The Alabama Department of Public Health cautions the public to protect themselves from West Nile virus (WNV) and other mosquito-borne illnesses.
Approximately 1 in 5 people who are infected with WNV will develop symptoms such as fever, headache, body aches, joint pains, vomiting, diarrhea or rash. Less than 1 percent will develop a serious neurologic illness such as encephalitis or meningitis (inflammation of the brain or surrounding tissues). Eight confirmed cases of WNV have been reported in Alabama to date this season, and additional suspected cases will be investigated statewide.
When a person is infected, early recognition and prompt supportive treatment for these illnesses can substantially lower the risk of developing severe disease. About 10 percent of people who develop neurologic infection due to WNV will die. People over 50 years of age and those with certain medical conditions, such as cancer, diabetes, hypertension, kidney disease and organ transplants, are at greater risk for serious illness.
Eastern Equine Encephalitis (EEE), WNV and other mosquito-borne viruses are transmitted by mosquitoes after they feed on birds. The same mosquitoes can then infect mammals, particularly humans and horses. Like humans, horses can sometimes become seriously ill from these infections.
Effective vaccination is available for horses. In 2012, there have been 7 cases of EEE in horses, including 4 cases in horses located in Dallas County, and 1 case each in Elmore, Mobile and Montgomery counties. Epidemiologists point out that EEE can be more dangerous to people and other mammals than other mosquito-borne viruses, but that the same mosquito prevention measures reduce exposures to any of these diseases.
In addition, 3 cases of WNV have been confirmed in horses. One case was in a horse in Jefferson County, 1 in Mobile County and 1 in Montgomery County.
For WNV and EEE in humans, there are no commercially available medications for treatment or vaccines for prevention. People with milder illnesses typically recover on their own, although symptoms may last for several weeks. In more severe cases, patients often need to be hospitalized to receive supportive treatment, such as intravenous fluids, pain medication and nursing care. Anyone who has symptoms that cause concern should contact a health care provider.
Other arthropod-borne viruses, St. Louis Encephalitis Virus and La Crosse Encephalitis Virus, have been detected periodically but not commonly within various areas of the state for several years.
According to the Centers for Disease Control and Prevention, the best way to prevent the most common mosquito-borne diseases such as WNV and EEE is to avoid mosquito bites by following these recommendations:
• Use insect repellents when going outdoors.
• Wear long sleeves and pants during dawn and dusk.
• Install or repair screens on windows and doors. Use air conditioning, if available.
• Empty standing water from items outside homes, such as flowerpots, buckets and children’s pools.
Repellents are an important tool to assist people in protecting themselves from mosquito-borne diseases. CDC recommends the use of repellents containing active ingredients which have been registered by the U.S. Environmental Protection Agency for use as repellents applied to skin and clothing. Products containing these active ingredients typically provide reasonably long-lasting protection. These include the following:
• Oil of Lemon Eucalyptus or PMD, the synthesized version of oil of lemon eucalyptus
Insect repellents must state any age restrictions. According to the label, oil of lemon eucalyptus products should not be used on children under 3 years of age. Parents should choose the type and concentration of repellent to be used by taking into account the amount of time a child will be outdoors, exposure to mosquitoes, and the risk of mosquito-transmitted disease in the area. People should consult their health care provider for advice about using repellent products on children.
Sentinel chickens are used to monitor the presence of mosquito-borne disease in an area. Five sentinel chickens in Baldwin County and 3 sentinel chickens in Mobile County have tested positive for WNV this summer.
"With many people enjoying outdoor activities, it is important that residents take every effort to reduce their exposure to mosquitoes," Dr. Dee W. Jones, State Public Health Veterinarian, advises. "Keep your mosquito repellent with you at all times when you are working or participating in recreational activities outdoors."
Mosquitoes that can spread these viruses to humans are commonly found in urban and suburban communities as well as rural, freshwater swamp areas. They will breed readily in storm sewers, ditches, waste lagoons and artificial containers around houses.
The Health Department will continue to notify local officials of test results and recommend methods of prevention. More information is available at adph.org/epi/.