WEST NILE VIRUS ACTIVITY UPDATE

Aug 5th, 2004

Health Alert Continues

The Mobile County Health Department announces today, Wednesday, August 4, 2004, that a bird collected from the 36695 zip code has tested positive for the West Nile Virus (WNV). To date Vector Control staff has tested 77 dead birds, 14 of which were positive for the virus from zip codes 36602, 36603, 36604, 36605, 36606, 36608, 36610, 36617, and 36695. Three human cases from Mobile County have been confirmed as well. Six other Alabama counties have reported West Nile activity in dead bird surveillance, horses, or mosquito pools. Baldwin County has reported Eastern equine encephalitis activity through a reported horse case and in sentinel chickens. Health Officials consider the disease to be widespread throughout Mobile County and urge citizens to use precautions to avoid exposure to mosquitoes.

According to Dr. Bernard Eichold, Mobile County Health Officer, "Most people who are infected with West Nile virus (WNV) do not even get sick. However, a small proportion of people - mostly people over 60 and those with immune compromised systems - may become ill with symptoms of encephalitis (inflammation of the brain) and require hospitalization." Humans with encephalitis often have symptoms of high fever, headaches, confusion and seizures that are severe enough to require medical attention. Bites to children should be watched for secondary infections that need to be treated by a physician. Mosquito bites can be treated with topical agents such as calamine and menthol lotions. Cortisone creams and oral antihistamines are available as over-the-counter medications that can reduce itching.

Dr. Eichold advises all horse owners to have their animals vaccinated against West Nile virus and Eastern equine encephalitis (EEE), and to call their veterinarian immediately if signs of encephalitis are observed. Clinical signs vary, but they include depression, staggering, incoordination, stupor, hyperexcitability, paralysis and coma.

Mosquitoes spread these viruses by feeding on the blood of infected birds. The diseases cannot be spread from person to person. Unlike other encephalitis viruses such as Eastern equine encephalitis and St. Louis encephalitis that maintain their cycle with wild birds, WNV kills many of the infected birds - especially crows, blue jays, and raptors. Public health officials are testing dead birds of those three types as one way to watch for the virus.

Dead crows, blue jays and raptors are often our first sign of virus activity in an area. The public should call Mosquito Control at 690-8124 for details on submitting newly dead birds for testing. Anything that has been dead for more than 24 hours in the summer heat is probably not testable. All species of birds can be reported.

The Mobile County Health Department has been monitoring encephalitis in sentinel poultry flocks for more than a decade. Poultry flocks serve as predictors of natural infection and can be good indicators that there may be potential risk of human infection. Additionally, mosquitoes are trapped throughout Mobile County and are being tested for Eastern equine encephalitis, St. Louis encephalitis, and West Nile Virus. No positives have been reported in mosquitoes or sentinel chickens from Mobile County to date.

Aggressive mosquito surveillance and control activities will continue throughout the county. The most effective and economical method to reduce adult mosquitoes is to reduce their emergence from as many breeding sites as possible- larviciding (killing the larvae). Inspectors regularly check areas with standing water for mosquito breeding and treat as necessary using both portable and truck mounted equipment. The inspectors also respond to service requests from citizens to inspect backyard areas as well as to treat identified breeding areas and to provide education. Due to large volumes of calls received daily, service requests will be responded to on a first call first served basis and may take a few days to be addressed.

Each day, the Mobile County Health Department evaluates surveillance data, inspection reports, and service requests, to target 10-12 routes out of a total of 50 routes, for nightly (Monday-Friday) mosquito control and spraying (when necessary, weekday morning, weekend and holiday spraying is provided). Spray trucks used for these operations dispense low volumes of aerosol insecticides and are equipped with a system that sprays the correct amount of insecticide for the speed of the vehicle. This allows for the proper application of insecticide at variable speeds.

Families enjoying outdoor activities such as picnics, concerts in the park, or playing at the playground should take extra precautions to avoid being bitten by mosquitoes. Remember mosquito activity peaks at dusk and again at dawn; restrict outdoor activity during these hours in heavily infested areas. Dr. Bernard Eichold suggests the following precautions:

PERSONAL PROTECTION: CLOTHING AND AROMATICS

• Wear loose fitting, light colored clothes to help prevent mosquitoes from reaching the skin and to retain less heat, making yourself less "attractive" to mosquitoes. Mosquitoes are more attracted to dark colors.


• When possible, wear long sleeves and long pants.


• Avoid perfumes, colognes, fragrant hair sprays, lotions and soaps, which attract mosquitoes.

PERSONAL PROTECTION: REPELLENTS

• Follow the label instructions when applying repellents. Permethrin repellents are only for clothes - not on the skin.


• When using repellents avoid contact with eyes, lips and nasal membranes.


• Use concentrations of less than 10 percent when applying DEET containing products on children.


• Apply DEET repellent on arms, legs, and other exposed areas, but never under clothing. After returning indoors, wash treated skin with soap and water.


• Citronella candles and repellents containing citronella can help, but their range is limited. Herbals such as cedar, geranium, pennyroyal, lavender, cinnamon, and garlic are not very effective.

PERSONAL PROTECTION: AROUND THE HOME

• Mosquito activity peaks at dusk and again at dawn; restrict outdoor activity during these hours.


• Keep windows and door screens in good condition.


• Replace porch lights with yellow light bulbs that will attract fewer insects.


• Mosquitoes breed in standing water; empty all water from old tires, cans, jars, buckets, drums, plastic wading pools, toys, and other containers.


• Clean clogged gutters.


• Remove the rim from potted plants and replace water in plant/flower vases weekly.


• Replenish pet watering dishes daily and rinse birdbaths weekly.


• Stock ornamental ponds with mosquito eating fish.


• Fill tree holes and depressions left by fallen trees with dirt or sand.


• Rake and bag or mulch fallen leaves, especially sturdy magnolia leaves, which can curl and hold water-allowing mosquitoes to breed. Do not blow leaves into the storm drain or put grass clippings into drainage ditches. Clogging the drains and ditches will only add new mosquito breeding sites close to your home.

For more information, call mosquito control at 690-8124.