A New Alum Precipitated Oil Formulation Vis-a-Vis Alum Precipitated and Toxoid Enterotoxaemia Vaccines for the Enhanced and Sustained Immune Response against Epsilon Toxin in Sheep

Enterotoxaemia represents one of the major limiting factors in small ruminant farming. Rapid lethal progression of the disease makes treatment impractical in most cases. Thus, suitable immunoprophylactic measures are necessary against this disease. The current study was aimed to test out the ability of novel alum precipitated oil adjuvant vaccine (AOV) for overcoming the difficulties associated with short-term immunity of current enterotoxaemia vaccines.

A new formulation named, AOV was prepared using a highly toxigenic strain of Clostridium perfringens type D. Immunogenicity and protective efficacy of this vaccine in comparison to presently available epsilon toxoid vaccine (TV) and alum precipitated vaccine (APV) was evaluated in the target species, sheep using indirect ELISA, mouse neutralization test (MNT).

Among the three vaccines tested, AOV produced higher and persistent protective antibody titer up to 150 days post-immunization without any booster dose while APV and TV protected only up to 60^th and 45^th day respectively. All vaccinated animals remained healthy for the whole duration of the study with no systemic or local reactions. The present study delineates the superiority of AOV over presently available TV and APV for the prevention of an extremely lethal disease of sheep and goats.