Since 1995 when the first case of hantavirus pulmonary syndrome (HPS) was reported in Patagonia, there have been more than 400 cases of HPS reported in five countries in South America. The first case of HPS was associated with Andes (AND) virus. In this study, we report on the genetic diversity, geographical distribution, and serological features of hantavirus infection in six countries in South America based on 87 HPS cases from Argentina, Bolivia, Chile, Paraguay, and Uruguay. An early immunoglobulin M (IgM), IgA, and IgG humoral response was observed in almost all HPS cases. The IgM response appears to peak 1 or 2 days after the onset of symptoms. Peak IgG antibody titers occur mostly after the first week. Low IgG titers or the absence of IgG was associated with higher mortality rates. The IgA response peaks around day 15 and then rapidly decreases. The results of phylogenetic analysis based on partial M-fragment G1- and G2-encoding sequences showed that HPS cases from the five countries were infected with viruses related to AND or Laguna Negra (LN) virus. Within AND virus-infected persons, at least five major genetic lineages were found; one lineage was detected in Uruguayan and Argentinean cases from both sides of the Rio de la Plata river. Two Paraguayan patients were infected with a virus different from LN virus. According to the results of phylogenetic analyses, this virus probably belongs to a distinct lineage related more closely to the AND virus than to the LN virus, suggesting that there is probably an Oligoryzomys-borne viral variant circulating in Paraguay. These studies may contribute to a better understanding of hantavirus human infection in South America.

Fil: Padula, Paula. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Virología; Argentina.

Fil: Colavecchia, Silvia. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Virología; Argentina.

Fil: Martínez, Valeria Paula. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Virología; Argentina.

Fil: Gonzalez Della Valle, Marcelo. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Virología; Argentina.

Fil: Edelstein, Alexis. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Virología; Argentina.

Fil: Miguel, Sergio. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Virología; Argentina.

Fil: Russi, J. Ministerio de Salud Pública. Departamento de Laboratorios; Uruguay.

Fil: Riquelme, J. Mora. Ministerio de Salud Pública de Chile. Seccion Virología; Chile.

Fil: Colucci, N. Ministerio de Salud Pública y Bienestar Social. Laboratorio Central de Salud Pública; Paraguay.

Fil: Almirón, María. Universidad Nacional de Asunción. Instituto de Investigaciones en Ciencias de la Salud; Paraguay.

Fil: Rabinovich, Roberto D. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Virología; Argentina.