Genomic and Immunological Identification of Canine Distemper Virus (CDV) and Investigation of Coinfection with Bordetella bronchiseptica Among Dogs in Iran

Canine distemper virus (CDV) is an extremely contagious pathogen that causes deadly diseases in carnivores worldwide.

Considering the effect of CDV on the host immune system and the increased risk of other infections, the present study aimed to investigate the incidence of coinfection with CDV and Bordetella bronchiseptica, using genomic and serological methods.

In this study, 50 blood samples, eye samples, respiratory swabs, and gastrointestinal tract swabs were taken from dogs, which showed symptoms of respiratory and gastrointestinal tract involvement, suggesting CDV infection. Also, 50 seemingly healthy dogs were included in this study. The animals were referred to Isfahan clinics between the spring of 2018 and the winter of 2019. For the initial diagnosis of CDV by immunological methods, a rapid CDV immunochromatography kit was used. To investigate for the genomes of both pathogens, after DNA and RNA extraction and reverse transcription of the extracted RNA samples, a PCR assay was performed using specific primers.

Based on the results of the RT-PCR assay, of 50 samples taken from dogs with suspected CDV infection, 37 were positive for the presence of CDV nucleic acids, and 20 were positive for the presence of B. bronchiseptica nucleic acids. Also, of 50 samples taken from seemingly healthy dogs, three were positive for CDV, and 15 were positive for B. bronchiseptica nucleic acids.

In the present study, of 100 samples taken from dogs with suspected CDV infection and apparently healthy dogs, 15 showed coinfection (12 samples from dogs with symptoms of CDV and three from seemingly healthy dogs). However, no significant relationship was found between CDV and B. bronchiseptica infections. It seems that future studies with a larger sample size can provide us with more accurate results.