Identification and characterisation of viral bloody diarrhoea aetiology in puppies, presented to the Animal Health hospital, North-West University
Abstract
Diarrhoea is a complex condition mostly encountered in small animal practices incriminating some common enteric pathogens including canine parvovirus type 2, canine coronavirus, canine distemper virus, canine rotavirus, endoparasites, bacteria as well as life style and diet. The CPV, CCoV and CRV are the main viral enteric pathogens responsible for severe gastroenteritis including diarrhoea; whereas CPV-2 is the cause of high morbidity and high mortality in dog populations. Since its appearance in the late 1970, several evolutions and mutations of CPV have been observed, resulting in the replacement of the original type by its new variants CPV-2a, CPV-2b and later on CPV-2c, circulating worldwide. Nowadays, in severe cases of CPV-2 infection, it was found that there is mix infection between CPV-2 and CCoV, or CPV-2 and CRV infection. Therefore, the monitoring of these infectious diseases is critical for control and prevention. Our study aimed to determine the epidemiology of bloody diarrhoea, to identify and discriminate viral enteric pathogens circulating among puppies presented to the North West University, Animal Health hospital, Mafikeng campus by means of Immunochromatography and molecular techniques. Faecal samples of 84 diarrhoeic dogs presented with signs suspected to be due to CPV-2 infection were collected at consultation. In addition, other demographic informations were collected for each dog. Two diagnostic methods were used: Immunochromatography assay (IC) for antigen detection and conventional PCR using the universal CPV primers for characterisation. Of the 84 samples, IC tested 66/84, 2/84 and 2/84 positive CPV-2, CCoV and CRV antigens respectively. Conventional PCR revealed 80/84, 0/84 and 12/84 positive CPV-2 DNA, CCoV-RNA and CRV-RNA respectively. The analysis of the sequences confirmed the presence of 80 CPV-2 strains and 12 CRV strains. The predominant circulating variant was the CPV-2c followed by CPV-2b (minor); and G3 rotavirus serotype. The statistical results showed a significance (P<0.05) correlation between the IC and PCR results on CPV-2 and CRV, whereas no significance were observe concerning CCoV. Additionally CRV showed a statistical significance between vaccinated and unvaccinated dogs, whereas CPV and CCoV did not. The phylogenetic analysis performed on CPV-2 and CRV sequences revealed similarities with strains from Korean, Peru, China, India, and Nigeria for CPV and Japan for CRV respectively. The study revealed that predominant positive samples were obtained from puppies aged between 0 – 12 weeks. However, no correlation was found between ages and the occurrence of the disease among patients. There was no significant correlation between sex and the occurrence of CPV virus, neither a correlation between the occurrence of the disease and the location of the dogs. Most of the affected animals had either been vaccinated once or never. In addition, the study noted that some animals had a co-infection of CPV and CRV viruses. In this survey, the characterisation of the CPV-2c and CPV-2b variants, and the one of CRV serotype will contribute to the understanding of the pathogenesis of the diseases and the awareness of monitoring strategies for an efficient control and prevention of infections for a better public health. In conclusion, this study revealed that the majority of animals presented with gastroenteritis to the Animal Health Hospital at the North West University, Mafikeng Campus were predominantly affected by the CPV virus and mainly the CPV-2 virus. There is a need of more awareness for pet owners on the issue of vaccination in order to reduce the prevalence of the diseases in the area.