title: Haemophilus influenzae serotype a invasive disease, Alaska, USA, 1983-2011.
abstract: Before introduction of Haemophilus influenzae type b (Hib) vaccines, rates of Hib disease in Alaska's indigenous people were among the highest in the world. Vaccination reduced rates dramatically; however, invasive H. influenzae type a (Hia) disease has emerged. Cases of invasive disease were identified through Alaska statewide surveillance during 1983-2011. Of 866 isolates analyzed for serotype, 32 (4%) were Hia. No Hia disease was identified before 2002; 32 cases occurred during 2002-2011 (p<0.001). Median age of case-patients was 0.7 years; 3 infants died. Incidence of Hia infection (2002-2011) among children <5 years was 5.4/100,000; 27 cases occurred in Alaska Native children (18/100,000) versus 2 cases in non-Native children (0.5/100,000) (risk ratio = 36, p<0.001). From 12/2009 to 12/2011, 15 cases of Hia disease occurred in southwestern Alaska (in children <5 years, rate = 204/100,000). Since introduction of the Hib conjugate vaccine, Hia infection has become a major invasive bacterial disease in Alaska Native children.
authors.affiliation: Arctic Investigations Program, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Anchorage, Alaska 99507, USA. zwa8@cdc.gov
authors.forename: Michael G
authors.initials: MG
authors.lastname: Bruce
authors.forename: Tammy
authors.initials: T
authors.lastname: Zulz
authors.forename: Carolynn
authors.initials: C
authors.lastname: DeByle
authors.forename: Ros
authors.initials: R
authors.lastname: Singleton
authors.forename: Debby
authors.initials: D
authors.lastname: Hurlburt
authors.forename: Dana
authors.initials: D
authors.lastname: Bruden
authors.forename: Karen
authors.initials: K
authors.lastname: Rudolph
authors.forename: Thomas
authors.initials: T
authors.lastname: Hennessy
authors.forename: Joseph
authors.initials: J
authors.lastname: Klejka
authors.forename: Jay D
authors.initials: JD
authors.lastname: Wenger
mesh_terms: D000293:Adolescent; D000328:Adult; D000413:Alaska / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D004196:Disease Outbreaks; D005843:Geography; D006192:Haemophilus Infections / Q000453:epidemiology* / Q000266:history; D006193:Haemophilus influenzae / Q000145:classification* / Q000235:genetics; D049673:History, 20th Century; D049674:History, 21st Century; D006801:Humans; D015994:Incidence; D007223:Infant; D008875:Middle Aged; D058885:Multilocus Sequence Typing; D062486:Public Health Surveillance; D012703:Serotyping; D055815:Young Adult
keywords: Alaska; Alaska Native people; H. influenzae; Haemophilus influenzae; Hia; Hib; United States; bacteremia; bacteria; cellulitis; coccobacillus; epiglottitis; invasive disease; meningitis; otitis media; pericarditis; pneumonia; septic arthritis