Rare Immunology News

Disease Profile

West Nile virus encephalitis

Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.


US Estimated

Europe Estimated

Age of onset

All ages





Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease.


Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype.


dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.


recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder.


Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.


Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.


Not applicable



West Nile encephalitis is a form of West Nile virus that affects the neurological system. Signs and symptoms may include headache, fever, neck stiffness, disorientation, tremors, seizures, paralysis, or coma. West Nile virus is generally spread to humans by infected mosquitos. West Nile encephalitis, specifically, occurs when the virus crosses the blood-brain barrier and infects the central nervous system. Although West Nile encephalitis can affect anyone, people who are over age 60, have received an organ transplant, or are affected by certain medical conditions such as cancer, diabetes, hypertension, and kidney disease have the highest risk of developing the condition. Treatment is supportive and hospitalization may be required to address the associated symptoms. Recovery may take several weeks or months and some of the neurologic effects may be permanent.[1][2][3]

Learn more

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

Where to Start

  • You can obtain information on this topic from the Centers for Disease Control and Prevention (CDC). The CDC is recognized as the lead federal agency for developing and applying disease prevention and control, environmental health, and health promotion and education activities designed to improve the health of the people of the United States.
  • The National Organization for Rare Disorders (NORD) has a report for patients and families about this condition. NORD is a patient advocacy organization for individuals with rare diseases and the organizations that serve them.

In-Depth Information

  • Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
  • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.


  1. Burke A Cunha, MD. West Nile Encephalitis. Medscape Reference. October 2015; https://emedicine.medscape.com/article/234009-overview.
  2. West Nile Virus. Centers for Disease Control and Prevention. September 2016; https://www.cdc.gov/westnile/index.html.
  3. West Nile Encephalitis. NORD. 2008; https://rarediseases.org/rare-diseases/west-nile-encephalitis/.