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An outbreak of Hemophilus influenzae type b meningitis in an enclosed hospital population
Abstract:
Five cases of HITB maningitis occurred within six months in an enclosed population of 28 to 32 chronically ill children. Studies of nasopharyngeal carriage and serum HITB anticapsular antibodies were started after the third case occurred. Two patients had low (less than 0.04 and 0.05mug/ml) antibodies and were not carriers when studied prior to onset of their disease. The carriage rate was approximately 20% among the children. Carriage was usually prolonged, and acquisition was not prevented by high antibody levels. Attempts to arrest this outbreak with type b polysaccharide immunization and ampicillin therapy are discussed in the context of HITB meningitis as a contagious disease.
Insights
Haemophilus influenzae type b (Hib) meningitis outbreaks in chronically ill children highlight its contagious nature. Low antibody levels and carriage rates suggest transmission dynamics requiring further investigation.
Area of Science:
- Pediatric Infectious Diseases
- Epidemiology
- Immunology
Background:
- Recurrent cases of Haemophilus influenzae type b (Hib) meningitis were observed within a small, closed population of chronically ill children.
- The outbreak occurred over a six-month period, affecting 5 out of 28-32 children.
- Nasopharyngeal carriage and serum antibody levels were investigated to understand transmission.
Purpose of the Study:
- To investigate the epidemiological factors contributing to the outbreak of Hib meningitis in a vulnerable pediatric population.
- To assess the role of nasopharyngeal carriage and anticapsular antibody levels in the transmission of Hib.
- To evaluate the effectiveness of interventions like polysaccharide immunization and ampicillin therapy in controlling the outbreak.
Main Methods:
- Conducted nasopharyngeal carriage studies among the children.
- Measured serum levels of Hib anticapsular antibodies in patients and potentially in carriers.
- Analyzed clinical data, including disease onset, antibody titers, and carriage status.
Main Results:
- Two patients diagnosed with meningitis had low pre-disease antibody levels (<0.04 and 0.05 µg/ml) and were not identified as carriers at the time of study.
- The overall carriage rate of Hib in the studied population was approximately 20%.
- Carriage was often prolonged, and high antibody levels did not appear to prevent acquisition of the bacteria.
Conclusions:
- Hib meningitis can manifest as a contagious disease, particularly in enclosed populations of immunocompromised children.
- Low antibody levels may predispose individuals to invasive disease, but carriage dynamics suggest complex transmission patterns.
- The study discusses the challenges and potential strategies for controlling Hib outbreaks, including immunization and antibiotic therapy.