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STUDIES ON MENINGOCOCCUS INFECTION : VI. THE CARRIER PROBLEM.
1Laboratories of The Rockefeller Institute for Medical Research.
The Journal of Experimental Medicine
|October 30, 2009
Summary
Chronic meningococcal carriers can harbor the same strain for over two years. Upper respiratory infections, particularly those with increased pathogens, can reduce meningococcal presence in carriers.
Area of Science:
- Microbiology
- Epidemiology
- Immunology
Background:
- The Rockefeller Institute group study provides insights into meningococcal carrier states.
- Understanding carrier dynamics is crucial for controlling meningococcal disease transmission.
Purpose of the Study:
- To categorize meningococcal carriers and investigate factors influencing carrier persistence.
- To characterize meningococcal strains isolated from carriers and compare them to clinical isolates.
Main Methods:
- Analysis of carrier states in 24 individuals from the Rockefeller Institute group.
- Isolation and characterization of 26 meningococcal strains from carriers.
- Serological testing, including absorption tests, to determine strain relationships.
- Investigation of the impact of upper respiratory infections (coryza, pharyngitis) on meningococcal carriage.
Main Results:
- Three carrier types identified: chronic (over 2 years), intermittent, and transient.
- Half of the carriers were chronic, persistently harboring the same strain.
- Spontaneous "cures" can be temporary, with strains reappearing after months.
- Coryza alone did not alter meningococcal levels, but streptococcal pharyngitis reduced them.
- Eight of 26 carrier strains matched Gordon's types; 18 were considered true meningococci.
- Serological analysis revealed strains belonged to broad serological Groups I and II.
- Atypical Type II* strains from carriers caused cerebrospinal fever.
- Group II strains predominated in carriers during interepidemic periods, while Group I strains were more common during epidemics.
- Carrier strains showed lower viability in defibrinated rabbit blood compared to meningitis strains.
Conclusions:
- Meningococcal carrier states can be long-lasting, with consistent strain carriage.
- Upper respiratory infections influence meningococcal carriage, with bacterial co-infections potentially reducing meningococcal load.
- Carrier strains exhibit diverse serological profiles, with implications for disease epidemiology.
- Further research is needed to understand the significance of reduced carrier strain viability and to conduct comparative virulence studies.
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