Molecular Characterization of canine parvovirus (CPV) antigenic variants from healthy and diarrheic dogs in Urmia region, Iran

Backgrounds: Canine parvovirus (CPV) has been incriminated as a primary pathogen related to acute hemorrhagic enteritis in dogs. Three major antigenic variants of CPV (CPV-2a/2b/2c) have so far been identified. Objectives: This study was carried out to investigate the frequency of CPV-2 and its variants (CPV-2a/2b/2c) in a population of healthy and diarrheic dogs in the north west of Iran. Methods: A total of 35 stool samples from healthy (n=16) and diarrheic (n=19) dogs were screened for all variants (2a, 2b, and 2c) by polymerase chain reaction (PCR) using primer pair 555for/555rev resulting in a PCR product of 583 bp in length. The resulting fragments were further digested by MboII endonuclease that selectively recognizes the restriction site “GAAGA” unique to CPV2c only. All undigested samples were subjected to PCR assays with primer pair Pab (which detects both CPV-2a and CPV-2b types) and primer pair Pb (which detect only CPV-2b type) primer pairs. The relationship of health status, breed, age, sex and vaccination status with PCR results were analyzed using statistical tests. Results: From a total of 35 samples, 10 samples were found to be positive by 555for/555rev primers that were further analyzed by MboII digestion of PCR products. One sample was characterized as CPV-2c and nine samples were categorized as CPV-2a or CPV-2b. All nine undigested samples resulted positive by PCR using Pab primers, out of which 7 resulted positive by PCR using Pb primer pairs, indicating that they are of CPV-2b variant. Conclusions: It seems that CPV-2b is prevalent variant circulating in the North West of Iran. Results also indicated that CPV-2a and CPV-2c are affecting dogs, suggests constant surveillance and monitoring of CPV variants.