A febrile disease caused by the West Nile virus that is transmitted from birds to the common Culex mosquito and then to people. The virus is named after the area it was first found in Uganda.
West Nile fever occurs in parts of Africa and Asia and, infrequently, in Southern Europe and the Middle East. The West Nile virus had never been seen in birds or people in the Western Hemisphere prior to an outbreak in the summer of 1999 in New York City.
> The virus has since moved across the United States.
Signs and symptoms include the sudden onset of drowsiness, headache and nausea due to encephalitis, pain in the abdomen, a rash, and swollen glands (lymphadenopathy). These features are usually but not always mild. Fatal cases tend to involve infants and small children under age 5, the aged, and people with an impaired immune system.
The outbreak in New York, which was entirely unexpected, reflects the reality of global travel today that can transport exotic viruses to new areas. If a mosquito-borne virus enters a new area, the entire mosquito population may be susceptible, putting everyone living there at risk.
West Nile fever is also known as West Nile encephalitis. The virus is closely related to other flaviviruses including those responsible for St. Louis encephalitis, Japanese encephalitis and Murray Valley encephalitis.
- West Nile virus
The mosquito-borne virus that causes West Nile fever. One of the flaviviruses, a family of viruses also responsible for dengue, yellow fever, and tick-borne encephalitis virus. Like the other flaviviruses, the West Nile virus is a positive-strand RNA virus containing three structural proteins and a host-derived lipid bilayer. The West Nile virus is an icosahedral […]
- West syndrome
Infantile spasms, a seizure disorder of infancy and early childhood with the onset predominantly in the first year of life of myoclonic seizures, hypsarrhythmia (abnormal, chaotic electroencephalogram), and mental retardation. The spasms are sudden, brief contractions of one or more muscle groups, and may be followed by a longer (less than 10 seconds) tonic phase. […]
- Western blot
A technique in molecular biology that is used to separate and identify particular proteins.
- Western medicine
Conventional medicine, as distinct from an alternative form of medicine such as ayurvedic or traditional Chinese medicine.
- Wet market
A live animal market, a common sight in many areas of the world and a source of influenza viruses and other infectious disease agents for human beings. SARS outbreaks have been traced to wet markets in southern China. Wet markets sell live poultry, fish, reptiles, and mammals of every kind. Animals may stay from days […]