Agents of the "suis-ide diseases" of swine: Actinobacillus suis, Haemophilus parasuis, and Streptococcus suis

In recent years, Actinobacillus suis, Haemophilus parasuis, and Streptococc us suis have emerged as important pathogens of swine, particularly in high health status herds. Their association with a wide range of serious clinica l conditions and has given rise to the moniker "suis-ide diseases." These o rganisms are early colonizers and, for that reason, are difficult to contro l by management procedures such as segregated early weaning, Vaccination, s erodiagnostic testing, and even serotyping are complicated by the presence of multiple serotypes, cross-reactive antigens, and the absence of clear ma rkers for virulence. In this review, we discuss our current understanding o f the pathogenesis, epidemiology, and management of the causative agents of the "suis-ide diseases" of swine.