Novel Cyclovirus Identified in Broiler Chickens With Transmissible Viral Proventriculitis in China

Abstract

In October 2018, an outbreak of transmissible viral proventriculitis (TVP) occurred in 30-day-old commercial broiler chickens on a farm in Weifang, China. TVP, an infectious viral disease characterized by runting and stunting, is associated with many viruses, and has a significant economic impact on the global poultry industry. TVP is diagnosed according to clinical symptoms, gross and histological lesions, and negative PCR results for pathogenic bacteria, avian leukosis virus subgroup J, Marek's disease virus, reticuloendotheliosis virus, infectious bursa disease virus, avian reovirus, chicken anemia virus, infectious bronchitis virus, chicken proventricular necrosis virus, gyrovirus 3 and chicken circovirus. To further detect the possible causative pathogens of TVP, we used PacBio third-generation sequencing to examine proventricular samples. A dominant abundance of the novel cyclovirus (CyCV), chCyCV-SDAU-1, was identified in broilers with TVP. The complete chCyCV-SDAU-1 genome was verified via inverse PCR, was 1936 bp long, and consisted of Rep, Cp, and two intergenic regions. Phylogenetic tree analysis showed that chCyCV-SDAU-1 formed an independent branch with other cycloviruses. The homology of chCyCV-SDAU-1 with 20 others known cycloviruses was < 40%. Retrospective investigation showed that the CyCV infection rate in the broilers with TVP was 80% (16/20), while no CyCV was found in healthy chickens. In conclusion, a novel CyCV was identified in chickens with TVP, though its role in this disease is unclear.

Diverse Single-Stranded DNA Viruses Identified in Chicken Buccal Swabs

“…Cycloviruses in chickens were found to be associated with transmissible viral proventriculitis (TVP) that resulted in lesions, runting, and stunting [58]. Lima et al [59] identified cycloviruses in malabsorption syndrome from chickens in Brazil.…”

Long read sequencing revealed proventricular virome of broiler chicken with transmission viral proventriculitis

“…Since then, CPNV was reported in the USA, Spain, France, UK, Poland and Brazil [ 8 – 13 ]. Studies on TVP etiopathology also imply the other viruses involvement, including infectious bursal disease viruses (IBDV) of the Birnaviridae family, infectious bronchitis viruses (IB) of the Coronaviridae family, reoviruses (REO), picornaviruses, fowl adenoviruses (FAdV), adeno-like viruses, Gyrovirus homsa1 (GyH1, also known as Gyrovirus 3, GyV3), Cyclovirus (CyCV) of the Anelloviridae [ 14 , 15 ] and chicken Circovirus (CCV) of the Circoviridae [ 16 ].…”

Novel Cyclovirus Species in Dogs with Hemorrhagic Gastroenteritis

“…Based on genome-wide pairwise nt sequence identities and a phylogenetic analysis, at least 52 cyclovirus species have been formally recognized by the International Committee on Taxonomy of Viruses (ICTV) (https://talk.ictvonline.org/ictv-reports/ictv_online_ report/ssdna-viruses/w/circoviridae/660/genus-cyclovirus, accessed on 18 September 2021). Cycloviruses have been detected in various mammals, birds and arthropods [1][2][3][4][5][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. Furthermore, an endogenous cyclovirus element was identified from a rodent-infecting nematode, suggesting that cycloviruses might infect non-arthropod parasitic invertebrates [12].…”

“…Furthermore, an endogenous cyclovirus element was identified from a rodent-infecting nematode, suggesting that cycloviruses might infect non-arthropod parasitic invertebrates [12]. Since the discovery of cycloviruses was solely based on the identification of viral DNA (by degenerate PCR and metagenomic sequencing) [1][2][3][4][5][8][9][10][11][12][13][14][15][16][17][18][19][20][21], the definitive hosts and pathogenesis of cycloviruses are largely unknown [1,2,4,5,12,13]. However, cycloviruses have been reported in humans with diarrhea [21], encephalitis [21], paralysis [14] and pneumonia [10].…”