THE DETECTION OF CANINE DISTEMPER VIRUS BY A NESTED REVERSE TRANSCRIPTASE-POLYMERASE CHAIN REACTION IN BLOOD SAMPLES COLLECTED AFTER VACCINATION

Abstract

The nested reverse transcriptase-polymerase chain reaction (nested RT-PCR) was used to study the canine distemper virus (CDV) could be detected in blood samples collected after vaccination. Blood samples were collected from 16 healthy puppies from 4 different litters on days 0, 3, 7, 10, 14, 17, 21, and 24, after vaccination with an attenuated, canine distemper virus, combined vaccine(Nobivac® Puppy DP) and from 3 puppies used as
non-vaccinated controls. Vaccines were given subcutaneously either once on day 0 or two times on days 0 and 14, starting at the age of 8 weeks. A total of 152 blood samples were collected. The results revealed CDV could be detected in 2 vaccinated puppies (12.5%) by nested RT-PCR on days 7 and 10 after vaccination, but was not detected in the other 14 puppies (87.5%) or in the non-vaccinated control puppies. CDV-specific antibody titers
were investigated before and after vaccination by a serum neutralization test (SN test). The CDV-specific antibody titer of all puppies was undetectable before vaccination. The log2 (geometric mean titers) were 2.00±1.87, 5.91±2.51, 8.33±0.58 and 7.38±2.67 on days 10, 14, 21, and 24 respectively. This study indicated that CDV could be detected
by nested RT-PCR 7 and 10 days after vaccination in blood samples of vaccinated puppies that showed no CDV-specific clinical signs.