Identification of Mammalian Orthoreovirus Type 3 in Italian Bats

Abstract

Summary This study describes the isolation and molecular characterization of Mammalian orthoreovirus (MRV) in microbats. Faecal samples and dead individuals available from rehabilitation centres or collected from known roost sites were virologically tested. In total, 112 carcasses of bats found dead, and 44 faecal samples were analysed. Nineteen viral strains were isolated by in vitro cell culture from faecal and tissue samples of different bat species (Pipistrellus khulii, Tadarida teniotis, Rhinolophus hipposideros and Vespertilio murinus), and they were morphologically identified as reoviruses by negative staining electron microscopy observation. The definitive assignment of all isolates to MRV was confirmed by RT-PCR assays targeting the L1 gene. Through a multiplex RT-PCR assay targeting the S1 gene, we typed 15 of 19 isolates as MRV type 3. Partial L1 (416 bp) and complete S1 (1416 bp) sequences of the isolates were analysed and compared with those of reference strains obtained from GenBank, belonging to the three serotypes. Molecular analysis of the S1 gene revealed that the amino acid residues associated with neurotropism (198-204NLAIRLP, 249I, 350D and 419E) were highly conserved among the Italian bat strains. These results suggest that potentially neurotropic MRV type 3 strains are widespread among Italian bats. Furthermore, the identification of MRV type 3 in bat species such as Pipistrellus Khulii, which is common in urban areas and known for its close contact with humans, underlines the need for vigilance.

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

“…For the S1 segment, the Slovenian SI-MRV01 strain was found in a specific bat cluster formed within the mammalian reovirus serotype 3 group. For this segment, the highest identity was shown with the bat reovirus characterized recently in Italy (12). In the S2 segment, SI-MRV01 did not show relatedness to any specific strain but was clustered in the serotype 3 group, together with porcine strain SC-A, MRV-HLJ/2007, civet strain MPC/04, and bat strain 342/08.…”

“…This was the first report of reoviruses in bats that were not clustered into the species Pteropine orthoreovirus but in MRVs. Almost at the same time, an Italian group published data on reovirus detection in various bat species, reporting nucleotide sequences of partial L1 and complete S1 segments, which showed the highest similarity to the German bat isolate (12). Both research groups speculated on bat-to-human interspecies transmission, but there was no evidence to support this hypothesis.…”

“…First, the detection of an MRV with high identity to MRV isolates found in European bats is an important indicator of bat-to-human interspecies transmission, as was already speculated by German and Italian groups (11,12). The real epidemiological situation regarding MRVs in bats and their transmission to other animal species should be further investigated in order to understand the full zoonotic potential and pathogenesis of these viruses.…”

“…This study is the first description of a bat MRV found in humans. Probably MRVs are widely distributed among bat species, since they have been found in insectivorous bats in Germany and in Italy (11,12).…”

Transient high level mammalian reovirus replication in a bat epithelial cell line occurs without cytopathic effect

“…Furthermore, in the last few years, novel strains of reoviruses have been isolated from different animals species, especially wild bats, or in humans in contact with bats (Chua et al, 2007(Chua et al, , 2008(Chua et al, , 2011Du et al, 2010;Kohl et al, 2012;Lelli et al, 2012;Pritchard et al, 2006;Thalmann et al, 2010;Wong et al, 2012). These animals present a special interest since they are presently the object of intense studies as important reservoirs for many pathogenic and emerging viruses (reviewed in: Calisher et al, 2006;Hayman et al, 2012;Hughes et al, 2007;Wang, 2011;Wang et al, 2011; , 2007).…”