Clostridia are prokaryotic bacteria of the phylum Firmicutes, which are large, anaerobic, spore-forming, rod-shaped, gram-positive organisms. They can be living cells (vegetative forms) or dormant spores. Their natural habitats are soils and intestinal tracts of animals, including humans.
Dormant spores of several clostridial species have been found in healthy muscular tissue of horses and cows. The endospores are oval, sometimes spherical, and are located centrally, subterminally, or terminally. The vegetative forms of clostridia in tissue fluids of infected animals occur singly, in pairs, or rarely in chains.
Clostridial diseases are not spread from animal to animal or from animals to humans. They have been classified into three forms:
Clinical Findings of Enterotoxemia Caused by Clostridium perfringens Types B and C
Lamb dysentery is an acute disease of lambs <3 weeks old. Many may die before clinical signs are seen, but some newborn lambs stop nursing, become listless, and remain recumbent. Fetid, blood-tinged diarrhea is common, and death usually occurs within a few days. In calves, there is acute diarrhea, dysentery, abdominal pain, seizures, and opisthotonos. Death may occur in a few hours, but less severely affected lambs may survive for a few days, and recovery is possible. Pigs become acutely ill within a few days of birth, and there is diarrhea, dysentery, reddening of the anus, and a high fatality rate; most affected piglets die within 12 hours. In foals, there is acute dysentery, toxemia, and rapid death. Struck in adult sheep is characterized by death without premonitory clinical signs.