| Epidemiology Case
Characteristics
For the latest counts and descriptive statistics on confirmed cases of HPS in the
United States, please see the HPS Case Information page.
Information on this page is updated as the case count changes.
HPS an Old Disease, Newly Recognized
Although the high-profile investigation of the HPS syndrome emphasized public health
authorities' warnings about new and emerging infectious diseases, HPS has turned out to be
a newly identified, but not a "new," disease (see Tracking
a Mystery Disease). In fact, the earliest case of a serologically confirmed SNV
infection was in a person who developed an HPS-compatible illness in July 1959 and was
found to have IgG antibodies in September 1994. The earliest case of HPS to be confirmed
by IHC with direct visualization of hantaviral antigens in postmortem tissue involved a
patient who died in 1978.
Risk Factors for Disease
Little is known about activities that lead to a greater risk of infection. However, an
early case-control study suggests that increased numbers of rodents in the household is
the strongest risk factor for infection. Entering rarely opened or seasonally closed
buildings may also contribute to infection. Among the confirmed cases of HPS for which
exposure information is available, 70% of the patients in the case control study had
exposures closely associated with peridomestic activities, such as cleaning, in homes that
showed signs of rodent infestation. Four clusters of HPS cases involving 2-4 persons have
been documented; for each cluster, exposure probably occurred within a shared, enclosed
structure. Taken together, these observations suggest that disturbing or inhabiting
closed, actively rodent-infested structures may constitute an important risk factor for
contracting HPS
Potentially occupationally acquired SNV infections have been recognized but are
infrequent. Among documented U.S. cases of HPS, patients with potential occupational
exposures have included grain farmers, an extension livestock specialist, field
biologists, and agricultural, mill, construction, utility and feedlot workers. Many of
these individuals had concurrent peridomestic exposures. Among U.S. mammalogists and
rodent workers with varying degrees of rodent exposure, the seroprevalence of SNV
antibodies was 1.14%. In contrast, a recent HPS seroprevalence study focused on selected
occupational groups with frequent contact with rodents and their excreta (e.g., farm
workers, laborers, professionals, home repairers, service industry and park service
workers, heating and plumbing contractors, utility workers, and technicians) found no
evidence of SNV infection.
Travel to and within all areas where hantavirus infection has been reported is not
considered a risk factor for infection with HPS. The possibility of exposure to hantavirus
for campers, hikers, and tourists is very small and is reduced further if steps are taken
to reduce rodent contact.
|
National
Center for Infectious Diseases
