Eleven states have reported West Nile cases this year. The virus circulated earlier than usual this summer, likely due to rising global temperatures, which allow mosquitoes to survive longer and expand to new habitats. West Nile is the most common mosquito-borne illness in the U.S. Most infected people fully recover. People can protect themselves from mosquito bites by getting rid of standing water and wearing DEET bug spray and long-sleeved clothing. 

About 1 in 5 people infected with West Nile will develop symptoms. These symptoms are flu-like and can include body aches, joint pain, headache, vomiting, diarrhea, and rash. Of those who are infected, 1 in 150 will develop a severe form of the illness that can affect the central nervous system causing issues like neck stiffness, disorientation, tremors, convulsions, paralysis and even death.  

Groups at higher risk of having complications from West Nile virus include people with cancer, diabetes, high blood pressure, organ transplant recipients, and those over the age of 60.

Cases of West Nile are being reported earlier than usual this year both in the U.S. and globally. This may be due in part to climate change causing milder winters.

Mosquitos are infected by feeding on blood of infected birds. Mosquitos can then spread the virus to humans and other mammals. An infected person does not have a high enough level of virus in their blood to later transmit it to other uninfected, biting mosquitos.

The best way to prevent West Nile Virus is to avoid mosquito bites. Steps like using bug sprays with DEET, spraying clothing with permethrin, and wearing long-sleeved shirts and pants can help keep mosquitoes from biting.

The mosquito that carries West Nile is most active at dusk and dawn, and mosquitos lay eggs in standing bodies of water. Therefore, draining standing water in your yard and avoiding being outside during the early morning and evening hours can reduce your exposure to these insects.

If you have symptoms of West Nile and you have been bitten by mosquitos in an area where West Nile virus has been detected, contact your healthcare provider. There is no specific treatment for the West Nile virus, and supportive care includes getting plenty of rest and fluids while monitoring for signs of severe illness. Over the counter medications can help ease symptoms. Most people who have had West Nile once are immune to getting it again.

Most people who are infected with the West Nile virus never show symptoms, these people will fight off the virus on their own and do not need additional medical care.

Climate change has increased the range of mosquitoes that carry diseases like West Nile. Public health departments continue to test mosquitoes and monitor these diseases to help detect this expansion of range. Scientists are still learning how this will affect the number of mosquito-borne diseases in the future.

Researchers are still learning if an infected person is immune to the virus after they recover. Current science suggests that if a person is infected with West Nile once they cannot get it again.