title: Carriage of Neisseria meningitidis and Neisseria lactamica in infants and children.
abstract: Asymptomatic carriage of Neisseria meningitidis and Neisseria lactamica was studied in a total of 2,969 healthy infants and children in Danbury, Conn., between October 1971 and June 1975. The prevalence of N. meningitidis averaged 0.71% during the first four years of life and increased to 5.4% by 14--17 years. Rates of carriage of N. lactamica increased from 3.8% in three-month-old infants to a peak of 21.0% at 18 months and then declined to 1.8% by 14--17 years of age. Of the children who acquired N. lactamica, 66% developed fourfold or greater rises in titers of IgG antibody to groups A, B, and/or C meningococci as determined by immunofluorescence compared with only 5% of control children. Of new carriers of N. lactamica, 40% developed increased titers of bactericidal antibody to groups A, B, and/or C meningococci as compared with 7% of noncarriers. Carriage of N. lactamica may assist in the development of natural immunity to N. meningitidis by induction of cross-reactive antibodies.
mesh_terms: D000375:Aging; D000907:Antibodies, Bacterial; D002353:Carrier State; D002648:Child; D002675:Child, Preschool; D003429:Cross Reactions; D006801:Humans; D007223:Infant; D009305:Nasopharynx / Q000382:microbiology; D009343:Neisseria / Q000254:growth & development / Q000276:immunology / Q000302:isolation & purification*; D009345:Neisseria meningitidis / Q000254:growth & development / Q000276:immunology / Q000302:isolation & purification*
chemical_list: D000907:Antibodies, Bacterial