Acyclovir is recommended for patients with HSV or varicellazoster virus pneumonia. Ganciclovir combined with immunoglobulin appears to be effective in reducing the mortality associated with cytomegalovirus pneumonia in bone marrow transplant patients. Aerosolized ribavirin and immunoglobulin may be effective for RSV pneumonia in such patients, and aerosolized and intravenous ribavirin have been used for severe measles. In May 1993, an outbreak of acute fatal respiratory illness was recognized in previously healthy adults residing in the southwestern United States. The principal animal reservoir of Sin Nombre virus is the deer mouse, Peromyscus maniculatus.
Human infections occur by inhalation of aerosols of infectious excreta.
The finding of multiple viruses suggests that other agents and clinical syndromes remain to be found. Most HPS cases have occurred in young to middle-aged adults with no underlying disease. The largest numbers of cases have occurred in New Mexico, Arizona, and California, but cases have also been identified throughout western North America and sporadically in eastern states. A history of exposure to a rural setting, rodents or their dwellings, or agricultural work may suggest the diagnosis. The disease is primarily caused by increases in permeability of the pulmonary endothelium vessels that appears to be immune mediated.