First evidence of circulation of the Alto Paraguay orthohantavirus genotype in Argentina: human case and reservoir rodent.

MARTIN ML; SEN CN; BRIGNONE JM; MONZANI MC; GONZALEZ ITTIG, RE

La Plata

Congreso; II Congress of the Latin American Society for Vector Ecology; 2022

Hantavirus pulmonary syndrome (HPS) is an acute viral illness caused by members of the genus Orthohantavirus, family Hantaviridae. In Argentina, there is evidence of the circulation of several pathogenic viral genotypes and their respective reservoir rodents (Bermejo - Oligoryzomys occidentalis, Oran – O. chacoensis, Laguna Negra - Calomys fecundus, Juquitiba – O. nigripes, Lechiguanas – O. flavescens and O. nigripes, HU39694 – O. flavescens, Andes – O. longicaudatus) and two non-pathogenic genotypes for humans (Pergamino - Akodon azarae and Maciel - Necromys benefactus). In 2020, the diagnosis of a patient with HPS was carried out from Colonia Montefiore (Santa Fe province), without a travel history. A serum sample of the patient was analyzed by IgM and IgG ELISA for antibody detection. The viral genome was detected by RNA extraction from the serum sample followed by nested RT-PCR using generic primers that amplified fragments from the S and M genome segments. The orthohantavirus genotype present in the sample was Alto Paraguay. This genotype had previously been only detected in Paraguay in rodents identified as Holochilus chacarius, but not in patients with HPS. Since the circulation of this genotype was unknown in Argentina, we developed a small and focused ecological sampling near dwellings in Colonia Montefiore. We captured 59 rodents with a sampling effort of 420 traps–nights, during three nights. An individual of H. chacarius infected with the Alto Paraguay genotype was detected. The viral sequence of the rodent was compared with that of the patient, finding 100% nucleotide identity for the S and M genomic segments. This result strongly suggest that H. chacarius would be the reservoir of Alto Paraguay in Argentina. Future studies should be conducted to determine whether the circulation of this viral genotype covers other areas of Argentina.