West Nile virus

From MEpedia, a crowd-sourced encyclopedia of ME and CFS science and history

West Nile virus is a mosquito-borne virus from the Flaviviridae, a viral family which also includes hepatitis C virus and dengue virus. It can be a trigger for ME/CFS.

Transmission[edit | edit source]

West Nile virus mainly infects humans when they are bitten by a mosquito carrying the virus; but more rarely, cases of transmission of by blood transfusion and during organ transplants have been described.

Prevalence[edit | edit source]

West Nile virus is prevalent in many countries, including the USA, Australia, parts of Canada, parts of Europe, but not the UK, Ireland or New Zealand. In a study conducted in Connecticut, USA, the seroprevalence of West Nile virus in the general population was found to be 8.5% (this is the percentage of people who had previously caught this virus at some point in their lives).[1]

Presentation[edit | edit source]

West Nile virus infection is asymptomatic in 80% of people who contract it; but in 20% of people, it produces acute symptoms such as fever, headache, body aches, joint pains, vomiting, diarrhea, or rash. About 0.7% of people who are infected develop a severe illness targeting the central nervous system, such as encephalitis or meningitis.[2]

Sequelae[edit | edit source]

People infected with West Nile virus can afterwards experience long-term fatigue lasting years. A 2014 study of 140 participants with a history of West Nile virus found 31% (44 participants) had more than six months of fatigue that inhibited their daily activities and 28 participants (or 20%) met the 1994 Fukuda criteria for ME/CFS.[3]

References[edit | edit source]

  1. Cahill, Megan E.; Yao, Yi; Nock, David; Armstrong, Philip M.; Andreadis, Theodore G.; Diuk-Wasser, Maria A.; Montgomery, Ruth R. (April 2017). "West Nile Virus Seroprevalence, Connecticut, USA, 2000–2014 - CDC". Emerging Infectious Diseases. 23 (4). doi:10.3201/eid2304.161669. PMC 5367428. PMID 28322715.
  2. CDC (May 17, 2024). "West Nile: Symptoms, Diagnosis, & Treatment". West Nile Virus. Retrieved May 31, 2024.
  3. Garcia, Melissa N.; Hause, Anne M.; Walker, Christopher M.; Orange, Jordan S.; Hasbun, Rodrigo; Murray, Kristy O. (September 1, 2014). "Evaluation of Prolonged Fatigue Post–West Nile Virus Infection and Association of Fatigue with Elevated Antiviral and Proinflammatory Cytokines". Viral Immunology. 27 (7): 327–333. doi:10.1089/vim.2014.0035. ISSN 0882-8245. PMC 4150370. PMID 25062274.