Causes

Each type of hantavirus has a preferred rodent carrier. The deer mouse is the primary carrier of the virus responsible for most cases of hantavirus pulmonary syndrome in North America. Other hantavirus carriers include the white-tailed mouse, cotton rat and rice rat.

Inhalation: Main route of transmission

Hantaviruses are transmitted to people primarily through the aerosolization of viruses shed in infected rodents' droppings, urine or saliva. Aerosolization occurs when a virus is kicked up into the air, making it easy for you to inhale. For example, a broom used to clean up mouse droppings in an attic may nudge into the air tiny particles of feces containing hantaviruses, which you can then easily inhale.

After you inhale hantaviruses, they reach your lungs and begin to invade tiny blood vessels called capillaries, eventually causing them to leak. Your lungs then flood with fluid, which can trigger any of the respiratory problems associated with hantavirus pulmonary syndrome.

Person-to-person transmission

People who become infected with the North American strain of hantavirus pulmonary syndrome aren't contagious to other people. However, certain outbreaks in South America have shown evidence of being transmitted from person to person, which illustrates variation across strains in different regions.