Pathogenicity of duck circovirus 1 in experimentally infected specific pathogen-free ducks

Ducks infected with duck circovirus (DuCV) show symptoms such as feather loss, growth retardation and low body weight in the flock. The virus induces immunosuppression and increases the preva-lence of infection with other pathogens. However, most studies on duck circovirus were focused on coinfection, and fewer studies had been conducted on the pathoge-nicity of duck circovirus alone. The aim of the present study was to investigate the pathogenesis of DuCV-1 in experimentally infected specific pathogen-free ducks. In this study, we sequenced the whole genome of a strain of duck circovirus and identified the virus genotype as DuCV-1b. This strain of duck circovirus was named SDLH(OR567883). Animal pathogenicity experiments were then conducted, wherein specific pathogen-free ducks were infected by mucosal injection and abdomi-nal injection. Infected ducks were sampled for 4 conse-cutive weeks after infection and showed symptoms of dwarfism. We further examined the replication of DuCV-1 in the ducks. The highest virus titers in the 2 infection groups were found in the liver and spleen, with different results for the different routes of infec-tion. Pathological sections of duck organs were made and it was found that organs such as the liver and spleen were damaged by DuCV-1. In conclusion, our experimental results indicate that DuCV-1 can infect ducks individually and cause widespread organ damage in infected ducks.