Molecular Characterization of Canine Parvovirus-2 (Cpv-2) in Dogs in Egypt

Abstract

Canine parvovirus-2 (CPV-2) causes a severe, often fatal, enteric disease in dogs worldwide. Molecular characterization of CPV-2 should be regularly carried out because of its high evolution rate. The present study aimed to molecularly characterize CPV-2 field strains, circulating in Giza Governorate, Egypt. A total of 22 rectal swabs collected from dogs with clinical signs suggestive of canine parvovirus enteritis were initially screened for CPV-2 using field (CPV-2 Ag rapid kit) and molecular (conventional PCR, using the primer pairs ParvoInt2FB/ParvoInt2CR) techniques. All swabs were further examined by conventional PCR, using the sequencing primer pairs 555for/555rev; samples that had showed strong PCR products were sequenced. Results showed all swabs (n = 22) were positive for CPV-2 by conventional PCR, using the primer pairs ParvoInt2FB/ParvoInt2CR, whereas 20 samples were positive for CPV-2 Ag rapid kit. All samples were positive for conventional PCR, using the primer pairs 555for/555rev; only 16 samples were further sequenced and molecularly characterized as CPV-2a (12/16, 75%), CPV-2c (3/16, 18.75) and CPV-2b (1/16, 6.25%). Additionally, Thr440Ala mutation was prevalent in the characterized samples (13/16, 81.25%). The majority of samples (16/22, 72.2%) were obtained from non-vaccinated dogs. Therefore, it could be concluded that there is cross-immunity between commercial vaccine strains (original strain or CPV-2b) and CPV-2a, the predominant variant in the study area; however, further challenge studies are necessary to confirm this conclusion.