Marshall County and South Dakota residents have been bracing for a second round of West Nile Virus (WNV) cases this summer, and seven cases have now been reported around the state in 2004.
The Department of Health announced Tuesday that there have been three more human WNV cases, one blood donor detection, two positive mosquito pools, and one positive bird.
Human cases were detected in Beadle, McCook, Charles Mix, and Minnehaha Counties. The positive bird finding was in Brown County, and the blood donor and mosquito pools in Minnehaha. Last week two more human WNV cases were
confirmed in Aurora and Davison Counties.
All five of the victims of the past two weeks have West Nile Fever - a flu-like illness with fever, headache, muscle weakness, possible rash, swollen lymph glands, and muscle aches. Four of the victims have been in the 40-60 age group, while one was in the 70-79 age category. Earlier cases were confirmed in Jackson and Pennington Counties, along with one positive blood donor in Hand County.
WNV is a mosquito-borne virus that primarily affects birds and horses. In humans the infection can range from a mild flu-like illness to encephalitis that causes swelling in the brain and can lead to death.
The virus first showed up in Marshall County in 2002. A number of horses died that year, but there were no human cases reported. That changed dramatically last summer when 20 residents were infected with WNV, ranking Marshall County 12th among the state's 66 counties in number of cases.
There were 1,041 human cases in the state last year and 14 people died. A total of 6,000 people were infected nationally with 119 recorded deaths.
Last year the state began receiving the first reports of human WNV cases during the third week of July, and this year seems to be following a similar pattern. Expectations are for a similar epidemic in 2004.
"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 of Health. "We now have WNV positive birds, positive mosquitoes, sick and dead horses, and human cases. It is now time for South Dakotans to protect themselves from mosquitoes, and if people are experiencing severe or unusual headaches they should
see their health provider.
Towns around the county have been on the offensive since early this summer. Communities received some grant money from the state to help in spraying efforts and have been attempting to curb mosquito populations.
Britton maintenance foreman Randy Hedge said plans called for spraying the city last night, Tuesday. He also hopes to spray again on Friday night or Saturday morning if weather permits. Hedge said the city has sprayed for the pests about seven times already this summer.
Langford city foreman Blair Healy said efforts seem to be paying dividends in the Langford area. He has sprayed six times in Langford and five times in the Roslyn and Pierpont areas. Eden has been using a backpack unit to control the insects, and Veblen has done city spraying as well.
"It seems like it's been working," said Healy. "The numbers of mosquitoes we've had in the traps have been low."
The female Culex tarsalis mosquito is the foremost carrier of WNV in North American, 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 repellent, residents 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; and the elderly and pregnant women should be especially mindful to take precautions.
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.
