(10/18/2005)

South Dakota West Nile Virus Cases Near 50

State second only to California

The Department of Health today reported 13 new human West Nile (WNV) detections, including 12 new cases and one new blood donor detection. This brings to 48 the number of human WNV detections this season. New detections were reported in Brown, Campbell, Codington, Davison, Grant, Hamlin, Hanson, Moody, Spink and Stanley counties. In addition, 20 positive Culex mosquito pools were detected in Beadle, Brookings and Hughes counties.

Thirty-three of South Dakota’s 66 counties, or 50 percent, have now had WNV detections.

“We are now at the height of the West Nile transmission season in South Dakota,” said Dr. Lon Kightlinger, State Epidemiologist for the department. “The increasing human cases and infectious mosquitoes are clear warnings for people to protect themselves and their families. Communities should bolster their mosquito control measures.”

Provisional data shows that the median age of the South Dakota cases is 43 years, with the range from 14 to 80 years old. Ninety-five percent of cases are white and five percent are American Indian. Fifty-one percent of cases are male and 49 percent female. Of the cases fully investigated, 16 percent have had WNV neuroinvasive disease and 84 percent have had WNV fever. At this time last year South Dakota had reported out 18 cases.

Nationally, 42 of the 48 continental states have had WNV detections, with 24 states reporting a total of 333 human WNV cases, 76 blood donors, and three deaths to CDC. At this time in 2004, 689 human cases had been reported nationally.

Total South Dakota detections to date include:

• Human disease (43 cases) – Aurora, Beadle, Brown (12), Brule, Butte, Campbell (2), Charles Mix, Davison (2), Dewey, Douglas, Edmunds (2), Grant, Hamlin, Hanson (2), Hughes, McCook (2), Mellette, Moody, Pennington, Roberts (2), Spink, Shannon, Stanley (2), Tripp and Union counties.

• Asymptomatic blood donors (5 donors) – Butte, Clay, Codington, Hand and Hughes counties.

• Positive mosquito pools (49) – Beadle (35), Brookings (8), Brown, Hughes (3), Lincoln and Pennington counties.

• Positive birds (9) – Davison (3), Douglas, Gregory, Lyman, Moody and Roberts (2) counties.

• Positive horses (2) – Clark and Spink counties.

The department recommends the following precautions to prevent mosquito bites and reduce the risk of WNV:

Use mosquito repellents containing DEET or picaridin. Wear shoes, socks, long pants and a long-sleeved shirt to limit mosquito exposure. Limit time outdoors at dusk and dawn when mosquitoes are most active. Eliminate standing water that gives mosquitoes a place to breed. Support local mosquito control efforts. Personal precautions are particularly important for the elderly, pregnant women, and transplant patients. People with a severe or unusual headache should see their physician.

For more information about West Nile visit the Department of Health web site at http://WestNile.sd.gov or call 1-800-592-1861. Information is also available from the SDSU Cooperative Extension Service at http://sdces.sdstate.edu/westnile/ and the South Dakota Animal Industry Board at www.state.sd.us/aib.