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Meningococcal carriage in close contacts of cases
K A Cartwright1, J M Stuart, P M Robinson
1Gloucester Public Health Laboratory.
Abstract:
Between 1 October 1986 and 31 March 1987, 55 cases of meningococcal disease were identified in the South-West of England, an attack rate of 1.54 per 100,000 during the study period. Antibiotics used in the treatment of the disease successfully eliminated nasopharyngeal carriage of meningococci in 13 out of 14 cases without use of rifampicin. The overall meningococcal carriage rate in 384 close contacts was 18.2% and the carriage rate of strains indistinguishable from the associated case strain was 11.1%. The carriage rate of indistinguishable strains in household contacts (16.0%) was higher than the carriage rate in contacts living at other addresses (7.0%, P less than 0.05). A 2-day course of rifampicin successfully eradicated meningococci from 46 (98%) of 47 colonized contacts. In one third of cases groupable meningococci were isolated from at least one household contact; 92% of these isolates were of the same serogroup as the associated case strain. When a meningococcus is not isolated from a deep site in a clinical case of meningococcal disease, culture of serogroup A or C strains from nasopharyngeal swabs of the case or of household contacts is an indication that the close contact group should be offered meningococcal A + C vaccine in addition to chemoprophylaxis. The failure in this and other studies to isolate meningococci from any household contact in the majority of cases may be due either to the relative insensitivity of nasopharyngeal swabbing in detecting meningococcal carriage or to the acquisition of meningococci by most index cases from sources outside the household.
Insights
Meningococcal disease spread is linked to close contacts, especially household members. Rifampicin effectively eliminates meningococci carriage, and vaccination is recommended for specific cases to prevent further spread.
Area of Science:
- Epidemiology
- Infectious Diseases
- Microbiology
Background:
- Meningococcal disease poses a public health risk, with understanding transmission dynamics crucial for control.
- Nasopharyngeal carriage of Neisseria meningitidis is a key factor in disease spread.
- Antibiotic resistance and treatment efficacy in carriage eradication require ongoing investigation.
Purpose of the Study:
- To investigate meningococcal disease transmission patterns in close contacts.
- To evaluate the efficacy of antibiotics, particularly rifampicin, in eradicating nasopharyngeal carriage.
- To determine the role of household contacts in disease transmission and inform vaccination strategies.
Main Methods:
- Retrospective analysis of 55 meningococcal disease cases and their close contacts (384 individuals).
- Assessment of nasopharyngeal carriage rates of meningococci, including specific strains.
- Evaluation of antibiotic treatment (including rifampicin) for carriage eradication.
Main Results:
- A significant proportion of close contacts carried meningococci, with higher rates in household contacts.
- A 2-day course of rifampicin eradicated carriage in 98% of colonized contacts.
- In cases where meningococci were not isolated from deep sites, nasopharyngeal carriage in cases or household contacts indicated potential for further spread.
Conclusions:
- Household contacts play a significant role in meningococcal disease transmission.
- Rifampicin is a highly effective chemoprophylactic agent for eradicating meningococcal carriage.
- Nasopharyngeal carriage data, combined with clinical presentation, can guide decisions on antibiotic prophylaxis and vaccination (e.g., meningococcal A + C vaccine).