West Nile Deaths Still Occurring as Season Enters its Final Weeks

With September here, the United States enters the last weeks of West Nile virus season; however, as states continue to report new cases and deaths associated with the virus, it is clear that the season is not over yet.

As of August 29, 2017, the Centers for Disease Control and Prevention (CDC) has reported 450 human cases of West Nile virus in 45 states this year. Neuroinvasive disease, such as meningitis or encephalitis, has accounted for 269 of those cases; 181 cases were non-neuroinvasive. West Nile cases in the United States typically begin to occur in the summer, during mosquito season, as the virus spreads via bites from infected mosquitoes, and continue to occur through early fall.

On August 31, 2017, the South Carolina Department of Health and Environmental Control reported the state’s first West Nile death of this year, an Anderson County resident. Health officials in South Carolina have seen 7 human West Nile cases — along with 10 birds and 55 mosquitoes testing positive for the virus – so far this season. South Carolina saw its highest number of human cases of West Nile in 2012 when it reported 29 cases; in 2015, the state did not report any human cases. The state’s health department emphasizes that while serious illness and death due to West Nile are rare, and up to 80% of individuals who are infected with the virus do not even present with any symptoms, it’s important to wear insect repellant to avoid mosquito bites.

"If you develop fever or other symptoms after being bitten by a mosquito, you should contact your health care provider," South Carolina state epidemiologist Melissa Overman, DO, MPH, reportedly said in a recent press release.

Meanwhile, the California Department of Public Health (CDPH) announced 3 confirmed West Nile deaths on September 1; occurring in Kern, Los Angeles, and San Berdardino counties, these are the first deaths caused by the virus this year in California. To date, California has seen 87 human cases of West Nile in 13 counties so far this year, as well as 264 birds and 2,545 mosquito samples that have tested positive for the virus. One local news report noted that the victim in Los Angeles County had been hospitalized in early August and died from neuroinvasive disease, a severe symptom associated with the virus. Los Angeles County has seen 46 human cases of West Nile thus far this season, down from 2016, when they reported 153 human cases.

"West Nile virus can cause a deadly infection in humans, and the elderly are particularly susceptible," CDPH director Karen Smith, MD, MPH, said in a recent statement. "August and September are peak periods of West Nile virus transmission in the state so we urge everyone to take every possible precaution to protect themselves against mosquito bites."

In addition, on September 1, the Georgia Department of Public Health confirmed 20 human cases of West Nile and 3 deaths so far this season. These numbers are up since last year, as the state only saw 7 human cases of West Nile and no deaths. With several weeks remaining in the 2017 West Nile season, health officials are reminding individuals that the best way to avoid falling ill is to avoid and manage mosquitoes.

“Georgians can reduce the number of mosquitoes around their homes and yards by getting rid of standing water,” said the state’s director of environmental health, Chris Rustin, PhD, DPH, in a press release. “Standing water is a breeding ground for mosquitoes that may be infected with West Nile virus and other mosquito-borne diseases.”