HANTAVIRUS PULMONARY SYNDROME
Hantavirus pulmonary syndrome (HPS) was first identified in the United States in 1993, though it has probably been around a lot longer. It is characterized by a severe lung disease for which there is no cure.
The virus that causes HPS belongs to a group of viruses of the genus Hantavirus. There are many hantaviruses, and each species has a specific rodent or group of rodents as its main reservoir. In Europe and Asia, Hantavirus causes hemorrhagic fever with renal syndrome and is usually not fatal. In North America, Hantavirus attacks the respiratory system causing HPS, which has a nearly 50% fatality rate.
Four rodents that have been identified as reservoirs for the HPS virus are the deer mouse, found throughout North America; the cotton rat, found primarily in the southeastern United States, in areas overgrown with shrubs and tall grasses; the rice rat, found in marshy and semiaquatic areas of the southeastern United States; and the white-footed mouse, found in all of the United States except New England. These animals prefer brushy and wooded areas but can be found in more open areas. The deer mouse was the first rodent identified as a reservoir.
Common house mice and common rats have not been associated with HPS.
The most common method of HPS virus transmission to humans is when people breathe air that contains aerosolized, fresh rodent urine, feces, or saliva (Figure 18). Aerosolization occurs when dust or nesting materials are stirred up and tiny droplets containing the virus become airborne. Other methods of transmission that have been identified or suspected are direct transfer, as when a rodent bites a person, or indirect transfer, as when people touch something that has been contaminated with infected rodent excrement and then touch their noses or mouths or when people eat food contaminated by rodent excrement.
Transmission occurs anywhere there is an active rodent population. Some of the more common places are homes, summer cottages that have been shut up all winter, barns, sheds, warehouses, storage facilities, restaurants, office buildings, garages, crawl spaces, and vacant buildings. Campers and hikers can become infected if they stay in rodent-infested shelters or pitch tents in rodent-infested habitats.