In mid-August 2003, mosquitoes carrying West Nile Virus (WNV) were found in California's Salton Sea, at the southern extension of an important bird migration route. While the West Nile Virus is common in mosquitoes in Africa and Europe, the first U.S. human case was reported in 1999 in New York State. The number of human cases has increased each year; so far in 2003 the U.S. Centers for Disease Control (CDC) reports 2,874 human cases and 53 deaths (as of September 9, 2003).
In the years since the first outbreak, the CDC and local vector control agencies have altered their public recommendations on dealing with West Nile. There is now much greater emphasis on public education, on the removal of standing water as mosquito breeding sites, and application of larvicides instead of widespread sprays targeting adult mosquitoes.
However the spraying of adulticides does continue, even though it is inefficient for controlling mosquitoes and may even increase mosquito populations by decimating the predators (such as dragonflies) that feed on mosquitoes and their larvae. In a new report on the risks of pesticide spraying for West Nile, Pesticide Watch lists two organophosphate pesticides, malathion and naled (sold as Dibrom) which are approved for use in California against mosquitoes. Organophosphates are a highly toxic class of pesticides affecting the central nervous, cardiovascular and respiratory systems. Malathion and naled have both been linked to cancer and malathion has been associated with blood, vision and reproductive disorders. Synthetic pyrethroids, such as sumithrin (Anvil) and permethrin are also widely used on mosquitoes. Both can cause dermatitis and asthma-like reactions.
Several cities and towns have vowed not to spray adulticides for West Nile. Lyndhurst, Ohio, a suburb of Cleveland, passed a landmark ordinance in early July of 2003, and Ft. Worth, Texas and Washington, DC have both pledged not to spray.
Alliance for Informed Mosquito Management (AIMM) This outline provided by Beyond Pesticides, is a valuable source when gathering talking points for meeting with decision makers, and it provides a list of member groups working on similar issues.