Related Experiment Videos
Summary
An outbreak of Tyzzer
Area of Science:
- Veterinary Pathology
- Microbiology
- Immunology
Background:
- An epidemic disease outbreak occurred in a specified-pathogen-free (SPF) rat breeding colony.
- Clinical signs and post-mortem findings were indicative of Tyzzer's disease.
Purpose of the Study:
- To identify the causative agent of the disease outbreak in rats.
- To characterize the pathogenicity of the isolated organism.
- To investigate the serological relatedness of Bacillus piliformis strains from different hosts.
Main Methods:
- Microscopic demonstration of Bacillus piliformis in affected tissues (ileum, liver, myocardium).
- Transmission studies to mice to assess pathogenicity.
- Indirect immunofluorescence technique for organism demonstration and antibody detection in sera.
Main Results:
- Bacillus piliformis was identified as the causative agent.
- The rat-derived strain showed similar pathogenicity to a mouse-derived strain in experimental mice.
- Antibodies against B. piliformis were detected in spontaneously infected mice, rats, and rabbits.
- Antibodies were also found in healthy rats from three different colonies, suggesting widespread subclinical infection.
Conclusions:
- Bacillus piliformis caused the epidemic disease in the SPF rat colony.
- The immunofluorescence technique is effective for detecting B. piliformis and antibodies.
- Serological cross-reactivity between rat and mouse strains indicates a common antigen.
- Subclinical infections with B. piliformis may be present in rat populations.