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St. Louis Encephalitis Virus – Tests Positive


Last updated 8/13/2015 at 9:39am

Six Coachella Valley mosquito samples have tested positive for the St. Louis Encephalitis virus.

Although once common across the region, no samples had been discovered in California since 2003, when the West Nile virus became common place.

Officials are now investigating how it has returned. "We don't really know why the virus has reappeared, but we do know its detection this year has been a trend in other parts of the country as well," Jeremy Wittie, district scientific operations manager, said in a statement.

It was first detected in 1933 during a "large urban outbreak" in St. Louis, before spreading throughout the western hemisphere and it was the only neuroinvasive mosquito-borne flavivirus in North America until the West Nile virus appeared in 1999.

Eighty samples have tested positive for West Nile this year in the Coachella Valley. That's the highest number to be detected by this time of year.

Both viruses are transmitted to humans via mosquitoes and symptoms are similar. They include fever, headache, nausea, vomiting and exhaustion.

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