Invasive Bacterial Diseases in Northern Canada

Abstract

International Circumpolar Surveillance (ICS) is a population-based invasive bacterial disease surveillance network. Participating Canadian regions include Yukon, Northwest Territories, Nunavut, and northern regions of Québec and Labrador (total population 132,956, 59% aboriginal). Clinical and demographic information were collected by using standardized surveillance forms. Bacterial isolates were forwarded to reference laboratories for confi rmation and serotyping. After pneumococcal conjugate vaccine introduction, crude annual incidence rates of invasive Streptococcus pneumoniae decreased from 34.0/100,000 population (1999)(2000)(2001)(2002)) to 23.6/100,000 population (2003)(2004)(2005); substantial reductions were shown among aboriginals. However, incidence rates of S. pneumoniae, Haemophilus infl uenzae, and group A streptococci were higher in aboriginal populations than in non-aboriginal populations. H. infl uenzae type b was rare; 52% of all H. infl uenzae cases were caused by type a. Data collected by ICS contribute to the understanding of the epidemiology of invasive bacterial diseases among northern populations, which assists in formulation of prevention and control strategies, including immunization recommendations.

Invasive bacterial diseases in Northern Canada, 2006–2013

“…These findings are consistent with previous Canadian and international circumpolar studies (3)(4)(5)(6)(21)(22)(23).…”

“…Some studies suggested that poor health, environmental and housing conditions of Indigenous children may be potential risk factors (28)(29)(30)(31). Hia has been a predominant serotype in Northern Canada since the beginning of ICS (5,22,32), whereas non-typaeble Hi and type f are more common in other circumpolar regions (32). This report also demonstrates the significant increasing trend of Hia.…”

“…Routine PCV7 vaccination of infants started in 2002 in some Northern regions and IPD incidence has reduced since then (5,6). This report demonstrates a further reduction and sustained decreasing trend in PCV7 serotype-caused IPD as well as the total incidence of IPD.…”

“…The last published study describing IBDs in Northern Canada included data from 1999 to 2005 (5). Since then, a number of vaccines against some bacterial pathogens have been introduced into the routine childhood immunization schedule.…”

Invasive disease caused by Haemophilus influenzae type a in Northern Ontario First Nations communities

“…There is concern that following widespread vaccination against Hib, H. influenzae strains may undergo capsule switching or replacement to fill the ecological niche previously occupied by Hib (Tsang, 2007). Indeed, the emergence of invasive non-type b H. influenzae disease has been reported in several countries (Heath et al, 2001;Ribeiro et al, 2003;Bajanca et al, 2004;Degani et al, 2008;Tsang et al, 2007;Brown et al, 2009). Interestingly, there are apparent geographical disparities in the prevalence of different types of H. influenzae, i.e.…”