Infection of the small intestine by type C strains of Clostridium perfringens causes a highly fatal, necrohemorrhagic enteritis. It most commonly affects piglets 1–5 days old; however, in rare cases it occurs in pigs up to 21 days old and other species Enterotoxemia Caused by Clostridium perfringens Types B and C Type A strains of C perfringens are commonly found as part of the normal intestinal microflora of animals and lack some of the powerful toxins produced by strains of other types. C perfringens... read more . Diagnosis is via a combination of lesion assessment and bacterial isolation and typing.
C perfringens proliferates rapidly in the intestinal contents and elaborates beta toxin, a potent, heat-labile, trypsin-sensitive exotoxin that causes necrosis of all structural components of the villi. Necrotizing inflammation usually extends to the mucosal crypts. The infection may continue caudally and involve the ileum; however, it rarely affects the colon. Necrosis of the mucosa is accompanied by blood loss into the intestinal wall and lumen.
Sudden onset of hemorrhagic diarrhea followed by collapse and death is characteristic of C perfringens type C enteritis in piglets 1–3 days old. Entire litters are typically affected, and mortality is close to 100%. In less severe cases, brownish liquid feces develop at 3–5 days. Infrequently, pigs develop a persistent, pasty-gray diarrhea and become progressively emaciated.
The small intestines of affected piglets are dark red, hemorrhagic, and filled with bloody fluid. At 3–5 days, less severe cases may have emphysema in the wall of the jejunum and necrosis of the mucosa of the jejunum and ileum. More chronic cases have a thickened small intestine lined by a pale yellow or gray necrotic membrane that adheres tightly to the submucosa. Microscopically, there is segmental hemorrhagic necrosis affecting the entire mucosa. Characteristic thick bacilli with square ends are commonly observed along necrotic villi and within the intestinal lumen.
Postmortem examination is usually sufficient to establish diagnosis of the peracute hemorrhagic form of C perfringens type C enteritis and of the peracute form with jejunal emphysema. A rapid presumptive diagnosis can be made by seeing large, rod-shaped bacteria in Gram-stained mucosal impression smears. Histologic demonstration of villous necrosis with mucosal colonization by numerous large, gram-positive rods is adequate for confirmation. Subacute and chronic forms of the disease in piglets 6–14 days old are easily confused at postmortem examination with Cystoisospora suis enteritis Also Veterinary.see page Gastrointestinal Parasites of Pigs and Veterinary.see page Coccidiosis of Pigs. Ascaris suum is the most common intestinal nematode of pigs. Adult nematodes in the intestine... read more ; however, diagnosis is usually possible via histologic examination of the jejunum and ileum or by observation of clostridia in mucosal smears (Gram or Giemsa stain). Isolates of C perfringens may be genotyped for the presence of genes that encode for beta toxin.
Treatment of pigs with clinical signs of C perfringens type C enteritis is of little benefit because lesions usually are irreversible at the onset of diarrhea. In an acute outbreak, prophylactic administration of type C antitoxin or antimicrobial (or both) parenterally or orally is protective if given to piglets within 2 hours of birth. C perfringens type C enteritis tends to recur on infected premises. Vaccination of gestating sows at 6 and 3 weeks before parturition with type C bacterin-toxoid confers some passive lactogenic immunity if piglets consume colostrum soon after birth. Naive gilts may benefit from three vaccinations before their first farrowing to ensure sufficient colostral antibodies. Once properly immunized, sows should receive one dose ~3 weeks before each subsequent farrowing.
Richard OK, et al. Vaccination against Clostridium perfringens type C enteritis in pigs: a field study using an adapted vaccination schedule. Porcine Health Manag. 2019;5:20.
Uzal FA, Songer JG. Clostridial diseases. In Zimmerman JJ, et al, eds. Diseases of Swine, 11th ed. John Wiley and Sons, Inc; 2019:792–806.