Berkeley mosquito eggs being tested

September 09, 1997


Staff Writer, Martinsburg

MARTINSBURG, W.Va. - Although no cases of LaCrosse encephalitis have been reported in the Eastern Panhandle, the Berkeley County Health Department recently assisted the Centers for Disease Control in a project to determine if the virus is present here.

Twila Carr, an environmental health supervisor with the county health department, said mosquito egg traps were set in two wooded areas of the county on Aug. 19. The 20 traps were collected a week later and sent on to the CDC.

"It won't be done for months," Dr. Roger Nasci of the CDC's Arbovirus Diseases Branch said of the testing program. The eggs will have to be hatched and then raised to adulthood. The species of the mosquitoes will then be determined to see if any treehole mosquitoes are among them.


"We know the mosquito is in Berkeley County. We want to find out if the virus is there as well," Nasci said. While the treehole mosquito seems to favor maple and beech trees, it can be found in a number of other wooded environments.

The treehole mosquito picks up the disease from squirrels or chipmunks and transfers it to humans. LaCrosse encephalitis does not affect the majority of those who are bitten, but it can produce symptoms such as fever, headache and nausea in some people, Nasci explained.

For about 10 percent of those who show symptoms, the effects can be severe. Nasci said symptoms can include seizures, disorientation and coma. About one percent of the clinical cases die, he added.

Nasci said children appear to be more susceptible to the virus than adults.

West Virginia has more LaCrosse encephalitis cases than any other state, although between 1987 and last year, all of the cases occurred in 16 counties in the southern portion of the state. The highest number of cases was in Nicholas County, according to Carr.

Last summer the CDC tested a dozen sites in that county and confirmed the virus in all 12. This summer the testing included 30 counties, seven of which reported the disease over the past decade.

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