A mosquito bite can turn into something much more severe if it infects you with the West Nile virus (sometimes called WNV). Mosquitoes transmit this virus by biting an infected bird and then biting a person. Not all people with infected mosquito bites get the disease, however.

WNV can be severe for people older than 60 years and people with weakened immune systems. If diagnosed and treated quickly, the outlook for West Nile virus recovery is good.

If you have West Nile virus, you will typically show the first virus symptoms within three to 14 days of being bitten. West Nile virus symptoms vary in severity. Severe symptoms can include: fever, confusion, convulsions, muscle weakness, vision loss, numbness, paralysis and even coma.

A severe infection can last for several weeks. In rare cases, a severe infection can cause permanent brain damage.

A mild infection doesn’t usually last as long. Mild forms of West Nile virus may be confused with the flu. Symptoms include: fever, headache, body aches, nausea, vomiting, swollen lymph glands, rash on your chest, stomach, or back.