Mosquito-borne: West Nile Virus

Mosquitos can transmit a number of diseases from animals to people. These diseases may be caused by viruses or parasites that are transferred through the mosquito’s bite during a bloodmeal from an infected host and a subsequent bite, bye that same mosquito of an uninfected host. The diseases are usually limited in location by the environmental requirements of the virus or parasite, its host, and the transmitting mosquito, but may be spread to other areas under favorable conditions.

The most commonly known of these diseases in the United States is West Nile virus or West Nile fever. This disease had never been reported in the Western Hemisphere until its identification in an outbreak in New York during the fall of 1999 and has since spread across the United States and Canada and south into Central America and the Caribbean. West Nile Virus is one of many pathogens known as arthropod-borne viruses or arboviruses. Many less well-known arboviruses, such as La Crosse encephalitis or Eastern Equine encephalitis are native to the Western Hemisphere.

Only a small number of mosquito species are capable of transmitting arboviruses. Each arbovirus is maintained in a different host. Humans and other animals, such as horses, are “dead-end” hosts in that they cannot infect a vector or pass the arbovirus to another host.

The USGS has been collaborating with state and federal agencies in a multi-state surveillance of West Nile Virus. USGS scientists have been testing dead birds for the presence of West Nile Virus and mapping the findings. The data collected will be used to determine the geographic spread of the Virus and possibly to predict future outbreaks.

USGS Research Related to West Nile Virus

• A Behavioral and Ecological Approach to the Evolution of Immunity and Disease Resistance
• West Nile Virus Studies at Patuxent Wildlife Research Center
• NBII Wildlife Disease Information: West Nile Virus
• NWHC West Nile Virus Project
• Habitat Partitioning by Neotropical Migrant Warblers, Lower Colorado River Corridor: Potential Influence on West Nile Virus Transmission

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U.S. Department of the Interior | U.S. Geological Survey
URL: http://health.usgs.gov/vector_zoonotic/west_nile.html
Page Contact Information: Herb Buxton
Page Last Modified: 18-May-2007@15:44