Genotype‐Specific Carriage ofNeisseria meningitidisin Georgia Counties with Hyper‐ and Hyposporadic Rates of Meningococcal Disease

Abstract

Carriage of Neisseria meningitidis in a Georgia county with hypersporadic incidence of meningococcal disease ("hypersporadic county") and in a county with no cases of meningococcal disease was determined by a cross-sectional pharyngeal culture study of high school students. Among 2730 students from whom culture samples were obtained, meningococcal carriage was 7.7% (140/1818) in the hypersporadic county and 6.1% (56/912) in the comparison county. Carriage rates by serogroup and genetic type (i.e., electrophoretic type [ET]) did not differ significantly between counties, but apartment or mobile home residency was a risk factor for carriage in the hypersporadic county. Although most cases of meningococcal disease in the hypersporadic county were caused by members of the serogroup C ET-37 clonal group, no ET-37 meningococcal isolates were recovered from carriers in this county. However, 38% of all meningococcal isolates recovered from carriers in both counties were members of the serogroup Y ET-508 clonal group, an emerging cause of meningococcal disease in Georgia and throughout the United States during 1996-2001. Shifts in carriage and transmission of meningococcal strains with different pathogenic potential are important determinants of meningococcal disease incidence.

Distribution of Serogroups and Genotypes among Disease-Associated and Carried Isolates of Neisseria meningitidis from the Czech Republic, Greece, and Norway

“…The disease and carrier isolate collections from all three countries were dominated by serogroup B and C meningococci. Although outbreaks of serogroup W135 and Y disease have occurred in other parts of the world in the period of our study (32,43,49), these serogroups were relatively uncommon among the disease isolates. Serogroup Y, however, was the third most common serogroup in carriage isolates in all three countries.…”

Prospects for Vaccine Prevention of Meningococcal Infection

“…It most commonly causes asymptomatic nasopharyngeal carriage and only relatively rarely causes invasive infection. The prevalence of carriage varies by study but is generally highest in adolescents and young adults (55,58,195).…”

“…Meningococci found in the nasopharynx are genetically quite diverse, whereas the strains causing invasive disease are much more genetically restricted (195).…”

Group A Antibody Persistence Five Years After Meningococcal Polysaccharide Vaccination in the Sudan

“…In the present study, we also included a reference group of immunized adults from North America who by virtue of where they live are unlikely to have been exposed to group A strains. [23][24][25][26][27] In contrast, there are high rates of endemic group A disease between epidemics in the Sudan and correspondingly high serum levels of naturally-acquired group A antibody. 28 Thus, the most likely reason for the higher prevalence of protective serum bactericidal titers in the Sudanese five years after vaccination than in the North Americans is asymptomatic exposure of the Sudanese to group A organisms.…”