Meningococcal Disease, 2008

Thirty cases of Neisseria meningitidis invasive disease (0.6 per 100,000 population) were reported in 2008, compared to 22 cases in 2007. There were 13 (43%) serogroup B cases, 13 (43%) serogroup C, 2 (7%) serogroup Y, and 1 (3%) serogroup Z. In addition, there was 1 culture-negative suspect case that was positive by polymerase chain reaction (PCR) in the PHL.

Case-patients ranged in age from 2 months to 92 years, with a median of 23 years. Fifty-three percent of the cases occurred in the metropolitan area. Six (20%) case-patients had bacteremia without another focus of infection and 18 (60%) had meningitis. Two cases from western Minnesota had serogroup B isolates that demonstrated fluoroquinolone resistance. These cases and a concurrent case in a North Dakota resident were the first ever documented in North America.

A cluster of serogroup B cases occurred in a southeastern Minnesota county during the first half of 2008. Three cases were residents whose isolates had nearly indistinguishable PFGE patterns. A fourth case was culture-negative, but PCR-positive, with a multi-locus variable tandem-repeat analysis (MLVA) sequence very similar to the other cases. Another case of serogroup B disease, occurred in an Iowa resident at the same time with a matching PFGE pattern, who had visited the same area just prior to onset of illness. No direct epidemiologic links were found for any of the cases. All other cases were sporadic, with no definite epidemiologic links.

Three deaths occurred; a 5-year-old died of bacteremia attributed to serogroup C, as well as a 33-year-old and a 53-year-old both with meningitis attributed to serogroup B.

In January 2005, a meningococcal polysaccharide-protein conjugate vaccine for serogroups A,C,Y, and W-135 (MCV4) was licensed for use in the United States for persons aged 11 to 55 years. In 2007, the license was approved to include 2 to 10 year olds. The Advisory Committee on Immunization Practices and American Academy of Pediatrics recommend immunization with the new vaccine at age 11-12 years, or at high school entry, as well as for college freshmen living in dormitories, and other groups in the licensed age range previously determined to be at high risk. In 2006, MDH in collaboration with the CDC and other sites nationwide, began a case-control study to examine the efficacy of MCV4.

In 2008, 6 cases occurred among 11-22 year olds, including one college and four high school students. Three cases had serogroup B disease. The two case-patients in this age had serogroup C disease; one was in high school and was vaccinated and the other was not in school and did not receive the meningococcal vaccine. In addition, one high school student had negative bacterial cultures but had a positive PCR result for serogroup B.

• For up to date information see>> Meningococcal Disease
• Full issue>> Annual Summary of Communicable Diseases Reported to the Minnesota Department of Health, 2008