Summary
The Pigeon circovirus (PiCV) containing a circular single
stranded DNA (approximately 2 kb) genome belongs to the genusCircovirus of the family Circoviridae . PiCV infections in
pigeons (Columba livia ) have been reported worldwide.
Currently, pigeon racing is
becoming increasingly popular and considered to be a national sport in
China, and even, the greatest
competitions of racing pigeons are taking place in China. However, there
are still no epidemiologic data regarding PiCV infections among racing
pigeons in China. To trace the prevalence, genetic variation and
evolution of PiCV in sick and healthy racing pigeons, 622 samples were
collected from 11 provinces or municipalities in China from 2016 to
2019. Samples were tested by polymerase chain reaction. The results
showed that the positive rate of PiCV was 19.3% (120/622) at the sample
level and 59.0% (23/39) at the club level, thus suggesting that the
virus was prevalent in Chinese racing pigeons. A sequence analysis
revealed that the cap genes of the PiCV strains identified in our
study displayed a high genetic diversity and shared nucleotide
homologies of 71.9%–100% and amino acid homologies of 71.7%–100%.
28 and 36 unique amino acid
substitutions were observed in the Cap and
Rep proteins derived from our PiCV
strains, respectively. Furthermore,
The ATT and GTG were highly
suspected to be the start codons of the Cap protein.
Acap -gene-based phylogenetic analysis showed that the strains in
this study could be further divided into seven clades
(A,
B, C, E, G, H, and I) and some of them were closely related to worldwide
strains from different types of pigeons. A large number of recombination
events (31 events) were also detected in the PiCV genomes from Chinese
racing pigeons. These findings indicate that PiCV strains circulating in
China exhibit a high genetic diversity.