Rainfall is a double-edged sword for Louisiana - KNOE 8 News; KNOE-TV; KNOE.com |

MONROE, La., (KNOE 8 News) - The much-needed rain which hit Louisiana this week may be helping with our drought conditions, but it's also providing an environment which increases mosquito populations. And that increases the likelihood of more cases of West Nile virus.

For the past few weeks the number of West Nile virus cases has risen to numbers not seen in recent years, and standing water seems to be the main reason, according to LSU AgCenter entomologist Tim Schowalter.

"Female mosquitoes require standing water to lay their eggs. And if we can deny this, there is a better chance of keeping their numbers low," Schowalter said. When standing water is available near the home, the mosquito has all it needs to reproduce.

"She has to have a blood meal or she will die before laying her eggs. But if humans or other animals are around, and the standing water is available, the conditions are favorable for the increase in populations that we've seen recently," he said.

It normally takes about two weeks for mosquitoes to go through their breeding cycle in standing water. Then they become the biting pests that are both feared and hated.

Schowalter said the recent statewide mosquito count shows that about one percent of the mosquitoes tested were positive for the virus.

If there's good news in all this, it is that of the nearly 70 species of mosquitoes found in Louisiana, there are only about 10 that people have to worry about, Schowalter said. 

Louisiana saw its first outbreak of the West Nile virus in 2002. Since that time, LSU AgCenter scientists have been looking for ways to keep mosquito numbers down and have enlisted the public's help in the process, Schowalter said. 

Some good news in all this, is that the disease does not cause most people to become seriously ill. However, Schowalter point out that "People over 50 years of age or with impaired immune systems are most likely to develop serious illness from the disease."

Symptoms occur three to 15 days after the initial infection and can range in mild cases from slight fever to headaches to extreme cases that can result in paralysis or death.   

There are a number of things that can be done around the home to reduce the mosquito population, including: 

• Removing containers that hold standing water, such as old tires and other debris.

• Emptying flower pots and other yard and patio containers.

• Drain fountains, ornamental ponds and swimming pools no longer being properly maintained or treat with Bt discs, which contains a bacterial pathogen of mosquito larvae.

• Fill low-lying areas to avoid standing water.

• Provide drainage ditches to promote rapid runoff of rainwater.