Manifestations of Clostridium perfringens and related bacterial enteritides in broiler chickens

Well known as the cause of necrotic enteritis, C. perfringens (CP) is now recognized as causing a spectrum of effects including subclinical infection, mild disease with focal intestinal necrosis, diarrhoeal illness and liver disease, as well as the classic form of acute fulminant necrotizing enteritis. The mild and subclinical forms of infection appear to be widespread, and, possibly increasing in incidence. Furthermore, bacterial enteritis is increasingly being recognized less as an invasion by pathogenic organisms per se and more as an expression of the normal process by which the intestinal bacterial population changes over time in response to changes in the intestinal environment. Such shifts in enteric bacterial populations have been referred to as dysbacteriosis. Management of the microbial ecology of the intestinal tract is therefore an important element of preventing disease, enhancing performance, and preventing foodborne illness. Diagnosis of emerging forms of bacterial enteritis including CP infection can be challenging and involves a comprehensive analysis of flock history and condemnation records, clinical signs, gross and histopathology, bacterial culture and empirical response to treatment, augmented by molecular techniques where available. Control measures are at present based on extensions of validated approaches to the control of the classical form of the disease: managing known risk factors for necrotic enteritis (coccidiosis, diet and litter quality) and the use of approved antimicrobial agents with proven efficacy against CP.