The Shelby County Health Department (SCHD), along with the Tennessee Department of Health (TDH), recently confirmed the first human case of West Nile Virus (WNV) in Shelby County. The reported case is also the first human case confirmed in the state of Tennessee.


At this time, WNV has not been detected in any ZIP codes within Shelby County using trap collections and state testing. With this confirmed human case, however, WNV is present, and SCHD health officials urge residents to take extra precautions to prevent mosquito bites and protect themselves against WNV.

Due to the unseasonably warm winter temperatures, the SCHD Vector Control Program began treating areas within all ZIP codes by applying larvicides to standing bodies of water in February. These actions, which will continue until the first frost of the year, are consistent with its efforts to be proactive in decreasing the adult mosquito population. Larviciding is the practice of applying an Environmental Protection Agency (EPA)-registered insecticide to areas where mosquito breeding has been confirmed and is the most effective way of eliminating mosquito populations.

As an additional precaution, SCHD will conduct scheduled truck-mounted sprayings of EPA-approved inseciticides, weather permitting, in specific ZIP codes once the presence of WNV has been confirmed. Truck-mounted spraying only effectively kills adult mosquitoes currently flying at the time the insecticide is released.

Mosquito populations are often at their peak between May and October. With no human vaccine for WNV, individuals are strongly encouraged to be vigilant when controlling mosquito populations around their homes and businesses. Eliminating the potential for standing water to accumulate around homes and businesses is one of the most effective ways to help reduce the mosquito burden.

Everyone is encouraged to practice the 4 D’s:

  • DEFEND yourself by using insect repellent with DEET. Follow label instructions.
  • DRESS in long sleeves and pants. Wear loose and light colored clothing when outdoors.
  • DUSK/DAWN is the time when mosquitoes are most active. Stay indoors.
  • DRAIN standing water and install or repair window screens.

Humans can become infected with WNV through the bite of an infected mosquito. Although the virus can occasionally cause severe disease, most human infections are mild, resulting in fever, headache and body aches lasting only a few days. Symptoms of severe disease include a high fever, neck stiffness, stupor, disorientation, coma or convulsions. Persons over age 50 and those with compromised immune systems are at higher risk of severe disease. They should be especially careful to avoid mosquito bites.

In 2016, there were six confirmed human cases of WNV statewide, two of those in Shelby County. One of the total confirmed cases ultimately resulted in death.