BATON ROUGE - Researchers at the LSU Veterinary School's Louisiana Animal Disease Diagnostic Lab are hard at work tracking the spread of viruses like West Nile.

"We are a testing lab where we do the surveillance on mosquito pools to understand how many are positive, where they are located," Lab Director Dr. Alma Roy said.

Mosquito abatement groups send vials filled with anywhere from one to around 100 dead mosquitoes from across the state.

"We test the mosquito pool for the RNA virus, West Nile Triple E, Eastern Equine encephalitis, and St. Louis encephalitis. All three of those are arboviruses or Vector-Borne diseases that are transmitted to humans by mosquitoes," Roy said.

The lab is looking for mosquitoes that test positive for West Nile Virus.

"We look for the viruses by way of a genetic RNA test which is called a Polymerase Chain Reaction. We are strictly looking for the RNA that identifies West Nile," Roy said.

PCR is a technique used to detect the presence of specific pathogens, like viruses, in mosquito samples. RNA from the virus in the mosquitoes is then put on plates in order to be tested.

The plate used has around 384 samples. It then moves to a machine called a Thermocycler, where it will be heated and cooled many times, doubling the amount of DNA each time. If West Nile is present, they'll end up seeing millions of copies of its DNA, signaling a positive test.

"At this point, of the 7,000 that we've tested, we've had 131 mosquito pools in different locations that are positive, but that number's going to go up. By the end of the testing season, we will have tested 30,000 Mosquito pools and we may have up to 500, 600, 700 positive, depending on the year," Roy said.

If tests show a positive case, the mosquito abatement's group of entomologists will be able to identify where the pool of mosquitoes is from and perform sprays in the area.