Investigation of the Efficacy of Various Proteinase-Treated "Serpula (Treponema) Hyodysenteriae" Vaccines

Abstract

The problem. Swine dysentery is a severe mucohemorrhagic diarrheal disease that primarily affects swine during the growing-finishing period. The etiological agent of swine dysentery is "Serpula hyodysenteriae", an anaerobic Gram-negative spirochete. Financial losses from swine dysentery are a result of losses from death as well as weight loss and unthriftiness of recovered swine (44). The mortality and morbidity due to swine dysentery can be as high as 50% in untreated herds (74). As many as 40% of midwestern United States herds are infected with the disease (20). Annual losses to the swine industry are estimated to be approximately 30 to 50 million dollars (111). Procedure. "S. hyodysenteriae" strain B-204 serotype 2 (porcine origin) was grown in pre-sterilized anaerobic media under anaerobic conditions. Five separate pH lysed aliquots of the concentrated bulk of the "S. hyodysenteriae" culture were subjected to enzymatic digestion of the following proteinases: Proteinase K, proteinase type X-15, proteinase type 2 fungal, papain proteinase, and pepsin proteinase. Sodium dodecyl sulphate polyacrylamide gel electrophoresis(SDS-PAGE) was performed on all bulk samples as well as control samples. The papain, pepsin, and proteinase K bulk samples were prepared into vaccines for use in a swine vaccine efficacy experiment. Findings: Both the pepsin and proteinase K vaccines aided in controlling a virulent "S. hyodysenteriae" B-204 challenge. These groups had significantly lower morbidity incidence and duration scores, lower clinical days, and lower clinical index scores than the control or papain group. The pepsin group had a significantly higher average daily weight gain pre-challenge as compared to all the other groups. Both of these groups had a greater than 100-fold increase in IgG antibody response 10 days after the second vaccination. Both the pepsin and PK vaccine groups had lower percent death, decreased bloody diarrhea, decreased shedding of "S. hyodysenteriae", and an increased period before clinical onset compared to the control or papain group. The pepsin and PK vaccines administered to swine in this experiment aid in controlling a virulent "S. hyodysenteriae" B-204 challenge and significantly reduce the clinical signs associated with swine dysentery. Conclusion. The subunit pepsin and PK vaccines administered to swine in this experiment aid in clinically controlling the symptoms associated with a virulent "S. hyodysenteriae" B-204 challenge. The overall clinical performance of these groups compared to the papain and control groups clinical performance indicates the effectiveness of these vaccines for prophylactic use against "S. hyodysenteriae" B-204 swine dysentery infection.