West Nile Neuroinvasive Disease Rate Lowest Since '01
There were 386 cases of WNV neuroinvasive disease and 33 WNV deaths reported in 2009
FRIDAY, July 2 (HealthDay News) -- There were 386 cases of West Nile virus (WNV) neuroinvasive disease reported in the United States in 2009, for an incidence of 0.13 cases per 100,000 population, the lowest incidence since 2001, according to a report published in the July 2 issue of the U.S. Centers for Disease Control and Prevention's Morbidity and Mortality Weekly Report.
Nicole P. Lindsey, of the CDC's National Center for Emerging and Zoonotic Infectious Diseases in Atlanta, and colleagues based the report on data collected through ArboNET, an Internet-based arbovirus surveillance system that tracks WNV, including WNV neuroinvasive disease (e.g., meningitis, encephalitis, or acute flaccid paralysis) and WNV non-neuroinvasive disease (e.g., acute systemic febrile illness that includes headache, myalgia, or arthralgia).
In addition to the 386 cases of WNV neuroinvasive disease reported for 2009, the CDC reported 334 cases of WNV non-neuroinvasive disease. A total of 33 WNV deaths were reported, all but one from neuroinvasive disease. There also were 116 presumptively viremic blood donors identified through screening of the blood supply: 79 percent asymptomatic, 20 percent non-neuroinvasive disease, and 1 percent neuroinvasive disease. States with the highest incidence of WNV neuroinvasive disease were Mississippi (1.05 per 100,000), South Dakota (0.74), Wyoming (0.73), Colorado (0.72), and Nebraska (0.61). Projecting from known infections, the CDC estimated there were a total of 54,000 WNV infections and 10,000 cases of WNV non-neuroinvasive disease for the year.
"The continuing disease burden caused by WNV affirms the need for ongoing surveillance, mosquito control, promotion of personal protection from mosquito bites, and research into additional prevention strategies," the authors write.