Protection Against Mosquitoes
West Nile Virus - Transmission, Signs & Symptoms
People become infected by the bite of a mosquito infected with West Nile Virus. Mosquitoes become infected when they feed on infected birds, which may circulate the virus in their blood for a few days. Infected mosquitoes can then transmit WNV to humans and animals while biting to take blood. The virus is located in the mosquito's salivary glands. During blood feeding, the virus may be injected into the animal or human where it may multiply possibly causing illness. West Nile encephalitis is NOT transmitted from person-to-person. There is no evidence that a person can get the virus from handling live or dead infected birds. However, persons should avoid bare-handed contact when handling any dead animals and use gloves or double plastic bags to place the carcass in a garbage can.
Most people infected with West Nile virus have no clinical symptoms of illness, but may become ill 3-15 days after the bite of an infected mosquito. Infections can be mild and include fever, headache, body aches, and occasionally with skin rash and swollen lymph glands. Sever symptoms are marked by headache, high fever, neck stiffness, stupor, convulsions, muscle weakness, paralysis and, rarely, death. It is assumed that if a person contracts West Nile virus they develop a lifelong natural immunity to future infection, but it may weaken in later years. While everyone is at risk of West Nile disease, those at highest risk are persons 50 years of age or older.
Using Insect Repellants Safely
Insect repellents help people reduce their exposure to mosquito bites that may carry potentially serious viruses such as West Nile virus, and allow them to continue to play and work outdoors. Many of the mosquitoes that carry the West Nile virus are likely to bite around dusk and dawn. Female mosquitoes bite people and animals because they need the protein found in blood to help develop their eggs. Mosquitoes are attracted to people by skin odors and carbon dioxide from breath. Repellents contain a chemical, which does not kill, but repels the mosquito and are effective only at short distances from the treated surface, so you may see mosquitoes flying nearby. When using repellents be sure to follow the directions on the product to determine how frequently you need to reapply repellent. Sweating, perspiration or getting wet may mean that you need to re-apply repellent more frequently. Repellents containing a higher concentration of active ingredient, such as DEET, provide longer-lasting protection. If you are no longer getting bites, there is no reason to apply more repellent. A product containing 23.8% DEET can provide an average of 5 hours of protection from mosquito bites.
Guidelines for Repellant Use
There are no reported adverse reactions following use of repellents containing DEET in pregnant or breastfeeding women. In rare cases, these products may cause skin reactions.