Emergence of canine parvovirus type 2c in domestic dogs and cats from Thailand

Abstract

Canine parvovirus type 2 (CPV-2) is an important pathogen causing haemorrhagic enteritis in domestic dogs and wildlife worldwide. In early 2000, canine parvovirus type 2c (CPV-2c) was first reported and subsequently became a predominant subtype circulating in Europe and the Americas. CPV-2c has also been reported in Asia, including cases in China, India, Taiwan and Vietnam. However, CPV-2c has never been reported in Thailand. In this study, we conducted viral enteric disease surveillance in dogs and cats in Thailand during 2016-2018. During 20 months of surveillance, 507 rectal swab samples were collected from dogs (n = 444) and cats (n = 63) with and without clinical signs. The samples were examined for parvovirus by using VP2 gene-specific PCR for parvovirus. Our results showed that the positivity of canine parvovirus (CPV) was 29.95% and that of feline parvovirus (FPV) was 58.73%. In this study, we characterized 34 parvoviruses by VP2 gene sequencing. Moreover, two Thai-CPV-2 (Dog/CU-24 and Cat/CU-21) were characterized by whole genome sequencing. The phylogenetic results showed that Thai-CPV-2 had the highest nucleotide identities and clustered with Asian-CPV-2c but were in separate subclusters from the North American and European CPV-2c. Similarly, whole genome analyses showed that Thai-CPVs are closely related to Asian-CPV-2c, with unique amino acids at positions 297A, 324I, 370R and 426E. In summary, our results demonstrated the emergence of Asian-CPV-2c in dogs and cats in Thailand. Thus, the surveillance of CPV-2 in domestic dogs and cats should be further conducted on a larger scale to determine the dynamics of predominant variants and their distributions in the country and in the Southeast Asia region.

Keywords: Thailand; canine parvovirus; characterization; detection; emergence.

Figure 1

Phylogenetic tree of VP2 gene of canine parvovirus type 2 and feline parvovirus. Circles and squares represent Thai‐CPV‐2 and FPV, respectively. The phylogenetic tree was constructed by using the Beast program with Bayesian Markov‐Chain Monte Carlo (BMCMC), with 10,000,000 generations and an average standard deviation of split frequencies <0.10. Values on branches represent times of most recent common ancestor (TMRCA) among CPV‐2 antigenic types [Colour figure can be viewed at http://www.wileyonlinelibrary.com]

Figure 2

Amino acid alignment of VP2 protein of CPV‐2. Dots represent matched amino acid residues. Open boxes indicate amino acid substitutions