Hantavirus risk from rodents may be higher in Pacific Northwest

Key Points:

• A study from Washington State University found that nearly 30% of rodents in the Palouse region of Washington and Idaho have been infected with Sin Nombre virus (SNV), a hantavirus strain that can cause deadly respiratory disease in humans, which is a higher rate than previously believed.
• About 10% of these rodents were actively infected and capable of shedding the virus, with evidence suggesting possible transmission between different rodent species such as deer mice, voles, and chipmunks.
• SNV, the most common hantavirus strain in the U.S., infects humans primarily through exposure to contaminated rodent droppings or urine, unlike the Andes strain which can spread between people; SNV has caused at least 864 cases since 1993 with a 36% fatality rate.
• Despite the high prevalence of SNV in rodents, human infections remain rare, indicating some cases may go undetected, especially in the Pacific Northwest where data has been limited until now.
• The study was published in the CDC’s Emerging Infectious Diseases journal and involved fieldwork conducted in summer 2023 across farms and natural areas in Washington and Idaho.