Neisseria meningitidis Invasive Disease, 2001

Twenty-seven cases of Neisseria meningitidis invasive disease (0.6 per 100,000 population) were reported in 2001, compared to 22 cases in 2000. The distribution of serogroups among case isolates was similar to 2000, with 11 (41%) serogroup C cases, nine (33%) serogroup B cases, and seven (26%) serogroup Y cases.

Ages of case-patients ranged from 1 month to 85 years, with a mean of 29 years. Forty-eight percent of the cases occurred in the Twin Cities metropolitan area. Twelve (44%) cases had meningitis; nine (33%) had bacteremia without another focus of infection; three (11%) had bacteremia with pneumonia, and three (11%) had septic arthritis. Two serogroup B cases with nearly identical PFGE subtype patterns reported having had close contact with the same individual, but these two case-patients did not have known direct contact with each other. All other cases were sporadic, with no apparent epidemiologic links.
Four deaths occurred. An 85-year-old female died of pneumonia, and a 19-year-old male died of meningitis; both were attributed to serogroup C. A 49-year-old male died of meningococcemia, and a 15-year-old male died of meningitis due to serogroup Y.

An increase in the proportion of meningococcal disease attributed to serogroup Y was noted in Minnesota in the latter half of the 1990s; the majority of cases occurred in elderly persons, and most of those cases presented as pneumonia. Serogroup Y continued to account for a significant proportion of meningococcal disease in Minnesota in 2001, but cases were younger and presented with more severe disease, such as meningococcemia.

Since the fall of 1998, MDH has collected additional information on college-aged students with Neisseria 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 W135 are covered by the quadrivalent vaccine. One serogroup C case reported in Minnesota in 2001 occurred in a college student. In the spring of 2002, MDH began a case-control study of risk factors for meningococcal disease among high school students in Minnesota, in collaboration with CDC and other EIP sites nationwide.

• For up to date information see>> Meningococcal Disease
• Full issue>> Annual Summary of Communicable Diseases Reported to the Minnesota Department of Health, 2001