RIDOH Announces First Human Case of West Nile Virus in 2026 WNV risk level has been lowered due to seasonally low mosquito populations

Published on Thursday, October 08, 2026

The Rhode Island Department of Health (RIDOH) and the Department of Environmental Management (DEM) are announcing the State’s first case of West Nile Virus (WNV) in 2026.

The case is a Washington County resident in their 60s who had symptom onset in early September. This person has been recovering in the hospital and is expected to be released soon. The positive WNV testing was confirmed last week at the Centers for Disease Control and Prevention (CDC).

The individual had a history of travel to an area with active WNV transmission. Based on the travel history, it is likely that the infection was acquired outside of Rhode Island.

Due to seasonally low mosquito populations, the risk of mosquito-borne disease has significantly decreased and the statewide risk level for WNV is low. However, until the entire State experiences a true hard frost (defined as three consecutive hours below 32 degrees), which kills adult mosquitoes, a low risk of mosquito-borne disease remains.

WNV is the leading cause of mosquito-borne disease in the continental United States and is much more prevalent than Eastern equine encephalitis (EEE) virus. Cases of WNV occur during mosquito season, which starts in the summer and continues through fall. There are no vaccines to prevent or medications to treat WNV in people. Fortunately, most people infected with WNV do not feel sick. About one in five people who are infected develop a fever and other symptoms. About one out of 150 infected people develop a serious, sometimes fatal, illness. For more information about WNV, visit health.ri.gov/wnv.

Although extremely rare in humans, EEE virus is very serious and has a much higher human mortality rate than WNV. Approximately 30% of people with EEE virus die, and many survivors have ongoing neurological problems. Unlike WNV, which is prevalent in Rhode Island every year, EEE virus risk is variable, changing from year to year. There have been no human or mosquito findings of EEE in Rhode Island this year. For more information on EEE virus and ways to prevent it, visit health.ri.gov/eee.

Mosquito trapping and testing have concluded for the 2026 mosquito season. Check RIDOH's arboviral surveillance data webpage for the mosquito trapping and testing totals for the 2026 season. Visit health.ri.gov/mosquito for additional mosquito prevention tips, videos, and local data.