Earlier this week, the Shelby County Health Department reported the first West Nile virus-infected mosquitoes were found in the 38126 zip code, which encompasses the southern part of downtown.
But despite fears that last month's flooding would lead to more potentially-infected mosquitoes, Dan Springer of Shelby County Vector Control said the first West Nile identified likely had nothing to do with the flooding.
"The event of the flooding is too far in the past," Springer said. "A mosquito only lives for a week or two."
In fact, Springer said the massive flooding event may have worked against mosquitoes this year. Mosquitoes typically lay eggs just below the water line of a small temporary water source, like a puddle. The puddle evaporates, and on the next successive rain event, the eggs will hatch.
"When there's flooding, it goes over those habitats, and they're not accessible for mosquitoes to lay their eggs anymore," Springer said. "The water was already high back in March when the first mosquito eggs hatched, so the floodplains were flooded at that time. We didn't generate mosquitoes."
So far, this has resulted in lower numbers of mosquitoes than usual. Springer said numbers are lower than in 2009, when the city had its last high water event.
As for West Nile, Springer said it's been detected in Shelby County every year since 2002, but the detection came later than usual this year. No humans have been infected. Those cases are more likely to begin showing up in August. The West Nile outbreak is expected to last through October, and Vector Control is focusing on truck-spraying zip code 38126 and surrounding areas this week. Vector Control has been larviciding every area in the county.
"The mosquito that spreads the West Nile virus is only active at night, and it primarily takes blood from birds," Springer said. "It rarely bites people, but those who sit outdoors at night and don't wear repellent and turn lights on right next to them are more prone to be bitten."
To combat both infected and non-infected mosquitoes, the health department gives away free Gambusia fish, known to eat mosquitoes, for ornamental outdoor ponds.
"We collect them in ditches and sloughs, and they're wonderful," Springer said. "They're a little minnow, and they love to eat mosquito larvae."
Contact Vector Control at 901-324-5547 to request free fish or to request NOT to have the area in front of your home sprayed by mosquito trucks.