Isolation and Characterization of Three Mammalian Orthoreoviruses from European Bats

Abstract

In recent years novel human respiratory disease agents have been described in South East Asia and Australia. The causative pathogens were classified as pteropine orthoreoviruses with strong phylogenetic relationship to orthoreoviruses of flying foxes inhabiting these regions. Subsequently, a zoonotic bat-to-human transmission has been assumed. We report the isolation of three novel mammalian orthoreoviruses (MRVs) from European bats, comprising bat-borne orthoreovirus outside of South East Asia and Australia and moreover detected in insectivorous bats (Microchiroptera). MRVs are well known to infect a broad range of mammals including man. Although they are associated with rather mild and clinically unapparent infections in their hosts, there is growing evidence of their ability to also induce more severe illness in dogs and man. In this study, eight out of 120 vespertilionid bats proved to be infected with one out of three novel MRV isolates, with a distinct organ tropism for the intestine. One isolate was analyzed by 454 genome sequencing. The obtained strain T3/Bat/Germany/342/08 had closest phylogenetic relationship to MRV strain T3D/04, isolated from a dog. These novel reoviruses provide a rare chance of gaining insight into possible transmission events and of tracing the evolution of bat viruses.

Isolation and genomic characterization of a novel orthoreovirus from a brown-eared bulbul (Hypsipetes amaurotis) in Japan

“…These viruses, including Melaka virus, Kampar virus, HK23629/07 and Miyazaki-Bali/2007 (Cheng et al, 2009;Chua et al, 2007Chua et al, , 2008Yamanaka et al, 2014), were identified as causative agents for respiratory tract infection in humans. However, MRVs were isolated from European bats, but the pathology of those viruses in bats is unclear (Kohl et al, 2012). From these observations, Pycno-1 could potentially infect various mammals, such as the Steller sea lion.…”

High Similarity of Novel Orthoreovirus Detected in a Child Hospitalized with Acute Gastroenteritis to Mammalian Orthoreoviruses Found in Bats in Europe

“…A 10-fold serial dilution of reovirus isolate was prepared to determine the 50% tissue culture infective dose (TCID 50 ) value (27). A known concentration of reovirus isolate helped us to estimate the reovirus concentration in the child's stool sample using real-time RT-PCR, as described previously (11).…”

“…In all three samples, the majority of the contigs from all 10 viral genome segments showed the highest identity values with the MRV strain 342/08 genome, deposited in GenBank under accession no. JQ412755 to JQ412764 (11). This strain was therefore selected as the reference genome.…”

“…The zoonotic potential of reoviruses has already been described and discussed elsewhere (6,7,11). The transmission of reoviruses from one host to another is not limited to close contacts but extends to indirect transmission.…”

“…There is consequently increasing concern about the widespread nature and pathogenesis of these viruses. A German group of researchers recently reported infections of bat species with MRVs, which resulted in evident pathological signs in the organs of infected bats (11). This was the first report of reoviruses in bats that were not clustered into the species Pteropine orthoreovirus but in MRVs.…”