HEALTH FEATURE ARCHIVE

Hantavirus A Threat ... Rodent Disease on the Rise

August 1999 -- The CDC (Centers for Disease Control) warns that it has confirmed seven new cases and suspects at least eleven more cases of the hantavirus lung (pulmonary) syndrome, a dread disease contracted from rodents.

Eight of the 18 confirmed or suspected cases of hantavirus pulmonary syndrome (HPS) came from the Southwest -- Arizona, Colorado, and New Mexico. The remaining ten cases were in California, Idaho, Iowa, Montana, New York State and Washington State.

HPS is a viral disease characterized by fever, a severe pulmonary (lung) illness and often a fatal outcome. The case-fatality ratio with HPS is 43% (meaning 43% of people with HPS die).

There are several related viruses that can cause HPS. The main one in the United States is called the Sin Nombre virus. In the United States the deer mouse (Peromyscus maniculatus) is the predominant carrier of the Sin Nombre virus and therefore the usual animal responsible for carrying the disease to people in the U.S.

The current outbreak of HPS is not a surprise. Research on rodent populations had, in fact, predicted an increased risk for infection for humans in some areas of the southwestern U.S. during the summer of 1999.

Hantavirus Infection

Hantavirus infection can occur after inhaling infectious aerosols from rodent saliva or excreta. HPS typically begins with headache, fever, and myalgia (muscle pain) soon followed by pulmonary edema (fluid in the lungs), which often leads to severe respiratory compromise. Laboratory findings include low platelets (thrombocytopenia), presence of immature immunologically active cells (immunoblasts), and high levels of red blood cells (hemoconcentration). Other than supportive care, no treatment exists for hantavirus infection. The probability of surviving an attack of HPS increases with early recognition, hospitalization, and aggressive pulmonary and hemodynamic (blood) support.