Adverse medical effects of pesticides.

• Author: McKeel, Daniel

The unfortunate practice about which I am writing is the excess aerial spraying from trucks of pesticides such as permethrin, sumithrin, DEET and the synergist, PBO or piperonyl butoxide. The latter agent, PBO, inhibits liver detoxifying enzymes and thus markedly prolongs the primary pesticide effects on the body. PBO is suspected of causing anorexia (loss of appetite), coma, convulsions, possibly cancer, skin irritation, liver and kidney damage, prostration due to circulatory collapse, tearing of the eyes, unsteadiness, vomiting and weight loss. Liver and kidney damage are the chronic effects of PBO.

Using these "safe" pesticides is far from innocuous, despite some claims by the manufacturer's and agencies that conduct the massive mosquito spraying campaigns. (1) In addition, the toxic compounds are not the most effective way to control culex vector populations. The pesticides of concern also are extremely toxic to fish and some bird species.

In the case of massive aerial pesticide spraying and West Nile virus diseases, truly, the "cure" is worse than the disease. The benefit-to-risk ratio of massive spraying to control culex is low compared to other more effective methods such as the elimination of mosquito breeding areas such as standing water. Remember also that less than 1% of people who are exposed to West Nile Virus ever develop any symptoms at all. Many persons with WNV have a very mild, self-limited illness that requires no specific medical treatment at all. The cases of serious WNV illness that require hospitalization are therefore a very small percentage of total infected cases. To put the WNV epidemic in perspective, as of September 4, 2002, the CDC in Atlanta reported 2,121 human cases of WNV and 95 deaths during all of 2002; a mortality rate of 4.5%.

The estimated number of pesticide deaths in the US is considerably higher on an annual basis. Much of the acute toxicity data on pesticides comes from worker illnesses and deaths during the manufacturing process.

Pesticides cause serious skin irritation to at least 30% of people who use them. Other known acute health effects of pesticides include exacerbation of asthma, induction of seizures with large overdoses (with resulting death in 30% of cases in children), headaches, nausea and vomiting.

The class of pesticides used to mosquitoes are also suspected of being possible carcinogens by impairing the function of bodily immune defenses. Estrogenic effects may contribute to breast...