Predominance and first complete genomic characterization of canine parvovirus 2b in Turkey

Whole-genome sequence analysis of canine parvovirus reveals replacement with a novel CPV-2c strain throughout India

Canine parvovirus (CPV) infection causes severe gastroenteritis in canines, with high mortality in puppies. This virus evolved from feline panleukopenia virus by altering its transferrin receptor (TfR), followed by the emergence of CPV-2 variants in subsequent years with altered immunodominant amino acid residues in the VP2 protein. While previous studies have focused on the VP2 gene, there have been fewer studies on non-structural protein (NS1 and NS2) genes. In the present study, CPV genome sequences from clinical samples collected from canines throughout India in 2023, previous Indian CPV isolates from 2009-2019, and the current Indian CPV vaccine strain were compared. The study showed that the CPV-2c (N426E) variant had almost completely replaced the previously dominant CPV-2a variant (N426) in India. The Q370R mutation of VP2 was the most common change in the recent CPV-2c strain (CPV-2c 370Arg variant). Phylogenetic analysis showed the existence of three clades among the recent CPV-2c strains, and sequence analysis identified several new sites of positive selection in the VP1 (N-terminus), VP2, NS1, and NS2 protein-encoding genes in recent CPV strains, indicating the emergence of new CPV-2c variants with varied antigenic and replication properties. The predominant 'CPV-2c 370Arg variants' were grouped with the Chinese and Nigerian CPV-2c strains but were separate from the CPV vaccine strain and earlier isolates from our repository. VP2 epitope analysis predicted nine amino acid variations (including two new variations) in four potential linear B-cell epitopes in the CPV-2c 370Arg variants that might make vaccine failure more likely. This pan-Indian study lays the foundation for further research concerning the dynamics of virus evolution and understanding genetic mutations.

Clinical and inflammatory response to antiviral treatments in dogs with parvoviral enteritis

BACKGROUND

Canine parvoviral enteritis (CPE) is a fatal disease worldwide. The treatment of CPE is based mainly on supportive and symptomatic treatment. Antiviral addition to the treatment may result in a higher survival.

OBJECTIVES

This study evaluated the effects of antiviral treatments with a standardized treatment (ST) on the clinical and inflammatory response of dogs with naturally occurring CPE.

METHODS

Twenty-eight dogs with CPE caused by canine parvovirus type 2 were divided randomly into treatment groups. The ST group received fluid, antibiotic, antiemetic, and deworming treatments. The antiviral treatment groups received the same ST with an additional antiviral drug, recombinant feline interferon omega (rFeIFN-ω), oseltamivir (OSEL) or famciclovir (FAM).

RESULTS

Compared to the healthy control, the tumor necrosis factor-α, interleukin-1β, interferon (IFN)-α, IFN-γ, haptoglobin, and C-reactive protein values were high (p < 0.05) on day zero. At presentation, mild lymphopenia, neutropenia, and a high neutrophil to lymphocyte (LYM) ratio (NLR) were also observed. Adding rFeIFN-ω to the ST produced the best improvement in the clinical score with a decreased NLR, while leucocytes remained low and inflammatory markers stayed high on day three. The survival rates of the groups were 85.7% in ST+IFN, 71.4% in ST+OSEL, 71.4% in ST+FAM, and 57.1% in ST groups on day seven.

CONCLUSIONS

Antiviral drugs may be valuable in treating CPE to improve the clinical signs and survival. In addition, the decrease in NLR in favor of LYM may be an indicator of the early prognosis before the improvement of leukocytes, cytokines, and acute phase proteins in CPE.

Canine Parvovirus in Turkey: First Whole-Genome Sequences, Strain Distribution, and Prevalence

Canine parvovirus (CPV) is a significant pathogenic virus with up to 100% morbidity and 91% mortality rates, especially in unvaccinated puppies. The emergence of new strains, interspecies transmission, and vaccine effectiveness can be enabled by just a few base changes in the CPV genome. Therefore, to cope with CPV disease, it is important to identify the viral agent and regularly monitor vaccine effectiveness against new strains. The present study has investigated CPV's genetic profile in Turkey by collecting 80 samples from dogs in Turkey between 2020 and 2022. These samples and all sequences previously studied for CPV in Turkey were analyzed for whole-genome sequences, nationwide strain distribution over the two years, and the central Turkey prevalence rate. Next-generation sequencing was used for the genome study, Sanger sequencing for strain detection, and PCR for the prevalence analyses. The CPV-2 variants circulating in Turkey form their own cluster while being closely related to Egypt variants. Substantial amino acid changes were detected in antigenically important regions of the VP2 gene. Moreover, CPV-2b has become the most frequent genotype in this region, while the incidence of CPV-2c is predicted to increase gradually over the coming years. The prevalence of CPV in central Turkey was 86.27%. This study thus provides powerful insights to further our understanding of CPV's genetic profile in Turkey and suggests that up-to-date vaccination efficacy studies are urgently needed.

Investigation of canine chaphamaparvovirus, canine bufavirus, and canine adenovirus in dogs with diarrhea: First report of novel canine bufavirus in Turkey

Viral enteritis is a significant cause of death among dogs younger than 6 months. In this study, the presence of canine chaphamaparvovirus (CaChPV), canine bufavirus (CBuV), and canine adenovirus (CAdV) was investigated in 62 diarrheal dogs previously tested for other viral pathogens (canine parvovirus type 2, canine coronavirus, and canine circovirus). CBuV was detected in two dogs (3.22%) and CaChPV in one dog (1.61%). One dog tested positive for three parvoviruses (CPV-2b, CBuV, and CaChPV). All dogs tested negative to CAdV-1/CAdV-2. A long genome fragment of one of the two identified CBuVs and of the CaChPV was obtained and analyzed. New Turkish CBuVs had high identity rates (96%-98% nt; 97%-98% aa) with some Italian CBuV strains (CaBuV/9AS/2005/ITA and CaBuV/35/2016/ITA). The phylogenetic analysis powerfully demonstrated that these viruses belonged to a novel genotype (genotype 2). A part of the genome ChPV-TR-2021-19 revealed high identity rates (> 98% nt and > 99% aa) with some Canadian CaChPV strains (NWT-W88 and NWT-W171) and the Italian CaChPV strain Te/37OVUD/2019/IT. This study is the first report on the detection of CBuV-2 and the concomitant presence of three canine parvoviruses in Turkey. The obtained data will contribute to the molecular epidemiology and the role in the etiology of enteric disease of new parvoviruses.