Beyond Pesticides/National Coalition Against the Misuse of Pesticides (NCAMP) is a national environmental organization, based in Washington, DC, with members all 50 states, which advocates for public protection from pesticides and promotes safer pest management practices.
As local spraying for adult mosquitoes begins throughout the Eastern U.S. for West Nile Virus (WNV), it must be recognized that these spray programs are of limited efficacy. That is, spraying does not appear to be an effective way to prevent death or illness associated with insect-borne West Nile Virus. A large part of this has to do with understanding the life cycle of mosquitoes and their biology. Another large part of this has to do with the inability, especially in an urban environment, to hit target insects with typical ground spraying from trucks or by aerial application.
While recognizing the public health threat of WNV and given limited pesticide spray efficacy, it becomes even more important to recognize the public health hazards associated with widespread pesticide exposure. Synthetic pyrethroids, used widely by across the country, are neurotoxic and have been linked to cancer. Children with respiratory problems, such as asthma, are particularly vulnerable to these pesticides and will suffer disproportionately from exposure.
While the many communities have moved in the right direction and in many cases resisted spraying upon finding dead infected birds, communities must reassess the real efficacy of spraying for adult mosquito control in the context of pesticide risks, especially for children whose respiratory systems are already weakened.
The Centers of Disease Control and Prevention (CDC) state that spraying adulticides, pesticides intended to kill adult mosquitoes, is usually the least efficient mosquito control technique. Aside from adverse health effects posed to humans, adulticiding may actually increase the number of mosquitoes by destroying their natural predators . Additionally, mosquitoes that survive the spraying may become resistant, longer-lived, more aggressive, and have an increased prevalence of the virus within their bodies . Despite these problems, adulticides are often used in the battle to control mosquitoes.
Synthetic pyrethroids, which include resmethrin (Scourge) and sumithrin (Anvil), are adulticides patterned after pyrethrum, an extract from the chrysanthemum flower. While similar to pyrethrum, synthetic pyrethroids have been chemically engineered to have greater toxicity and longer breakdown times . Additionally, almost all synthetic pyrethroid mosquito products are combined with synergists, which increase potency and compromise the human body's ability to detoxify the pesticide. Symptoms of exposure include: dermatitis and asthma-like reactions, nasal stuffiness, headache, nausea, incoordination, tremors, convulsions, facial flushing and swelling, and burning and itching sensations . Synthetic pyrethroids are endocrine disruptors and have been linked to breast cancer . Deaths due to exposure have resulted from to respiratory failure. People with asthma and pollen allergies should be especially cautious. Breakdown times range from a few hours in direct sunlight, to several months in damp, dark environments.
Organophosphates, which include malathion (Fyfanon), naled (Dibrom) and chlorpyrifos (Mosquitomist), are a highly toxic class of pesticides that affect the central nervous, cardiovascular and respiratory systems. Symptoms of exposure include: numbness, tingling sensations, headache, dizziness, tremors, nausea, abdominal cramps, sweating, incoordination, blurred vision, difficulty breathing, slow heartbeat, unconsciousness, incontinence, convulsions and fatality . Some organophosphates have been linked to birth defects and cancer. Breakdown times range from a few days in direct sunlight, to several months in damp, dark environments.
Communities must aggressively deliver the following message:
The following programs must be put in place in order to protect public health.
Communities have a duty to warn the public about the dangers of pesticides, while providing information on ways to minimize exposure to dangerous pesticides. Communities should embrace and utilize the following guidelines:
Communities should notify the public of ways to "Protect Yourself from Pesticide Exposure!"
Leave the area (Infants,
children, pregnant women, the elderly, and individuals with compromised
immune systems should take extra care to avoid pesticide exposure.)
The critical point that continues to be lost on city officials in the management of West Nile Virus is that pesticides are poisons. Because they are poisons, officials are charged with ensuring that laws, specifically intended to protect the public and the environment, are not violated.
We understand that people are concerned about the West Nile Virus. We also know that people are concerned about the widescale spraying of pesticides and the associated public health and environmental hazards. It makes no sense to spray for adult mosquitoes if the spray program does not offer adequate controls and the use of the pesticides presents a greater risk than the target disease.
In the United States, West Nile Virus (WNV) is primarily associated with the Culex mosquitoes. Within this genus, three species, namely C. pipiens, C. restuans, and C. salinarius make up the majority of those mosquitoes found to be infected with WNV. Only female mosquitoes take blood meals, the male's only purpose is to provide sperm and they usually die one or two days after emerging as adults. In contrast, the adult females may live 2-4 weeks or more, depending on climate, species, predation, and a host of other factors.
All mosquitoes go through a complicated life cycle called "complete metamorphosis." Complete metamorphosis involves four distinct stages - egg, larva, pupa, and adult. The length of time that each stage lasts depends on a number of variables with temperature having the greatest impact.
Eggs are laid in "rafts" on standing bodies of water. The eggs require one to two days in water before hatching into 1st instar larvae.
Larvae, or wigglers, develop as four instars. They molt three times during ten to twelve days before pupating.
Pupae, or tumblers, metamorphose over one to two days into adults.
Adults emerge from their pupal cases approximately twelve to sixteen days after being laid as eggs by their mother.
After mating, the female requires a blood meal in order to produce over 250 eggs. It takes her three to four days to digest the blood and produce the eggs. Females transmit diseases when they live long enough to spread infection from the first blood meal victim to the second blood meal victim. Only a very small percentage of females live this long. Culex mosquitoes are generally weak fliers and do not move far from their larval habitat, although they have been known to fly up to two miles.