EFFICACY OF AN ACTINOBACILLUS-PLEUROPNEUMONIAE BACTERIN AGAINST SEROTYPE-1, SEROTYPE-3, SEROTYPE-5 AND SEROTYPE-9

A trial was performed in a swine research facility to ascertain the pr otection provided by a polyvalent Actinobacillus pleuropneumoniae (APP ) bacterin containing serotypes 1,3,5 and 9. The test animals consiste d of 60, eight-week-old, piglets, which were randomly divided into fou r main groups. The four main groups were further divided into three su b-groups (I, II, III) of five pigs each. Sub-group I was vaccinated in tramuscularly, sub-group II was vaccinated subcutaneously, and sub-gro up III served as the unvaccinated control group. Each main group was c hallenged with a single APP serotype (1,3,5 or 9). Criteria for evalua tion of the bacterin efficacy were mortality, lung lesions, pleural ad hesions, and isolation of APP from tonsil or lung. Significant effects of vaccination over nonvaccination were reduced mortality, lung lesio ns, pleural adhesions, and isolations of APP from tonsil and lung. The re were no significant differences between the intramuscular and subcu taneous routes of vaccination. It was concluded that the four-way APP bacterin used in this study provided satisfactory protection against h omologous challenge. Evidence of protection was lower mortality and lu ng lesions and increased daily weight gains in vaccinates as compared with controls.