Arizona Reports Record High West Nile Virus Activity as Case Counts Rise Nationwide

A total of 543 human cases of West Nile virus disease have been reported to the US Centers for Disease Control and Prevention (CDC) in 46 states and the District of Columbia as of September 24, 2019.

Arizona is leading the nation in case counts, with 156 confirmed and probable cases reported as of September 20, 2019, according to the state Department of Health Services. Additionally, 16 fatalities have been reported.

“West Nile virus causes symptoms in about 20% of infected people, which can range from fever, headaches, and body aches, to more serious things like inflammation of the brain or spinal cord in rare cases,” Cara M. Christ, MD, MS, director of the Arizona Department of Health Services, wrote in a blog post last month noting that, typically, the area only sees an average of about 20 cases during the summer months.

“This summer a record high West Nile virus and Saint Louis Encephalitis positive mosquitoes have been reported in the state, particularly in Maricopa County,” Christ continued. “The increase is likely due to the wetter conditions that Arizona has experienced during the last winter.”

Elsewhere, Ohio reported its first West Nile virus human case and death of the year last week. The Lucas County Health Department confirmed the death of a 68-year-old man who had been hospitalized with encephalitis, Toledo’s WTVG reported.

"It only takes 1 bite. That is the saddest thing about mosquito-borne disease is it only takes 1 bite," Paul Bauman, a biologist and general manager for the Toledo Area Sanitary District, told the local station.

In 2018 there were 2544 reported cases of West Nile virus in the United States, a slight uptick from the case counts reported in the previous 5 summer seasons. The last time the United States saw more cases was in 2012 when there were 5674 cases reported. According to CDC, West Nile virus is now the leading cause of mosquito-borne disease in the continental United States

To prevent mosquito bites, the CDC recommends the use of Environmental Protection Agency-registered insect repellents with active ingredients including DEET, picaridin, IR3535, lemon eucalyptus oil, para-methane-diol, or 2-undecanone. For babies younger than 2 months of age, insect repellent is not recommended, and infants should instead be dressed in clothing that covers their arms and legs. Strollers and baby carriers should be covered with mosquito netting, particularly during the hours of dusk and dawn when mosquitos are most active.