Related Experiment Videos
Abstract:
An outbreak of an epidemic disease occurred in a specified-pathogen-free (SPF) breeding colony of rats. The clinical signs and the post-mortem findings were characteristic for Tyzzer's disease. The causative agent, Bacillus piliformis, was demonstrated microscopically in ileum, liver and myocardium, and transmitted to mice where its pathogenicity appeared to be similar to that of another strain isolated from mice. B. piliformis from spontaneously-infected rats was demonstrated by indirect immunofluorescence technique. By means of the same technique it was found that the fluorescence antibody titre obtained of the individual sera from spontaneously-infected mice, rats and rabbits was the same, whether the antigen employed was organisms isolated from rats or mice. By testing sera from healthy rats in 3 different colonies by use of immunofluorescence technique, antibodies were found in several sera.
Insights
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.