Rapid Approaches for Diagnosis of Canine Distemper Virus in Live and Dead Dogs in Egypt

Abstract

Background: Canine Distemper Virus infection (CDV) is a highly contagious disease of high morbidity and mortality rates in dogs. The causative virus is CDV which is a Morbillivirus, CDV is a pantropic virus characterized by multisystemic infection and high case fatality, with worldwide distribution, so rapid diagnosis and quarantine of the infected dogs with starting suitable treatment was required. The aim: this studyaimed to achieve rapid diagnosis of canine distemper virus infection on ante mortem and post mortem aspects. Material and Methods: One healthy control disabled dog, 53 infected dogs with suggestive clinical signs for CDV infection were checked by (a) clinical examination; (b) Rapid immunochromatgrophy (IC) onconjunctival swabs (c) qRT- PCR on blood and tracheal exudates to confirm presence or absence of CDV, by expression analysis of CDV-F gene. Then all 53 examined dogs isolated and received supportive treatment but all died and disabled controlled one exposed to soft death. qRT-PCR were conducted on tissue samples from all 54 dogs for detection CDV-F gene expression values in different tissues.(d) Statistical analysis to study effect of sex and breed using Chi-square test, to evaluate sensitivity, specificity, accuracy, PPV, negative PV, respectively of used test and prevalence of CDV. Results: Clinical signs suggestive for CDV infection recorded in all 53 examined dogs, 24 of 54 dogs were positive for IC. Gene expression analysis test detected high values for CDV- F gene expression in tracheal exudates and blood samples of 36 live dogs, while the expression values were also high in tissue samples from different organs of 36 dead dogs. Statistical comparison of IC to qRT-PCR showed that values were 72%, 100%, 81.4%, 100% and 64.2 for sensitivity, specificity, accuracy, PPV, negative PV, respectively. No effect of sex , age, and breed on results using Chi-square test. Prevalence of CDV infection was 66% among population of this study. Conclusion: this study concluded that detection of clinical signs suggestive for CDV with application of IC and qRT-PCR together should be applied as rapid diagnosis on ante mortem level, while qRT-PCR could be used for rapid post mortem diagnosis of CDV infection.