Special Pathogens Branch, Viral and Rickettsial Zoonoses Branch, and Molecular Pathology and Ultrastructure Activity, Division of Viral and Rickettsial Diseases, National Center for Infectious Diseases, and Epidemic Intelligence Service, Epidemiology Program Office, Centers for Disease Control and Prevention, Universidad de Chile, Hospital de Filadelfia, Hospital de Loma Plata, Centro Medico Bautista, Pan American Health Organization, Atlanta, Georgia, Chile
During an investigation of hantavirus pulmonary syndrome (HPS) in Paraguay in 1995, sera from persons with HPS-like illness, houshold contacts of confirmed HPS case-patients, and a sample of the area residents were analyzed by ELISA for antibodies to Sin Nombre virus (SNV). Rodent serosurveys and analysis of precipitation records were also conducted. Twenty-three of 24 available probable cases were SNV antibody-positive, 17 of whom were ill between July 1995 and January 1996. Four (14.8%) of 27 case-contacts and 44 (12.8%) of 345 community residents were also seropositive. Calomys laucha (vesper mouse) was the most common rodent species captured and the most frequently SNV-seropositive. Rainfall in May 1995 was 10-fold greater than that seen in May over the preceding 11 years. This 17 case-cluster represents the largest documented outbreak since HPS was first recognized in 1993. Calomys laucha is the likely primary rodent reservoir for a SNV-like hantavirus in western Paraguay. Fluctuations in monthly precipitation rates may have contributed to increased risk for HPS in this region.