Epidemiology of Haemophilus influenzae serotype a, North American Arctic, 2000-2005.
Before the introduction of Haemophilus influenzae type b (Hib) conjugate vaccines, rates of invasive H. influenzae disease among indigenous people of the North American Arctic were among the highest in the world. Routine vaccination reduced rates to low levels; however, serotype replacement with non-type b strains may result in a reemergence of invasive disease in children. We reviewed population-based data on invasive H. influenzae in Alaska and northern Canada from 2000-2005; 138 cases were reported. Among 88 typeable isolates, 42 (48%) were H. influenzae type a (Hia); 35 (83%) occurred in indigenous peoples. Among Hia patients, median age was 1.1 years; 62% were male; 1 adult died. Common clinical manifestations included meningitis, pneumonia, and septic arthritis. Overall annual incidence was 0.9 cases per 100,000 population. Incidence among indigenous children <2 years of age in Alaska and northern Canada was 21 and 102, respectively. Serotype a is now the most common H. influenzae serotype in the North American Arctic; the highest rates are among indigenous children.
Bruce
Michael G
MG
Arctic Investigations Program, National Center for Preparedness, Detection, and Control of Infectious Diseases, Centers for Disease Control and Prevention, 4055 Tudor Circle Drive, Anchorage, AK 99508, USA. zwa8@cdc.gov
Deeks
Shelley L
SL
Zulz
Tammy
T
Navarro
Christine
C
Palacios
Carolina
C
Case
Cheryl
C
Hemsley
Colleen
C
Hennessy
Tom
T
Corriveau
Andre
A
Larke
Bryce
B
Sobel
Isaac
I
Lovgren
Marguerite
M
Debyle
Carolynn
C
Tsang
Raymond
R
Parkinson
Alan J
AJ
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000413:Alaska / Q000453:epidemiology; D001110:Arctic Regions / Q000453:epidemiology; D002170:Canada / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D005260:Female; D006192:Haemophilus Infections / Q000453:epidemiology*; D006193:Haemophilus influenzae / Q000145:classification* / Q000472:pathogenicity; D006801:Humans; D015994:Incidence; D007223:Infant; D004930:Inuit / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D011159:Population Surveillance; D012703:Serotyping