First identification of canine parvovirus -2a/2b variant in unvaccinated domestic dogs with gastrointestinal signs in Türkiye.

Abstract

Background: Canine parvovirus type 2 (CPV-2) is the most common enteric virus that infects canids. CPV is the causative agent of a contagious disease defined mostly by clinical gastrointestinal signs in dogs. During the late 1970s, CPV-2 emerged as a new virus capable of infecting domestic dogs and growing across the world. The VP2 gene stands out as a key determinant in the pathogenicity, antigenicity, and host interactions of CPV-2.

Aims: The molecular characterization of the VP2 gene is crucial for understanding CPV evolution and epidemiology.

Materials & methods: Genes encoding the VP2 protein were sequenced and compared to reference strains worldwide. The maximum likelihood method was used to build a phylogenetic tree using CPV VP2 gene nucleotide sequences.

Results: Our phylogenetic analysis of the VP2 gene revealed that five strains were very similar and clustered together, and three strains were in the 2b clade, whereas the other two were in the 2a/2b clade.

Discussion: This paper reports the molecular characterization of two novel CPV-2a/2b subtypes in dogs with gastrointestinal symptoms. Genetic analysis was conducted on a CPV genomic region encompassing one of the open reading frames (ORFs) encoding the structural protein VP2. Sequence analysis indicates new and unreported sequence changes, mainly affecting the VP2 gene, which includes the mutations Ser297Ala and Leu87Met. This study represents the first evidence of a new CPV-2a/2b subtype in Türkiye. Due to VP2's crucial role in encoding the capsid protein of CPV-2 and its significant involvement in the host-virus interaction, it is critical to closely monitor its evolutionary changes and be cautious while searching for novel or pre-existing subtypes.

Conclusion: This study highlights the significance of continuous molecular research for acquiring more insights on the circulation of novel CPV mutants.