What Is West Nile Encephalitis?

West Nile encephalitis, also known as WNE, is, in itself, recognized as a virus borne from arthropods which are known to carry it with them. In addition, it is characterized from where it is based, what are its clinical features and findings.

Known to have originated and become an endemic in the eastern hemisphere, it has already spread across the United States. Culex, Anopheles and Aedes mosquitoes are said to be the ones that transported the diseases to wild birds which in turn have infected humans.

Birds are said to have been the most efficient transmitter of the virus since the pathogen itself remains in their bodies for one to two weeks. Horses and other domestic animals like cats and dogs are not as efficient yet have been reported to have transmitted WNE to humans nonetheless.

WNE passes through the barrier of the brain and the blood, resulting to the infection of the brain parenchyma. This in turn manifests clinically as viral encephalitis. Furthermore, it may affect the leptomeninges causing aseptic meningitis, or in some cases, when it is accompanied by encephalitis, meningoencephalitis.

Worldwide Frequency

In the United States, its initial occurrence was accounted in a greater area of New York City. But it has now spread in several states including Canada.

Though there have been reported outbreaks in countries like Romania, Russia, and the United States, there have been little reports regarding manifestations of WNE itself but the rate of death and encephalitis are high.

Approximately 50% of children of children in Egypt have West Nile virus seropositivity.


  • Those infected develop a flu-like disease while number of people a neurologic disease.
  • Vomiting and diarrhea.
  • Sore throat back ache, myalgia, arthralgia.
  • Headache, tremors, mental confusion, flaccid paralysis.
  • Symtoms are most prominent in very young and very old people.


  • WNE usually occurs in the summer, when mosquitoes, wild migratory birds, and humans are in close proximity outdoors.
  • Mosquito bites, which are particularly likely during feeding times (dawn and dusk) in the summer months, transmit West Nile virus.
  • Prolonged contact or multiple mosquito bites enhances the risk.
  • West Nile virus may be transmitted in organ transplants.
  • West Nile virus has been found in breast milk.