Epidemiology of argentine hemorrhagic fever

Abstract

Present knowledge points to horizontal transmission as the most significant mechanism for Junín virus maintenance in the main natural reservoirs, namely Calomys musculinus and Calomys laucha. The existence of naturally infected Akodon azarae, both within and outside the endemic area, as well as the finding that other species, ecologically and phylogenetically related to the main reservoirs, such as Akodon molinae and Calomys callidus, can experimentally develop persistent infections with virus shedding through fauces, suggest a potential role for these cricetids as alternative reservoirs. Furthermore, since those rodents inhabit the borders of the area in which Argentine Hemorrhagic fever is endemic, the risk of spread of this area is to be expected. Whether the establishment of Junín virus persistence in Calomys musculinus and other reservoirs depends on viral or host factors, such as a selective defect in L3T4+ lymphocytes as recently shown for mice, remains to be explored.

Providing management options to control corn mouse (Calomys musculinus) reservoir populations using a cohort structured model

“…Reproduction, and consequently population density, increases from a minimum in spring to a peak in late autumn, then decreases during winter (de Villafan˜e et al 1977;Kravetz 1977;Mills et al 1991aMills et al , 1992aPolop et al 2007). This pattern of annual fluctuation is in agreement with epidemiological characteristics of AHF, whose epidemics occur predominantly during autumn, coinciding with the major harvesting season in Argentina (Carballal et al 1988;Mills et al 1992b).…”

“…The endemic area of AHF encompasses more than 150,000 km 2 in northern and central Buenos Aires, southern Santa Fe, south-eastern Cordoba and north-eastern La Pampa provinces, with more than three million people at risk (Carballal et al 1988;Mills et al 1991b;Enrı´a et al 1998). The dynamics of AHF is closely related to population dynamics of C. musculinus which exhibits a seasonal breeding pattern in the field.…”

Environmental determinants of the small mammal assemblage in an agroecosystem of central Argentina: The role of Calomys musculinus

“…Hundreds of human cases occurred annually until the deployment of the vaccine in 1992 (Mills and Childs 1998). The Junín arenavirus, etiological agent of the AHF, is maintained in nature by C. musculinus (Vanella 1964;Sabattini et al 1965), and it is transmitted to humans primarily via inhalation of aerosolized particles of contaminated rodent excreta contained in soil, plant litter, and other debris (Maiztegui 1975;Carballal et al 1988;Mills et al 1992). Because of this way of transmission, farmers are the primary demographic at risk.…”

Structure and floristics of habitats associated with five rodent species in an agroecosystem in Central Argentina

“…The presence of C. musculinus in crop fields later in the growing season may help explain the clustering of Argentine haemorrhagic fever cases around harvest time (Carballal et al, 1988).…”

“…Before 1991, when a live-attenuated vaccine was made available, up to 1000 human cases of Argentine haemorrhagic fever were observed annually. The disease primarily affects farm workers (Carballal, Videla & Merani, 1988). Lymphocytic choriomeningitis virus (LCMV) is carried by M. musculus.…”