90-Second Read: Hantavirus is gaining ground in the US, startling researchers: ‘Widespread and complex virus’

As passengers from the Hantavirus-stricken cruise ship are being monitored, unusually high levels of the virus have been detected in rodents in the US. SNV is the strain most strongly linked to Hantavirus pulmonary syndrome (HPS), the more common form in the US. The findings also suggest the need for expanded Hantavirus monitoring in agricultural areas of the Pacific Northwest, as well as how often people are exposed and how human behavior influences risk. Researchers found that a significant portion of rodents in the Pacific Northwest were carrying the Sin Nombre virus (SNV).

Published in the Emerging Infectious Diseases journal, researchers from Washington State University's College of Veterinary Medicine collected samples from 189 deer mice, voles and chipmunks in summer 2023. SNV has remained rare since it was first identified back in 1993 in the Four Corners region of the US, with 864 cases reported between 1993 and 2022. A total of 109 of those cases occurred in Idaho, Oregon and Washington. Instead, it typically transfers to humans through inhalation of aerosolized rodent urine, droppings or saliva.

Nearly 30% of rodents from both farm and forest settings showed evidence of past infection with the virus and 10% had active infections. The condition can cause flu-like symptoms that quickly progress to breathing difficulties and significantly damage lung tissue, leading to fluid accumulation in the lungs and serious lung and heart problems. This research helps to better understand how the virus spreads throughout a region and offers precautions, according to experts. Sweeping or using a leaf blower can disturb rodent droppings and increase the risk of exposure by sending virus particles into the air.