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Image of a mosquito.About West Nile Virus

The discovery of West Nile Virus (WNV) in the United States in 1999 has put a great deal of focus on the issues of mosquito-borne illnesses and the use of chemical pesticides for mosquito control. CCE has monitored the virus since its discovery, and it has done a great deal of research on the nature of WNV and its effects on public health. CCE continues to monitor new developments and the latest information from public health agencies regarding the virus.

WNV is here to stay. WNV was first identified in 1937 in Uganda, Africa. In the late 1990s it spread to Eastern Europe and then, in 1999, WNV was diagnosed for the first time in the Western Hemisphere in Queens, NY. Since then, WNV has swept across the much of the United States and Canada..

WNV infection is caused by a virus called a flavivirus. It is carried by birds and is mainly spread to humans by mosquitoes. Approximately 80% of humans exposed to the virus remain symptom free and 20% develop flu like symptoms. Of those infected, the Centers for Disease Control and Prevention (CDC) found that 1 in 150 develop West Nile Encephalitis or meningitis.

U.S. researchers have identified 36 species of mosquito that can carry and transmit the virus to humans, although 3 species of Culex mosquito seem to be responsible for most US cases. According to the US Department of Agriculture Pest Management Center, WNV is transmitted by infected mosquitoes, primarily Culex, Aedes, and Ochlerotatus spp. Culex pipiens, the northern house mosquito, is a common household mosquito and the primary vector of WNV.

Mosquitoes become infected after biting infected wild birds that serve as the primary host of the virus. Infected mosquitoes are capable of transmitting the virus 10 to 14 days after feeding on the infected bird. CCE works for sensible policies and actions to address WNV

CCE has taken a strong stand against the widespread spraying of pesticides as a way to reduce WNV. To date, there is no significant credible scientific evidence that shows that pesticide spraying is an effective method for reducing human exposure to WNV. Massive, widespread use of pesticides is harmful to both human and environmental health. By law, no pesticide can be called "safe", and there are many documented health risks associated with exposure to pesticides. CCE is committed to working to ensure public health and safety and to protect the health of our supporting ecosystems. CCE feels that WNV cannot be, simply, poisoned away.

CCE has been working since the discovery of the virus to limit and eliminate the blanketed, broad-based application of pesticides as a tool for use against WNV. CCE has been working with other environmental and public health advocacy groups to advocate for a non-spraying approach to deal with mosquito control.

CCE has conducted public outreach to inform our members about WNV and about the pesticides being used by the counties. CCE staff held numerous public meetings, workshops, and other events in an effort to educate the public about WNV and about the health effects of pesticides.
During 2000 - 2001, CCE worked closely with New York State Audubon Society, the State Department of Health, the City Health Department and many county health departments to develop a plan for dealing with WNV. The result of this process is the New York State West Nile Virus Response Plan. The plan is a set of recommendations to the counties on how to best respond to WNV. Each county has the choice to implement the recommendations in this plan or to devise a strategy of their own. However, in order to receive state reimbursement for WNV control activities, counties must act in a manner that is consistent with the recommendation of the NYS WNV Response Plan.

The state plan advises counties that public education is the number one component to an effective WNV prevention strategy. Also, increased efforts for mosquito and bird monitoring are highly recommended. The plan incorporates spraying as an option for the counties, but only as a "last resort".

The New York State Department of Health (NYSDOH) has stated the use of pesticides for adult mosquito control is a last resort activity, which should be considered only when there is an imminent risk to human health. Accordingly, the New York State West Nile Virus Response Plan establishes a hierarchical approach to respond to mosquito-borne diseases, beginning with: Education; Larval Habitat Source Reduction; Larval Mosquito Control; and Adult Mosquito Control, in that priority.

To conform with this new approach, however, the state program to reimburse local health departments for their mosquito control activities must be changed. Currently, DOH pays the highest amount for adult mosquito spraying and the least for education and larval control. Under this current approach, state funding provides a financial incentive for high impact chemical use and nothing for benign activities or education. Under this approach, the state reimbursement provides a greater financial incentive for high impact chemical use compared to more environmentally benign activities such as public education. The Plan requires significant evidence that WNV is present in the environment before counties can receive state reimbursement for pesticide spraying for the control of WNV. Overall, CCE supports the Plan.

In addition, the NYSDOH has developed informational fact sheets about the insect repellent DEET as well as for the pesticides commonly used for mosquito control. The fact sheets include health information. 

The animals most sensitive to WNV are birds, especially crows, and horses. The chance of humans becoming seriously ill from WNV is extremely small. This is because people with healthy immune systems are able to overcome any infection by the normal response of their immune system.

Pesticides Were Ineffective in WNV Control

According to the U.S. Environmental Protection Agency (EPA), no pesticide can be considered safe. Federal law prohibits pesticide manufacturers from claiming that the EPA registration of their products means they are safe. The New York State Department of Health (DOH) acknowledges that the use of chemical pesticides is not without inherent risk to human health.

Presently, no studies compare the relative risk of contracting a severe case of WNV versus suffering adverse health reactions from pesticide exposure. In 2000, 14 people were hospitalized in New York State with WNV, but 100s of people reported to health officials adverse reactions from exposure to WNV pesticides. The DOH Pesticide Poisoning Registry listed 14 cases of adverse pesticide reactions, in spite of very limited surveillance for such reactions.

Pesticides can cause both acute and chronic health effects. Acute health effects appear shortly after exposure and can range from headaches, dizziness, nausea and difficulty breathing, to coma and death. Chronic health effects may not be apparent until months or years after exposure. For example, some pesticides may cause nerve disorders with repeated low level exposures. Others may cause cancer.

Currently, there is no credible scientific evidence that shows the spraying of pesticides to kill adult mosquitoes in an urban environment is effective for preventing or reducing WNV in human populations. However, it is indisputable that the use of pesticides was completely ineffective at stopping the spread of WNV throughout the entire state of New York and the country. The Centers for Disease Control and Prevention (CDC) predicted that within 5 years, WNV would be found throughout the continental United States. It only took three years for the disease to reach 40 states.

CCE has taken several strong positions on the issue of West Nile Virus and pesticide spraying. CCE believes that the aerial spraying of pesticides is not a viable option because of the associated health risks of the pesticides used (at least one of the pesticides has been shown to enhance tumor growth in women with estrogen-dependent breast cancer). CCE believes that the counties should be monitoring not just for signs of WNV but also for the human and ecological effects of pesticide spraying.

In addition, CCE believes that the counties should be aggressively pursuing long-range plans to deal with WNV that rely on preventative measures and non-toxic alternatives to pesticide spraying. CCE also believes that the state and federal governments should not reimburse the counties for money spent on pesticide spraying but, rather, for public education and pilot programs. These positions are all taken because it is believed that exposure of many people to pesticides is a dangerous strategy for public health agencies to utilize.

Tips to Eliminate Mosquitoes Around Your Home

Additional Information:

CCE publication, "Health Effects of Pesticides Used for Mosquito Control"

CCE flyer by the same name, "Health Effects of Pesticides Used for Mosquito Control"

CCE tri-fold Brochure, "For Mosquito Protection...Use Prevention!":
Cover & Back Panels
Inside Panels

Centers for Disease Control and Prevention, Division of Vector-Borne Infectious Diseases

N.Y.S. Department of Health, West Nile Virus

More information on mosquito control in Suffolk County, NY:

The Suffolk County Vector Control and Wetlands Management Draft Long-Term Plan and  Draft Generic Environmental Impact Statement (DGEIS)

Suffolk County “No Spray List”

Updated by bsmith 3/31/10