Prevalence of infection with hantavirus in rodent populations of central Argentina

We studied hantavirus seroprevalence and virus variability in rodent populations in Diego Gaynor, northwest of Buenos Aires province, Argentina. Rodent samplings were conducted in railroads and cropfield borders in March and July 1999, September and December 2000, and March 2001. Antibody detection was performed by an enzyme link immunosorbent assay (ELISA), using the recombinant nucleoprotein of Andes (AND) virus as antigen. Tissue samples were taken from positive antibody individuals in order to confirm the presence of hantavirus genomic material and to identify virus genotypes. Akodon azarae was the most abundant species, followed by Oligoryzomys flavescens, while Calomys laucha and C. musculinus were rarely caught. We found a rate of seroprevalence of 9.3 percent for a total sample of 291 A. azarae and 13.5 percent for 37 O. flavescens. After molecular analyses of hantavirus, we confirmed the presence of hantavirus genomic material in 16 individuals with ELISA (+) results and two individuals with ELISA (-). Four amplimers for each species were sequenced and compared to the corresponding sequences of representative hantaviruses. We identified the AND Cent Lec from three O. flavescens, and the Pergamino virus from four A. azarae and from one O. flavescens. A. azarae males had higher seroprevalence than females, and heavier individuals showed higher seroprevalence than lighter ones. We did not find seroprevalence differences according to sex in O. flavescens, although this result may have been produced by the low sample size. The lowest seroprevalence was found in a period of high rodent density, when juveniles prevailed in the population. We found higher seroprevalences than those detected in previous studies for other localities of central Argentina where cases of hantavirus pulmonary syndrome (HPS) have been reported. The presence of AND Cent Lec virus in rodent populations of the study area, which is responsible of HPS cases in central Argentina, suggests that human populations are at risk of HPS disease, although there were not reported cases of this disease until today

Hantavirus en poblacion humana y de roedores de un area endemica para el hantavirus pulmonary syndrome in Argentina / Hantavirus in human and rodent population in an endemic area for hantavirus pulmonary syndrome in Argentina

This paper analyzed the prevalence and distribution of serological reactivity to hantavirus (antibody against ANDES virus) of human population exposed to hantavirus and rodents trapped in the studied area. This study was developed in Salta (Oran and San Martin Departments), area with the highest incidence for Hantavirus Pulmonary Syndrome (HPS) in Argentina. In December 1997, 453 healthy people were studied by serology and 39 rodents by serology and PCR. The studied individuals were distributed as: 145 farm inhabitants (FI), 212 people living in the same dwelling with healthy individuals (controls) (Cco), 87 people living in the same dwelling with persons undergoing SPH in 1997 (cases) (Cca). Moreover, 19 physicians and nurses who cared for patients with SPH in 1997 were also studied. The prevalence of hantavirus infection among the studied population was 6.3 percent. The prevalence was 10.3 percent among FI, 6.9 percent among Cca and 3.3 percent among Cco (p < 0.02). There was no serological reactivity among PS. The prevalence in 39 trapped rodents was 10.2 percent, with infection only for Oligoryzomys chacoensis, O. flavescens and Akodon varius species.The prevalence of human cases with asymptomatic infection in Salta is higher than in other regions of the country, and we are presenting a hypothesis to explain these differences. The analyzed data suggest that in this region up to the time this study was performed, there would not have been person to person transmission of hantavirus. The transmission would be from rodent contact exclusively and mainly in ongoing deforestation areas and domestic habitat surrounding rural dwellings.