Mosquito control efforts increased

West Nile tests show sudden outbreak

West Nile virus
West Nile virus

Lafayette city-parish government is intensifying mosquito control efforts and considering aerial spraying to fight a sudden outbreak of the mosquito-borne West Nile virus.

Tests used to monitor the presence of the virus have shown increasing positive results throughout the parish this month, said city-parish Emergency Operations and Security Coordinator Mike Mouton, who oversees the mosquito control program.

“I’ve been doing this for years, and I’ve never seen this many positives at one time,” Mouton said. “It is in the last two weeks that it started building like this.”

Last year was an unusually active West Nile season that saw 397 reported infections and 21 deaths, but no human cases have been reported this year in Lafayette Parish or anywhere else in Louisiana, according to the state Department of Health and Hospitals.

Despite the lack of human cases, the presence of the disease can be measured by testing mosquitoes and birds — either dead birds that have fallen victim to the virus or so-called “sentinel” chickens that are placed in cages outside and regularly bled to screen for West Nile.

Lafayette tests mosquitoes, dead birds and chickens, and there have been 18 sites in Lafayette Parish that tested positive for West Nile by at least one of those methods since July 5, according to figures from Mouton.

“We started getting positive cases all over the parish, and that’s unusual,” he said.

Mosquito Control Contractors, which has the contract for mosquito control in Lafayette Parish, has begun testing more and doing focused spraying in areas with positive tests, Mouton said.

He said aerial spraying will be considered if the ground strategy proves ineffective.

“By Friday, we will know if what we are doing is working,” Mouton said.

The sudden outbreak seems all the more unusual to him, Mouton said, because testing has not showed an abnormally large number of mosquitoes.

“The mosquito population is not really heavy. It’s just the ones that are here are infected,” he said.

West Nile virus generally appears earlier in the season in Louisiana, but the onset has been delayed largely because of the unusually cool spring this year, said Dr. Raoult Ratard, the state epidemiologist.

Even considering the recent positive test results in Lafayette, Ratard said the virus is not expected to be a major problem for the state this year.

“More than likely, it’s not going to be a very serious year,” he said. “Of course it is difficult to predict.”

Still, he and other public health officials said residents should take precautions, which include using insect repellent; wearing loose fitting, light-colored long pants and long-sleeved shirts; and avoiding the outdoors at dawn and dusk.

City-parish government also has asked residents to empty standing water in boats, tarps, toy wagons and other areas that could serve as breeding grounds for mosquitoes.

Residents should take action and not let the increased mosquito spraying lead to complacency, said Dr. Tina Stefanski, the regional director for the state Office of Public Health.

“They can still not eliminate every mosquito in the parish,” she said.

West Nile virus has no obvious effect on 70 percent to 80 percent of people infected, but the disease can bring on fever and other flu-like symptoms in about 20 percent of those infected and, in a small number of worst-case scenarios, lead to severe illnesses that can cause death or long-term health problems, according to the Centers for Disease Control and Prevention.