- West Nile virus: 30,062 cases in the U.S. since 1999.
- 1,247 fatal cases.
- Mosquitoes the world's No. 1 vector for disease transmission.
In 1999, a Madison, Miss., boy laid bed-ridden for more than two weeks, and breathing treatments, inhalers and bronchitis medication all failed to treat his mysterious flu-like symptoms and high fever.
“It was just a total energy drain,” said Joe Short, the once-sick junior high student who graduated from Mississippi State University last spring with a degree in marketing.
No one knew the origin of Short’s sickness until years later, when he tested positive for West Nile virus antibodies. This mosquito-spread disease hit the United States the same year Short fell ill.
According to the Centers for Disease Control and Prevention, since 1999 the United States has had 30,062 cases of West Nile virus. Of those, 1,247 were fatal. Mississippi has had 842 cases, including 48 fatalities.
West Nile virus and malaria cases together make mosquitoes the world’s No. 1 vectors for disease transmission.
After Hurricane Katrina, coastal states became prime mosquito breeding grounds, creating the possibility for a spike in West Nile cases and associated deaths.
“After the hurricane, planes were sent out to spray mosquitoes,” said Dr. Kristine Edwards, a Mississippi Agricultural and Forestry Experiment Station post-doctoral associate and a veterinarian. “That’s like a wartime situation. Obviously, it’s a last resort.”
As a precautionary measure, the U.S. congress earmarked a sizeable grant to enhance mosquito control in states most vulnerable to post-Katrina mosquito infestation — Mississippi, Louisiana, Alabama and Texas. Mississippi received $2.8 million.
The Mississippi Department of Health issued a request for proposals to all 49 counties declared disaster areas following Katrina. Oktibbeha County, home of Mississippi State University, was one of the northernmost counties included.
Before distributing any money, the MDH held mosquito-education workshops throughout the state. The state agency conducted pre- and post-grant surveys designed to gauge practices, knowledge and attitudes of local personnel in mosquito control programs before and after disbursement of funds.
Edwards and associate MSU Extension professor Jerome Goddard, both in the university’s department of entomology and plant pathology, conducted research based on survey responses.
The workshops stressed that mosquito control efforts should follow a hierarchy, and the use of spray trucks should be a low-priority option, said Edwards.
Educating the general public on how to protect themselves has always been the most important way to control mosquitoes. Source reduction, or removing breeding grounds such as standing water in old tires and water containers, comes next. Destroying mosquito larvae in standing water is third.
The final solution, which Edwards said is too often the first approach taken, is killing adult insects. This is done with slow-rolling trucks equipped with $8,000 bug sprayers rumbling down neighborhood streets.
Edwards said that before 2007, many Mississippi communities had their mosquito control priorities reversed.
“You usually see the trucks go first, but all that does is kill adult mosquitoes. By then it’s usually too late,” Edwards said. “How can you kill all the mosquitoes out there, especially if they continue to breed?”
Mosquito control in Starkville, Miss., was just one of many examples of Mississippi’s well-intended, but sometimes misguided mosquito control tactics.
“Before funds were awarded to Oktibbeha County, Starkville, like many other communities, often employed routine, scheduled truck sprays based loosely on complaints of increased mosquito activity,” said Joseph Goddard, Starkville’s pest control expert.
Goddard helped Starkville design an extensive, well-planned mosquito control program called integrated pest management.
Goddard’s techniques follow the guidelines outlined in the Mississippi State study.
“The program combines three techniques to tackle the population: surveying to find which ditches have mosquitoes; larvaciding to kill larvae in standing water; and adulticiding to kill adult mosquitoes,” he said. “We spray only when and where necessary.”
The program also funds adult mosquito trapping, which captures seven to 10 mosquitoes on a typical night. When the count swells to 50 to 100 specimens, usually a week after a good rain, Goddard knows it’s time to spray.
Edwards said simple tactics like surveying and trapping can save local government time and effort.
“You have to know where to put the effort, especially when funds are limited,” Edwards said.
According to the MDH survey distributed a year after the grant was implemented, other programs like Starkville’s can now be found in several counties across the state. Most notably, 60 percent of personnel in various programs reported an increase in larvaciding because of the grant and the educational workshops. A similar number increased source reduction efforts and a majority began surveying for mosquito larvae.
However, several areas of mosquito control still need further attention. Only 3 percent of participants used adult mosquito trapping and only 11 percent dipped for larvae before treating sites.
“Mississippi has very small towns, and they have to do a lot with limited resources. In sparsely populated regions with limited funds, everyone is doing what they can to help,” said Edwards. “In two cases, we found that the mayor was in charge of the mosquito control program.”
Whatever the case, both Edwards and Goddard said that education is the best way to prevent disease.