Etiology and pathogenesis of necrotic enteritis

Area of Science:

• Veterinary Medicine
• Poultry Science
• Parasitology

Background:

• Eimeria acervulina causes mild coccidiosis in broilers.
• Clostridium perfringens infection leads to necrotic enteritis.
• The interaction between these pathogens is not fully understood.

Purpose of the Study:

• To investigate the synergistic effects of Eimeria acervulina and Clostridium perfringens on broiler health and mortality.
• To determine the impact of the timing of infections on disease severity.

Main Methods:

• Broilers were orally administered Eimeria acervulina oocysts.
• Birds were fed rations inoculated with Clostridium perfringens at varying times relative to Eimeria acervulina infection.
• Mortality rates, intestinal pH, serum protein, and intestinal passage time were monitored.

Main Results:

• Eimeria acervulina infection alone caused mild subclinical coccidiosis.
• Clostridium perfringens alone resulted in 8% mortality.
• Co-infection significantly increased mortality, reaching 35% when infections were simultaneous and 41% when Clostridium perfringens followed Eimeria acervulina by two days.
• Eimeria acervulina infection reduced intestinal pH, decreased serum protein, and increased intestinal passage time.
• Pre-infection with Clostridium perfringens before Eimeria acervulina led to 18% mortality, while post-infection four days later resulted in 10% mortality.

Conclusions:

• Mild intestinal coccidiosis induced by Eimeria acervulina creates conditions favoring severe necrotic enteritis by Clostridium perfringens.
• Intestinal stasis and lesions caused by Eimeria acervulina facilitate the proliferation of toxigenic Clostridium perfringens strains.
• The timing of these infections critically influences the outcome and severity of the disease complex in broilers.