West Nile Virus (WNV) & Mosquitoes
HOW IS WNV TRANSMITTED?
Most people become infected with West Nile virus (WNV) from the bite of an infected mosquito. Mosquitoes pick up the virus when they feed on infected birds and these infected mosquitoes can then spread the virus to humans and other animals.
In a very small number of cases, WNV is caused by blood transfusions, organ transplants and from mother to baby during pregnancy, delivery or breastfeeding.
WHAT TYPE OF MOSQUITOES TRANSMIT WEST NILE VIRUS?
Mosquitoes in the genus Culex transmit WNV. This virus is not transmitted from person to person. Since dead birds may have died from the effects of WNV, wear protective gloves when handling dead birds or any other animal.
WHERE ARE THE MOSQUITOES TYPICALLY DISTRIBUTED?
Culex pipiens in the northern states, Culex tarsalis in the western states and Culex quinquefasciatus in the southern states are the mosquitoes most often implicated in WNV transmission.
SYMPTOMS OF WNV
Many people (70-80 percent) who get WNV are asymptomatic, while the other 20 percent of people show signs of:
- Bodily aches
A majority of people fully recover with only fatigue and weakness remaining for up to a few months. However, some people (less than one percent) develop illnesses such as encephalitis (inflammation of the brain or surrounding brain tissues).
IS WNV IN THE US?
In 1999, West Nile virus made its first U.S. appearance in New York. Since then, WNV has spread throughout the continental U.S. states and the District of Columbia.
In 2015, slightly more than 2,000 cases of WNV were reported, and California, Texas and Colorado had the most cases.
PREVENTION & TREATMENT OF WNV
Simply protecting against mosquito bites is the most effective way to prevent WNV.
There is no vaccine or specific, effective antiviral drug treatments for WNV. Supportive care and pain relievers can be used to relieve some symptoms. In severe cases patients that are WNV infected will require hospitalization.