules from squeezing-through and entering the brain cell network. Unfortunately, the tight-junctions can become "lose" after exposure to some chemicals in the environment - thereby, allowing toxic chemicals into the brain cell network with potential for causing elevated damage to the brain. Chemicals now being found to damage the blood brain barrier take on new interest as research over the past decade has found defects in blood brain barrier function in people with Psychosis (1), Epilepsy (2), Alzheimers (3) and Parkinson's Disease (4).

One of several compounds found to weaken and damage the blood brain barrier is the chlorophenoxy herbicide MCPA. This pesticide is used to kill broadleaf weeds and is used when growing alfalfa, barley, clover, flax, lespedeza, oats, grass, peas, rice, rye, sorghum, trefoil, triticale, and wheat. It is also used on sod farm turf, golf courses, public walkways, pastures, rangelands and residential lawns. EPA estimates that 4.6 million pounds of MCPA are used each year in agricultural and residential applications.

To determine if the weed killer could damage the blood brain barrier, rats were given single doses of MCPA at 100, 250, and 500 mg/kg at various intervals before sacrifice. A blue dye was injected into the animals to determine if staining occurred to the brain. Staining occurs when the blood brain barrier is not working properly (as a properly working barrier would block the dye from entering the brain). Blood brain barrier damage was observed with the 250 and 500 mg/kg doses. Most severe damage occurred 4.5 hr after administration of 250 mg/kg MCPA. After approximately 24 hours, no evidence of blue dye could be observed.

1. British Journal of Psychiatry Volume 141(3):273-281, September, 1982
2. Epilepsia, Volume 47(11):1761-1774, November, 2006
3. Neurobiology of Aging, Volume 28(7):977-986, July, 2007

4. Annals of Neurology, Volume 57:176–179, 2005

Department of Biomedical Sciences, University of Tampere,
Box 607, SF-33101 Tampere 10, Finland


Non-Hodgkin's Lymphoma Linked to Agricultural Pesticide

SOURCE: Epidemiology: Volume 1(5):349-56, September, 1990
View Journal Online

Men who mixed or applied the weed killer 2,4-D experienced a 50% higher rate of the cancer known as Non-Hodgkin's Lymphoma (also called NHL). The risk of NHL was dose-dependent and increased with the frequency of use of the pesticide. For example, men who were exposed to the weed killer 20 or more days per year had over a 3 times greater chance of developing the disease. Non-Hodgkin's Lymphoma is the name given to a group of blood cell cancers that develop from lymphatic cells within the lymph nodes. Lymph nodes are oval or bean shape structures that range in size from 1/16th up to 1 inch and located under the arm pits, stomach and many other areas in the body. Lymph nodes contain high concentrations of immune system cells which can attack and eliminate bacteria, viruses and even cancer cells. The image at left shows a lymph node that has become cancerous resulting in uncontrolled growth of lymphatic cells inside the lymph node.

CHEM-TOX COMMENTS: Of significant concern regarding 2,4-D, it contains the chemical Dioxin (TCDD) as a contaminant. Dioxin has been found to weaken the immune system of mammals at exremely low levels (parts per billion). The incidence rate of NHL has been rising 3-4% a year. In the United States, the annual incidence rate for NHL was 5.9 per 100,000 people in 1950 - In 1975, it had risen to 9.3 per 100,000 people. By 1989 it had reached 13.7 per 100,000. (This was reported in the Annals of Oncology, Vol. 5(1):S19-S24, 1994). After 1989 it had risen further and is currently at appoximately 20 new cases per 100,000 people (more than 3 times the rate as in 1950). According to researchers Devesa and Fears at the the National Cancer Institute in Bethesda, Maryland, the incidence rates for NHL have increased at about 3-4% per year (Cancer Research, 1;52(Suppl 19):5432s-5440s, October, 1992).


Large Scale Study Provides Evidence on
Non-Hodgkin's Lymphoma & Agricultural Pesticide

SOURCE: International Journal of Environmental Research & Public Health
Volume 11(4): 4449-4527, April 2014

View Journal Online

NHL is a cancer of the blood in which white blood cells known as lymphoctyes increase in numbers far beyond what is normal - in effect crowding out and blocking proper function of other essential white blood cells.

In this study, investigators reviewed 3 decades of epidemiological research on the relationship of non-Hodgkin's lymphoma (NHL) and exposure to agricultural pesticide ingredients and "chemical groups." They found 44 research papers showing increased rates of Non-Hodgkin's Lymphoma for people exposed to different types of pesticides. 20 papers investigated weed killers, 4 papers investigated fungicides and 17 papers investigated insecticides.

Rather than summarizing their research,
we are including direct quotes from the scientists involved in the study.

1. Striking increases in the incidence of non-Hodgkin's Lymphoma (NHL) cancer have occurred in the last 30 years. (Introduction Paragraph)
2. Of the many exposures experienced in farm settings, pesticides have drawn particular attention, especially since the increased incidence of NHL in the mid- to late-1900s followed widespread use of synthetic organic pesticides. (Introduction Paragraph)
3. McDuffie et al. and Eriksson et al. observed increased odds of NHL in association with a greater number of days/year of glyphosate exposure.
(section 3.3)
4. In analyses of Agricultural Health Study data, Lynch et al. observed a nearly three-fold increase in the rate of NHL among those with ≥26 lifetime- and intensity-weighted exposure days to butylate (section 3.3)
5. In the Agricultural Health Study, Delancey et al. observed a fairly strong dose response relationship between exposure to metribuzin, a triazinone herbicide, and NHL (P for trend: 0.13). Waddell et al. (section 3.3 paragraph 3)
6. There was a positive association between exposure to organophosphorus herbicide, glyphosate, and B cell lymphoma (2.0, 95% CI: 1.1–3.6, CLR: 3.2).
(section 3.4, paragraph 3)
7. There were positive and precise estimates of association between NHL and organophosphorus insecticides (meta RR, 95% CI: 1.6, 1.4–1.9, CLR: 1.4), and the organophosphorus insecticides diazinon (meta RR, 95% CI: 1.6, 1.2–2.2, CLR: 1.8), and malathion (meta RR, 95% CI: 1.8, 1.4–2.2, CLR: 1.5). 
(section 3.4, paragraph 8)
8. There was a positive and precise association with lindane, an organochlorine insecticide (meta RR, 95% CI: 1.6, 1.2–2.2, CLR: 1.8); estimates of association with other organochlorine insecticides were closer to the null.
(section 3.4, last paragraph)

LeahSchinasi & Maria E. Leon
Section of Environment and Radiation
International Agency for Research on Cancer, Lyon Cedex, France

 


Autoimmune Disorders from Chlorpyrofos (Lorsban)

SOURCE: Archives of Environmental Health, 48(2):89-93, March/April 1993
View Journal Online

The chemical chlorpyrifos (Lorsban) is commonly used in agriculture as an insecticide. In 2001, it was banned for indoor home use after being linked with a variety of health disorders, however, it is still permitted in agriculture settings. In a study by the Department of Health Science at California State University, 12 individuals, which included a teacher, six housewives, a retail owner, a musician and an engineer, were studied for 1 to 4.5 years after they became ill when their home or place of employment was treated with the pesticide. The researchers were investigating for any abnormalities in immune system function. Immediately following each patient's exposure to the pesticide, common complaints included an initial flu-like illness followed by chronic complaints of fatigue, headaches, dizziness, loss of memory, upper and lower respiratory symptoms, joint and muscle pain and gastrointestinal disturbances. The subjects were found to have an elevated number of CD26 cells and a higher rate of autoimmune problems, compared with two other control groups. (Autoimmune disorders occur when the person's own immune system mistakenly makes antibodies which attack their own body.) Autoantibodies were found toward smooth muscle, parietal cell, brush border, thyroid gland, myelin, and ANA. 83% of the pesticide exposed people were found to have autoantibodies in their blood, in comparison to only 15% for non-pesticide exposed control group. 50% of the pesticide exposed people were also found to have two or more autoantibodies in comparison to only 4% for the non-exposed group.

In conclusion the researchers stated,

The presence of several different types of autoantibodies, e.g., antimyelin, antismooth muscle, anti brush boarder, and antimicrosomal, indicates that generalized tissue injury has occurred. Moreover, these identical observations have been made in additional chlorpyrifos patients (research in progress). Thus, chlorpyrifos (Dursban), as used in pesticide spray, should be examined more closely as a probable immunotoxin.

Jack D. Thrasher Ph.D., Roberta Madison, Alan Broughton
Department of Health Science, California State University


Arthritis & Lupus Linked to Agricultural Pesticides

SOURCE: Arthritis Care & Research, February 2011
View Journal Online

Lupus is an autoimmune disease in which the body's immune system mistakenly attacks a person's healthy tissue including the heart, lungs and brain. Rheumatoid arthritis is an autoimmune disease in which the body's immune system mistakenly attacks tissues of the joints. Dr. Christine G Parks of the National Institute of Environmental Health studied health reports from nearly 77,000 women participating in the Women's Health Initiative. The strongest association between pesticides and these autoimmune disorders appeared in women who lived on a farm and reported personally applying pesticides.

Dr. Christine G. Parks
National Institute of Environmental Health


Neuroblastoma Linked to Homes Treated with Pesticides

SOURCE: Epidemiology: 12(1):20-26, January, 2001
View Journal Online

Although this study was done regarding home pesticide use, we are including it as it is related to pesticide exposure and could be applied to an agricultural setting.

One of the largest studies to date has found that pesticide use around the home can more than double the chance of a child developing neuroblastoma.

Neuroblastoma accounts for approximately 10% of all childhood tumors. There are 550 new cases in the United States each year, with an annual incidence rate of 9.2 cases per million children under 15 years of age. This works out to approximately 1 per 100,000 children under age 15 on a national level. (These rates were reported in the book "Principles and Practice of Pediatric Oncology, Lippincott-Raven, 1997). Neuroblastoma is a very serious cancer as approximately 60% of children over age 1 who develop neuroblastoma do not live more than 3 years even when receiving treatments of radiation and chemotherapy. Children under age 1 have a more positive prognosis. As statistics show that neuroblastoma rates have increased over the past 50 years, it is reasonable to assume environmental factors are involved.

One of the largest collaborative efforts to date, 7 Universities and medical facilities worked together to determine if pesticide use in the home could increase child neuroblastoma rates. 390 neuroblastoma children and 460 non-cancer controls were included in the study. Investigators questioned both parents regarding use of pesticides in and around the home.

Results showed that using pesticides in and around the home resulted in a 60% increased likelihood of children developing the disease (Odds Ratio=1.6). Looking at pesticide use for the lawn and garden resulted in an increased risk of 120% (Odds Ratio=2.2) when the mother had applied pesticides in the yard and 50% higher (Odds Ratio=1.5) when the father had applied pesticides in the yard. (Chem-Tox Note: Outdoor pesticides are much different from indoor pesticides as they include fungicides and herbicides some of which have been reported to contain dioxin).

Julie L. Daniels, Andrew F. Olshan, Kay Teschke, Irva Hertz-Picciotto, Dave A. Savitz, Julie Blatt, Melissa L. Bondy, Joseph P. Neglia, Brad H. Pollock, Susan L. Cohn, A. Thomas Look, Robert C. Seeger, Robert P. Castleberry
Department of Epidemiology, School of Public Health, University of North Carolina, Chapel Hill, University of British Columbia, University of Texas, University of Minnesota, University of Florida, Northwestern University, Department of Experimental Oncology, St. Jude Children's Research Hospital and University of Alabama


Immune System Problems & Agricultural Pesticide Lorsban

SOURCE: Archives of Environmental Health, 48(2):89-93, March/April 1993
View Journal Online

The pesticide chlorpyrifos (called Lorsban in agriculture) is showing evidence of causing immune system disorders in people. In a study by the Department of Health Science at California State University, 12 individuals, which included a teacher, six housewives, a retail owner, a musician and an engineer, were studied for 1 to 4.5 years after they became ill when their home or place of employment was treated with the pesticide. The researchers were investigating for any abnormalities in immune system function. Immediately following each patient's exposure to the pesticide, common complaints included an initial flu-like illness followed by chronic complaints of fatigue, headaches, dizziness, loss of memory, upper and lower respiratory symptoms, joint and muscle pain and gastrointestinal disturbances. The subjects were found to have an elevated number of CD26 cells and a higher rate of autoimmune problems, compared with two other control groups. (Autoimmune disorders occur when the person's own immune system mistakenly makes antibodies which attack their own body.) Autoantibodies were found toward smooth muscle, parietal cell, brush border, thyroid gland, myelin, and ANA. 83% of the pesticide exposed people were found to have autoantibodies in their blood, in comparison to only 15% for non-exposed control group. 50% of the pesticide exposed people were also found to have two or more autoantibodies in comparison to only 4% for the non-exposed group. 

In conclusion the researchers stated, 

"The presence of several different types of autoantibodies, e.g., antimyelin, antismooth muscle, anti brush boarder, and antimicrosomal, indicates that generalized tissue injury has occurred. Moreover, these identical observations have been made in additional chlorpyrifos patients (research in progress). Thus, chlorpyrifos (Lorsban), as used in pesticide spray, should be examined more closely as a probable immunotoxin."

Jack D. Thrasher Ph.D., Roberta Madison, Alan Broughton  
Department of Health Science, California State University  


Hydrocephaly & Cleft Palet Linked to Agriculture Fungicide

SOURCE: Bulletin of Environmental Contamination Toxicology, 54:363-369, 1995
View Journal Online

Of the many different types of pesticides (which include insecticides, herbicides and fungicides), it was found that the common fungicide "cyproconazole" caused serious defects when administered to test animals. This chemical is reported to be widely used in agriculture and is a member of the family of fungicides known as triazole fungicides. It's closely related family members include the fungicides triadimefon, triadimenol, bitertanol, flusilazole, 1,2,4-triazole, and propiconazole. Each of these pesticides were reported in this article as being capable of causing birth defects in test animals when administered at doses as low as 30 mg/kg. These chemicals are far more toxic than even standard insecticides. The "No Observable Effect Level" (which means the maximum amount of the chemical that test animals can be exposed to without seeing any adverse effects) is reported to be only 2 mg/kg for flusilazole.

The study on the effects of cyproconazole (lets call it CPZ for simplicity) was headed by Dr. K. Machera, at the Laboratory of Pesticide Toxicology in Athens, Greece. Dr. Machera exposed 10 pregnant animals to different levels of CPZ ranging from 20-75 mg/kg from the 6th to the 16th day of pregnancy. On the 21st day of pregnancy the animals were sacrificed and the number of implantations, resorption sites and live and dead fetuses were recorded. The fetuses were weighed and examined for abnormalities. 

Results showed the number of resorptions (similar to an early miscarriage) was over 8 times greater for the animals exposed to the 50 and 75 mg/kg doses. The fetal length was significantly smaller in doses from 50 mg/kg up. The fetal body weight was significantly less even at the lowest dose of 20 mg/kg. 

Cleft Palate did not occur in any of the 100 offspring not exposed to CPZ. However, cleft palate did occur in 2% of animals exposed to 20 mg/kg of CPZ, 20% of animals exposed to 50 mg/kg of CPZ and 91% of animals exposed to the highest 100 mg/kg dose. 

The same trend was also seen with hydrocephalus - 0% for the animals not exposed to CPZ, 6% for animals exposed to 20 mg/kg, 19% for animals exposed to 50 mg/kg, 32% for animals exposed to 75 mg/kg and 100% for the 12 animals exposed to the 100 mg/kg level. 

These studies demonstrate the definite potential for pesticides in the triazole family to increase the risk of lower birthweight, lower body length, as well as strongly increasing the risk of cleft palate and hydrocephalus. With results such as this in test animals, it would certainly be worthwhile to investigate the incidence of these conditions among people living in close proximity to agricultural areas. Dr. Machera did not state if these chemicals were used on residential lawns as an anti-fungal agent. Keep in mind that these studies were looking for physical defects and were not looking for neurological defects in offspring (which typically occur at much lower levels). 

Dr. K. Machera  
Laboratory of Pesticide Toxicology  
Benaki Phytopathological Institute, Athens, Greece  


Intestinal Disorders in Children - Pregnancy & Malathion

SOURCE: Epidemiology, 3(1): 32-39, January, 1992
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The pesticide malathion is one of the most widely applied pesticides. It is often said to be a "safer" pesticide because it requires a larger exposure to cause death in test animals. However, malathion can cause many serious health disorders other than death. Investigators surveyed 933 pregnancies identified through hospitals in the Sanfrancisco Bay area, in relation to exposure to the pesticide malathion that was applied aerially to control the Mediterranean fruit fly. No association was found between malathion exposure and spontaneous abortion, intrauterine growth retardation, stillbirth, or most categories of congenital abnormalities. However, it was found that mothers exposed to malathion during the second trimester of pregnancy had children with 2 1/2 times more gastrointestinal disorders (affecting the stomach and small intestines) in comparison to children not exposed to malathion during pregnancy.

Department of Preventive Medicine
University of Sourthern California, Los Angeles


Second-Generation Toxicity of Malathion
Second-Generation Toxicity of Malathion in Rats

SOURCE: Nature, Volume 192(4801): 464-465, November 4, 1961

Researchers here wanted to investigate if future generations of animals would show health problems after exposing only the first generation. Pregnant test animals were exposed to the common agricultural pesticide malathion at levels that did not cause any apparent health effects. When their offspring were born, these animals were tested for different health effects such as size, weight and immune system effects and none were seen here as well. While this is where most studies end, the researchers in this study continued through one more generation to test animals for health effects. This time they found this newest litter had significantly lower body weight, grew slower and had approximately twice the number of infections (thereby implying immune system damage). All of these health effects were believed to be from the low levels of malathion exposure to the first generation.

ChemTox Comments: If this research is extrapolated to people living in farming areas, this basically states that while grandparents and parents may not show health problems living near agriculture, the children being born now will, thereby showing some genetic toxicity that doesn't show until future generations. Currently, there are no required studies on this sequence of pesticide exposure, but as can be seen here, it is critical to investiagate 2nd generation health effects.


Trouble on the Farm - Children at Risk

SOURCE: Natural Resource Defense Council Report
View Original Report

The Natural Resource Defense Council completed an extensive report on the health dangers faced by children who live on a farm. Highlights of the report include the following:

1. Fetuses, infants, and children are particularly susceptible to pesticides compared with adults because their bodies cannot efficiently detoxify and eliminate chemicals, their organs are still growing and developing, and because they have a longer lifetime to develop health complications after an exposure.
2. More than 320,000 children under the age of six living are living on farms in the U.S while hundreds of thousands more live adjacent to fields and have family members who work on farms.
3. Many pesticides that are never used indoors are tracked into the home and accumulate there at concentrations up to 100 times higher than outdoor levels.[
4. Children living on farms have pesticide levels that exceed "safe levels" as determined by the United States EPA.
5. The cost of illness from pesticides nationwide total as much as $786 billion per year.
6. Metabolites of organophosphate pesticides used only in agriculture were detectable in the urine of two out of every three children of agricultural workers and in four out of every ten children who simply live in an agricultural region.
7. Expanded integrated pest management (IPM) programs and organic farming will ultimately help most in reducing pesticide exposures for our children and grand children.


Autism - Depression & Alzheimers Linked to Weed Killer

SOURCE: Entropy, 15:1416-1463, April 18, 2013
View Journal Online

Autism has been shown to occur more frequently among children living near agriculture (two reports at the top of this page). The weed killer (herbicide) known as Glyphosate (also called Round-Up) is the most popular herbicide used in agriculture world-wide. In this 2013 study, published in the journal Entropy, by Anthony Samsel and Dr. Stephanie Seneff (Massachusetts Institute of Technology), the researchers show how the chemical glyphosate is linked to increasing autism rates by causing changes in body chemistry that affect important enzyme and biological systems critical in brain development and maintaining brain integrity. According to Dr. Seneff, the autism rate has risen from 1 in 10,000 in 1970 to 1 in 68 in 2012. At current trends, Dr. Seneff, predicts a 50% autism rate by 2025. The table below summarizes 2 ways that the pesticide glyphosate can damage body systems and increase the likelihood of Autism and Alzheimers.

Glyphosate
amplifies
toxicity of
other toxic
chemicals
The body protects itself from toxic compounds in the environment through enzymes known as cytochrome P-450. Glyphosate targets the liver and reduces its ability to remove toxic chemicals that the body has consumed, inhaled, etc. This results in the toxic chemicals staying in the body for longer periods, thereby having more time to damage cells in the brain or any part of the body. Also of concern, Dr. Seneff states that compounds in today's modern vaccines (e.g. mercury & aluminum) are able to cause more harm if glyphosate is present.

Beneficial
gut bacteria
damaged by
glyphosate

Serotonin is a brain neurotransmitter essential for the regulation of mood, appetite and sleep. Serotonin is manufactured in the body from the essential amino acid tryptophan.This report cites research showing low blood levels of tryptophan have been linked to depression, autism and Alzheimer's disease. Glyphophate has been found to damage gut bacteria which are responsible for tryptophan production, hence, showing potential to decrease serotonin levels.


Obesity Higher in Children with Higher Pesticide Levels

SOURCE: Reviews of Environmental Health, 26(3): 215-9, 2011
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This study was conducted to investigate the link between exposure to environmental pesticides and childhood obesity. A total of 6,770 subjects aged 6-19 were selected from the National Health and Nutrition Examination Survey (NHANES). Exposure to pesticides was based on concentrations in urine samples. Results showed a dose-dependent increase in the rates of obesity for the pesticide "2,5-DCP." This pesticide is used as a soil fumigant in agricultural settings and is highly volatile after application. According to the Centers for Disease Control Biomonitoring Summary, 2,5-Dichlorophenol is a likely carcinogen. Median levels of 2,5-DCP in adults in a non-agricultural setting were 6.6 to 10/4 mcg/l (NHANES 2003-2008). Levels of the pesticide in pregnant women living in an agricultural region of California had median urinary levels 2 to 3 times higher at 21.5 and 18.5 micrograms/liter (mcg/l) and 95th percentile values of approximately 1950 mcg/l (Castorina et al., 2010).

The authors concluded by stating -

"This study suggests a possible relationship between exposure to 2,5-DCP and obesity in children."

Department of Community Medicine
Mercer University School of Medicine
Macon, GA 31207


Hyperactivity Linked to Very Low Levels of Pesticides

SOURCE: Environmental Health, 14:44, May, 2015
View Journal Online or Download PDF

Children with even the lowest detectable levels of pyrethroid pesticides were twice as likely to have ADHD (Attention Deficit Hyperactive Disorder) than children with no detectable pesticides in their bodies. 687 children were tested for urinary levels of the pyrethroid pesticide metabolite called "3-PBA." (Metabolites occur after the original pesticide is processed by the liver). Along with the doubling of ADHD for children testing positive for the pesticide, every 10-fold increase in 3-PBA resulted in an additional 50% increase in hyperactive-impulsive behavior.

CHEM-TOX COMMENT: This study is of concern as pyrethroid pesticides are commonly used in agriculture and have replaced previously banned organophosphate pesticides. Along with use in agriculture, these chemicals are the used in school pest control - home pest control and community mosquito control applications from trucks and planes. The pesticide is also found in commercially grown foods but not in organically grown foods. 

Cincinatti Children's Hospital Medical Center, Cincinatti, Ohio
Rutgers Robert Wood Johnson Medical School and 
Environmental & Occupational Health Sciences Institute.
Brown University of Public Health, Providence, RI


Lower IQ in 7 Year Old Children

SOURCE: Environmental Health Perspectives, Volume 119(8) August 2011
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329 mothers took part in a study to determine if pesticide exposure during pregnancy could result in lowering IQ scores in children. 44% of mothers performed agricultural work during pregnancy, while others lived close to an agricultural setting. The first stage of the study determined the mother's level of pesticide exposure through urine analysis looking for a metabolite called dialkylphosphate (DAP). This chemical is a breakdown product from the liver's interaction with organophosphate pesticides. Urine tests of mothers were done during week 13 of pregnancy and week 26. Results were recorded to a database for future reference. After 7 years - all mothers were contacted and their children tested for intellectual performance using the Wechsler Intelligence Scale for Children, 4th edition. Results showed that mothers whose pesticide levels were in the lowest 25% of all mothers tested had children whose IQ scores were 7 points higher than children whose mothers were in the highest quartile (top 25%) of pesticide exposure. Deficits for the higher pesticide exposed children occurred over all four cognitive domains on the Wechsler IQ Test.

Providing an explanation, authors stated, "Developing fetal nervous systems may be more vulnerable to (OP) pesticides because of the many unique processes occurring during this stage of development, such as cell division, migration, differentiation, formation of synapses, pruning of synapses, apoptosis, and myelination (Tau and Peterson 2010)."

In concusion, the authors stated:

Our findings suggest that prenatal exposure to OP pesticides, as measured by urinary DAP metabolites in women during pregnancy, is associated with poorer cognitive abilities in children at 7 years of age.

University of California-Berkeley
Center for Environmental Research and Children's Health
School of Public Health, Berkeley, California


Iron Overload
Hemochromatosis from Low Level Pesticide Exposure

SOURCE:  International Journal of Molecular Medicine, Vol. 34(8), Nov 2014
View journal summary at -
http://www.ncbi.nlm.nih.gov/pubmed/25176568
View original article at - http://www.spandidos-publications.com/ijmm/34/5/1395

The common pesticide chlorpyrifos (also called dursban or lorsban) was shown to damage the ability of the body to properly control iron levels in the blood. Although the pesticide was banned for home and yard pest control in the United States in 2000, it is still used extensively in agriculture and is routinely a contaminant in non-organic food sources and can be found in homes treated with the pesticide in the 80's and 90's.

While iron is essential for many functions in the body (i.e., liver enzymes and hemoglobin for oxygen carrying red blood cells), too much iron can cause accelerated damage to organs, including the liver and heart. In a condition known as hemochromatosis, iron levels above 1000 ng/mL typically require the individual to endure periodic "bloodletting" (removal of blood) to bring iron levels down to a normal range. While some people have mutations of cells that predispose them to the disease, it now appears that low level exposure to the pesticide chlorpyrifos can accelerate or worsen this condition by impairing the liver's ability to produce the hormone hepcidin. Under normal circumstances, when iron levels become too high in the blood, the liver responds by producing the hormone hepcidin. As hepcidin levels increase in the blood, the small intestines react by blocking iron from being re-absorbed back into the body.

Scientists at the Research Center for Eco-Environmental Sciences in China found that low levels of the common pesticide chlorpyrifos (also called dursban or lorsban) caused a highly significant 50% decrease in the amount of hepcidin produced by the liver. Of great concern, the effects on the liver occurred at very small levels of pesticide exposure which did not cause liver cell death or changes in liver cell appearance. In other words, even very low levels of the pesticide was able to weaken the genes in liver cells controlling hepcidin levels in the blood (without affecting other parts of the cell). This would suggest that the pesticide could also cause an accelerated worsening of the condition for individuals who already have an inherited form of the disease.

In conclusion the researchers stated,

We have demonstrated that chlorpyrifos exposure significantly altered the expression of central iron genes (i.e., chlorpyrifos elevates ferroportin expression in macrophages (which uptake iron for transfer to red blood cells) and represses hepcidin expression in hepatocytes (liver cells).

State Key Laboratory of Environmental Chemistry and Ecotoxicology
Research Center for Eco-Environmental Sciences
Chinese Academy of Sciences, Haidian, Beijing, China


Microcephaly (Small Head Size) in Animals

SOURCE: Neurochemical Research, 27:231-240, 2008
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Microcephaly is a medical condition in which the brain is considerably smaller than normal, resulting in decreased intelligence and behavior problems. Although the research described here is not directly linked to living near agriculture, it does show how common pesticides can cause microcephaly. The chemical trichlorfon is an ingredient in the commonly used mosquito control pesticide dibrom (also referred to as naled).  

The photograph above shows the brain of a normal guinea (left) and the brain of guinea pig that was exposed to the chemical trichlorfon and the pesticide dibrom. Both of these chemicals are used in agriculture. In this current study, the chemical trichlorfon was found to cause a - severe reduction - in brain weight and shape of test animals.   The timing of exposure appeared to be the key factor in determining brain damage.  Brain damage was observed when guinea pigs were exposed to a non-lethal dose of the pesticide between 42-46 days of gestation at levels of 15 mg/kg. Scientists say this time period correlates with the brain growth spurt period for the animal.

The powerful neurotoxic nature of the pesticide was further emphasized when the scientists found that these brain abnormalities did not occur when animals were exposed to the other pesticides tested - soman - TOCP and ethyl-trichlorfon.

Scientists concluded by stating they suspect the nervous system abnormality occurred due to direct damage to DNA at a time when the animals' repair systems are not developed.

CHEM-TOX COMMENT:  The fact that this study shows serious neurological damage can occur after one pesticide exposure to animals (who are often less sensitive than humans to harmful neurological effects) is enough to warrant serious re-evaluation regarding the use of these chemicals close to populated areas.

University of Oslo, Institute of Biology
Department of Molecular Cell Biology, Oslo, Norway
Norwegian Defense Research Establishment
Division for Environmental Toxicology, Kjeller, Norway


Diabetes/Pre-Diabetes Higher in Pesticide Applicators

SOURCE: Journal of Agromedicine, Volume 19(4): 417-26, 2014
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Rates of diabetes and pre-diabetes were found to be 11 times higher in 116 men employed as pesticide sprayers from public mosquito vector control programs in Bolivia. The prevalence of diabetes and prediabetes was 61% among men employed to spray pesticides and only 8% among 92 non-exposed controls. A dose-response effect was also found showing that sprayers reporting the highest number of hours spraying pesticides had diabetes and prediabetes rates 14x greater.

Section for Environment, Occupation and Health
Department of Public Health
Aarhus University, Aarhus, Denmark


Diabetes Linked to Higher Blood Pesticide Levels

SOURCE: Environmental Science and Pollution Research, 22(1):379-386, Jan 2015
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Having higher levels of pesticides in the blood was shown to increase rates of diabetes. Saudi Arabia has one of the highest rates of diabetes in the world - nearly 30% of adult population had diabetes in a sample of 1,792 people in 2011 (Annals of Saudi Medicine). This is 2-3 times higher than seen in other developed countries. Investigators at King Saud University measured blood levels of the pesticide DDT and its metabolites among 280 Saudi adults - 136 with diabetes and 144 contols who did not have diabetes. Results showed that higher levels of the breakdown product of DDT (DDE) was associated with increased risk of diabetes.

CHEM-TOX COMMENT:  Primary exposure routes for organochlorine pesticides is living in homes built before 1980 (termite control) and consuming non-organic food. DDT and its metabolites are still found in commercially grown non-organic foods due to its continued use in South America and imports into other countries.

College of Applied Medical Sciences
King Saud University
Riyadh, Saudi Arabia

Diabetic Children Have Higher Blood Pesticide Levels

SOURCE: Journal of Clinical Toxicology, Vol. 2(6): 2012
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Does eating non-organic commercially grown food increase the rate of diabetes in children? This was one of several questions researchers at Mansoura University Children Hospital in Egypt wanted to answer. The study was started with 75 young children, all under age 10, who were recently diagnosed with type-1 diabetes. Blood samples were taken from 75 children with diabetes and 35 control children who did not have diabetes. Blood samples in both groups were then tested for nine different pesticides. This included the head-lice pesticide lindane, the farming/food pesticides malathion and chlorpyrifos and also the pesticides DDT and DDE. Most people assume DDT is no longer used, but this is incorrect as some countries in Africa and South America still use DDT in agriculture, and these foods are frequently exported into Europe and the United States, especially during the winter months. Another source of DDT in foods comes from a little publicized fact that the legal pesticide dicofol (routinely used on citrus) contains DDT as an unintended by-product during manufacture.

By comparing the pesticide blood test results between both groups of children, the doctors could easily see if any pattern exists. For example, if pesticide levels were the same in both groups, it suggests that pesticides do not harm the body in a way that increases diabetes. However, if pesticide levels are higher in children with diabetes, we then start painting a picture that eating conventional pesticide grown foods, living near agriculture or using pesticides in the home, may very well be a major contributing factor to diabetes.

Below are the results of the tests, and as can be seen, there is a very strong link suggesting that eating conventional pesticide grown food increases the rate of diabetes. All measurements are in levels of what is called nanograms per milliliter of blood

1. Healthy children had no mesureable levels of the pesticide lindane,
but diabetes children had a level of 0.54.

2. Healthy children had no measureable levels of the pesticide DDT, 
but diabetes children had levels of 0.20

3. Healthy children had no measurable levels of the pesticide DDE, 
but diabetes children had levels of 0.37

The same pattern was seen with the common pesticides chlorpyrifos and malathion. Chlorpyrifos levels were averaging .02 in the healthy non-diabeteic children and .24 in children with diabetes. Therefore, diabetes children had 12 times higher levels of this common pesticide.

The same pattern was also seen for the pesticide malathion. Healthy non-diabetic children had malathion levels of .03, but children with diabetes had blood levels 15 times higher at .54.

When using these numbers to determine increased risk from the pesticides, the researchers found that the children having high levels of malathion in their blood had a 4 times greater risk of developing diabetes than children with low levels of malathion.

In a related study directly below, researchers found that switching to organic food resulted in a dramatic drop in blood levels of malathion in children. When results of both of these studies are viewed together, it provides strong support for the importance of switching to a 100% organic diet for children with newly diagnosed type-1 diabetes and also for parents wishing to prevent diabetes in their children. It also suggests that the 38% of the U.S. population currently with pre-diabetes may also experience improvements in blood sugar levels from an organic diet. Unlike other more complex studies, the benefits of glucose/sugar control could be quickly evaluated through a basic glucose monitor.

 

Eating Organic Lowers Blood Pesticides in Children

SOURCE: Environmental Health Perspectives, 114(2): 260-263, Feb 2006
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As found in the above study, children with diabetes had considerably higher blood levels of several types of pesticides when compared to children who did not have diabetes.

In this study, researchers found that when children switched to organic food (foods grown without pesticides), the levels of pesticides in their bodies dropped dramatically.

Conducted in part by the Centers for Disease Control, scientists studied the effects of eating organic (non-pesticide) food among 23 elementary school children ages 3 to 11. Each child was tested daily for pesticide levels over 15 consecutive days. During the first 5 days (called phase 1) - children consumed their typical (pesticide) food diets. During phase 2 (days 6 to 10) - children ate only organic foods. In phase 3 (days 11 to 15), all children switched back to eating conventional foods grown with pesticides.

RESULTS: After switching from the chemically grown to organic foods during phase 2, all children showed a dramatic drop in levels of the pesticides chlorpyrifos and malathion (see chart above). Average levels of malathion metabolites was approximately 1.2 micrograms per liter (of urine) while eating conventional foods, but after switching to organic foods, it dropped to about less then 0.1 micrograms/liter. This represents a 12-fold decrease in pesticide levels in children. For the pesticide chlorpyrifos (which has been linked to many health disorders affecting the brain and weakening of the immune system), levels were approximately 6 micrograms/liter on conventional foods and then dropped to 2 micrograms per liter after eating organic (a 3-fold reduction). Both malathion and chlorpyrifos are used extensively in agriculture with chlropyrifos also being used in home pest and termite control prior to 2002.

In conclusion, the researchers stated,

We were able to demonstrate that an organic diet provides a dramatic and immediate protective effect against exposures to organophosphorus pesticides that are commonly used in agricultural production....The persistent existence of OP pesticide metabolites in urine during the conventional diet periods raises a concern of the possible chronic exposures to OP pesticides in children

Rollins School of Public Health, Emory University, Atlanta, Georgia, USA
University of Washington, Seattle, Washington, USA
Centers for Disease Control and Prevention, Atlanta, Georgia, USA

CHEM-TOX COMMENT:  It is important that people realize that so-called safe levels of exposure are based upon studies done on "adults." Children have far lower levels of important liver enzymes that remove pesticides from the blood (i.e. paraoxanase) and this level can vary dramatically from one child to the next.. Therefore, chidren have pesticides remain in their blood for longer periods and at higher levels than adults. Also, critics of this study (such as those funded by agricultural interests) do not take into account that EPA guidelines on pesticide safety consider only at one pesticide at a time, however, children (and all of us) are exposed to many pesticides in food simulneously. This has been shown to result in far more harm than one pesticide alone, and can sometimes result in an exponential effect (1+1=100). Also, current EPA pesticide safety guidelines do not consider what is called subtle neurotoxicity (effects on learning/behavior) - subtle immune system effects (increased autoimmunity - lowering of white blood count - natural killer cell effects, etc.). The bottom line is that pesticides are designed specifically to kill - and our children are being exposed to small levels of these continuously in food. A follow-up study now needs to be done to determine if natural killer cells and autoimmunity are affected by these levels of pesticides.

Guillain-Barre Higher in Rural Farming District
Source: Archives of Environmental Toxicology, Vol. 59(11): 575-80, Nov 2004
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Background on Guillain-Barre syndrome.
Guillain-Barre is a rapid-onset autoimmune disease characterirzed by muscle weakness. Symptoms can appear over hours or weeks and is caused by the immune system attacking and damaging the peripheral nervous system. It can be life threatening if affecting breathing muscles. Interestingly, it has been theorized to be a consequence of ZIKA Virus infection, however, in this research Guillain-Barr was found to occur with far greater frequency in areas of high pesticide use. As pesticide applications are also high in areas of ZIKA virus, this needs to be considered and studied further.

Abstract from Journal:

Although organophosphate (OP) insecticides have been recognized as having neuropathic potential, a relationship with Guillain-Barre syndrome (GBS) has not been previously confirmed. A cluster of 7 cases of GBS was noted over an 11-yr period in an isolated farming region in the Northern Cape Province of South Africa, an area subject to intensive aerial application of OP insecticides. Observed cases were more than 4 times higher than expected based on a Poisson probability distribution. Four cases were clustered in an area where the topography showed a marked hollow, and where spray drift of aerial OP insecticides was anticipated. The rate of GBS in this subcluster was more than 14 times higher than expected. The authors explored the hypothesis that aerial OP insecticide application was related to the raised incidence of GBS in this area and made suggestions for future research.

STOPSPRAYING COMMENT: Naled is also an organophosphate pesticide