Health Officials Unveil 2001 West Nile Virus Response Plan

Education, Prevention Remain Key Components of Fight Against Mosquito–borne Disease

Albany, April 5, 2001 – Warning that West Nile virus seems to be here to stay, New York State Health Commissioner Antonia C. Novello, M.D., M.P.H., Dr.P.H. today unveiled the State's proposed 2001 West Nile Virus Response Plan, calling on New Yorkers to continue to educate themselves about, and take steps to help prevent the mosquito–borne disease during the coming year. The plan will be available for public comment on the State Health Department's website until April 22.

For the second consecutive year, the West Nile Virus Response Plan has been developed in collaboration with representatives from other State agencies, county health departments, environmental organizations and academic institutions. The plan begins with an emphasis on public education about prevention and mosquito larval habitat management, then proceeds to higher levels of prevention, including personal protection messages, and larval mosquito control (larvaciding) as the need arises.

"Our plan calls for careful surveillance to know when West Nile virus is present and increasing in a particular area, followed by a measured response appropriate to the level of human health risk," Dr. Novello said. "As the threat increases, the public health response will change as well. We are emphasizing that spraying to control adult mosquitoes should be reserved only for those situations where there appears to be an imminent risk to human health."

The response plan provides specific guidance to help counties address the public health threat during 2001. For instance, the plan calls for county health departments to gauge the potential for human illness by tracking the number of dead crows, that are reported by local residents; submitting a certain number of dead birds for testing to confirm the virus' presence; and, in selected areas, trapping and submitting mosquitoes for testing.

Because West Nile virus already has firmly established itself in New York State, with virus confirmed last year in 61 of the State's 62 counties, the plan's goal is not to eradicate the virus, but to prevent its amplification to the point that it causes serious illness in humans or domestic animals. To fight the virus, Governor Pataki's 2001–2002 budget calls for nearly $22 million to help defray the cost of West Nile virus prevention, surveillance and response. The Governor has fought on behalf of New York State taxpayers and has aggressively pursued federal funds to help defray the cost of New York's State's West Nile virus response activities.

During 2000, 14 New Yorkers (all from New York City) were hospitalized after being infected by West Nile Virus, one of whom later died. To learn more about the extent of human risk, researchers collected blood samples this past autumn from individuals in parts of Staten Island and Long Island and tested them for West Nile virus antibodies.

Evidence from these serosurveys indicates that the chance of human infection and illness resulting from West Nile virus is quite low, even when the virus is present in the environment. Only when there is an extraordinary amplification of the virus as a result of transmission among birds and mosquitoes does it pose a serious human health threat. Reflecting this finding, the response plan envisions citizen involvement, through mosquito prevention activities and reports of dead crow sightings, to serve as an early warning of human disease risk, as a powerful weapon to protect public health.

"Even though the chances of a person getting encephalitis from West Nile virus are small, we must work together to reduce the risk even further," Dr. Novello said. "Individual New Yorkers can take simple steps to decrease the number of mosquitoes around their residential and commercial properties by eliminating places where they breed, and, thus, help reduce the need for more aggressive interventions later on."

"Audubon New York applauds the efforts of the State Health Department on the West Nile virus issue. The Department's continued openness and inclusiveness has ensured that any new information is considered, which is critically important in dealing with any emerging health issue. The collaboration between the public health and environmental communities ensures that the plan and its implementation continue to get better and better," said William Cooke, Director of Governmental Relations for Audubon New York.

"We would like to thank the New York State Health Department for recognizing the legitimate concerns voiced by health care providers, environmentalists and members of the public about the over reliance on chemical pesticides as a solution to West Nile virus," said Sarah Meyland, Executive Director of the Citizens Campaign for the Environment. "The 2001 plan reflects a movement away from the atmosphere of crisis management that existed when the disease was first identified, towards a more measured response, appropriate for long term management. We hope that this plan marks a change in response activities as well."

Following are Some Highlights of the Draft Plan:

Prevention Response and Control:

Prevention strategies must be based on a well–planned, area–wide Integrated Mosquito Management (IMM) based program. IMM includes surveillance, education, source reduction and larval and adult mosquito control. Source reduction and larval control help limit the number of mosquitoes by reducing breeding sites and eliminating mosquito larvae before they hatch, decreasing the need for spraying later on. In general, the finding of a West Nile virus positive bird or mosquito pool does not by itself constitute evidence of an imminent threat to human health and warrant mosquito adulticiding (spraying to control adult mosquitoes).

Mosquito Surveillance:

High priority mosquito surveillance will be conducted in counties where the virus was most active last year. Ideally, all counties should conduct some level of mosquito surveillance. The action plan for mosquito surveillance includes identifying larval breeding sites using aerial and ground–based surveillance methods; mapping larval breeding sites using GIS technology; identifying potential vector species of West Nile virus within each county through the collection of adult mosquitoes; mapping distribution of vector species using GIS technology; and, as indicated, submitting potential vector species to New York State for viral testing. Initial efforts should focus on Culex species in human population centers and high–use recreational areas.

Bird and Mammal Surveillance:

Tracking the possible risk for a human West Nile virus outbreak is recommended using weekly dead crow sightings per square mile–the best measure identified so far to indicate human risk. The critical dead crow surveillance time period for forecasting the risk of human West Nile virus cases appears to be April through September. Guidelines are being provided to county health departments on the number of birds to submit for laboratory testing, with increases recommended depending on the density of crow mortalities, West Nile virus activity in surrounding areas, and the level of West Nile virus activity compared to previous years. Although less laboratory testing of birds will be required for public health purposes, especially after West Nile virus has been confirmed in a county, bird necropsies at the New York State Department of Environmental Conservation's Wildlife Pathology Unit will be readily available for purposes of surveillance and research into West Nile virus and other important causes of bird mortality. Mammals have not provided the first indication of West Nile virus activity in any county or state, so they are not recommended to be a part of core surveillance activities.

Human Surveillance:

Currently, no clear predictor for the risk of human illness from West Nile virus has been identified except for certain host factors such as being age 50 or older. Therefore, all county health departments, in cooperation with the New York State Department of Health, need to enhance surveillance for West Nile virus infection in humans to improve the ability to promptly detect a human outbreak. An essential component of an enhanced surveillance program for viral encephalitis includes rapid and complete laboratory diagnosis on all suspect cases. Thus, enhanced passive case surveillance is recommended for all counties from May through October. Enhanced passive case surveillance includes, among other activities, communicating at the beginning of the season with all hospitals and select physicians to stress the importance of reporting all cases of viral encephalitis. Active case surveillance is recommended when there is evidence of West Nile virus activity during the current year.

Active case surveillance, conducted at sentinel acute care hospitals, includes weekly contact with key medical staff regarding hospitalized patients with suspected viral encephalitis and/or viral meningitis. County health departments are asked to ensure that appropriate specimens are obtained on all suspected cases and tested.

Surveillance of Possible Health Effects from Pesticide Exposure:

During the mosquito control season, the New York State Department of Health should collect information on calls received reporting health symptoms possibly related to pesticide applications used to control adult mosquitoes. In addition, the Department should contact agencies receiving similar reports to collect those data and maintain communication to encourage sharing of information. By monitoring reports of health effects possibly related to pesticide use, the Department may identify serious, unusual or repeated acute health effects that show a pattern of association with local or aerial spraying that might need further evaluation; unexpected avenues of exposure that might require investigation and referral to the appropriate agency; and issues in responding to concerns and inquiries about pesticide health effects, including knowledge gaps or problems with educational materials.

Public Communications:

The New York State West Nile virus public communication program will emphasize health promotion strategies to encourage individual behavior change. The enhanced program will have three inter–related components: health education, media relations and risk communication.

All communication activities will emphasize that persons age 50 and older are at an increased risk of serious illness from West Nile virus, and will stress that children are not currently considered to be a high–risk group. High–risk individuals will be advised of the array and the relative merits of personal protection techniques/measures. Members of the general public will be encouraged to report dead crows to local health units, to assist in monitoring the outbreak, but they will be advised that not all dead birds will, or should be tested for West Nile virus.

As part of the 2001 West Nile virus response, the State will expand its "Fight the Bite" public awareness campaign which includes print and web–based materials such as brochures, posters, and fact sheets, television and radio spots, novelty items and other incentives to prompt individuals to report dead crows that may signal the presence of West Nile virus and also to clean up locations where container breeding mosquitoes lay their eggs. One such species, the Culex pipiens, has been closely associated with amplification of West Nile virus in New York State.

Culex pipiens mosquitoes, along with several other mosquito species that have tested positive for West Nile virus, breed in man–made collections of stagnant water such as unchlorinated swimming pools, dirty bird baths, discarded tin cans, old tires and similar items in which water can accumulate. Although not all mosquitoes from which West Nile virus has been isolated are container breeders, people can still help protect themselves from mosquito bites by using common sense and diligence:

  • Dispose of tin cans, plastic containers, ceramic pots and similar water–holding containers.
  • Remove all discarded tires on your property. Used tires have become the most common mosquito breeding ground in the country.
  • Drill holes in the bottom of recycling containers that are kept outdoors.
  • Make sure gutters drain properly, and clean clogged gutters in the spring and fall.
  • Turn over plastic wading pools and wheelbarrows when not in use.
  • Change the water in bird baths.
  • Clean and chlorinate swimming pools, outdoor saunas and hot tubs.
  • Drain water from pool covers.
  • Use landscaping to eliminate stagnant water that collects on your property; clean up leaf litter and similar organic debris.

To keep mosquitoes from getting inside the home, persons should make sure that all their doors and windows have screens and that the screens are in good repair.

An information campaign also will be targeted at health care providers, as part of the State's heightened surveillance for possible human cases of encephalitis caused by West Nile virus. Providers will be reminded, as well, about the requirement to report cases of suspected pesticide poisoning to the State's Pesticide Poisoning Registry.

The 2001 West Nile Virus Response Plan is posted on the New York State Department of Health website: www.health.state.ny.us/nysdoh/westnile/response_plan/index.htm.

4/5/01–32 OPA