In a weekly surveillance report covering the period of August 16 through August 22, 2026, Utah health officials provided updates on arboviral diseases. The data indicates 15 human cases of West Nile virus have been reported in Utah so far in 2026.
Regarding West Nile virus, officials reported 6 positive horse cases across Box Elder, Cache, Duchesne, Morgan, Utah, and Weber counties. No positive bird cases have been reported in Utah during 2026. In terms of mosquito surveillance, 1,050 positive West Nile virus mosquito pools have been identified across several counties, including Davis and Salt Lake.
The report also tracked other mosquito-borne diseases, noting that all cases reported in Utah for 2026 are travel-associated. This includes 7 malaria cases, 5 dengue cases, and 1 chikungunya case. One new dengue case was reported during the week ending August 22, 2026.
Utah health officials noted that while mosquito vectors for malaria and dengue exist in the state, the risk of local transmission remains very low due to small vector numbers. The department continues to conduct year-round surveillance for reportable arboviral diseases.
