Neisseria meningitidis Invasive Disease, 2002

Thirty-six cases of Neisseria meningitidis invasive disease (0.7 per 100,000 population) were reported in 2002, compared to 27 cases in 2001. The distribution of serogroups among case isolates from 2002 was similar to 2001, with 17 (47%) serogroup C cases, eight (22%) serogroup B cases, nine (25%) serogroup Y cases, one (3%) serogroup W-135 case, and one (3%) serogroup X case.

Case-patients ranged in age from 2 months to 83 years, with a mean of 31 years. Seventy-eight percent of the cases occurred outside the seven county Twin Cities metropolitan area. Sixteen (44%) case-patients had meningitis, 17 (47%) had bacteremia without another focus of infection, and three (8%) had bacteremia with pneumonia.

Two of the cases of meningococcal disease occurred in siblings living in the same household. An infant developed meninogococcemia and died. A few days later, after completing prophylaxis with rifampin, her school-aged sister was hospitalized with fever and lethargy; her blood culture grew N. meningitidis. The isolates from both children were serogroup C with indistinguishable PFGE patterns. While National Committee for Clinical Laboratory Standards cutoffs for N. meningitidis have not been established, the infant's isolate appeared susceptible to rifampin. However, the sibling's isolate appeared highly resistant, and an amino acid substitution was found in the rpoB gene. All other cases were sporadic, with no apparent epidemiologic links.

Five deaths occurred among cases reported in 2002. An 83-year-old female died of pneumonia and a 4- year-old male died of meningococcemia; both were attributed to serogroup Y. A 2-month-old female died of meningococcemia due to serogroup C. A 23-year-old female died of meningococcemia due to serogroup W-135. And, a 73-year-old female died of meningococcemia due to serogroup B.

Since the fall of 1998, MDH has collected additional information on college-aged students with N. meningitidis invasive disease as part of a nationwide effort to determine whether providing meningococcal vaccine to incoming college freshmen effectively prevents disease in this age group. In the fall of 1999, the CDC Advisory Committee on Immunization Practices recommended that health care providers inform college students about meningococcal disease and the availability of vaccine. Serogroups A, C, Y, and W-135 are covered by the quadrivalent vaccine. One serogroup C case and one serogroup W-135 case reported in Minnesota during 2002 occurred in college students.

In the spring of 2002, MDH in collaboration with CDC and other EIP sites nationwide, began a case-control study of risk factors for meningococcal disease among high school students in Minnesota. Two culture-confirmed serogroup C cases occurred among high school students in 2002. One culture-negative, PCR-positive, suspected case of meningococcal disease in a high school student also was included in the study.

• For up to date information see>> Meningococcal Disease
• Full issue>> Annual Summary of Communicable Diseases Reported to the Minnesota Department of Health, 2002