Virological Investigation in Synanthropic Rodents in North Italy

Intro: Several rodents, including mice and the brown rat, are synanthropic animals usually found in rural and urban environments in contact with other animals and humans. Rodents are natural reservoirs of infectious agents and could harbour a plethora of zoonotic pathogens of public health importance. Taking advantage of a parallel study on presence and distribution of Hantaviruses, we aimed to investigate the occurrence in mice of other viruses with zoonotic or economic impact. Method(s): From May to July 2022, 41 mice (Mus domesticus) were captured and killed by using baited snap traps in 13 selected cattle, goat and poultry farms located in the Piedmont region. Gut and lung samples were homogenised and tested by PCR methods for pan-Coronavirus (CoV) and SARS-CoV-2, pan-Pestivirus, Mammalian orthoreoviruses, Canine Distemper virus (CDV), Flaviviruses, Influenza A (IAV) and D (IDV) viruses. Finding(s): All captured animals did not present at necropsy lesions related to infectious diseases. Virological investigations detected the presence of CoV in six mice. By sequencing Rodent CoVs was identified in two samples (four more pending). Mammalian orthoreovirus was detected in nine animals and typing and characterization are in progress. One mouse, captured in a bovine farm, tested slightly positive for IDV and confirmation of positivity is in progress by complete sequencing with NGS approach. All samples were negative for Flaviviruses, IAV, CDV, pan-Pestivirus and SARS-CoV-2. Conclusion(s): Rodents are well adapted to a wide range of habitats, including peri-urban and rural environments, where they benefit from human activities. These results, although preliminary, underline the importance of enhancing surveillance in rodents in anthropized areas to better assess the presence of zoonotic agents and the potential risk of transmission.Copyright © 2023

Coronaviruses Detection in Italian Alpine Marmots (Marmota Marmota)

Intro: Coronaviruses infect humans and a wide range of wild and domestic animals. Some CoVs could be zoonotic, being able to mutate, crossing the species barrier and infecting humans (e.g. SARS-CoV and MERS-CoV). Since the emergence of SARS-CoV-2, several studies were carried out to ascertain the susceptibility of both domestic and wild animals to SARS-CoV-2. However, information on some species is lacking, and for others only RDB-ACE receptor affinity studies have been carried out. Considering the high densities of Marmota marmota in the alpine environment, where livestock and recreational activities are commonly present, this study aims to investigate the presence and characterization of CoVs in this species. Method(s): During provincial relocation plan carried out in 2021 and 2022, 170 alpine marmots were captured in municipality of Livigno in Sondrio province (North-Italy) for decreasing animal density and, after a quarantine period, they were released in other alpine places. Faecal samples were collected from each animal and then subjected to RNA extraction and nested RT-PCR pan-Coronavirus and real time RT-PCR for SARS-CoV-2. PCR positive samples for pan-CoV were then sequenced. Finding(s): The pan-Coronavirus RT-PCR detected CoVs in seven marmots. The CoV sequence originating from one marmot sampled in 2021 had 97% affinity to strains isolated in lagomorphs. The other six sequences from 2022 were highly correlate with Bovine Beta-CoVs. This could be explained by the fact that marmots share alpine pastures with these species;in fact, the trapping area in 2022 represented grazing and forage production areas. All samples tested for SARS-CoV-2 resulted negative. Conclusion(s): Despite the absence of zoonotic coronaviruses, marmots show high plasticity in harbouring CoVs of sympatric species. For this reason, and considering the affinity of their ACE-receptor demonstrated for SARS-CoV, it would be worthwhile to increase surveillance for CoVs in this species.Copyright © 2023

Pathological and Microbiological Findings in Free-Ranging Bats in Italy

Introduction: Recent studies have shown that bats are the reservoir hosts of several novel viruses, increasing the interest in bats as potential vectors of zoonotic pathogens. Several studies investigated the presence of infectious agents in bats, but their impact on the individual host and their importance on bat mortality is largely unknown. The aim of this study was to describe the microbiological and histopathological findings in 77 deceased bats belonging to nine European species (families Vespertilionidae and Molossidae). Materials and Methods: Bat carcasses were collected in the Piedmont region (Italy) by the Unconventional Rehabilitation Centre (CANC), Torino University, and submitted to necropsy. Species, age and sex of each bat were recorded. Virological (orthoreovirus, coronavirus, flavivirus, rhabdovirus, poxvirus, kobuvirus) and histopathological examinations were performed on the main organs (liver, spleen, kidney, gut, lung, heart and brain). Results: Traumatic injuries (fractures, haemorrhages, skin lesions;43%) and predation injuries (8.4%) represented the two main causes of death. Regardless of species, age and sex, the pathological examination revealed inflammatory/degenerative lesions mainly involving liver (non-suppurative hepatitis and vacuolar degeneration;20.8%) and lung (bronchopneumonia;29.9%). Coronavirus, flavivirus, rhabdovirus and kobuvirus were not detected. Poxviruses were detected in three lungs, two with pneumonia, and 14.3% of animals were positive for reoviruses. Conclusions: This study demonstrates the importance of inflammatory lesions in bat mortality, and shows that bats can harbour infectious agents. However, there is no evidence that Italian bats may represent a severe risk for human health.