Morphological and molecular analyses confirm the presence of the newly described bat species Molossus melini in the Espinal ecoregion from Argentina.

Until now, Molossus melini was known only from its type locality, in the south of Santa Fe province, Argentina. Specimens of this species were collected in 2021 from a roost in a Fraxinus tree of the urban woodland of Paraná city, Entre Ríos province, Argentina. Bat identification was made by comparing external and cranial characters and measurements with those reported in the bibliography and corroborated by a phylogenetic analysis based on the cytochrome b gene. Also, multivariate morphometric analyses showed that cranial measurements, but not external ones, are informative enough to discriminate M. melini from the other Molossus species in Argentina (M. currentium, M. fluminensis, and M. molossus). This new record extends the distribution of M. melini from the south of Santa Fe province by 230 km to the northeast and represents the first record of the species in the Espinal ecoregion. Supplementary information: The online version contains supplementary material available at 10.1007/s13364-023-00679-1.

The Role of Molossidae and Vespertilionidae in Shaping the Diversity of Alphacoronaviruses in the Americas.

Bats are reservoirs of diverse coronaviruses (CoVs), including progenitors of severe acute respiratory syndrome CoV (SARS-CoV) and SARS-CoV-2. In the Americas, there is a contrast between alphacoronaviruses (alphaCoVs) and betaCoVs: while cospeciation prevails in the latter, alphaCoV evolution is dominated by deep and recent host switches. AlphaCoV lineages are maintained by two different bat family groups, Phyllostomidae and Vespertilionidae plus Molossidae. In this study, we used a Bayesian framework to analyze the process of diversification of the lineages maintained by Molossidae and Vespertilionidae, adding novel CoV sequences from Argentina. We provide evidence that the observed CoV diversity in these two bat families is shaped by their geographic distribution and that CoVs exhibit clustering at the level of bat genera. We discuss the causes of the cocirculation of two independent clades in Molossus and Tadarida as well as the role of Myotis as the ancestral host and a major evolutionary reservoir of alphaCoVs across the continent. Although more CoV sampling efforts are needed, these findings contribute to a better knowledge of the diversity of alphaCoVs and the links between bat host species. IMPORTANCE Bats harbor the largest diversity of coronaviruses among mammals. In the Americas, seven alphacoronavirus lineages circulate among bats. Three of these lineages are shared by members of two bat families: Vespertilionidae and Molossidae. Uncovering the relationships between these coronaviruses can help us to understand patterns of cross-species transmission and, ultimately, which hosts are more likely to be involved in spillover events. We found that two different lineages cocirculate among the bat genera Molossus and Tadarida, which share roosts and have common viral variants. The bat genus Myotis functions as a reservoir of coronavirus diversity and, as such, is a key host. Although there were some spillovers recorded, there is a strong host association, showing that once a successful host jump takes place, it is transmitted onward to members of the same bat genus.

Human Rabies by Secondary Transmission in Argentina, 2021.

Rabies is a zoonotic disease caused by the rabies virus (RABV) that causes fatal encephalitis in mammals. Bats can transmit the disease to urban canines and felines, which rarely infect humans, establishing a secondary link. The last case of human rabies in Argentina was transmitted by a dog in 2008. We present the first case of human rabies originating from an insectivorous bat, Tadarida brasiliensis, transmitted by a feral cat in Buenos Aires province, Argentina.