Molecular detection and phylogenetic analysis of pigeon circovirus in
China during 2016-2019
Abstract
The Pigeon circovirus (PiCV) which contains a circular single stranded
DNA (approximately 2 kb) belongs to the genus Circovirus and the family
Circoviridae. PiCV infections in pigeons (Columba livia) have been
reported worldwide. Nowadays, pigeon racing is becoming increasingly
popular and considered to be a national sport in China, and even, the
greatest competitions of racing pigeons are stake place in China.
However, there is no epidemiologic data on 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 of 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; 59.0% (23/39) at the club level, 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 display high
genetic diversity and shared nucleotide homologies of 71.9%–100% and
amino acid homologies of 71.7%–100%. 28 and 37 unique amino acid
substitutions were observed among the cap proteins and rep proteins of
our PiCV strains, respectively. Furthermore, two initiation codons (GTG
and ATT) of cap gene were newly found. A cap-gene-based phylogenetic
analysis showed that the strains in this study could be further divided
into six groups (A, B, C, E, G, H and I) and some of our strains are
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 suggest
that PiCV strains circulating in China exhibits higher genetic
diversity.