Southeast Florida entomologists on watch for West Nile, other mosquito transmitted viruses

West Nile virus and other mosquito-borne illnesses have not taken flight on the Treasure Coast so far this year, but scientists are watching nature to sound an early warning if that situation changes.

"It's actually fairly early (in the season)," said Don Shroyer, medical entomologist for the Indian River Mosquito Control District. "It's usually August through October that we have the most activity here in Florida."

West Nile and the similar St. Louis encephalitis virus cause flu-like symptoms and can cause fatal neurological damage in about 5 percent of cases. Scientists monitor the prevalence of the viruses by testing blood samples of chickens left exposed in mosquito-ridden areas.

So far in 2012, one so-called sentinel chicken has tested positive in Indian River County. That happened in May and was not enough to cause alarm, Shroyer said.

Mosquito control officials in Martin and St. Lucie counties confirm there has been no evidence of the viruses in their areas this year.

"We don't even have many mosquitoes," said Gene Lemire, director of Martin County Mosquito Control. "It's so dry, we just find little, tiny pockets."

Jim David, director of mosquito control in St. Lucie County, said this has been a "relatively light" summer for mosquito breeding in his territory.

Elsewhere in Florida and the U.S., the West Nile virus is causing more concern.

Public health officials in Duval County near Jacksonville have issued a mosquito-borne illness alert, with four human cases confirmed. None were fatal, according to records kept by the federal Centers for Disease Control and Prevention.

However, other states have fared worse. Texas had reported 205 human cases by last week, with three deaths; Mississippi and Louisiana each reported 39 cases with one death; while California had 13 cases with one death.

Oklahoma had no deaths from West Nile virus as of last week. However, one of its 22 human cases was discovered in a resident visiting Jacksonville, Shroyer said.