Molecular detection and phylogenetic analysis of pigeon circovirus from
racing pigeons in China during 2016-2019
Abstract
The Pigeon circovirus (PiCV) containing a circular single
stranded DNA (approximately 2 kb) genome belongs to the genus
Circovirus 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. A cap-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.