Protective effect of inactivated bovine herpesvirus-1 in calves experimentally infected with bovine herpesvirus-1 and Pasteurella haemolytica.
The protective effect of an inactivated whole-virion bovine herpesvirus-1 (BHV-1) immunising inoculum, without adjuvant, against viral-bacterial respiratory disease was studied in three experimental treatment groups of five calves each. One group was boosted 14 days after the first vaccination and at this time the second group received their initial inoculation. Seven days later, calves were challenged with BHV-1 in aerosol and four days after this challenge all calves were exposed to Pasteurella haemolytica A1 in aerosol. Among the three groups, differences in rectal temperature responses four days after viral challenge (P less than 0.01) did not relate to protection. However the main response variable, viral-bacterial pneumonia, was reduced in boosted calves (P less than 0.05).
The humoral immune response in cattle after immunization with a multivalent IBR/PI3/Pasteurella haemolytica A1 leukotoxin vaccine.
A multivalent vaccine consisting of inactivated bovine herpes virus-1 (BHV-1), also known as infectious bovine rhinotracheitis virus (IBR), para-influenza type-3 virus (PI3) and the leukotoxin of Pasteurella haemolytica A1, were combined with the addition of aluminium hydroxide as adjuvant, and administered to post-weaned calves, and the serum tested for seroconversion to each antigen. Two groups of calves (n = 150 and n = 68) were used and were randomly divided into three subgroups. The first group of 150 calves were immunized with the multivalent vaccine (three batches) to test its first-stage stability (vaccine 3 months old) and the second group were immunized with the same vaccine 1 year later, in order to test its immunogenicity. A significant increase in titres occurred after the day 0 and 28 immunizations, for each of the three antigens in the multivalent vaccine, as measured on days 0 and 42. Immunoconversion occurred after immunization with the 3-month- and 1-year-old vaccine. The immunogenic stability of antigens in the vaccine was demonstrated after a 1-year period when the vaccine was kept at 4-6 degrees C.
Evaluation of Quantum II microbiology system for identification of gram-negative bacteria of veterinary origin
The ability of a rapid, semiautomated bacterial identification system, the Quantum II microbiology system (Abbott Laboratories, Irving, Tex.), to accurately identify gram-negative bacteria from veterinary sources was evaluated. A total of 378 isolates were tested, including 298 organisms in the family Enterobacteriaceae and strains representing Acinetobacter sp., Aeromonas sp., Flavobacterium sp., Pasteurella multocida, Plesiomonas sp., and Pseudomonas spp. Of these isolates, 333 (88.1%) were correctly identified, 20 (5.3%) were not identified, 10 (2.6%) were incorrectly identified at the genus level, and 15 (4.0%) were incorrectly identified at the species level. The Quantum II system correctly identified 268 (89.9%) of the isolates of Enterobacteriaceae and 65 (81.3%) of the nonenteric isolates. P. multocida was not identified correctly, and some nonenteric gram-negative bacteria of clinical significance in veterinary medicine are not included in the data base. The Quantum II system provided an accurate identification system for isolates of Enterobacteriaceae but had limited usefulness for the identification of other gram-negative bacteria of clinical significance in veterinary medicine.