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HomeMy WebLinkAboutIR 8417 * INFORMAL REPORT TO CITY COUNCIL MEMBERS No. -8417 PATIrk Date: July 23, 2002 To the Mayor and Members of the City Council SUBJECT: Mosquito Monitoring, Surveillance & Education Program In response to recent media attention regarding the advance of the West Nile Virus (VrNV) into Texas and the confirmation of WNV infected birds and a WNV infected horse in Harris County, the City of Fort Worth is continuing its educational efforts aimed at personal protection and source reduction with regards to mosquitoes. The program is being focused through the Fort Worth Public Health Department with support from the Department of Environmental Management, Tarrant County Public Health Department and the Texas Department of Health. At the end of last year, questions regarding dead birds (specifically crows and blue jays) were added to the surveillance program that is nuisance based. The Health Promotion and Education section has tracked citizen calls since 2000 (see attached map) concerning nuisance levels of mosquitoes. The Public Health Department's Animal Care & Control Division is charged with collecting dead birds and will for-ward them to the Texas Department of Health (TDH) for testing. Birds must meet certain criteria before they are forwarding to the lab. TDH is responsible for operating the lab where all birds from the state are being tested, Even with birds in North Texas (Dallas County) testing positive for the West Nile Virus and with the advent of spraying by Dallas' Environmental Health Services Department (city department), Fort Worth city staff does not plan to spray. Background TDH has been working with local health departments to promptly detect and control all mosquito-borne illnesses. Endemic mosquito-borne illnesses have been reported in Texas throughout the 20'h century including yellow fever (1903), dengue (1920s-1940s, 1980s-1990s), malaria (1940s, 1950s), Venezuelan equine encephalitis (VEE, 1971) and Saint Louis encephalitis (SLE, 1950s, 1990s). Encephalitis is a "notifiable" condition that, by law, must be reported to TDH. West Nile Virus is a strain of encephalitis. Tarrant County has not had a case of mosquito-borne encephalitis since the late 1980s. To date, no incidences of the WNV have been reported in Tarrant County, and no cases of human exposure have occurred in North Texas. This year, the Tarrant County Public Health Department began to monitor for the presence/absence of West Nile and other viruses in Tarrant County mosquito groups, including several sites within the city limits of Fort Worth. Sampling began in June with no arbovirus detected from the sample of mosquitoes sent for testing. Arbovirus refers to insect- or mosquito-transmitted virus and would include all forms of Primary Prevention Since its initial Western Hemisphere appearance in New York in 1999, WNV has spread across the eastern United States. With its entry into Texas and as it spreads, the virus will likely become a part of the state ecology, like Eastern equine encephalitis, St. Louis encephalitis and Western equine encephalitis. e nitial public health response to WNV is important in order to: ISSUED BY THE CITY MANAGER FORT WORTH, TEXAS INFORMAL REPORT TO CITY COUNCIL MEMBERS No. 8417 Te Date: July 23, 2002 To the Mayor and Members of the City Council Page 2 of 3 f a SUBJECT: Mosquito Monitoring, Surveillance & Education Program • Minimize human illness through public education, early diagnosis of the disease and vector control; • Track the virus as its geographic range expands; • Identify locations where the disease poses the greatest threat; and • Identify key vector species that contribute to the transmission of the disease. As with other diseases, one of the keys to proper response lies in ensuring that prompt, accurate information reaches the public so they may institute personal protective measures without panic and confusion. TDH has prepared a response plan, which is divided into four levels based on the risk of human diseases. With no evidence of WNV activity in Tarrant County, we would be at Risk Level 1. The probability of human outbreak at this level is low. Surveillance of mosquitoes will continue along with testing of dead birds. All educational efforts center on staff encouraging citizens that most mosquito vectors of encephalitis are home grown (i.e., species of interest have a flight range of less than 1 mile) and that the best way for individuals to reduce their risk of mosquito-borne disease is to eliminate mosquito breeding sites near their homes and in their neighborhoods (source reduction, see Menacing Mosquitoes citizen information attached). Additionally personal protection is always stressed with all information communicated via water bill inserts, press releases, personal communication, city page articles, the City's Web site and interviews. To spray or not to spray? Spraying for mosquitoes will temporarily reduce the number of adult mosquitoes in the immediate vicinity. But similar to some medications, the toxins used in spraying have side effects that generally outweigh the limited positive impacts. First, spraying will not rid the city of mosquitoes. The chemical must make direct contact with the insect to kill it, making it difficult to destroy mosquitoes hiding in grass, bushes, trees or backyards. Moreover, the chemicals have no residual effects and do nothing to kill mosquito larva thriving in stagnant water. Second, spraying for mosquitoes may give residents a false sense of security. The risk of someone being infected with West Nile might then increase if fewer people decide not to use insect repellant before working or playing outdoors. Third, adding harmful chemicals to the environment can have unwanted secondary effects. The city has four lakes that have fishing bans or restrictions tied to them. Use of pesticides many years ago is tied to the presence of the contamination in these lakes today. Lastly, thousands of Fort Worth residents living with respiratory problems such as asthma would be in danger of an outset of symptoms. The killing of a few mosquitoes does not warrant the potential hazard to the general population. The Texas Department of Health's response plan supports the City of Fort Worth's position in that it does not call for spraying of adulticides in the immediate area until a Public Health Risk has escalated to a level where the probability of human outbreak is high. Large number of birds dying from the virus or a human case could trigger the need for spraying. If the city were to contract spraying services, an estimated cost would be $250/hour or $3,000 for every 20 miles of spraying. Should the city launch a spraying ISSUED BY THE CITY MANAGER FORT WORTH, TEXAS A INFORMAL REPORT TO CITY COUNCIL MEMBERS No. 8417 Date: July 23, 2002 To the Mayor and Members of the City Council Page 3 of 3 a SUBJECT: Mosquito Monitoring, Surveillance & Education Program program, initial setup of $22,500 could be expected with an annualized program budget of $97,600 needed. By taking the responsibility for reducing their exposure to mosquito bites, residents can go much farther in preventing a human case of WNV than can the city by spraying. Source reduction (eliminating standing water were mosquitoes breed and grow), personal protection (protective clothing, use of insect repellent and limiting exposure to insects during feeding times) and larvacide reduction (so they do not develop into biting adults) remain the key factors to stress to citizens. Nevertheless, the Public Health Departments will continue their surveillance and education programs to continually monitor the situation and respond accordingly. ary W. son City Manager ISSUED BY THE CITY MANAGER FORT WORTH, TEXAS City of Fort Worth 2000 & 2001 Citizen Mosquito Complaints 2001 Complaints 2000 Complaints Highways Hydrology City Limits do A y • ,� ' ►• • A- AA,'' � AA. a 5 miles bars data:CITY OF FORT WORTH HEALTH DEPARTMENT bare saa CITY OF FORT WORTH GEOGRAPHIC INFORMATION SYSTEM