LAFAYETTE — Intense spraying for mosquitoes appears to have reined in a sudden outbreak of West Nile virus in Lafayette Parish, but the virus seems to be lingering.
City-parish officials raised an alarm last week, reporting that tests used to screen for the mosquito-borne virus showed increasing positive results throughout the parish.
Glenn Stokes, owner of Mosquito Control Contractors, said Friday that the number of positive tests has been tapering off, but the virus was identified in three mosquito samples this week from the southern part of the parish and in a dead blue jay.
“We still have some virus, so our work is not finished,” Stokes said.
His company has the contract for mosquito monitoring and spraying in Lafayette Parish.
No human cases of West Nile have been reported in Lafayette this year, but tests used to monitor the presence of the disease in the mosquito and bird populations had identified 18 sites where the virus appeared to be active earlier this month.
The number of positive tests has dropped, a decline that Stokes attributed to twice daily spraying that targeted areas with positive test results for West Nile.
Lafayette Parish monitors the presence of West Nile through the testing of mosquitoes, of dead birds that have fallen victim to the virus and of so-called “sentinel” chickens that are placed in cages outside and regularly subjected to blood screens.
Thirteen out of the parish’s 21 sentinel chickens had tested positive earlier this month for West Nile — five last week and eight the week before, Stokes said.
But the most recent tests results received Friday from the LSU School of Veterinary Medicine were negative for all 21 birds, Stokes said.
Positive tests for West Nile in mosquitoes that are collected in traps have also fallen, as well as the total number of mosquitoes, Stokes said.
But he said tests this week indicate there are still some problem areas, though none within the city limits of Lafayette.
“We will have plenty of trucks out all weekend,” he said.
City-parish Emergency Operations and Security Coordinator Mike Mouton, who oversees the mosquito control program, said there are no plans to move forward with aerial mosquito spraying at this time.
“It looks like we are getting control and the numbers are going down,” he said.
Mouton didn’t rule out an aggressive aerial attack later this year, especially in the event of post-hurricane mosquito explosion.
“We’ll just have to play it by ear and see,” he said. “It’s looking better.”
Stokes cautioned that the peak of the mosquito season, August, is yet to come.
Dr. Raoult Ratard, the state epidemiologist, said in an interview earlier this week that he did not expect this year to be particularly bad for West Nile virus, mainly because an unusually cool spring gave the mosquito season a slow start.
But Ratard also said such predictions are difficult to make with certainty.
City-parish government has advised residents to continue to take precautions, such as using insect repellent; wearing loose fitting, light-colored long pants and long-sleeved shirts; and avoiding the outdoors at dawn and dusk.
Residents are also asked to try to reduce mosquito breeding grounds by emptying water in boats, tarps and other areas.
West Nile virus 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 U.S. Centers for Disease Control and Prevention.
The virus has no obvious effect on 70 percent to 80 percent of people infected, according to the CDC.
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