Rapid molecular detection and isolation of canine distemper virus in naturally infected dogs

The canine distemper virus (CDV), which infects dogs and a broad range of animal species, remains a serious concern in Turkiye and across the world. The current study shows that CDV can be detected and isolated rapidly and specifically in naturally infected dogs. Whole blood, nasal swab, ocular swab, rectal swab, and urine samples from 50 stray dogs were used in the study (n = 250). The presence of the CDV genome was confirmed in 105 (42%) samples using one-Step real-time RT-PCR. In total, 39 dogs were diagnosed with CDV infection based on the detection of cytopathic effects in MDCK, which was verified by the fluorescent antibody technique. A total of 12 one-Step realtime RT-PCR negative samples, consisting of 4 rectal swabs and 8 urine samples, were found to be positive by virus isolation. Blood, nasal swab, ocular swab (P<0.01, r = 1), rectal swab (P<0.01, r = 0.844), and urine samples (P<0.01, r = 0.697) all showed positive correlations in the tests for viral genome detection and virus isolation. CPE levels of high 37 (31.62%), medium 26 (22.23%) and low 54 (46.15%) were detected in a total of 117 (46.8%) samples with viral growth in cell culture. The highest CPE levels detected by FAT were for rectal swab and urine samples. In conclusion, the one-step real-time RT-PCR method on rectal swab samples proved to be a very sensitive method for the rapid and reliable CDV detection. Besides, non-modified MDCK can be used to isolate CDV from naturally infected dogs.