Cause
In Canada and the United States, most cases of
hantavirus pulmonary syndrome (HPS) are caused by one
strain of hantavirus primarily carried by the deer mouse (Peromyscus maniculatus). These rodents appear healthy but shed
the virus in their saliva, urine, and droppings. Deer mice are found in rural,
semi-rural, and suburban areas, but not usually in cities.
How the virus is spread
Experts believe that most people become infected with
hantaviruses by:
- Breathing in tiny airborne particles formed
when rodents urinate.
- Coming into direct
contact with infected rodent urine, saliva, or droppings.
- Being
exposed to dust particles contaminated with the virus.
- Being bitten
by a rodent infected with the virus (a rare source of infection).
There is no evidence that pregnant women infected with hantavirus
can spread the virus to their babies before or after birth or through
breast-feeding.4
Ticks, fleas, mosquitoes, and other biting insects are not known
to carry or spread hantaviruses. In North America, cats and dogs are not known to be
carriers of hantavirus. Guinea pigs, hamsters, gerbils, and other similar pets
also are not known to carry hantaviruses.
Contagious and incubation periods
In most cases, the incubation period—the time between infection
with the hantavirus and development of symptoms of the infection—is believed to
be 1 to 5 weeks.
A person who has HPS usually cannot spread the infection to
another person. Spread of hantavirus infection from one person to another has
never been documented in North America, but there has been one report in South
America (Argentina) of an outbreak of HPS that was spread by person-to-person
contact.