Why the Sympathy for Mosquitoes? Pesticides Get an Undeserved Rap
”Save Our Mosquitoes" isn't a plea one expects to see these days with the mosquito-borne West Nile virus killing hundreds and making thousands of people sick. But someone posted that very appeal on a sign in Chagrin Falls, Ohio. These "poor bugs" were indeed at risk as the town was debating whether to spray pesticides that year. Residents decided to show their mercy; they gave the mosquitoes a stay of execution. No spraying in 2002.
Discovered by an official from the local department of health, the sign shows how bizarre the debate about mosquito spraying has become. Radical environmental activists have been leading the pack, making a host of unsupported claims about the risks associated with pesticides. While some might sympathize with the plight of the mosquito, the anti-pesticide crowd has shown little concern for those humans suffering from the sometimes deadly, and often debilitating, virus transmitted by the bugs.
In the past, these groups have downplayed the risks by pointing out that the illness only kills the elderly, the sick and children as if that offered any comfort! However, it isn't even true. In 2003, the median age of those who died from the virus was 47 years with a range of 1 month to 99 years old.
Radical environmentalist comments on this topic may have played better before 2002, when the death toll remained relatively low. In 2002, West Nile took a disturbing turn. The federal Centers for Disease Control and Prevention reported that more than 4,000 people became ill and 300 died. The CDC's tally for cases in 2003 is nearly 10,000 and more than 250 deaths. Almost 3,000 of these were reported to be West Nile meningitis or encephalitis, which is a particularly painful and potentially debilitating form of the disease.
As a point of comparison, consider the CDC data on the cases of health problems related to pesticide exposures from spraying during 1999-2002. According to the CDC report, there were a total of 133 "potential" cases of temporary illness over four years among a population that CDC estimates was 118 million in 2000. CDC concluded: "The findings in this report indicate that serious adverse outcomes potentially related to public health insecticide application were uncommon. When administered properly, in a mosquito-control program, insecticides pose a low risk for acute, temporary health effects."
Only one case was considered severe, and that case was related to asthma and chronic obstructive pulmonary disease. CDC explained the circumstances as: "When her neighborhood was sprayed, a woman aged 54 years was exposed to sumithrin, which passed through operating window fans and a window air conditioner." Window fans suck in air from the outdoors, which is something a COPD patient should avoid because even minute amounts of air-borne substances can initiate respiratory complications. Fortunately, this individual recovered, but her case does not justify inadequate protection of the public from vector- related risks. In fact, COPD patients would be particularly vulnerable should they be struck with West Nile, which could easily kill someone with a compromised respiratory system.
Environmental activists have also claimed that application of chemical insect repellants--particularly those that contain DEET--can increase risks of seizures among children. Researchers recently published a review of the literature on this topic in the Canadian Medical Association Journal. They report that none of these studies was conclusive that DEET was in fact the cause of seizures. Similarly, the New England Journal of Medicine published a study in 2002 that addressed the relative effectiveness of various repellants. It found that DEET posed minimal public health risks and repelled bugs longer than any other product. The next best alternative provided protection for not even a third as long as DEET. For these reasons, the journal dubbed DEET the "gold standard" for protection against insect-borne illnesses.
This year, West Nile is expected to spread throughout the West Coast, anddebates and misinformation about spraying will likely spread along with it. But hopefully sympathy for humans will prevail over the "plight" of the mosquito.