Two human West Nile cases, first positive mosquitoes and more positive birds reported in South Dakota

PIERRE, S.D. – The Department of Health today announced two human West Nile Virus cases.  Once case is an Aurora County resident in the 40-year age group and the other case is a Davison County resident in their 50’s.  Both cases have West Nile Fever, which is a flu-like illness with fever, headache, muscle weakness, possible rash, swollen lymph glands, and muscle aches.  

Also reported today are three positive birds and the first laboratory detection of WNV infected mosquitoes.  Positive birds were detected in Pennington (1 crow) and Minnehaha (1 crow and 1 blue jay) counties. The positive mosquitoes were Culex tarsalis species from Brookings County.  

A testing summary follows:

·         Humans:  4 positive cases (Aurora, Davison, Jackson, and Pennington counties), 1165 human WNV tests performed at the State Public Health Laboratory;
 1 positive blood donor (Hand)

·         Birds:  83 negative, 8 positive (Brookings, 2; Clark, 1; Hughes, 2; Minnehaha, 2; and Pennington, 1)

·         Horses:  3 positive (Brookings, Charles Mix and Pennington)

·         Mosquitoes:  12,024 mosquitoes tested, 50 positive Culex tarsalis (Brookings County)

·         Sentinel chickens:  203 tested, all negative (Brookings, Hughes).

“These recent human West Nile cases and animal detections are clear evidence that the virus is now being transmitted in South Dakota,” said Dr. Lon Kightlinger, State Epidemiologist for the department. “We now have WNV positive birds, positive mosquitoes, sick and dead horses, and human cases.  It is now time for South Dakotan’s to protect themselves from mosquitoes.  If people are experiencing severe or unusual headaches they should see their health care provider”  Last year during this week (third week in July) we were just receiving our first reports of human cases in South Dakota. 

The female Culex tarsalis mosquito is the foremost carrier of WNV in North America and it is found all over South Dakota.  Reports indicate that the numbers of this dangerous mosquito are increasing.  In addition to using DEET based mosquito repellents, South Dakotans are encouraged to reduce their risk of West Nile by taking the following precautions:

·        Screen all windows and doors and keep screens in good repair.

·        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. .

·        The elderly and pregnant women should be especially mindful to take precautions.  

A special television broadcast “Mosquitoes and the West Nile Virus” airs Sunday, July 25^th at 2:30 PM/CT or 1:30 PM/MT.  The program highlights scientists from the Centers for Disease Control who are unraveling the diseases evolution and analyzing its future threat.  

For more information about West Nile visit the Department of Health web site at www.state.sd.us/doh/WestNile/ 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 .