Role of Clostridium perfringens Necrotic Enteritis B-like Toxin in Disease Pathogenesis

Necrotic enteritis (NE) is a devastating enteric disease caused by Clostridium perfringens type A/G that impacts the global poultry industry by compromising the performance, health, and welfare of chickens. Coccidiosis is a major contributing factor to NE. Although NE pathogenesis was believed to be facilitated by α-toxin, a chromosome-encoded phospholipase C enzyme, recent studies have indicated that NE B-like (NetB) toxin, a plasmid-encoded pore-forming heptameric protein, is the primary virulence factor. Since the discovery of NetB toxin, the occurrence of NetB⁺ C. perfringens strains has been increasingly reported in NE-afflicted poultry flocks globally. It is generally accepted that NetB toxin is the primary virulent factor in NE pathogenesis although scientific evidence is emerging that suggests other toxins contribute to NE. Because of the complex nature of the host-pathogen interaction in NE pathogenesis, the interaction of NetB with other potential virulent factors of C. perfringens needs better characterization. This short review will summarize the primary virulence factors involved in NE pathogenesis with an emphasis on NetB toxin, and a new detection method for large-scale field screening of NetB toxin in biological samples from NE-afflicted commercial broiler flocks.