HOUMA -- Though it’s the height of mosquito season, state health officials say there are still no new human infections of the West Nile virus in Louisiana.

AP

Mosquitoes can carry the disease.

There have several reports of possible infections around the state, including some in Terrebonne and Lafourche, but none have been confirmed as new cases, said State Epidemiologist Dr. Raoult Ratard.

When someone is infected, the body’s immune system will create two kinds of antibodies to neutralize the disease, Ratard said. One stays in the body for only a year, and another is in the body for a lifetime.

For this reason, some people who come down with a flu or another illness can go to the doctor and still test positive for the West Nile virus. State labs always double-check the antibodies before declaring a positive West Nile test as a new infection.

So far, the state has seen several of these cases this year but no new infections.

Usually the first cases of West Nile infection in humans are reported at the beginning of July each year. Before now, the longest a season had gone without a human case was July 15.

In 2006, Louisiana had 202 cases of West Nile virus and nine deaths.

"There hasn’t been much West Nile this year," Ratard said. "So far, all the cases we had this year look like they were cases from two or three years ago. But it may pick up."

The virus is carried by birds, so it is nearly impossible to track and contain, said Steve Pavlovich, an entomologist with Mosquito Control Inc., the company charged with protecting both Terrebonne and Lafourche parishes from the disease-carrying bugs.

"You really can’t stop the virus from coming in," he said. "It comes in with birds and mosquitoes that are feeding on these birds."

The disease attacks the lining of the brain, causing early symptoms like headaches and blurred vision.

"If it starts attacking the brain, you might not feel awake, your speech will be impaired, you could have funny feelings in your arms and legs, or they might start to go to sleep," Ratard said.

Meanwhile, there have been mosquitoes infected with the West Nile virus found in the area, and Mosquito Control Inc. has stepped up its control efforts in response, Terrebonne Parish’s public-works director, Al Levron, said.

Mosquito Control’s work goes far beyond simple spraying, Levron said. The company conducts a carefully scouted battle against the heavy mosquito population annually, laying traps to catch live mosquitoes to test for disease and scout population numbers.

Entomologists with Mosquito Control also collect and test dead birds for signs of the virus.

The company even keeps strategically located chickens around the two parishes to act as disease "sentinels." Chickens, Pavlovich said, are ideal for this job because they carry West Nile but don’t die from it.

"It’s all based on some level of science," Levron said. "This isn’t just some guy in a truck spraying once a month."

The company uses a variety of different methods to control mosquitoes, including applying chemicals to standing water in ditches, a process that prevents mosquito larvae from developing into fully grown bugs.

Workers also use biological controls if possible, planting a species of minnow called "mosquito fish," for its hunger for the insect, that can consume a lot of larvae in ponds filled with standing water.

A fleet of chemical-control vehicles pick up service when populations mount, including truck-mounted sprayers, four-wheelers, handheld foggers, and even a plane when the mosquito problem is widespread enough, Levron said.

"We have 64-plus different varieties of mosquitoes in Louisiana," Pavlovich said. "We are concerned about 15 or more, depending on whether you’re thinking about spreading disease or just being a general nuisance."

The company targets mainly breeding sites, and Pavlovich said most disease-carrying mosquitoes tend to breed close to home, in standing water in yards and around homes.

When diseased bugs or animals are found in a certain community, Pavlovich said he will send crews out to homes to conduct on-site inspects for standing water and possible mosquito-breeding sites.

"Our crews will go out in that area and pass out pamphlets and notify people that there are positive mosquitoes in that area," he said. "We try to warn people for things that might be of concern, like birdbaths or kiddie pools. We point those out to the homeowner and let them know."

Follow-up testing is done in the weeks after to find out if diseased mosquitoes remain in the area.

Though West Nile hasn’t popped up yet, Pavlovich added that keeping it that way is up to local residents.

"This is a communitywide effort, not just in the hands of mosquito control," he said.