Arbovirology Unit, Center for Disease Control, U. S. Public Health Service, Health Services and Mental Health Administration, Instituto Nacional de Microbiologia, Centro de Educación Médica y Investigaciones Clínicas, Atlanta, Georgia 30333, Argentina
A study of rodent frequency in various habitats in the Pergamino area revealed that rodent density is greatest along railroad rights-of-way, roadsides, and fence rows. Cornfields and pastures, although the principal form of land use in the region, are not as important to annual production of rodents as the above areas. However, weedy cornfields do help preserve the lives of young rodents as they disperse from the favored linear habitats, and thus probably serve as important links in the infection of man with Junín virus, the cause of Argentinian hemorrhagic fever. These findings indicate that future control measures should be aimed at curtailing rodent reproduction along the linear habitats to prevent their spread into the cornfields.