Emerging hantaviruses in Central Argentina: First case of Hantavirus Pulmonary Syndrome caused by Alto Paraguay virus, and a novel orthohantavirus in Scapteromys aquaticus rodent

Orthohantaviruses are emerging rodent-borne pathogens that cause Hantavirus Pulmonary Syndrome in humans. They have a wide range of rodent reservoir hosts and are transmitted to humans through aerosolized viral particles generated by the excretions of infected individuals. Since the first description of HPS in Argentina, new hantaviruses have been reported throughout the country, most of which are pathogenic to humans. We present here the first HPS case infected with Alto Paraguay virus reported in Argentina. Until now, Alto Paraguay virus was considered a non-pathogenic orthohantavirus since it was identified in a rodent, Holochilus chacarius. In addition to this, with the goal of identifying potential hantavirus host species in the province of Santa Fe, we finally describe a novel orthohantavirus found in the native rodent Scapteromys aquaticus, which differed from other hantaviruses described in the country so far. Our findings implicate an epidemiological warning regarding these new orthohantaviruses circulating in Central Argentina as well as new rodent species that must be considered as hosts from now on. Author summary The term Hantavirus groups viruses that can cause human diseases and also viruses considered non-pathogenic. An increasing number of rodents, bats, shrew and moles have been identified as hantavirus reservoirs. Hantavirus pulmonary syndrome (HPS) is a severe disease caused by some of these viruses transmitted by rodent species. HPS is considered an emerging disease due to the enormous diversity of reservoirs that have been identified, which implicate new geographical areas affected and novel potential transmission routes. Their high fatality rates make it a serious public health concern. In the COVID-19 pandemic context, we described an HPS case in Central Argentina but outside the known endemic area. The infecting hantavirus characterized was Alto Paraguay virus, considered non-pathogenic to date. In order to identify the reservoir implicated, a study was carried out in available rodent samples from a nearby area. Although we were not able to find its reservoir, unexpectedly, a new hantavirus was identified: Leyes orthohantavirus. Additionally, a new reservoir was also identified, Scapteromys aquaticus. Our findings implicate an epidemiological warning regarding these new hantaviruses circulating in Central Argentina. There are no vaccines or specific treatments for HPS, therefore prevention actions are a key to reduce the impact of this disease.