The response of pigs inoculated with a thymidine kinase-negative (TK-) pseudorabies virus to challenge infection with virulent virus.

摘要

12 Large-White-Landrace piglets were divided into 4 groups of 3 and housed in separate units. The piglets of 3 groups were inoculated with the 86/27V 6C2 thymidine kinase negative (TK-) mutant of Aujeszky's virus (AV), by different routes. A secondinoculation with the same mutant was given to the pigs 21 days later. Piglets of the fourth group were uninoculated controls. 21 days after the second inoculation with the TK- mutant all pigs were challenge infected with the virulent AV. On post challenge day (PCD) 30 all pigs were killed and samples for virus detection and histology were taken from several organs. The inoculated TK- mutant of AV did not induce any ill effects in the pigs except a transient febrile reaction in some. Virus was recoveredfrom nasal swabs from 1 pig 2 days after the first inoculation of the mutant. After challenge exposure with virulent AV, the TK- mutant-inoculated pigs were apparently protected, whereas the control pigs were all severely affected and recovered very slowly over 3 weeks. Virus was isolated from nasal swabs from the TK- mutant-inoculated pigs on PCDs 2 and 4, whereas nasal swabs from the control piglets were all positive for virus from PCD 2 to 10. DNA analysis of the virus recovered showed a pattern identical to that of the virulent AV. Histological lesions were found in the respiratory and the central nervous systems, however, the lesions in the TK- mutant-inoculated pigs were much milder compared with those in control pigs. Virus was not isolated fromany of the tissue samples tested, but viral DNA with sequences typical of AV genome was detected by PCR in all samples of trigeminal ganglia from either the TK- mutant-inoculated pigs or from the controls.