Canine Parvoviral Enteritis Incidence in Rostov-on-Don in 2017-2022: A Retrospective Analysis

Abstract

Introduction. The canine parvoviral enteritis, first detected in 1978 [1], remains a widespread cause of morbidity and mortality in young dogs. The virus high virulence and resistance are attributed to its ability to mutate and undergo changes, that partly explains the continuing epidemic of the canine parvoviral enteritis.The nature of the disease itself got modified since the first time of virus detection. Although the initial outbreaks had the panzootic character implying high morbidity and mortality, nowadays the majority of adult dogs have either vaccinal immunity or immunity acquired through natural infection, thus the parvoviral infection is primarily manifested in young dogs aged from weaning to six months old as the enteric disease form.The objective of the study was to investigate the antigenic essence of the canine parvoviral enteritis by analysing the strain phylogenetic relationships in the absence of grouping the same antigenic type viruses upon emerging the mutations.Materials and Methods. The material for the study was selected by the method of continuous sampling of the medical records (by generating random numbers in the range of 1–255) and conducting interviews with the personnel (veterinary doctors) at the «Animal Clinic» veterinary hospital in Rostov-on-Don from September 2017 to October 2022. Data on the dog owners was concealed, hypotheses were not communicated to the clinic management, that excluded possible errors and conflict of interest. The study focused on the analysis of the epidemiological situation in Rostov-on-Don with regard to the canine parvoviral enteritis incidence and mortality rate, the analysis was based on the practices of the «Animal Clinic» veterinary hospital, volunteer organisations, homeless animal care foundations and «Dog Patrol» nonprofit organisation and was interpolated to the epidemiological situation in the city as a whole.The study of the canine parvoviral enteritis cases, the disease epidemiology and its combat methods, treatment, prophylaxis and the cutting-edge developments in the field was carried out based on the scientific data of the last 5 years. The objects of the study were dogs of various breeds and ages admitted to the clinic.Results and Discussion. The established phylogenetic interrelation of the divergent CPV-2b strain with the alike genetic strain-ancestor CPV-2c, indicates a complete replacement of the circulating strains, which has practical value for the veterinary science as it does not merely enable formation of a disease model for a specific region but also allows evaluating the speed and features of spreading the disease and predicting its course and mortality.Conclusion. For the southern region the parvoviral enteritis is a severe and life-threatening disease due to the rates of its overall incidence and mortality. The results of the statistical analysis of 307 medical records of the dogs diagnosed with the parvoviral enteritis in a number of Rostov-on-Don veterinary clinics revealed twice as high mortality rate in male dogs compared to females, although the distribution of the number of disease cases was relatively equal, except for the range of 30-90 days when a statistically significant difference in mortality was not registered. A separate local surge in mortality rate by over 36 %, which is not correlated either with the reduced number of cases during this period or the average level of fatal outcomes, indicates the need to correlate the patients’ immune status with the applied treatment protocols and the CPV-2c strain penetration, having the higher virulence in Europe (in 2015–2017) [2] and the European part of Russia.When analysing the «age-number of cases» data, the correlation was made with the surge in patients at the age of about 1 year old. The vaccination reduced the incidence rate in dogs and disease severity in those infected, but at the same time increased the mutation numbers in the virus genome (especially in the genes encoding the protein responsible for binding to the receptor cells [3]), which in turn led to increased virulence.