2012 West Nile virus update: September 4

As of September 4, 2012, 48 states have reported West Nile virus infections in people, birds, or mosquitoes. A total of 1,993 cases of West Nile virus disease in people, including 87 deaths, have been reported to CDC. Of these, 1,069 (54%) were classified as neuroinvasive disease (such as meningitis or encephalitis) and 924 (46%) were classified as non-neuroinvasive disease. 

The 1,993 cases reported thus far in 2012 is the highest number of West Nile virus disease cases reported to CDC through the first week in September since West Nile virus was first detected in the United States in 1999. Over 70 percent of the cases have been reported from six states (Texas, South Dakota, Mississippi, Oklahoma, Louisiana, and Michigan) and almost 45 percent of all cases have been reported from Texas.

• West Nile Virus (WNV) Human Infections Reported to ArboNET, by State, United States, 2012 (as of September 4, 2012) 
• West Nile virus (WNV) activity reported to ArboNET, by county, United States, 2012 (as of September 4, 2012)
• Statistics, Surveillance, and Control Archive
• West Nile Virus: What You Need To Know

West Nile virus (WNV) activity reported to ArboNET, by state, United States, 2012 (as of September 4, 2012)

Footnote: The map displays white areas that represent no WNV activity reported, light green areas that represent any WNV activity* , dark green circles that represent disease cases, and dark green triangles that represent presumptive viremic blood donors.

* Includes WNV human disease cases, presumptive viremic blood donors, veterinary disease cases and infections in mosquitoes, birds, and sentinel animals.
† Presumptive viremic blood donors have a positive screening test which has not necessarily been confirmed.

Map shows the distribution of WNV activity* (shaded in light green), human infections (dark green circles), and presumptive viremic blood donors (dark green triangles) occurring during 2012 by state. If West Nile virus infection is reported from any area of a state, that entire state is shaded.

Data table:

Non-human West Nile virus infections have been reported to CDC ArboNET from the following states:

Alabama, Arizona, Arkansas, California, Colorado, Connecticut, Delaware, Florida, Georgia, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Hampshire, New Jersey, New Mexico, New York, North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Utah, Vermont, Virginia, Washington, West Virginia, Wisconsin and Wyoming.

Two thousand two hundred eighty human West Nile virus infections have been reported to CDC ArboNET from Alabama, Arizona, Arkansas, California, Colorado, Connecticut, Delaware, District of Columbia, Florida, Georgia, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Hampshire, New Jersey, New Mexico, New York, North Carolina, North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, South Carolina, South Dakota, Tennessee, Texas, Utah, Virginia, West Virginia, Wisconsin, and Wyoming.