Ulcerative enteritis is an acute or chronic enteritis seen primarily in bobwhite quail ( Colinus virginianus ) but often seen in chickens 5-7 wk old and also reported in young turkeys, pheasants, grouse, and other gallinaceous birds. It occurs worldwide.
Etiology, Epidemiology, and Pathogenesis: Clostridium colinum is a fastidious, spore-forming, anaerobic rod, ~1 µm wide by 3-4 µm, that is difficult to culture. The spores are oval and subterminal.
The organism is shed in the feces of infected birds. Quail and chickens that develop chronic disease remain carriers. To induce experimental infection in quail, =106 organisms are given PO; chickens require =109 organisms. Outbreaks of ulcerative enteritis in chickens may follow outbreaks of coccidiosis, infectious bursal disease, and inclusion body hepatitis. After oral infection, the organism produces enteritis and ulcers in the lower third of the intestinal tract. Some organisms may pass to the liver via the portal circulation and produce diffuse or focal liver necrosis. Although large numbers of bacteria resembling C colinum can be seen in the ulcerative lesions of the gut and necrotizing lesions of the liver, histological features of these lesions suggest that, in addition to bacterial invasion, a toxin also may be involved in the pathogenesis of this disease. However, no toxin has yet been identified.
Clinical Findings: In susceptible quail, the disease is acute, and mortality may be 100% in a few days. In chickens, signs are usually less dramatic, and mortality is =10% during the clinical course of the disease (=2-3 wk). Some affected quail or chickens may die without obvious signs of disease or weight loss. Infected birds discharge characteristic droppings that are streaked with urates surrounded by a watery ring. Chronically affected birds are listless and anorectic; they appear humped-up, with the neck retracted and eyes partially closed.
Lesions: The primary lesions are found in the lower third of the small intestine, ceca, and liver. Lesions in the intestine and ceca vary from punctate hemorrhages to ulceration. The well-defined ulcers vary in size and may be 5 mm in diameter. The larger ulcers may have yellow, diphtheritic membranes with a depressed center and raised edges. Perforating ulcers are frequent and cause local or diffuse peritonitis. Liver lesions appear as isolated, yellow, necrotic foci or irregularly shaped, yellow, necrotic areas in the parenchyma. The only other organ that may show lesions is the spleen, which may be enlarged and either hemorrhagic or necrotic.
Diagnosis: Although Histomoniasis and inclusion body hepatitis (Inclusion Body Hepatitis) may superficially resemble ulcerative enteritis, Coccidiosis causes the greatest problem in differential diagnosis. Often, both infections occur simultaneously. In ulcerative enteritis, the spore-forming rods that resemble C colinum can be demonstrated in gram-stained blood, liver, and spleen in septicemic birds. Clostridium colinum can be isolated from infected livers and spleens cultured under strict anaerobic conditions on pre-reduced, anaerobic blood agar plates.
Treatment and Control: Bacitracin and streptomycin are the most effective drugs. Bacitracin is used in the feed at 0.005-0.01%, streptomycin at 0.006%. Either drug can be given in the drinking water prophylactically or therapeutically. The tetracyclines and furazolidone at 0.02% in the feed are also effective.
Medicated flocks often have little resistance against reinfection. Therefore, contaminated litter should be removed, and treatment may need to be continued or repeated periodically. Because bobwhite quail are highly susceptible, they should be raised on wire or slat floors as a prophylactic measure.