Epidemiology of Meningitis Caused by Haemophilus influenzae, Neisseria meningitidis, and Streptococcus pneumoniae in the North American Arctic, 2000‒2010
In the 1970s, the annual incidence/100,000 persons of meningitis caused by Haemophilus influenzae, Neisseria meningitidis, and Streptococcus pneumoniae in indigenous Alaskans was 62.8, 2.4, and 19.3, respectively, and in indigenous Canadians was 46.3, 42.8, and 7.1, respectively; updated estimates for these populations are unavailable. Therefore, we estimated the incidence of H. influenzae, N. meningitidis, and S. pneumoniae meningitis in the North American Arctic during 2000‒2010.
METHODS:
Surveillance data for Alaska, Northern Canada, and Greenland were obtained from International Circumpolar Surveillance (ICS). We defined a case of bacterial meningitis caused by H. influenzae, N. meningitidis, or S. pneumoniae as a culture-positive isolate obtained from a normally sterile site in a resident with a meningitis diagnosis. Population estimates were obtained from national census statistics (Greenland does not record residents’ indigenous status). We assumed ICS identified all cases so 95% confidence intervals (CI) are not presented.
RESULTS:
The mean population in Alaska, Northern Canada, and Greenland during the study period was 668,662 (19% indigenous), 136,921 (58% indigenous), and 56,550 (% indigenous unknown), respectively. The annual incidence/100,000 persons for meningitis caused by H. influenzae, N. meningitidis, and S. pneumoniae among all North American Arctic residents was: 0.6, 0.5, and 1.5, respectively; among North American Arctic children aged <2 years was: 15.4, 5.1, and14.4, respectively; among indigenous persons (in Alaska and Canada) was: 2.1, 0.8, and 2.4, respectively.
CONCLUSIONS:
The incidence of meningitis caused by H. influenzae, N. meningitidis, and S. pneumoniae among indigenous Alaskans and Canadians declined since the 1970s, but remains higher compared with all North American Arctic residents. Compared with published reports on the incidence of meningitis caused by H. influenzae, N. meningitidis, and S. pneumoniae in the overall US population during 2006-2007, the incidence in North American Arctic residents was 7.5, 2.6, and 1.9-times higher, respectively.