• Evidence supporting a Zoonotic Origin of human coronavirus strain NL63

      Huynh, J.; Li, S.; Frieman, M.B. (2012)
      The relationship between bats and coronaviruses (CoVs) has received considerable attention since the severe acute respiratory syndrome (SARS)-like CoV was identified in the Chinese horseshoe bat (Rhinolophidae) in 2005. Since then, several bats throughout the world have been shown to shed CoV sequences, and presumably CoVs, in the feces; however, no bat CoVs have been isolated from nature. Moreover, there are very few bat cell lines or reagents available for investigating CoV replication in bat cells or for isolating bat CoVs adapted to specific bat species. Here, we show by molecular clock analysis that alphacoronavirus (α-CoV) sequences derived from the North American tricolored bat (Perimyotis subflavus) are predicted to share common ancestry with human CoV (HCoV)-NL63, with the most recent common ancestor between these viruses occurring approximately 563 to 822 years ago. Further, we developed immortalized bat cell lines from the lungs of this bat species to determine if these cells were capable of supporting infection with HCoVs. While SARS-CoV, mouse-adapted SARS-CoV (MA15), and chimeric SARS-CoVs bearing the spike genes of early human strains replicated inefficiently, HCoV-NL63 replicated for multiple passages in the immortalized lung cells from this bat species. These observations support the hypothesis that human CoVs are capable of establishing zoonotic-reverse zoonotic transmission cycles that may allow some CoVs to readily circulate and exchange genetic material between strains found in bats and other mammals, including humans.
    • Metagenomic analysis of the viromes of three North American bat species: Viral diversity among different bat species that share a common habitat

      Donaldson, E.F.; Haskew, A.N.; Frieman, M.B. (2010)
      Effective prediction of future viral zoonoses requires an in-depth understanding of the heterologous viral population in key animal species that will likely serve as reservoir hosts or intermediates during the next viral epidemic. The importance of bats as natural hosts for several important viral zoonoses, including Ebola, Marburg, Nipah, Hendra, and rabies viruses and severe acute respiratory syndrome-coronavirus (SARS-CoV), has been established; however, the large viral population diversity (virome) of bats has been partially determined for only a few of the ?1,200 bat species. To assess the virome of North American bats, we collected fecal, oral, urine, and tissue samples from individual bats captured at an abandoned railroad tunnel in Maryland that is cohabitated by 7 to 10 different bat species. Here, we present preliminary characterization of the virome of three common North American bat species, including big brown bats (Eptesicus fuscus), tricolored bats (Perimyotis subflavus), and little brown myotis (Myotis lucifugus). In samples derived from these bats, we identified viral sequences that were similar to at least three novel group 1 CoVs, large numbers of insect and plant virus sequences, and nearly full-length genomic sequences of two novel bacteriophages. These observations suggest that bats encounter and disseminate a large assortment of viruses capable of infecting many different animals, insects, and plants in nature.