Spontaneous necrotic enteritis in young RFM/Ms mice

Area of Science:

• Veterinary Pathology
• Microbiology
• Animal Science

Background:

• Necrotic enteritis is a significant enteric disease in various animal species.
• Outbreaks can cause substantial morbidity and mortality in research animal colonies.
• Understanding causative agents and effective treatments is crucial for animal welfare and research integrity.

Purpose of the Study:

• To identify the cause of fatal necrotic enteritis in a mouse colony.
• To characterize the gross and histological lesions associated with the disease.
• To determine an effective treatment strategy for the observed condition.

Main Methods:

• Observation of clinical signs and mortality in mice (24-52 days old).
• Gross pathological examination of affected ileum and caecum.
• Histological analysis of intestinal tissues, including Gram staining.
• Bacteriological isolation and identification from intestinal contents.
• Therapeutic trial using chlortetracycline hydrochloride in drinking water.

Main Results:

• Fatal necrotic enteritis characterized by hyperaemia, petechiae, erosion, and pseudomembranes in the ileum and caecum.
• Histopathology revealed necrotic enteritis with Gram-positive, spore-forming bacilli and a lack of inflammatory response.
• Non-type-A Clostridium perfringens was isolated from intestinal contents.
• Addition of chlortetracycline hydrochloride (11 mg/l) to drinking water resolved the disease.

Conclusions:

• Non-type-A Clostridium perfringens was identified as the causative agent of fatal necrotic enteritis in this mouse colony.
• The disease presentation was characterized by severe mucosal necrosis without significant inflammation.
• Chlortetracycline hydrochloride is an effective treatment for this specific Clostridium perfringens infection in mice.