90-Second Read: High prevalence of Hantavirus in some areas of the Pacific Northwest

The Sin Nombre virus, a Hantavirus that can cause a deadly respiratory disease in humans, may be more widespread among rodent populations in parts of the Pacific Northwest than previously recognized. Hantavirus has been in the headlines because of an outbreak of Andes virus on a cruise ship. While rare, Andes virus, which is found in South America and is a different species than SNV, is the only Hantavirus known to spread between people. The study, which was led by researchers in Washington State University's College of Veterinary Medicine, was published in the Emerging Infectious Diseases journal.

A total of 109 of those cases occurred in Idaho, Oregon, and Washington. Sweeping or using equipment like leaf blowers in enclosed areas can be particularly hazardous. Field work for the study was done in the summer of 2023 when researchers trapped rodents across farms and natural areas in Whitman County, Washington, and Latah and Benewah counties in Idaho. A recent study conducted in the Palouse region of Washington and Idaho found that nearly 30% of rodents showed evidence of past infection with the virus.

Rodents can spread the virus among themselves through saliva and direct contact, but human infections typically occur when people inhale airborne particles from contaminated rodent droppings, urine, or nesting materials. Instead, health officials recommend ventilating spaces and using wet-cleaning methods to reduce the risk of inhalation. The information can help public health officials and scientists track how the virus evolves in the future, in addition to assisting in identifying sources of infection and improving surveillance and testing. Despite the relatively high prevalence of the virus in rodents, reports of human infections remain rare, which could indicate some infections are going unnoticed.

The researchers also used the samples to produce the first full genome sequences of SNV strains from the Northwest. DOI: 10.3201/eid3205.251476 Journal information: Emerging Infectious Diseases MA in English, copy editor since 2021 with experience in higher education and health content. In total, samples were collected from 189 animals, including deer mice, voles, and chipmunks.