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West Nile Virus Update --- United States, January 1--August 19, 2008

This report summarizes 2008 West Nile virus (WNV) surveillance data reported to CDC through ArboNET as of 3 a.m. Mountain Daylight Time, August 19, 2008. A total of 28 states have reported 236 cases of human WNV illness to CDC (Figure, Table). A total of 137 (58%) cases for which such data were available occurred in males; median age of patients was 48 years (range: 10 months--86 years). Dates of illness onset ranged from January 17 to August 14; two cases were fatal.

A total of 37 presumptive West Nile viremic blood donors (PVDs) have been reported to ArboNET during 2008. Of these, 20 were reported from California, four from Texas, three each from Louisiana and Minnesota, two from Mississippi, and one each from Arizona, Iowa, Kentucky, Nevada, and Wisconsin. Of the 37 PVDs, one person aged 24 years subsequently had neuroinvasive illness, one person aged 48 years subsequently developed other/unknown illness, and 10 persons (median age: 43 years [range: 29--55 years]) subsequently had West Nile fever.

In addition, 881 dead corvids and 212 other dead birds with WNV infection have been reported in 17 states during 2008. WNV infections have been reported in horses in 14 states and Puerto Rico, in five squirrels in California, and in one unidentified animal species in Puerto Rico. WNV seroconversions have been reported in 88 sentinel chicken flocks in five states (Arizona, California, Florida, Louisiana, and Utah) and Puerto Rico. A total of 3,083 WNV-positive mosquito pools have been reported from 33 states, District of Columbia, and New York City.

Additional information about national WNV activity is available from CDC at http://www.cdc.gov/ncidod/dvbid/westnile/index.htm and at http://westnilemaps.usgs.gov.

Table

TABLE. Number of human cases of West Nile virus (WNV)
illness, by state — United States, 2008*
West Other Total
Neuroinvasive Nile clinical/ reported
State disease† fever§ unspecified¶ to CDC** Deaths
Alabama 0 1 0 1 0
Arizona 5 0 0 5 1
Arkansas 5 0 0 5 0
California 46 18 9 73 0
Colorado 1 19 0 20 0
Connecticut 0 1 0 1 0
Idaho 1 7 0 8 0
Iowa 1 0 0 1 0
Louisiana 1 5 0 6 0
Michigan 1 0 0 1 0
Minnesota 1 9 0 10 0
Mississippi 9 24 0 33 1
Missouri 1 2 0 3 0
Nebraska 1 1 0 2 0
Nevada 1 1 0 2 0
New York 2 0 0 2 0
North Dakota 2 12 0 14 0
Ohio 1 0 0 1 0
Oklahoma 2 3 0 5 0
Oregon 0 3 0 3 0
Pennsylvania 1 0 0 1 0
South Dakota 3 11 0 14 0
Tennessee 3 3 0 6 0
Texas 8 6 0 14 0
Utah 0 2 0 2 0
West Virginia 1 0 0 1 0
Wisconsin 0 0 1 1 0
Wyoming 0 1 0 1 0
Total 97 129 10 236 2
* As of August 19, 2008.
† Cases with neurologic manifestations (i.e., West Nile meningitis, West
Nile encephalitis, and West Nile myelitis).
§ Cases with no evidence of neuroinvasion.
¶ Illnesses for which sufficient clinical information was not provided.
** Total number of human cases of WNV illness reported to ArboNET by
state and local health departments.
Return to top.
Table

FIGURE. Areas reporting West Nile virus (WNV) activity —
United States, 2008*
Return to top.

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All MMWR HTML versions of articles are electronic conversions from typeset documents. This conversion might result in character translation or format errors in the HTML version. Users are referred to the electronic PDF version (http://www.cdc.gov/mmwr) and/or the original MMWR paper copy for printable versions of official text, figures, and tables. An original paper copy of this issue can be obtained from the Superintendent of Documents, U.S. Government Printing Office (GPO), Washington, DC 20402-9371; telephone: (202) 512-1800. Contact GPO for current prices.

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Date last reviewed: 8/20/2008

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