WASHINGTON -- Animal experiments at Duke University Medical Center show
that harmless doses of three chemicals used to protect Gulf War soldiers
from insect-borne diseases and nerve-gas poisoning are highly toxic when
used in combination, researchers reported Wednesday. They said the findings
may explain the wide array of symptoms reported by an estimated 30,000 Gulf
In studies using chickens, the researchers specifically found that two pesticides, DEET and permethrin, and the anti-nerve gas agent pyridostigmine bromide (PB) were harmless when used alone, even at three times the doses soldiers likely received. But when used in combination, the chemicals caused neurological deficits in the test animals similar to those reported by some Gulf War veterans, according to Duke pharmacologist Mohamed Abou-Donia and Tom Kurt, a toxicologist at The University of Texas Southwestern Medical Center in Dallas.
Chickens were selected over rodents as test animals because their susceptibility to neurotoxic chemicals more closely resembles that of humans, the scientists said.
The findings were prepared for presentation Wednesday at the annual meeting of the Federation of American Societies for Experimental Biology and will be published in the May issue of the Journal of Toxicology and Environmental Health.
The researchers said their findings are similar to those reported in Scotland last month and by an Israeli team last year.
Adding to those findings, the Duke and UT Southwestern scientists have developed a theory to explain why the chemical mix is dangerous. They said their results indicate the anti-nerve gas agent reduces the body's normal ability to inactivate the two pesticides, which can then travel to and damage the brain and nervous system. Such a mechanism could explain the wide array of symptoms reported by some Gulf War veterans, including memory loss, headache, fatigue, muscle and joint pain, weakness, short
Contact: Rebecca Levine