West Nile Virus FAQs

How do people get the West Nile Virus?

People contract the virus from bites of a mosquito that is infected with the West Nile Virus. It is primarily the Culex genus that transmits the virus.

How do mosquitoes get infected with the West Nile Virus?

Mosquitoes become infected by feeding on birds that are infected with the virus. The infected birds may or may not become ill. The birds are vectors, or intermediate carriers, of the virus that is important for the Virus’ life cycle and transmission cycle.

Who is at risk for getting West Nile Virus?

All residents of areas where active cases have been identified are at risk of developing West Nile Virus infection. People age 50 years or older are at highest risk for getting the infection.  Also babies and anyone who has a compromised immune system is at risk.

Is a woman’s pregnancy at risk if she gets West Nile Virus?

There is no clear evidence that a pregnancy is at risk due to infection with West Nile Virus. However in 2003 and 2004, a CDC registry identified 77 women who acquired West Nile Virus illness while pregnant. 71 of these women delivered live infants, 2 had elective abortions, and 4 miscarried in the first trimester. The CDC is continuing to gather research and outcome data for pregnancies of West Nile Virus infected mothers.