Dr. Kevin A. Caillouet spoke Nov. 4 at Loyola about the impact of hurricanes on mosquito-transmitted diseases.

The lecture was part of Loyola’s Biological Sciences Research Seminar Series and took place in Monroe Hall.

Caillouet engaged his audience of about 100 people by asking who had ever been bitten by a mosquito. Almost everyone raised their hands.

He continued by explaining that there are over 60 species of mosquitoes found in Louisiana. There are some commonly held beliefs about mosquitoes, however, that are not entirely true, Caillouet said.

He had conducted a study looking at the affects of Hurricane Katrina on the number of reported cases of West Nile Neuroinvasive Disease in the regions of Louisiana and Mississippi the storm directly affected.

West Nile Fever is common, but often presents with flu-like symptoms so not everyone infected visits a doctor. One out of 150 people who have West Nile Fever will develop West Nile Neuroinvasive Disease, which presents with stronger symptoms, Caillouet said.

People who have symptoms of West Nile Neuroinvasive Disease, which can be fatal, almost always visit a doctor, so reporting is good as it is easier to measure, Caillouet said.

Previously, most had found that natural disasters in the continental U.S. have not had large effects on mosquito-transmitted diseases. “One study found that Katrina had no real affect on mosquito borne disease in the states of Louisiana and Mississippi,” Caillouet said.

This study looked at he entire states of Louisiana and Mississippi, though it did not paint an accurate picture of the regions Katrina directly affected, Caillouet said. His study looked specifically at the nine parishes in Lousiaiana and 22 counties in Mississippi over which Katrina moved when it was still a hurricane.

During the three weeks before the storm, there were no reported cases of the disease in the studied regions of either state. During the three weeks after the storm, the studied regions of Louisiana had 11 reported cases and those of Mississippi had 10 reported cases, Caillouet said.

Before the highest rates of this disease were reported in 2002, when it was first introduced to this area; however, 2006 had higher rates, Caillouet said.

Many scientists hold that rates of West Nile Neuroinvasive Disease are sporadic, which would make this point unimportant. The study had other limitations as well, including confounding factors that may have influenced the results, Caillouet said.

If nothing else, “It at least shows that the increase in cases was contemporaneous with the storm,” Caillouet said.

Megan Pitts can be reached at [email protected].