Enterotoxaemia (pulpy kidney) is a common bacterial disease of sheep caused by Clostridium
perfringens type D epsilon toxin. It has mortality rates of up to 30% in non-vaccinated animals.
Current vaccines from whole cell cultures are expensive to manufacture and can induce local
inflammatory responses in sheep. They usually have reduced immunogenicity because of the
difficulty of standardising the inactivation step in vaccine manufacturing. In the current study,
we evaluated the safety and potency of a recombinant plant-made epsilon toxoid protein
(r-Etox) as an affordable and safer alternative vaccine for developing countries. Results of
injection site reactions, rectal temperature and toxin neutralisation test in single and prime–
boost inoculations of mice, guinea pigs and sheep suggest that the product is not toxic to
animals and could protect sheep against enterotoxaemia.