ABSTRACT
In the context of COVID-19, we often ask ourselves what conditions favor the spread of zoonoses. Recent reviews point to its direct relationship with the decline in biodiversity due to habitat destruction or land use changes. When this occurs, some species become extinct, but those that survive and thrive, such as some rodents, are more likely to harbor pathogens that can affect humans. Our research focused on the study of molecular systematics and population genetic structure in rodent hosts of Mammarenavirus and Orthohantavirus affecting humans. From the analysis of phylogenetic relationships in Oligoryzomys and Calomys in South America, we were able to resolve contradictory taxonomic reports, obtaining the following rodent/viral genotype relationships in the endemic areas of Hantavirus pulmonary syndrome (HPS) in Argentina: Patagonia: O. longicaudatus/Andes;northwestern Argentina: O. occidentalis/Bermejo, O. chacoensis/Oran and C. fecundus/Laguna Negra;Misiones: O. nigripes/Juquitiba;Southern Litoral, Parana River Delta and the coast of the Uruguay River: O. flavescens/Lechiguanas and exceptionally, O. nigripes/Lechiguanas. We also detected the following rodent/mammarenavirus relationships: C. musculinus/Junin, C. venustus and C. fecundus/Latino-like. We observed that, in general, in conserved environments, the abundance of rodents was low although with high species diversity, while in places with greater disturbance, less diversity but a greater abundance of species transmitting zoonoses was found. It is not surprising then that the Argentine hemorrhagic fever endemic area is strongly associated with crops of the Humid Pampas and that HPS endemic areas are located in regions with high deforestation and introduction of crops or invasive exotic species. In times of pandemics, we should think about how diseases arise when our species advances over natural environments.