Genetic and Antigenic Characterization and Retrospective Surveillance of Bovine Influenza D Viruses Identified in Hokkaido, Japan from 2018 to 2020.

Jun Hayakawa,Tomomi Masuko,Tohru Suzuki,Tae Takehana

doi:10.3390/v12080877

Jun Hayakawa, Tomomi Masuko + Show 2 more

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https://doi.org/10.3390/v12080877

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Abstract

Influenza D virus (IDV), which is a new member of the Orthomyxoviridae family, is potentially involved in bovine respiratory diseases (BRDs). Bovine IDVs (BIDVs) from Japan have been distributed nationwide since 2010 and are genetically distinct from foreign IDVs. We isolated BIDVs from three BRD outbreaks, in Hokkaido during 2018–2020, to understand their genetic and antigenic characteristics. Retrospective surveillance was performed using sera collected throughout the last decade in Hokkaido to investigate BIDV existence. Three BIDVs were isolated using cell culture. Comparative and phylogenetic analyses using sequence data of the three BIDVs and IDVs from Japan and other countries available in GenBank demonstrated that Japanese BIDVs, including the three BIDV isolates, were genetically distinct from other IDVs. Genotype classifications based on the rotavirus genotype classification revealed multiple genotypes of RNA segments 1–7. Two BIDVs were of a new genotype, different from those of other Japanese BIDVs. Neutralization assays against two BIDVs with different genotypes using sera collected in acute and recovery phases of BRD revealed differences in cross-reactivity to heterogenous BIDVs. Retrospective surveillance suggested that BIDV existed in Hokkaido, in 2009. Our findings suggest that BIDVs of different genotypes and antigenicity are distributed and maintained in Hokkaido and provide new insights into molecular characteristics and the evolution of IDVs.

Highlights

Influenza viruses are enveloped, segmented, single-stranded, negative-sense RNA viruses, which belong to the family Orthomyxoviridae, and are currently classified into the following four species: influenza A, B, C, and D (IAV–Influenza D virus (IDV))
We found that Bovine IDVs (BIDVs) were associated with bovine respiratory diseases (BRDs) outbreaks the occurred in Hokkaido, in recent years
In Outbreak 2, bovine respiratory syncytial virus (BRSV) and BIDV were identified by reverse transcription-PCR (RT-PCR) and qRT-PCR, respectively

Summary

Introduction

Influenza viruses are enveloped, segmented, single-stranded, negative-sense RNA viruses, which belong to the family Orthomyxoviridae, and are currently classified into the following four species: influenza A, B, C, and D (IAV–IDV). The genomes of IAV and IBV consist of eight RNA segments, whereas ICV and IDV have seven segments. Both IAV and IBV contain two major surface glycoproteins, i.e., hemagglutinin (HA) which binds to host cell receptors and mediates membrane fusion, and neuraminidase (NA) which cleaves receptor sialic acids resulting in the release of newly assembled virus particles [1]. ICV and IDV have only one major glycoprotein, the hemagglutinin-esterase-fusion (HEF) protein, which possesses “all-in-one” activities of receptor binding, receptor cleavage, and membrane fusion [2,3,4,5]. The IDV HEF glycoprotein is structurally and Viruses 2020, 12, 877; doi:10.3390/v12080877 www.mdpi.com/journal/viruses.

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