ABSTRACT
*Presenting author Emerging infectious diseases have been causing outbreaks in humans for centuries and most infectious diseases originate in animals. Re-emerging zoonotic pathogens are rapidly increasing in prevalence or geographic range and causing a significant and growing threat to global health. The present work provides an insight of zoonotic viruses risk at human-bat/rodent interfaces in Cambodia. We conducted studies to investigate the circulation of zoonotic viruses and the risk of exposure in human living at the interfaces with bats and rodents. Rodent's samples were collected in rural and urban areas of Cambodia. Organs were tested for Hantavirus, Orthohepevirus species C and Arenavirus. Bat's samples were collected in Steung Treng for Sarbecovirus and in Battambang and Kandal for Nipah virus detection. People working/living at the human-animal interfaces were screened for IgG antibodies. In rodents (750), hantavirus was detected in 3.3% rodents from urban areas only. Seoul orthohantavirus was the most predominant virus followed by Thottapalayam virus. HEV-C was detected only in rodents from urban settings (1.8%). Arenavirus was detected in both rural (6.8%) and urban (2.5%) areas. In humans (788), the seroprevalence of IgG antibodies against hantavirus, HEV-A and Arenavirus was 10.0%, 24% and 23.4% respectively. NiV was detected in flying fox's urines collected between 2013-2016 in Kandal (0.63%) and in Battambang (1.03%). Blood samples collected in both provinces were negative for NiV antibodies. SARS-CoV-2 related virus was detected in Rhinolphus shameli in Steung Treng in 2010, 2020 and 2021. Blood samples from people living at the vicinity of positive bats were positive for antibodies against CoV (7.7%), but no specific neutralizing SARS-CoV2 antibodies were detected. Our studies provided insight of the risk of zoonoses in Cambodia and highlighted the importance of zoonotic surveillance and further One Health effort to prevent, detect, and respond to future cross-species transmission.Copyright © 2023
ABSTRACT
The human pandemic caused by Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that started in December, 2019 is still continuing in various parts of the world. The SARS-CoV-2 has evolved through sporadic mutations and recombination events and the emergence of alternate variants following adaptations in humans and human-to-animal transmission (zooanthraponosis) has raised concerns over the efficacy of vaccines against new variants. The animal reservoir of SARS-CoV-2 is unknown despite reports of SARS-CoV- 2-related viruses in bats and pangolins. A recent report of back-andforth transmission of SARS-CoV-2 between humans and minks on mink farms in the Netherlands has sparked widespread interest in zooanthroponotic transmission of SARS-CoV-2 followed by reemergence to infect human populations. The risk of animal to human transmission depends on virus-host interaction in susceptible species that may be short-term or long term risks. The short term risk might be due to infection to humans during the viremic stage in susceptible animals. The long term risk might be either due to persistence of the virus at population level or latency of infection leading to risk of evolution and re-emergence of the virus. Experimental studies have identified a range of animals that are susceptible and permissive to SARS-CoV-2 infection viz. cats, ferrets, hamsters, mink, non-human primates, tree shrews, raccoon dogs, fruit bats, and rabbits. The health impacts of SARS-CoV-2 infection in animals are unknown and it is likely that other susceptible species have not been discovered yet. Apart from farmed animals, stray cats and rodents have been identified as a potential opportunity for ongoing transmission in intense farming situations. Recognizing animal species that are most susceptible to infection is the first step in preventing ongoing transmission from humans. Minimizing the risk of zooanthraponosis requires multi-sectoral coordination that includes implementation of strict biosecurity measures such as controlled access to farms that house susceptible animals, bio-secure entry and exit protocols, disinfection protocols in farm, down time for animal transport vehicles and daily assessments of human handlers for exposure to SARS-CoV- 2. Hence, active surveillance in animal species that are prioritized based on risk assessment need to be initiated in coordination with health and environment sectors for early identification of emerging and re-emerging variants of SARS-CoV-2 virus in animals.
ABSTRACT
Bats are important reservoirs for viruses of public health and veterinary concern. Virus studies in Australian bats usually target the families Paramyxoviridae, Coronaviridae and Rhabdoviridae, with little known about their overall virome composition. We used metatranscriptomic sequencing to characterise the faecal virome of grey-headed flying foxes from three colonies in urban/suburban locations from two Australian states. We identified viruses from three mammalian-infecting (Coronaviridae, Caliciviridae, Retroviridae) and one possible mammalian-infecting (Birnaviridae) family. Of particular interest were a novel bat betacoronavirus (subgenus Nobecovirus) and a novel bat sapovirus (Caliciviridae), the first identified in Australian bats, as well as a potentially exogenous retrovirus. The novel betacoronavirus was detected in two sampling locations 1375 km apart and falls in a viral lineage likely with a long association with bats. This study highlights the utility of unbiased sequencing of faecal samples for identifying novel viruses and revealing broad-scale patterns of virus ecology and evolution.
Subject(s)
Chiroptera , Coronavirus , Sapovirus , Animals , Humans , Retroviridae/genetics , Virome , Australia , MammalsABSTRACT
Flying fox (Pteropushypomelanus) belongs to the frugivorous bats, which play a crucial role in maintaining proper functioning of an ecosystem and conservation of the environment. Bats are well-known carriers of pathogenic viruses, such as BatCov RaTG13 from the coronavirus family that share 90.55% with SARS-CoV-2, the pathogen causing recent global pandemic coronavirus disease 19 (COVID-19). However, bats' possible role as a carrier of pathogenic bacteria is less explored. Here, using metabarcoding analysis through high-throughput sequencing, we explored the gut microbiome composition of different island populations on the east and west coasts of Peninsula Malaysia. The 16S rRNA gene in samples from Redang Island, Langkawi Island, Pangkor Island and Tinggi Island was amplified. Bacterial community composition and structure were analysed with α and ß diversity metrics. A total of 25,658 operational taxonomic units at 97% similarity were assigned to eight phyla, 44 families, 61 genera and 94 species of microbes. The Proteobacteria was the dominant phylum in all populations. Meanwhile, the genera Enterobacter, Pseudomonas and Klebsiella, isolated in this study, were previously found in the rectum of other fruit bats. Our analyses suggest that Redang Island and Langkawi Island have high bacteria diversity. Thus, we found geographic locality is a strong predictor of microbial community composition and observed a positive correlation between ecological features and bacterial richness.
ABSTRACT
The ongoing COVID-19 pandemic is caused by the severe acute respiratory corona virus-2 (SARS-CoV-2) which as of right now has infected 10% of world’s population and has caused >1.5 million deaths worldwide. In addition to respiratory symptoms, COVID-19 causes nausea, vomiting and diarrhea in more than half of infected subjects. This indicates that SARS-CoV-2 not only infects the respiratory tract, but also the gastrointestinal. Bats are thought to be the original reservoir for SARS-CoV-2, since SARS-CoV-2 is 96% identical to the bat coronavirus RatG13, which was identified in horseshoe bats. However, coronaviruses fail to cause overt disease in the bats, whereas strong cytopathic effects were observed in human respiratory and gastrointestinal epithelial cells upon SARS-CoV-2 infection. The goal of our research is to compare the response of primary intestinal epithelial cells of bats and humans to SARS-CoV-2 infection in order to better understand the cellular mechanism that allow bats to harbor coronaviruses without developing disease symptoms. To study the SARS-Co-V-2 infection in bats, we have, for the first time, established organoids lines from the stomach, proximal and distal small intestine of three adult Jamaican Fruit Bats (Artibeus jamaicensis). Organoids were successfully generated from both fresh and frozen tissue and could be passaged at least 25 times and frozen and thawed with no apparent changes in growth and morphology. Microscopic analysis showed that bat gastric and intestinal organoids were composed of a simple columnar epithelium and secreted variable amounts of mucus. We also observed spontaneous development of gland and crypt structures, indicating appropriate differentiation (Fig. 1). When seeded on transwell inserts, both gastric and intestinal organoid cells consistently developed a transepithelial resistance, demonstrating intact barrier function. Using confocal microscopy, we showed that both gastric and intestinal organoids from bats expressed angiotensin I converting enzyme 2 (ACE2), a key receptor for SARS-CoV-2 entry. Our innovative experimental platform will enable us to study multiple aspects of coronavirus infection including viral evolution and determinants of spillover events in a relevant primary cell model system. Importantly, we will utilize the bat organoid model to identify nonpathogenic cellular pathways that enable tolerance to SARS-CoV-2 in the reservoir hosts for this virus, potentially informing novel treatment strategies in human COVID-19 patients.
ABSTRACT
Many infectious pathogens can be transmitted by highly mobile species, like bats that can act as reservoir hosts for viruses such as henipaviruses, lyssaviruses and coronaviruses. In this study, we investigated the seroepidemiology of protein antigens to Severe acute respiratory syndrome virus (SARS-CoV-1) and Middle eastern respiratory syndrome virus (MERS-CoV) in Grey-headed flying foxes (Pteropus poliocephalus) in Adelaide, Australia sampled between September 2015 and February 2018. A total of 301 serum samples were collected and evaluated using a multiplex Luminex binding assay, and median fluorescence intensity thresholds were determined using finite-mixture modelling. We found evidence of antibodies reactive to SARS-CoV-1 or a related antigen with 42.5% (CI: 34.3%-51.2%) seroprevalence but insufficient evidence of reactivity to MERS-CoV antigen. This study provides evidence that the Grey-headed flying foxes sampled in Adelaide have been exposed to a SARS-like coronavirus.