Canine distemper is a worldwide, highly contagious disease, which often induces severe neurological signs. The aim of this study was to evaluate different biological samples (conjunctival and genital swabs, urine and peripheral blood mononuclear cells/PBMCs) by Reverse Transcription-hemi-nested PCR.

All collections were done from dogs with neurological manifestation, examined at the Veterinary Hospital of Faculdade de Medicina Veterinária e Zootecnia da Universidade de São Paulo (HOVET-FMVZ-USP), from October of 2004 to May 2007. Only dogs without vaccine or vaccinated more than 50 days before the samples were collected, were included to avoid positive results from vacinal virus.

Fragments of the nucleoprotein (NP) gene of canine distemper virus was detected in 43 from 50 dogs evaluated by hemi-nested-PCR. A greater number of positive results were obtained from genital swabs (40), followed by conjunctival swabs and urine (37) and PBMCs (33). Sensitivity in detecting positive results was increased by using two clinical samples together (genital swab and urine), especially in dogs that had not shown extra neural signs or during the convalescent and late stage of canine distemper.