Seven-week interval between acquisition of a meningococcus and the onset of invasive disease. A case report

Invasive meningococcal disease (IMD) is thought to occur within a few days of pharyngeal acquisition of Neisseria meningitidis. During a longitudinal study of carriage and acquisition among 2453 first-year undergraduates we i dentified a male student from whom N. lactamica was isolated in October 199 7 followed by N. meningitidis in December 1997. In mid-January 1998 this st udent suffered a mild episode of IMD (meningitis) during which N. meningiti dis was isolated from his CSF. The meningococcus carried in December 1997 w as phenotypically and genotypically indistinguishable from the invading org anism, suggesting the possibility that the organism may have been carried f or 7 weeks prior to the onset of invasive disease. Further studies are need ed to assess more accurately the range of asymptomatic carriage prior to di sease onset.