2005 Indiana Report of Infectious Diseases |
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*Rate per 100,000 population based on the U.S. Census Bureau’s population data as of July 1, 2005 |
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Meningococcal infection 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 percent of United States residents may be colonized with N. meningitidis in the nasopharynx and have no symptoms of illness.
In 2005, there were 19 confirmed cases, including 3 deaths, of invasive meningococcal disease in Indiana (Table 1). Deaths ranged in age from 1-48 years. The meningococcal disease case rate of 0.30 per 100,000 population represents the lowest reported since 1998. Figure 1 shows the number of reported cases for the five-year period 2001-2005.
Incidence of meningococcal disease usually climbs in early spring and late winter. Figure 2 indicates an increase of incidence in the late spring and early summer of 2005. Seasonality is difficult to generalize given the small number of cases. Cases of meningococcal disease tend to occur more frequently in infants under the age of 1 year, children aged 1-4 years, and young adults aged 10-19. In 2005, children aged 1-4 years (1.45) had the highest case rate, followed by infants less than 1 year of age (1.16) (Figure 3).
Of the 11 counties reporting cases in 2005, only Marion County (0.7) reported 5 or more cases.
Serogroups A, B, C, Y, and W-135 are most frequently associated with invasive disease in the United States. As of October 2000, laboratories are required to submit N. meningitidis isolates from normally sterile sites to the Indiana State Department of Health (ISDH) Laboratories for serogrouping. Additionally, molecular subtyping can be performed by pulse-field gel electrophoresis (PFGE) on selected meningococcal isolates that may indicate a cluster of cases. In 2005, serogroup C accounted for approximately 32 percent of meningococcal isolates confirmed in the ISDH Laboratory. With 37 percent of the isolates not typed, the prevalence of a particular serogroup circulating is unknown. Thus, an increased effort must be made to submit isolates for serogrouping in order to provide meaningful data. Table 2 lists the available serogroups for the five-year reporting period, 2001-2005.
| Serogroup | 2001 | 2002 | 2003 | 2004 | 2005 |
|---|---|---|---|---|---|
| A | -- | -- | -- | -- | -- |
| B | 17(36.2%) | 8(22.8%) | 22(44.8%) | 8 (31%) | 4 (21%) |
| C | 8(17.0%) | 7(21.2%) | 6(12.2%) | 2 (8%) | 6 (32%) |
| Y | 12(25.5%) | 9(27.7%) | 10(20.4%) | 5 (19%) | 1 (5%) |
| W-135 | -- | -- | -- | -- | -- |
| Z | 1(2.1%) | 1(2.8%) | -- | -- | -- |
| Not Groupable | 1(2.1%) | 4(11.4%) | 2(4.1%) | 3 (11%) | 1 (5%) |
| Not Typed/ Unknown |
8(17.0%) | 6(17.1%) | 9(18.3%) | 8 (31%) | 7 (37%) |
| Total | 47 | 35 | 49 | 26 | 19 |
Measures that would decrease the likelihood of transmission of the disease include:
You can learn more about meningococcal disease by visiting the following Web
site:
http://www.cdc.gov/ncidod/dbmd/diseaseinfo/meningococcal_g.htm
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