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Experimental meningococcal meningitis in the infant rat
1National Public Health Institute, Helsinki, Finland.
Abstract:
Experimental infection of the infant rat could be established with intraperitoneal challenge with strains of all three meningococcal groups A, B, and C tested. 5-day-old rats were challenged with 3 different doses (10(2), 10(4), and 10(6) bacteria/animal) and the development of peritonitis, bacteraemia and meningitis detected as a function of time at 3, 6, and 9 h. Mortality was followed up to 24 h. Group B strains caused a rapidly developing and sustained high level bacteraemia and meningitis with all challenge doses. Bacteraemia and meningitis following challenge with MenA and MenC were of somewhat shorter duration and reached lower peak levels. Repeated 'rat passages' of meningococcal strains that had been kept stored for long periods markedly increased their virulence. This study shows that the infant rat model can be applied for studying pathogenesis of meningococcal bacteraemia and meningitis. Previous work from this laboratory has shown it to be suited also for studying antibody-mediated protection from this disease.
Insights
The infant rat model effectively simulates meningococcal (Neisseria meningitidis) infection, showing group B strains cause severe meningitis and bacteremia. This model aids in studying meningococcal disease pathogenesis and antibody protection.
Area of Science:
- Microbiology
- Infectious Diseases
- Animal Models
Background:
- Neisseria meningitidis causes bacterial meningitis and sepsis.
- Infant rat models are valuable for studying infectious diseases.
Purpose of the Study:
- To establish and validate an infant rat model for experimental meningococcal infection.
- To compare the virulence of different Neisseria meningitidis serogroups (A, B, C) in this model.
Main Methods:
- Infant rats were intraperitoneally challenged with varying doses of Neisseria meningitidis strains.
- Peritonitis, bacteremia, and meningitis were monitored over time.
- Mortality was assessed up to 24 hours post-infection.
Main Results:
- All tested meningococcal groups (A, B, C) established experimental infections.
- Group B strains induced rapid, sustained bacteremia and meningitis.
- Repeated passage increased meningococcal virulence in the rat model.
Conclusions:
- The infant rat model is suitable for studying meningococcal pathogenesis.
- This model can be used to investigate antibody-mediated protection against meningococcal disease.