| West Nile fever | |
|---|---|
 | |
| West Nile virus | |
| Specialty | Infectious disease |
| Symptoms | None, fever, headache, vomiting or diarrhea and muscle aches rash[1] |
| Complications | Encephalitis, meningitis[1] |
| Usual onset | 2 to 14 days after exposure[1] |
| Duration | Weeks to months[1] |
| Causes | West Nile virus spread by mosquito[1] |
| Diagnostic method | Based on symptoms and blood tests[1] |
| Prevention | Reducing mosquitoes, preventing mosquito bites[1] |
| Treatment | Supportive care (pain medication)[1] |
| Prognosis | 10% risk of death among those seriously affected[1] |
West Nile fever is an infection by the West Nile virus, which is typically spread by mosquitoes.[1] In about 80% of infections people have few or no symptoms.[2] About 20% of people develop a fever, headache, vomiting, or a rash.[1] In less than 1% of people, encephalitis or meningitis occurs, with associated neck stiffness, confusion, or seizures.[1] Recovery may take weeks to months.[1] The risk of death among those in whom the nervous system is affected is about 10 percent.[1]
West Nile virus (WNV) is usually spread by mosquitoes that become infected when they feed on infected birds, which often carry the disease.[1] Rarely the virus is spread through blood transfusions, organ transplants, or from mother to baby during pregnancy, delivery, or breastfeeding,[1] but it otherwise does not spread directly between people.[3] Risks for severe disease include being over 60 years old and having other health problems.[1] Diagnosis is typically based on symptoms and blood tests.[1]
There is no human vaccine.[1] The best way to reduce the risk of infection is to avoid mosquito bites.[1] Mosquito populations may be reduced by eliminating standing pools of water, such as in old tires, buckets, gutters, and swimming pools.[1] When mosquitoes cannot be avoided, mosquito repellent, window screens, and mosquito nets reduce the likelihood of being bitten.[1][3] There is no specific treatment for the disease; pain medications may reduce symptoms.[1]
The virus was discovered in Uganda in 1937, and was first detected in North America in 1999.[1][3] WNV has occurred in Europe, Africa, Asia, Australia, and North America.[1] In the United States thousands of cases are reported a year, with most occurring in August and September.[4] It can occur in outbreaks of disease.[3] Severe disease may also occur in horses, for which a vaccine is available.[3] A surveillance system in birds is useful for early detection of a potential human outbreak.[3]
- ^ a b c d e f g h i j k l m n o p q r s t u v w x y "General Questions About West Nile Virus". www.cdc.gov. 19 October 2017. Archived from the original on 26 October 2017. Retrieved 26 October 2017.
- ^ "Symptoms, Diagnosis, & Treatment". www.cdc.gov. 15 January 2019. Archived from the original on 26 October 2017. Retrieved 15 January 2019.
- ^ a b c d e f "West Nile virus". World Health Organization. July 2011. Archived from the original on 18 October 2017. Retrieved 28 October 2017.
- ^ "Final Cumulative Maps and Data | West Nile Virus | CDC". www.cdc.gov. 24 October 2017. Archived from the original on 27 October 2017. Retrieved 28 October 2017.