Haemophilus influenzae Serotype a Invasive Disease, Alaska, USA, 1983–2011 - Vol. 19 No. 6 - June 2013 - Emerging Infectious Disease journal - CDC
Table of Contents
Volume 19, Number 6–June 2013
Volume 19, Number 6—June 2013
Haemophilus influenzae Serotype a Invasive Disease, Alaska, USA, 1983–2011
Suggested citation for this article
Haemophilus influenzae is a bacterial pathogen that can cause serious invasive disease. The organism is classified by the presence of a capsular polysaccharide (6 STs, a-f) or its absence (nonencapsulated or nontypeable strains). In Alaska, before introduction of H. influenzae serotype b (Hib) vaccine, rates of invasive Hib disease among Alaska Native people were among the highest in the world (1,2). Disease caused by Hib was reduced significantly after the 1991 introduction of the Hib conjugate vaccine, polyribosylribitol phosphate outer membrane protein (PRP-OMP) (3); however, this vaccine does not provide protection against the other capsular or nontypeable strains (4). H. influenzae serotype a (Hia), in particular, has been reported as the cause of serious disease in young children (5–7). We previously described invasive Hia disease in the North American Arctic (Northern Canada and Alaska) from 2000 through 2005 (8) and reported an outbreak of 5 episodes of invasive Hia disease in 3 children during 2003 in southwestern Alaska (9). Sporadic cases were reported from 2005 through 2009. In this report, we describe an outbreak of 15 cases of invasive Hia disease that occurred from December 2009 through December 2011 in neighboring areas and review the microbiology and epidemiology of Hia disease in Alaska from 1983 to 2011.