Arboviral diseases, including West Nile virus, were reported from nearly every state in 2019, according to the Centers for Disease Control and Prevention (CDC) in its Morbidity and Mortality Weekly Report. Arboviruses (viruses spread by arthropods like mosquitoes or ticks) cause severe illness in the United States each year.
In 2019, there were more than 1,000 reported cases of domestic arboviral diseases, 83% of which were caused by West Nile virus. The incidence of West Nile virus disease was 53% lower in 2019 than the median annual incidence during 2009-2018. The 971 cases of West Nile virus were reported from 285 counties in 43 states and Washington, DC
Notable trends in 2019 include an increase in the number of reported Powassan and eastern equine encephalitis virus disease cases, which were higher than any other previous year.
The CDC said healthcare providers should consider arboviral infections in patients with aseptic meningitis or encephalitis, perform recommended diagnostic testing, and promptly report cases to public health authorities. Surveillance is important to identify outbreaks and guide prevention strategies.
Communities can prevent arboviral diseases by implementing mosquito and tick control measures and screening blood donations. People can take steps to prevent mosquito and tick bites by wearing insect repellent and long-sleeved shirts and pants when outdoors.
