Local officials keep wary eye out for new mosquito-borne virus _lowres

Advocate staff photo by JOHN McCUSKER -- As part of conference this week, scientists who study mosquitos and diseases associated with them took a field trip to the New Orleans Mosquito, Termite & Rodent Control Board offices on Leon C. Simon at the lakefront Wednesday, April 1, 2015. Etymologist Sonja Swiger looks at an exhibit of live toxorhynchites amboinensis specimens. The large mosquito doesn't survive on blood meals like other mosquitos, in fact its diet includes other mosquitos. It is also known as the cannibal or vamprie mosquito.

Hundreds of mosquito control specialists are in town this week for their industry’s annual conference, and much of the buzz has been about chikungunya, a generally nonfatal but debilitating virus that recently saw its first case of local transmission in Florida — the first such instance in the continental United States.

The disease, which has flourished in Brazil and the Caribbean, otherwise has cropped up in the United States only in travelers who have returned home after being infected abroad.

Symptoms last about a week and include a high fever, rash and intense joint pain, though arthritic symptoms can linger for months or years.

“It’s not particularly fatal, but it can be quite debilitating,” said Roger Nasci, of the National Center for Emerging and Zoonotic Infectious Diseases at the federal Centers for Disease Control and Prevention.

The disease is communicable from about two days before symptoms start to show until about five days after the symptoms first appear.

The main focus now is on using public education and mosquito control to make sure chikungunya doesn’t get a toehold beyond the occasional travel case, said Dr. Claudia Riegel, director of the New Orleans Mosquito, Termite and Rodent Control Board.

“One of the things we’ve done is really prepare for the arrival of this virus,” Riegel said. “We don’t want it to even come in, and we’re doing everything we can to keep it out.”

Much of that work is already part of the regimen used to combat other mosquito-borne diseases, such as West Nile virus, and generally to keep the mosquito population at tolerable levels, said Steven Pavlovich, an entomologist with Mosquito Control Services, the company that contracts with Jefferson Parish.

But in the four cases last year in Orleans and Jefferson parishes where a traveler returned with the chikungunya virus, authorities stepped up their efforts in the areas around where the disease was reported.

Riegel said parish officials are given only the street name and block number where the case was reported, but they use that information to increase spraying, test specimens and canvass neighborhoods to get residents to clean up yards, empty containers of standing water and watch for symptoms.

“As soon as we knew, we descended on that … block,” Riegel said.

“We did some extra larval control in the area and looked for containers because the mosquitoes we’re concerned about with this disease are the container breeders,” Pavlovich said.

The New Orleans area has both mosquito species that can transmit the virus — Aedes albopictus, the Asian tiger mosquito, and Aedes aegypti, the yellow fever mosquito.

Riegel said the public education campaign includes increasing awareness among local doctors to help them properly diagnose the disease, as well as alerting travelers on cruises and flights serving the Caribbean. If someone comes home and begins feeling sick, they should get treated immediately.

“What we don’t want you to do is go outside and sit on your porch and potentially infect (local) mosquitoes,” Riegel said.

Nasci said travelers have always carried viruses to new locales, but having the virus establish itself in the Caribbean — which sees millions of U.S. travelers a year — was the game changer.

“It’s really a numbers game, and the odds were changed when the virus became established on our doorstep,” he said.

Still, Nasci said, efforts to lessen the odds of transmission at each step of the chain will mean that outbreaks here will be relatively contained, similar to dengue fever, which also follows a person-mosquito-person chain.

“We haven’t seen big outbreaks of dengue,” he said. “We’ve had some, but they’ve been small and limited. And by getting the mosquito control programs and public health agencies more aware, we can prepare for those events and can prevent them from becoming bigger.”

“That’s why it’s so important for people to look at their yards,” Riegel said. “It seems basic, but it’s so critical because you can miss things. We want people to turn over (and drain) their containers and really pay attention and help us out.”

The 81st annual meeting of the American Mosquito Control Association ends Thursday. This is the sixth time New Orleans has hosted the meeting.

Follow Chad Calder on Twitter, @Chad_Calder.