South Dakota reports 3 human West Nile cases The South Dakota Department of Health reported three new human West Nile cases Sept. 10, in residents of Douglas, Grant and Minnehaha counties. One case has been reclassified from Lake to Miner County.
There have now been 33 WNV disease cases and three blood donor detections reported in South Dakota during the 2004 transmission season. Also reported today are two WNV positive mosquito pools from Minnehaha County. West Nile has been detected in 32 of South Dakota's 66 counties to date.
Fifteen percent of human cases have been diagnosed with neuroinvasive disease and 85 percent with WNV fever. Seventy percent of cases are male and 30 percent female. Ninety-one percent of cases are white, 6 percent Native American and 3 percent other races. The median age of cases is 41 years with an age range from 9 to 77 years. The elderly are at greatest risk of the most severe form of WNV disease and complications.
"The West Nile virus will be a concern until the first hard frost," said Dr. Lon Kightlinger, state epidemiologist for the department. "Last year five South Dakotans became ill during the first two weeks of October, so precautions are still warranted.
A testing summary follows:
* Humans: 33 cases (Brown four, Minnehaha four, Pennington three, Beadle two, Butte two, Charles Mix two, Meade two, Aurora, Codington, Davison, Dewey, Douglas, Grant, Jackson, Hughes, McCook, Miner, Moody, Roberts, Spink and Tripp counties) and three positive blood donors (Hand, Minnehaha, Tripp). There has been one WNV associated death in South Dakota.
* Birds: 69 positive (Day 45, Marshall three, Brookings two, Brown two, Hamlin two, Hughes two, Minnehaha two, Pennington two, Beadle, Clark, Charles Mix, Davison, Grant, Kingsbury, Lincoln, Potter and Yankton). Positive bird detections include 45 pelicans, 14 blue jays, five crows, two red-tail hawks, one kestrel, one mourning dove, and one Swainson's hawk. One hundred eight birds have tested negative at the S.D. Public Health Laboratory.
* Veterinary: four positive horses (Brookings, Charles Mix, Minnehaha and Pennington), and one positive dog (Turner). Mosquitoes: 647 positive Culex tarsalis (encephalitis mosquito), 150 positive Culex pipiens (northern house mosquito) and 32 Aedes vexans.
(floodwater mosquito) in Beadle, Brookings, Minnehaha and Pennington counties. 36,475 mosquitoes have been tested at the S.D. Public Health Laboratory.
* Mosquitoes: Positive mosquitoes have been detected in Beadle, Brookings, Minnehaha and Pennington counties. Nationally, as of Sept. 7, 47 states had reported West Nile activity to the Centers for Disease Control and Prevention, including 1,191 human cases in 35 states. This compares to 2,923 cases at this time last year. Thirty-one deaths have been reported nationally this year. Arizona and California have reported 55 percent of the nation's cases. Ninety-eight WNV positive blood donors have been reported nationally in 2004, including three from South Dakota.