West Nile virus case numbers growing in South Dakota The Department of Health reported 45 new human WNV disease cases today and cautioned residents not to be complacent as the disease continues to spread.
This brings the number of human WNV cases in South Dakota to 142 during the WNV transmission season. Counties reporting new human detections include Beadle (two).
"Surprisingly enough, the more drought-stricken areas of our state are seeing the greatest numbers of West Nile cases, with Pennington, Fall River, Dewey and Hughes counties particularly hard hit," said Dr. Lon Kightlinger, state epidemiologist. "The virus is clearly circulating all across South Dakota and we are seeing new cases almost daily. We strongly encourage all residents and visitors to protect themselves by using repellent and wearing long pants and sleeves when they must be outside."
Dr. Kightlinger said 33 percent of cases with a known diagnosis have been diagnosed with meningoencephalitis and 67 percent with West Nile fever. Diagnosis is still pending on some cases. Forty-nine percent of the cases have been male and 51 percent female. The median age is 46 years and the ages range from 6 to 88 years.
The elderly are at greatest risk of meningoencephalitis, the most severe form of WNV disease; 58 percent of the cases are over 50 years old.
There have also been 35 asymptomatic individuals who were detected through routine screening of blood donations since 1 July. There are 177 human WNV disease cases or blood donor detections.
Early indicators of West Nile virus activity were horse, bird and mosquito surveillance detections across the state. There have been 116 WNV positive birds detected, 54 positive ill horses, and 19 positive mosquito pools.
There are now human WNV cases or blood donor detections in many South Dakota communities. Human cases and detections indicate the extent of the epidemic in South Dakota and the increasing level of risk.
Communities with multiple cases or detections include: Rapid City 23, Pierre 11, Aberdeen eight, Sioux Falls seven, Eagle Butte six, Mitchell five, Hot Springs four, Ft. Pierre four, Onida four, and Wagner four. Communities having three or less West Nile cases or detections include Allen, Belle Fourche, Black Hawk, Box Elder, Britton, Bruce, Chamberlain, Corsica, Delmont, DeSmet, Dupree, Edgemont, Faith, Faulkton, Fort Pierre, Fulton, Gettysburg, Highmore, Hill City, Hoven, Hurley, Huron, Ipswich, Isabel, Kennebec, Kimball, Lake Andes, Lesterville, Letcher, Lower Brule, Martin, McIntosh, Menno, Miller, Mina, Mission, Mobridge, Murdo, New Underwood, Newell, Olivet, Oral, Parkston, Philip, Piedmont, Pierpont, Pine Ridge, Platte, Presho, Pukwana, Raymond, Redfield, Rosebud, Spearfish, Sturgis, Viborg, Volga, Wakonda, Wall, Warner, Wessington Springs, White River, Wolsey, Woonsocket, Wounded Knee, and Yankton.
In addition to individual precautions, Kightlinger said the department is encouraging communities to strongly consider adult mosquito control measures, including removing places where mosquitoes grow, larvicide application, spraying adult mosquitoes, and local public education.
Detailed information on county bird, mammal and mosquito detection numbers can be found on the SD West Nile Web site at www.state.sd.us/doh/WestNile.