title: An expanded age range for meningococcal meningitis: molecular diagnostic evidence from population-based surveillance in Asia.
abstract: BACKGROUND
  To understand epidemiologic patterns of meningococcal disease in Asia, we performed a retrospective molecular analysis of cerebrospinal fluid (CSF) specimens collected in prospective surveillance among children aged < 5 years of age in China, South Korea, and Vietnam.
  
  
  METHODS
  A total of 295 isolates and 2,302 CSFs were tested by a meningococcal species- and serogroup-specific polymerase chain reaction (PCR) assay targeting the Neisseria meningitidis (Nm) ctrA gene. Multi-locus sequence typing (MLST) was performed in Nm gene amplification analysis and incidence rates for meningococcal meningitis were estimated.
  
  
  RESULTS
  Among 295 isolates tested, 10 specimens from Vietnam were confirmed as serogroup B and all were Sequence Type (ST) 1576 by MLST. Among the 2,032 CSF specimen tested, 284 (14%) were confirmed by PCR (ctrA gene), including 67 (23.6%) from China, 92 (32.4%) from Korea, and 125 (44.0%) from Vietnam. Neonates and infants aged < 6 months of age accounted for more than 50% of Nm-PCR positive CSF. Two CSF specimens from Vietnam were identified as serogroup B using MLST. In addition, 44 specimens underwent sequencing to confirm meningococcal serogroup; of these, 21 (48%) were serogroup C, 12 (27%) were serogroup X, 9 (20%) were serogroup Y and 2 (5%) were serogroup B. The incidence rates of meningococcal meningitis among children < 5 years of age was highest in Vietnam (7.4/100,000 [95% CI, 3.6-15.3] followed by Korea (6.8/100,000 [95% CI, 3.5-13.5] and China (2.1/100,000) [95% CI, 0.7-6.2]).
  
  
  CONCLUSIONS
  These results suggest that there is a previously undetected, yet substantial burden of meningococcal meningitis among infants and young children. Standardized, sensitive and specific molecular diagnostic assays with Nm serogrouping capacity are needed throughout Asia to understand the true burden of N. meningitidis disease.
authors.affiliation: Translational Research Division, International Vaccine Institute, SNU Research Park, San 4-8 Nakseongdae-Dong, Kwanak Gu, Seoul 151-919, South Korea. sakim@ivi.int
authors.forename: Soon Ae
authors.initials: SA
authors.lastname: Kim
authors.forename: Dong Wook
authors.initials: DW
authors.lastname: Kim
authors.forename: Bai Qing
authors.initials: BQ
authors.lastname: Dong
authors.forename: Jung Soo
authors.initials: JS
authors.lastname: Kim
authors.forename: Dang Duc
authors.initials: DD
authors.lastname: Anh
authors.forename: Paul E
authors.initials: PE
authors.lastname: Kilgore
mesh_terms: D002555:Cerebrospinal Fluid / Q000382:microbiology; D002675:Child, Preschool; D002681:China / Q000453:epidemiology; D016000:Cluster Analysis; D062665:Epidemiological Monitoring; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008585:Meningitis, Meningococcal / Q000175:diagnosis* / Q000453:epidemiology*; D025202:Molecular Diagnostic Techniques / Q000379:methods; D017720:Molecular Epidemiology; D058885:Multilocus Sequence Typing; D009345:Neisseria meningitidis / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D056910:Republic of Korea / Q000453:epidemiology; D012189:Retrospective Studies; D014744:Vietnam / Q000453:epidemiology