Abstract

Background:
Canine parainfluenza virus (CPIV-5) is a significant viral pathogen in dogs, widely distributed and key in canine infectious respiratory disease.

Aim:
This study aimed to detect CPIV-5 in dogs in Baghdad city, using reverse transcriptase-quantitative polymerase chain reaction (RT-qPCR) and conventional nested (RT-nPCR) techniques, along with phylogenetic analysis.

Methods:
Nasal swabs were obtained from 150 dogs, (100 sick dogs showing respiratory distress and 50 apparently healthy dogs), from January 2023 to April 2024.

Results:
CPIV-5 was detected by RT-qPCR in 51 out of 100 sick dogs (51%) and 17 out of 50 apparently healthy dogs (34%). All positive RT-qPCR samples were rechecked by RT-nPCR. Ten final RT-nPCR products were sequenced, and the data were deposited in NCBI Gene Bank. These samples were categorized as CPIV-5 based on nucleocapsid protein gene analysis. The phylogenetic analysis based on amino acids revealed that local strains were distinct, with the first cluster sharing identity and similarity scores with international isolates, while the second cluster differed significantly from international isolates and could be Iraqi strains.

Conclusion:
This study concluded for the first time on the presence of CPIV-5 in both sick and apparently healthy dogs. The latter could act as reservoirs of the virus, contributing to the transmission of the disease to susceptible dogs, ultimately leading to increased morbidity.

Key words: CPIV-5, RT-qPCR, Nested RT-PCR, Phylogenetic analysis, Iraq