MOLECULAR EPIDEMIOLOGY OF SPORADIC (ENDEMIC) SEROGROUP-C MENINGOCOCCAL DISEASE

Understanding the basis of sporadic (endemic) meningococcal disease ma y be critical to prevention of meningococcal epidemic outbreaks and to understanding fluctuations in incidence, Active, prospective, populat ion-based surveillance and molecular epidemiologic techniques were use d co study sporadic serogroup C meningococcal disease in a population of 2.34 million persons (Atlanta area), During 1988-1994, in which no outbreaks or case clusters were reported, 71 patients developed sporad ic serogroup C meningococcal disease (annual incidence, 0.51/100,000), Eighty-three percent of patients were > 2 years old. By multilocus en zyme electrophoresis, pulsed-field gel electrophoresis, and serotyping , 84% (52/62) of the isolates available for study were identical or cl osely related members of the electrophoretic type 37 (ET 37) complex r esponsible for multiple serogroup C outbreaks in the United States in the 1990s, Sporadic disease caused by 9 clonal strains occurred over p eriods up to 4 years and accounted for 45% (28/62) of cases, Sporadic serogroup C meningococcal disease was most often due to a limited numb er of related strains that appear to slowly circulate in the populatio n.