October 2002 West Nile Virus and What We Can Do West Nile Virus (WNV) is a bird virus that can cause disease in man and other animals. Birds are the reservoir for the virus and mosquitoes are the vector. Transmission occurs when a specie of mosquito capable of vectoring the virus feeds on an infected bird and picks up the disease. Once infected, the mosquito passes the disease to other animals it feeds on. It was thought that this was the only way the disease could be transmitted but now it is known that a person who is infected with WNV can pass the disease to recipients of organs or blood from infected donors.
West Nile Virus is common in Africa, the Middle East and West and Central Asia. The disease first appeared in the New York City area in 1999 and has now spread to almost all of the U.S. and into Canada and will probably spread to wherever migrating birds travel in this hemisphere, North and South America.
The symptoms of WNV are wide ranging. The majority of people who are infected show no symptoms, their immune system responds quickly, the virus is destroyed before it multiplies and causes symptoms. In others it takes a little longer for the immune system to respond, the virus has time to multiply and the person will experience a mild illness with flu-like symptoms including headache, upset stomach, a slight fever, rash, swollen lymph nodes, and body aches before making a full recovery. However, in people with an impaired immune system, a system that is slow to respond, suppressed by medication or not yet fully developed, infection from WNV can cause a serious disease called West Nile Encephalitis. The symptoms of West Nile Encephalitis (inflammation of the brain) are high fever, disorientation, stiff neck, muscle weakness, paralysis, coma or death. Survivors of this severe form of the disease can recuperate fully or have permanent neurological damage.
West Nile Virus has no specific therapy or treatment. To date there are no vaccines available to protect against this disease. Researchers are presently testing an experimental vaccine, if safe and effective, it could be available within 3 years. Symptoms and complications from this virus can be treated. In severe cases, supportive therapy is needed, such as hospitalization and nursing care, airway management and respiratory support, intravenous fluids and prevention of secondary infections such as pneumonia.
Control of West Nile Virus requires an extensive Integrated Mosquito Management Program. Key components of such a plan include: ○ Bird surveillance to detect and monitor for WNV activity ○ Mosquito surveillance to identify and monitor the populations of suspected vectors ○ Community education ○ Larviciding all accessible breeding areas ○ Effective, properly timed spraying for adult mosquitoes to reduce potential vector populations.
Another key component to the control of WNV must be done by the individual, you, at the residential level. You can help by simply eliminating standing water that mosquitoes use to lay their eggs in. Dispose of all trash that can hold water such as cans, containers or tires. Drill holes in the bottom of trash receptacles and recycling bins. Clean you home’s roof gutters frequently… this is very important. Check storm drains and window wells to make sure they are functioning properly. Empty water from boats, trailers, toys, wheelbarrows and pots… turn them over when not in use. Do not allow water to stagnate in swimming pools, water gardens, ornamental pools or birdbaths… call us, we will provide mosquito fish for these water-holding situations. Inspect and change the landscaping of your property to eliminate standing water. Develop a sense of awareness and maintain it, this is probably the most important thing an individual can do and then of course act on such situations as they come up.
So what have we done at South Walton County Mosquito Control to control WNV? In 2002, this past year, we have helped fund a research project, being done by the John A. Mulrennan, Sr., Public Health Entomology Research and Education Center located in Panama City, to try and determine what mosquito species in our area are vectors and which wild birds are the reservoirs. We have increased our sentinel bird coops from 10 to 15 locations. We have increased our light trap collection of mosquitoes from 10 to 16 locations. We bleed our sentinel birds once per week and collect our mosquito light traps every day. We collect these mosquito traps and bleed our birds 12 months a year instead of just during the mosquito season. We have also incorporated the 6 mosquito collection sites that the Panama City Lab’s research project has and 2 citizen’s Mosquito Magnet collections into our surveillance program… this gives us more data, better focus, and justification for our adulticiding operation. We have dumpsters at our facility provided by Walton County, for residents to drop off appliances and tires free of charge. We place newspaper articles and provide educational presentations to schools and civic organizations to keep the public informed. We have and continue to refine our adulticiding spray routes to target problem areas and increase the efficiency and effectiveness of our pesticide usage. We take on the maintenance of existing drainage ditch systems, that have been dug by the State in the past, to insure that they function properly. And we treat the catch basins throughout the district, year round now, not just during the summer months.
In summary, protect yourself, especially if you are immune deficient. Make sure window and door screens are “bug tight”. Stay indoors when mosquitoes are most prevalent, during morning, dusk, and early evening. If you are outdoors wear long-sleeved shirts, socks, long pants, and apply insect repellants containing DEET to exposed skin. If the public does their part and we at South Walton County Mosquito Control do our part, West Nile Virus can be controlled.
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