Comparison of diagnostic efficacy of Canine distemper between quick test and RT-PCR method, analysis of a hemagglutinin gene segment of field viruses

Abstract

The objective of this study aimed at comparing the diagnostic results of Canine distemper Virus by quick test (CDV Ag – Canine distemper Virus Antigen) and RT-PCR technique. The study was conducted at Hoc Mon Veterinary Station and Nong Lam University Veterinary Hospital, Ho Chi Minh city. Clinical symptoms of the CD infected dogs were high fever, pneumonia, cough, mucous discharging from eyes and nose, loss of appetite or anorexia, vomiting, diarrhea, pustules on abdominal skin, claw hyperkeratosis and nervous symptoms. The studied result indicated that 42 out of 72 dogs were positive with CDV by quick test method, accounting for 58.33%. Meanwhile, 48 out of 72 cases were positive with CDV by the RT-PCR technique, accounting for 66.67%. CDV Ag-Quick test had a lower sensitivity. Therefore, it is necessary to use RT-PCR technique to increase the accuracy in diagnosis of CDV, especially in the cases are negative by quick tests but having the suspected clinical signs of CDV. Five samples of the field CDV and one commercial vaccine virus were selected to amplify a 613 bp segment of hemagglutinin gene. The analysed result on these amplified gene segments indicated that the similarity level of nucleotides of a hemagglutinin gene segment among five field CDV samples was very high (99.3% – 100%), meanwhile, the similarity level of the same gene segments of the field CDVs and vaccine virus was 96.1% – 96.6% and comparison with the hemagglutinin gene segment of the CDV strains from gene bank, the similarity level reached 89.1 – 98.0%.