A deadly hantavirus outbreak aboard a cruise ship in the Atlantic has raised new questions about how the rare, rodent-borne disease may have spread. The outbreak has left at least three people dead with five additional suspected cases, as the World Health Organization investigates.
Although hantavirus is usually transmitted through contact with infected rodent droppings, experts say the close quarters of the vessel could have amplified the risk.
Dr. Carrie Horn, chief medical officer at National Jewish Health in Colorado, explained that the virus is typically found in rodent saliva, urine and feces, becoming airborne near contaminated surfaces. Unlike COVID-19, person-to-person transmission is very unlikely. The virus most often becomes airborne when a rodent nest is disturbed, such as during cleaning, and is then inhaled into the lungs.
It is technically possible that the virus could be aerosolized through a ventilation system, or that passengers could become infected if they attempted to clean up a rodent infestation, though the risk is low. Another possibility is that exposure occurred off the ship.
Dr. Jacob Glanville, CEO of Centivax, noted the possibility of infected mice on the ship or human-to-human transmission, particularly if the Andes strain is involved. He cautioned that until a more transmissible strain is ruled out, removing passengers from the ship could pose risks of creating a lethal international outbreak.
Historically, hantavirus has been far less transmissible than COVID-19, and the risk to the general public remains very low. However, if any new transmission cases are found from contacts who were not on the ship, the situation would become much more concerning.
Hantavirus can be 30% to 50% lethal, has a long silent incubation period of one to six weeks, and has the potential for droplet transmission. Symptoms begin with fever, muscle aches, fatigue, and headaches, followed by cough, shortness of breath, and fluid buildup in the lungs. In severe cases, it can lead to respiratory failure and death.
Experts advise avoiding areas where rodents may be present, particularly dusty or enclosed spaces with signs of infestation. If cleaning such areas, wearing a filtered mask can help reduce risk. Travelers should also avoid contact with rodents and contaminated materials, while taking basic precautions like handwashing and disinfecting surfaces.
This is a very unusual situation, and hantavirus poses a very low risk to the general public, especially for those not on the affected ship.