RESUMO
BACKGROUND: Haemophilus influenzae (Hi) can cause severe disease in children. This study aimed to identify risk factors related to invasive Hi disease in Alaska children and evaluate carriage in people around them. METHODS: From 2005 to 2011, we investigated episodes of invasive, typeable Hi disease in Alaska children <10 years old. Three age-matched control children were enrolled for each case-patient. We evaluated oropharyngeal Hi carriage in people in close contact with Hi case-patients (contacts) as well as control children and their household members. Individual and household risk factors for illness and carriage were evaluated using questionnaires and chart reviews. RESULTS: Thirty-eight of 44 (86%) children with invasive, typeable Hi disease were recruited: 20 Hi serotype a (53%), 13 serotype b (Hib) (34%) and 5 serotype f (13%). Children with the invasive Hi disease were more likely than controls to have underlying health problems (67% vs. 24%, P = 0.001), other carriers of any Hi in their household (61% vs. 15%, P < 0.001), and inadequate Hib vaccination (26% vs. 9%, P = 0.005). People who carried Hi were younger than noncarriers (mean 12.7 vs. 18.0 years, P = 0.008). The carriage was clustered within case-patient households, with carriage in 19% of household contacts, while only 6.3% of nonhousehold contacts and 5.5% of noncontacts carried the Hi serotype of interest ( P < 0.001). CONCLUSIONS: Factors associated with invasive Hi disease in children included underlying health problems, household carriage and inadequate Hib vaccination. The high level of carriage in case-patient households is important to consider when evaluating treatment and prophylaxis strategies.
Assuntos
Portador Sadio , Infecções por Haemophilus , Haemophilus influenzae , Humanos , Infecções por Haemophilus/epidemiologia , Infecções por Haemophilus/microbiologia , Haemophilus influenzae/isolamento & purificação , Haemophilus influenzae/classificação , Pré-Escolar , Masculino , Feminino , Lactente , Alaska/epidemiologia , Criança , Estudos de Casos e Controles , Fatores de Risco , Portador Sadio/epidemiologia , Portador Sadio/microbiologia , Inquéritos e QuestionáriosRESUMO
Haemophilus influenzae serotype a is a rare cause of invasive disease. We report 5 cases of invasive H. influenzae type a that occurred in 3 infants living in a remote region of Alaska during the last 6 months of 2003. H. influenzae type a isolates from this outbreak were closely related as determined by pulsed field gel electrophoresis. Continued surveillance is necessary to monitor trends in H. influenzae invasive disease.