Meningococcal Disease

View ISDH's Quick Facts on Meningococcal Disease

View CDC's Meningococcal Disease page

Rates presented are per 100,000 population and are based on the 2000 U.S. Census.

Meningococcal disease most commonly manifests as meningitis or meningococcemia. It is transmitted person-to-person via respiratory droplets from the nose and throat secretions of a person infected with Neisseria meningitidis. Up to 10% of United States residents may be colonized with N. meningitidis in the nasopharynx and have no symptoms of illness.

The case fatality rate for meningococcal disease is between 5-15%. Diagnosis in a clinically compatible case is confirmed by isolating meningococci from a normally sterile site (e.g., cerebrospinal fluid [CSF], blood, synovial fluid, pleural fluid, or pericardial fluid). A probable diagnosis may be made in the absence of a positive culture if clinical purpura fulminans is present or when both clinically compatible symptoms and a positive CSF antigen test are present.

In 2001, in Indiana, 47 cases of meningococcal disease were reported as confirmed.  Of these reported cases, seven persons died, for a case fatality rate of 14.9%.  The case fatality rate in 2000 for Indiana was 4.0%.  Those that died were ages 1-70.  Five of those who died were female.  The median number of cases for 1997-2000 was 55 (Figure Men1).  No significant differences by race, ethnicity, or sex were noted.  Only Lake County (6 cases) and Marion County (8 cases) reported at least five cases in 2001.

Meningococcal disease tends to strike infants, children, and young adults. The age-specific incidence rate for infants (7.1) was higher than that for any other age group (Figure Men2).  There was one case in a student attending college or university.

There are 13 known sero-groups (A, B, C, D, 29E, H, I, K, L, W-135, X, Y, and Z) of N. meningitidis. Sero-groups A, B, C, Y, and W-135 are most frequently associated with invasive disease. As of October 2000, laboratories are required to submit N. meningitidis isolates to the ISDH Laboratories for sero-grouping. Additionally, molecular sub-typing can be performed by pulse-field gel electrophoresis (PFGE) on selected meningococcal isolates.  When PFGE patterns match, this may indicate that a cluster of cases has some common source. Figure Men3 shows the sero-groups identified in Indiana in 2000.  Table Men1 shows the sero-groups indentified in Indiana since 1997, when sero-grouping became available.

No clusters of more than 5 cases were reported in 2001.  There was a cluster of one probable and three confirmed cases from one Indiana county.

There is a safe and effective vaccine used for persons ages 2 and older that protects against infection with serogroups A, C, Y, and W-135. Current use includes providing the vaccine to persons with functional or anatomic asplenia, those with terminal complement component or properdin deficiencies, and travelers to countries with a high number of cases of meningococcal disease. College students, especially freshmen living in dormitories, are at increased risk for the disease and should consider vaccination.

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Footnotes

1 - Race was unknown for 8 of the reported cases.

2 - "Other" includes American Indian/Alaska Native, Asian, Native Hawaiian/Pacific Islander, and multiracial.

* - Rate based on less than 20 cases and should be considered unstable.

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