Genetic and pathogenic characterisation of 11 avian reovirus isolates from northern China suggests continued evolution of virulence.

Li Zhong,Miao Wang,Yulong Gao,Yongzhen Liu,Xiaole Qi,Xiaomei Wang,Li Gao,Kai Li

doi:10.1038/srep35271

Li Zhong, Miao Wang + Show 6 more

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https://doi.org/10.1038/srep35271

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Abstract

Avian reovirus (ARV) infections characterised by severe arthritis, tenosynovitis, pericarditis, and depressed growth have become increasingly frequent in recent years. In this study, we isolated and identified 11 ARV field strains from chickens with viral arthritis and reduced growth in northern China. Comparative analysis of the σC nucleotide and amino acid sequences demonstrated that all isolates, except LN05 and JS01, were closely related to ARV S1133 and clustered in the first genetic lineage. LN05 and JS01 strains were clustered in the third lineage with the ARV 138 strain. Using S1133 as a reference, five isolates were selected to infect specific-pathogen-free chickens, and we found that the recent isolated Chinese ARV strains had higher replication ability in vivo and caused enhanced mortality than the S1133 strain. These findings suggest that the pathogenicity of Chinese ARVs has been changing in recent years and disease control may become more difficult. This study provides genetic and pathogenic characterisations of ARV strains isolated in northern China and calls for a sustained surveillance of ARV infection in China in order to support a better prevention and control of the disease.

Highlights

Avian reoviruses (ARVs) are important poultry pathogens that cause considerable economic losses in poultry husbandry[1]
ARV strains have been associated with disease conditions such as viral arthritis, tenosynovitis, and malabsorption syndrome[17]; these viruses have been isolated from chickens without any clinical symptoms
Economic losses in poultry husbandry resulting from ARV infections highlight the critical need to study the pathogenicity of ARV strains

Summary

Introduction

Avian reoviruses (ARVs) are important poultry pathogens that cause considerable economic losses in poultry husbandry[1]. Reoviruses were responsible for outbreaks in England and the United States in the 1960s and 1970s3,4 These viruses are apparently ubiquitous among poultry flocks, and field outbreaks, especially in broiler breeders, have been reported in many parts of the world[5]. ARVs are classified in the family Reoviridae under the genus Orthoreovirus[6] They are icosahedral non-enveloped double-stranded RNA (dsRNA) viruses with a particle size of 70–80 nm containing ten genome segments[6]. The cell attachment protein σCis encoded by the third and largest open reading frame of the ARV S1 genome segment[8]. This protein is useful for comparing strains because it is the most variable protein produced by www.nature.com/scientificreports/. Much research has been conducted to characterise the σC protein at the molecular and nucleotide sequence levels[15]

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