Abstract:
Actinobacillus suis is considered an opportunistic pathogen in swine that can cause disease in animals of all ages, especially in high health status herds. The objective of this study was to developed an indirect enzyme-linked immunosorbent assay (ELISA) using boiled whole cell antigen for the detection of antibody against A. suis. The selected herd has clinical problems associated with A. suis infection. In addition, this herd was not received any Actinobacillus pleuropneumoniae (APP) vaccine nor diagnosed with APP infection before the study. The isolation of A. suis was recovered from lung of the infected pig in the selected herd. Moreover, the antigen of A. suis was prepared in form of boiled whole cell antigen for coated ELISA plate. Blood samples were collected from pigs in the same herd at 3, 5, 7, 9, 11, 12, 13, 14, 15, 17, 18, 20, 21-25 and 25 weeks of age. Moreover, blood collection was collected from Parity 0 (34-36 weeks of age), P1-P2, P3-P4, and P5 of sows for detection of antibodies against A. suis in indirect ELISA test. The ELISA was optimized by using checkerboard titration. As a result, the cut-off value was set at 0.36 (OD450). The higher level of optical density (OD) was observed when the pigs more than 20 weeks of age (p<0.05). The highest level of OD related A. suis antibody was observed in the sows at the Parity 1-4 in which the level of the A. suis antibody was different to gilt aged less than 25 weeks (p<0.01). In conclusion, the development of indirect ELISA technique may not be a gold standard or completely used as diagnostic tool due to the difficulty to detect the conserved antigenicity of A. suis antigen. It could be used as an alternative tool for study the dynamic serological profile of the suspected pigs infected with A. suis in the herd and these data could be applied to develop the appropriate vaccination protocol against these pathogens for herd health management.
