Sessions

Canine parvovirus-2 (CPV-2) and Canine circovirus (CanineCV) are important viral pathogens associated with gastrointestinal disease in companion animals. CPV-2, a member of the family Parvoviridae, was first identified in the late 1970s. Its rapid evolution, driven by point mutations and recombination events, has resulted in the emergence of multiple antigenic variants, including CPV-2a, CPV-2b, and CPV-2c, thereby complicating both diagnostic approaches and vaccination strategies. CanineCV, a small DNA virus belonging to the family Circoviridae, was first described in 2012. Although its pathogenic potential is less well defined than CPV-2, several clinical studies have reported its detection in outbreaks of haemorrhagic enteritis, frequently in co-infection with CPV-2. Characterising the genetic diversity and evolutionary dynamics of these viruses is therefore essential for disease surveillance, vaccine development, and the implementation of effective control measures.

Despite gastroenteritis being a commonly reported condition in dogs and cats in Malta, no genetic data on CPV-2 or CanineCV have been published to date. The present study was undertaken to (i) screen faecal samples collected from dogs and cats across Malta for the presence of CPV-2 and CanineCV, (ii) sequence the detected viral strains, and (iii) perform phylogenetic analyses in comparison with reference sequences available in GenBank, with the objective of genotyping and investigating patterns of viral genome evolution.

A total of 10 faecal samples (four from dogs and six from cats) were collected in 2025 from CPV-2 ELISA-positive patients. DNA was extracted from faecal swabs and screened for CPV-2 and CanineCV using quantitative PCR. Positive samples were subjected to Sanger-sequencing. After proofreading, the obtained nucleotide sequences were aligned with reference datasets and analysed using the Maximum Likelihood algorithm.

CPV-2 was detected in seven samples, while CanineCV was not detected in any of the specimens. Whole and partial VP2 sequences were determined in all positive cases. All CPV-2 sequences clustered within the CPV-2c lineage and were found to be genetically closest to strains previously identified in Italy. In contrast, FPV sequences showed highest similarity to strains reported in Asia.The genetic relatedness of Maltese CPV-2 strains to those circulating in Italy highlights potential regional epidemiological links. These findings contribute to the global understanding of CPV-2 molecular epidemiology and underscore the need for continued surveillance to inform effective disease management and vaccination strategies.