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High Diversity of Genogroup I Picobirnaviruses in Mammals

View Article: PubMed Central - PubMed

ABSTRACT

In a molecular epidemiology study using 791 fecal samples collected from different terrestrial and marine mammals in Hong Kong, genogroup I picobirnaviruses (PBVs) were positive by RT-PCR targeting the partial RdRp gene in specimens from five cattle, six monkeys, 17 horses, nine pigs, one rabbit, one dog, and 12 California sea lions, with 11, 9, 23, 17, 1, 1, and 15 sequence types in the positive specimens from the corresponding animals, respectively. Phylogenetic analysis showed that the PBV sequences from each kind of animal were widely distributed in the whole tree with high diversity, sharing 47.4–89.0% nucleotide identities with other genogroup I PBV strains based on the partial RdRp gene. Nine complete segment 1 (viral loads 1.7 × 104 to 5.9 × 106/ml) and 15 segment 2 (viral loads 4.1 × 103 to 1.3 × 106/ml) of otarine PBVs from fecal samples serially collected from California sea lions were sequenced. In the two phylogenetic trees constructed using ORF2 and ORF3 of segment 1, the nine segment 1 sequences were clustered into four distinct clades (C1–C4). In the tree constructed using RdRp gene of segment 2, the 15 segment 2 sequences were clustered into nine distinct clades (R1–R9). In four sea lions, PBVs were detected in two different years, with the same segment 1 clade (C3) present in two consecutive years from one sea lion and different clades present in different years from three sea lions. A high diversity of PBVs was observed in a variety of terrestrial and marine mammals. Multiple sequence types with significant differences, representing multiple strains of PBV, were present in the majority of PBV-positive samples from different kinds of animals.

No MeSH data available.


Circulation and evolution model of otarine PBVs in California sea lions. Possible otarine PBVs detected in the serial fecal samples of California sea lions collected in different years are shown. Possible reassortment of segments 1 and 2 of different clades (C1–C4 and R1–R9) circulating in the California sea lions are also indicated.
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Figure 4: Circulation and evolution model of otarine PBVs in California sea lions. Possible otarine PBVs detected in the serial fecal samples of California sea lions collected in different years are shown. Possible reassortment of segments 1 and 2 of different clades (C1–C4 and R1–R9) circulating in the California sea lions are also indicated.

Mentions: Picobirnaviruse probably evolves through mechanisms similar to other segmented RNA viruses (Figure 4). The most thoroughly studied segmented RNA viruses are the influenza viruses (negative-sense single-stranded RNA virus) and rotaviruses (double-stranded RNA virus). Influenza viruses evolve through reassortment of RNA segments resulting in antigenic shifts and RNA mutations leading to antigenic drifts and causing major pandemics, lots of mortalities and morbidities, and economic lost (Smith et al., 2009). As for rotaviruses, virus strains belonging to the same group can also reassort their genomes resulting in enormous diversity (Kirkwood, 2010). This provides one of the mechanisms for the emergence of new rotavirus strains leading to disease outbreaks and loss of vaccine efficacy (Kirkwood, 2010). The presence of multiple segment 1 and segment 2 in the same animal observed in this study provides the PBV genome a good opportunity for reassortment (Figure 4). In addition, in the serially collected fecal samples from sea lions, it was also observed that two segment 1 sequences that belonged to the same clade (C3) can be present in the same animal (GiGi) from two consecutive years (Table 4). There were 18 nucleotide changes in these two segment 1 sequences, leading to 11 amino acid changes. This could be due to persistence of the same PBV with mutational changes over 2 years or re-infection by another otarine PBV with segment 1 of the same clade but of a different sequence type.


High Diversity of Genogroup I Picobirnaviruses in Mammals
Circulation and evolution model of otarine PBVs in California sea lions. Possible otarine PBVs detected in the serial fecal samples of California sea lions collected in different years are shown. Possible reassortment of segments 1 and 2 of different clades (C1–C4 and R1–R9) circulating in the California sea lions are also indicated.
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Related In: Results  -  Collection

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Figure 4: Circulation and evolution model of otarine PBVs in California sea lions. Possible otarine PBVs detected in the serial fecal samples of California sea lions collected in different years are shown. Possible reassortment of segments 1 and 2 of different clades (C1–C4 and R1–R9) circulating in the California sea lions are also indicated.
Mentions: Picobirnaviruse probably evolves through mechanisms similar to other segmented RNA viruses (Figure 4). The most thoroughly studied segmented RNA viruses are the influenza viruses (negative-sense single-stranded RNA virus) and rotaviruses (double-stranded RNA virus). Influenza viruses evolve through reassortment of RNA segments resulting in antigenic shifts and RNA mutations leading to antigenic drifts and causing major pandemics, lots of mortalities and morbidities, and economic lost (Smith et al., 2009). As for rotaviruses, virus strains belonging to the same group can also reassort their genomes resulting in enormous diversity (Kirkwood, 2010). This provides one of the mechanisms for the emergence of new rotavirus strains leading to disease outbreaks and loss of vaccine efficacy (Kirkwood, 2010). The presence of multiple segment 1 and segment 2 in the same animal observed in this study provides the PBV genome a good opportunity for reassortment (Figure 4). In addition, in the serially collected fecal samples from sea lions, it was also observed that two segment 1 sequences that belonged to the same clade (C3) can be present in the same animal (GiGi) from two consecutive years (Table 4). There were 18 nucleotide changes in these two segment 1 sequences, leading to 11 amino acid changes. This could be due to persistence of the same PBV with mutational changes over 2 years or re-infection by another otarine PBV with segment 1 of the same clade but of a different sequence type.

View Article: PubMed Central - PubMed

ABSTRACT

In a molecular epidemiology study using 791 fecal samples collected from different terrestrial and marine mammals in Hong Kong, genogroup I picobirnaviruses (PBVs) were positive by RT-PCR targeting the partial RdRp gene in specimens from five cattle, six monkeys, 17 horses, nine pigs, one rabbit, one dog, and 12 California sea lions, with 11, 9, 23, 17, 1, 1, and 15 sequence types in the positive specimens from the corresponding animals, respectively. Phylogenetic analysis showed that the PBV sequences from each kind of animal were widely distributed in the whole tree with high diversity, sharing 47.4–89.0% nucleotide identities with other genogroup I PBV strains based on the partial RdRp gene. Nine complete segment 1 (viral loads 1.7 × 104 to 5.9 × 106/ml) and 15 segment 2 (viral loads 4.1 × 103 to 1.3 × 106/ml) of otarine PBVs from fecal samples serially collected from California sea lions were sequenced. In the two phylogenetic trees constructed using ORF2 and ORF3 of segment 1, the nine segment 1 sequences were clustered into four distinct clades (C1–C4). In the tree constructed using RdRp gene of segment 2, the 15 segment 2 sequences were clustered into nine distinct clades (R1–R9). In four sea lions, PBVs were detected in two different years, with the same segment 1 clade (C3) present in two consecutive years from one sea lion and different clades present in different years from three sea lions. A high diversity of PBVs was observed in a variety of terrestrial and marine mammals. Multiple sequence types with significant differences, representing multiple strains of PBV, were present in the majority of PBV-positive samples from different kinds of animals.

No MeSH data available.