Related Experiment Videos
Intercontinental spread of an epidemic group A Neisseria meningitidis strain
P S Moore1, M W Reeves, B Schwartz
1Meningitis and Special Pathogens Branch, Centers for Disease Control, Atlanta, Georgia 30333.
Abstract:
Electrophoretic enzyme typing revealed that a single group A Neisseria meningitidis clonal complex, designated III-1, was responsible for recent epidemics in Nepal, Saudi Arabia, and Chad. Epidemiological investigations and enzyme typing profiles indicated that this clone was brought from South Asia to the Middle East by Muslims making their pilgrimage (haj) to Mecca, Saudi Arabia, in 1987. Pilgrims who became group A carriers introduced this clonal group into sub-Saharan Africa on their return from the haj. The introduction of this clonal group into sub-Saharan Africa may be responsible for the current wave of epidemics affecting the region. Although the findings suggest that clonal virulence is an important factor in the development of epidemics of meningococcal disease, other factors also seem to be necessary for the development of an epidemic.
Insights
A specific strain of Neisseria meningitidis (group A clonal complex III-1) caused recent epidemics across multiple continents. This virulent clone spread globally through religious pilgrimages, highlighting the role of clonal expansion in meningococcal disease outbreaks.
Area of Science:
- Microbiology
- Epidemiology
- Public Health
Background:
- Neisseria meningitidis is a significant cause of bacterial meningitis and sepsis.
- Epidemics of meningococcal disease are often linked to specific bacterial clones.
- Understanding the geographic spread and origins of virulent strains is crucial for disease control.
Purpose of the Study:
- To identify the specific clonal complex of Neisseria meningitidis responsible for recent epidemics in Nepal, Saudi Arabia, and Chad.
- To trace the origin and dissemination pathways of this epidemic clone.
- To investigate the factors contributing to meningococcal disease epidemics.
Main Methods:
- Electrophoretic enzyme typing was used to characterize Neisseria meningitidis isolates.
- Epidemiological investigations were conducted to determine disease spread and potential sources.
- Analysis of strain profiles and travel patterns of affected populations.
Main Results:
- A single clonal complex, designated III-1, of group A Neisseria meningitidis was identified as the cause of recent epidemics in Nepal, Saudi Arabia, and Chad.
- Evidence suggests this clone was introduced to the Middle East via the Hajj pilgrimage in 1987.
- The clone was subsequently introduced into sub-Saharan Africa by returning pilgrims, potentially initiating current epidemics.
Conclusions:
- Clonal virulence is a key factor in the emergence of Neisseria meningitidis epidemics.
- The global dissemination of specific clones can be facilitated by human travel, such as religious pilgrimages.
- While clonal factors are important, other elements are likely necessary for the full development of meningococcal disease epidemics.