Genomic Characterization of Chicken Anemia Virus in Broilers in Shandong Province, China, 2020–2021

Abstract

Chicken infectious anemia (CIA), caused by chicken anemia virus (CAV), is an immunosuppressive disease characterized by growth retardation, aplastic anemia, lymphoid depletion, and immunodepression in young chickens. In this study, 33 CAV strains were isolated from broilers in Shandong Province during 2020–2021. Phylogenetic analysis of full-length genome sequences showed that most CAV strains isolated in this study were scattered across different branches, but mainly clustered in two genotypes, indicating a certain regional characteristic. Analysis of VP1 protein identified several amino acid substitutions which were relevant with the virulence and virus spread efficiency. Interestingly, four putative DNA recombination events were detected in the genomes of novel isolated CAV strains. In summary, this study demonstrated a genomic diversity of CAV in broilers isolated in Shandong Province during 2020–2021, and provided information for the further study of CAV molecular epidemiology and viral evolution.

Genetic diversity, distribution, and evolution of chicken anemia virus: A comparative genomic and phylogenetic analysis

“…The chicken anemia virus is responsible for immunosuppressive poultry disease CIA ( Pope, 1991 ; Schat, 2009 ; Liu et al, 2022 ), causing huge economic losses to the poultry industry in many parts of the world ( Schat, 2009 ; Fatoba and Adeleke, 2019 ). According to the International Committee on Taxonomy of Viruses (ICTV), the virus is placed in the family Anelloviridae and genus Gyrovirus ( Rosario et al, 2017 ; ICTV, 2020 ; Di Francesco et al, 2022 ), however, there is no classification on the clades and sub-clades level as per ICTV, and CAV strains are usually classified into different groups and sub-groups by the researchers reporting the new strains ( Craig et al, 2009 ; Zhang et al, 2013 ; Liu et al, 2022 ; Zhang et al, 2022 ). Previously, CAVs were sorted into five groups (A to E) based on 54 partial genomic sequences ( Zhang et al, 2013 ), or into four major groups (A, B, C, and D) based on 55 VP1, VP2, and VP3 complete coding sequences ( Eltahir et al, 2011 ).…”

“…CAVs exhibit a low efficiency of recombination as they are DNA viruses. Nevertheless, earlier studies have provided evidence of genetic recombination events in CAVs ( Eltahir et al, 2011 ; Tan et al, 2020 ; Li et al, 2021 ; Liu et al, 2022 ). In this study, we detected eleven recombination events among the CAVs isolated from 1991–2020.…”

“…Chicken infectious anemia (CIA), caused by the chicken anemia virus (CAV), is an immunosuppressive poultry disease that typically causes aplastic anemia, immunosuppression, growth retardation and lymphoid tissue atrophy ( Pope, 1991 ; Schat, 2009 ; Liu et al, 2022 ), causing huge economic losses to the poultry industry all around the world ( Schat, 2009 ; Fatoba and Adeleke, 2019 ). In adult chickens, CAV causes a mild subclinical infection, however, the infected chickens are usually manifested immunosuppression and become more sensitive to secondary infections with bacterial, viral or fungal pathogens ( Adair and Immunology, 2000 ).…”

“…It also causes a sub-optimal response to the vaccinations, making it difficult to control ( Techera et al, 2021 ). Though chicken is the main host of CAV and all kinds of chicken breeds are susceptible to this virus, several reports support the presence of CAV in the feces of other birds and some animals, e.g., mice and dogs ( Rijsewijk et al, 2011 ; Chu et al, 2012 ; Zhang et al, 2014 ; Fang et al, 2017 ; Li et al, 2017 ; Liu et al, 2022 ). CAV strains generally have a 30% mortality ( Li et al, 2021 ), which may reach 60%, particularly in complicated cases ( Gelderblom et al, 1989 ).…”

DNA Prime and Recombinant Protein Boost Vaccination Confers Chickens with Enhanced Protection against Chicken Infectious Anemia Virus

“…Since its first isolation in Japan, CIAV has been widely prevalent worldwide [ 7 , 8 , 9 , 10 ]. CIAV can be transmitted vertically or horizontally [ 11 ], is spread persistently in a chicken flock, and is difficult to eliminate [ 12 ], while bringing great economic losses to the global poultry breeding industry [ 13 ].…”