Understanding the ecology and host-switching potential of Hantavirus in South America

Ecological and environmental factors play a role in the prevalence and spillover of hantaviruses. For rodent-borne zoonotic viruses, extrinsic pressures may include climate and land-use affecting resource availability, habitat... [ view full abstract ]

Ecological and environmental factors play a role in the prevalence and spillover of hantaviruses. For rodent-borne zoonotic viruses, extrinsic pressures may include climate and land-use affecting resource availability, habitat and/or rodent community structure. In Eastern Paraguay, Akodon montensis and Oligoryzomys nigripes are the reservoir hosts of co-circulating Jabora and Juquitiba virus respectively. Using field studies, we examine the hypothesis that forest habitat, rodent community structure and demographics influence hantavirus prevalence in wild rodent reservoirs, and could leading to pathogen host switching. In a 2014 baseline study, rodents were collected along 22 transects within Mbaracayú Reserve, each with 50 Sherman traps. Morphological rodent identification was confirmed molecularly using Cytb sequencing. Blood samples were screened for presence of antibody using IFA; lungs were screened for viral RNA by RT-PCR and sequencing. Urine and saliva were collected to assess viral shedding. Based on prevalence in this initial survey, we will focus in on specific sites in future years and examine effect of land-use on viral genetic diversity. Of the 422 mice captured in 2014, A. montensis was the most frequently captured rodent; overall, mouse species diversity increased with forest degradation. Hantavirus antibodies were detected in 21 mice, and viral RNA in 11 mice (seven also being seropositive). Sequencing confirmed both Juquitiba and Jabora virus at the Reserve, and to date, each virus has come from the expected rodent host reservoir. Hantavirus-positive prevalence occurred at half the surveyed regions across the forest. We evidence recent circulation of hantavirus (two strains) at Mbaracayú, involving at least two wildlife hosts. There is primary intra-species genetic diversity in both reservoir and potential spillover mice species which could affect individual susceptibility to hantavirus infection. We suggest disturbed habitat has the potential to change rodent population structure and contact frequency, increasing prevalence of hantaviruses.