A comparison of bats and rodents as reservoirs of zoonotic viruses: Are bats special?

Department of Biology, Colorado State University, Fort Collins, CO 80523, USA, Fogarty International Center, National Institutes of Health, Bethesda, MD 20892, USA, Disease Dynamics Unit, Department of Veterinary Medicine, University of Cambridge, Cambridge CB3 OES, UK, Wildlife Zoonoses and Vector-borne Diseases Research Group, Animal Health and Veterinary Laboratories Agency (Weybridge), New Haw, Addlestone, Surrey KT15 3NB, UK, Institute of Zoology, Zoological Society of London, Regent's Park, London NW1 4RY, UK, US Geological Survey (retired), Fort Collins Science Center, Fort Collins, CO 80526, USA, US Geological Survey, Fort Collins Science Center, Fort Collins, CO 80526, USA, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA, Department of Biology, University of Florida, Gainesville, FL 32611, USA, Emerging Pathogens Institute, University of Florida, Gainesville, FL 32611, USA, Population Biology, Ecology, and Evolution Program, Emory University, Atlanta, GA 30322, USA, Department of Biology and Centre for Forest Interdisciplinary Research, University of Winnipeg, Winnipeg, Manitoba, Canada R3B 2E9, National Consortium for Zoonosis Research, Leahurst, Neston, South Wirral CH64 7TE, UK, The Global Alliance for Rabies Control, Manhattan, KS 66502, USA.
Proceedings of the Royal Society B: Biological Sciences (Impact Factor: 5.05). 02/2013; 280(1756):20122753. DOI: 10.1098/rspb.2012.2753
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Bats are the natural reservoirs of a number of high-impact viral zoonoses. We present a quantitative analysis to address the hypothesis that bats are unique in their propensity to host zoonotic viruses based on a comparison with rodents, another important host order. We found that bats indeed host more zoonotic viruses per species than rodents, and we identified life-history and ecological factors that promote zoonotic viral richness. More zoonotic viruses are hosted by species whose distributions overlap with a greater number of other species in the same taxonomic order (sympatry). Specifically in bats, there was evidence for increased zoonotic viral richness in species with smaller litters (one young), greater longevity and more litters per year. Furthermore, our results point to a new hypothesis to explain in part why bats host more zoonotic viruses per species: the stronger effect of sympatry in bats and more viruses shared between bat species suggests that interspecific transmission is more prevalent among bats than among rodents. Although bats host more zoonotic viruses per species, the total number of zoonotic viruses identified in bats (61) was lower than in rodents (68), a result of there being approximately twice the number of rodent species as bat species. Therefore, rodents should still be a serious concern as reservoirs of emerging viruses. These findings shed light on disease emergence and perpetuation mechanisms and may help lead to a predictive framework for identifying future emerging infectious virus reservoirs.

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    • ") and possibly harbouring more zoonotic viruses than mammals of any other group (Luis et al. 2013), including some deadly viruses (Wynne & Wang 2013), it is necessary to understand the mechanisms of immune resistance that allow bats to harbour pathogens, the pathogenetic bases of infectious diseases in bats and the mechanisms underlying disease emergence (Calisher et al. 2006, Dobson 2006, Daszak et al. 2013, Mandl et al. 2015). To address these issues, it is necessary to perform eco-epidemiological field studies and laboratory experiments using bats and bat cell cultures. "
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    ABSTRACT: An increasingly asked question is ‘can we confidently link bats with emerging viruses?’. No, or not yet, is the qualified answer based on the evidence available. Although more than 200 viruses – some of them deadly zoonotic viruses – have been isolated from or otherwise detected in bats, the supposed connections between bats, bat viruses and human diseases have been raised more on speculation than on evidence supporting their direct or indirect roles in the epidemiology of diseases (except for rabies). However, we are convinced that the evidence points in that direction and that at some point it will be proved that bats are competent hosts for at least a few zoonotic viruses. In this review, we cover aspects of bat biology, ecology and evolution that might be relevant in medical investigations and we provide a historical synthesis of some disease outbreaks causally linked to bats. We provide evolutionary-based hypotheses to tentatively explain the viral transmission route through mammalian intermediate hosts and to explain the geographic concentration of most outbreaks, but both are no more than speculations that still require formal assessment.
    Memórias do Instituto Oswaldo Cruz 02/2015; 110(1):1-22. DOI:10.1590/0074-02760150048 · 1.59 Impact Factor
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    • "R odents are recognized as hosts of more than 60 zoonotic diseases that represent a serious threat to human health (Meerburg et al. 2009, Luis et al. 2013). This special issue emerges from a workshop organized in Bangkok at the Faculty of Veterinary Medicine of Kasetsart University and supported by the French ANR project CERoPath (Community Ecology of Rodents and their Pathogens in a Southeast Asian changing environment), which aimed at better understanding the relationships between rodent-borne diseases, rodents and their habitats using intensive field works, serology, and molecular screenings. "

    Vector borne and zoonotic diseases (Larchmont, N.Y.) 01/2015; 15(1):1-2. DOI:10.1089/vbz.2015.15.1.intro · 2.30 Impact Factor
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    • "Bats harbor more zoonotic viruses per species than rodents and are now recognized as a significant source of zoonotic agents, some of which are of particular interest because they cause severe human diseases (Luis et al. 2013). Bats often live in large colonies and practice roosting; they fly, travel, and disseminate viruses over considerable distances (Wynne et al. 2013). "
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    ABSTRACT: Abstract Background: Bat-borne viruses pose a potential risk to human health and are the focus of increasing scientific interest. To start gaining information about bat-transmitted viruses in Hungary, we tested multiple bat species for several virus groups between 2012 and 2013. Fecal samples were collected from bats across Hungary. We performed group-specific RT-PCR screening for astro-, calici-, corona-, lyssa-, othoreo-, paramyxo-, and rotaviruses. Positive samples were selected and sequenced for further phylogenetic analyses. A total of 447 fecal samples, representing 24 European bat species were tested. Novel strains of astroviruses, coronaviruses, and caliciviruses were detected and analyzed phylogenetically. Out of the 447 tested samples, 40 (9%) bats were positive for at least one virus. Bat-transmitted astroviruses (BtAstV) were detected in eight species with a 6.93% detection rate (95% confidence interval [CI] 4.854, 9.571). Coronaviruses (BtCoV) were detected in seven bat species with a detection rate of 1.79% (95% CI 0.849, 3.348), whereas novel caliciviruses (BtCalV) were detected in three bat species with a detection rate of 0.67% (95% CI 0.189, 1.780). Phylogenetic analyses revealed a great diversity among astrovirus strains, whereas the Hungarian BtCoV strains clustered together with both alpha- and betacoronavirus strains from other European countries. One of the most intriguing findings of our investigation is the discovery of novel BtCalVs in Europe. The Hungarian BtCalV did not cluster with any of the calcivirus genera identified in the family so far. We have successfully confirmed BtCoVs in numerous bat species. Furthermore, we have described new bat species harboring BtAstVs in Europe and found new species of CalVs. Further long-term investigations involving more species are needed in the Central European region for a better understanding on the host specificity, seasonality, phylogenetic relationships, and the possible zoonotic potential of these newly described viruses.
    Vector borne and zoonotic diseases (Larchmont, N.Y.) 12/2014; 14(12):846-55. DOI:10.1089/vbz.2014.1637 · 2.30 Impact Factor
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