Genomic Analysis of the Chicken Infectious Anemia Virus in a Specific Pathogen-Free Chicken Population in China

Yang Li,Yingjie Zhao,Shuai Cui,Zhizhong Cui,Lichun Fang,Shuang Chang,Peng Zhao,Yixin Wang,Jiayuan Fu

doi:10.1155/2016/4275718

Yang Li, Yingjie Zhao + Show 7 more

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https://doi.org/10.1155/2016/4275718

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Abstract

The antibody to chicken infectious anemia virus (CIAV) was positive in a specific pathogen-free (SPF) chicken population by ELISA test in our previous inspection, indicating a possible infection with CIAV. In this study, blood samples collected from the SPF chickens were used to isolate CIAV by inoculating into MSB1 cells and PCR amplification. A CIAV strain (SD1403) was isolated and successfully identified. Three overlapping genomic fragments were obtained by PCR amplification and sequencing. The full genome sequence of the SD1403 strain was obtained by aligning the sequences. The genome of the SD1403 strain was 2293 bp with a nucleotide identity of 94.8% to 98.5% when compared with 30 referred CIAV strains. The viral proteins VP2 and VP3 were highly conserved, but VP1 was not relatively conserved. Both amino acids 139 and 144 of VP1 were glutamine, which was in accord with the low pathogenic characteristics. In this study, we first reported that CIAV exists in Chinese SPF chicken populations and may be an important reason why attenuated vaccine can be contaminated with CIAV.

Highlights

Chicken infectious anemia virus (CIAV) can cause the atrophy of bone marrow hematopoietic and lymphoid tissues in young chickens, leading to aplastic anemia and immune suppression
Comparison between the whole genome sequences of the SD1403 strain and 30 other strains was carried out, and the results demonstrated that the homology was 94.8%–98.5%
The main reason for this phenomenon is that vaccines made from specific pathogen-free (SPF) chicken embryos contaminated by viruses have been used

Summary

Introduction

Chicken infectious anemia virus (CIAV) can cause the atrophy of bone marrow hematopoietic and lymphoid tissues (e.g., thymus) in young chickens, leading to aplastic anemia and immune suppression. CIAV belongs to the Gyrovirus genus of the Circoviridae family, and the genome has three open reading frames (ORFs) which encode VP1, VP2, and VP3 [2]. Previous studies have indicated that AAs 139–151 are a highly variable region of the VP1 gene, and AA 139 or 144 could especially affect virus replication and cell infection [7]. Speaking, if both AA 139 and 144 in the loci are glutamines, replication and infective ability of the virus are relatively weaker [7]

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