Challenges of Establishing Routine Influenza Sentinel Surveillance in Ethiopia, 2008-2010

Ethiopian Health and Nutrition Research Institute.
The Journal of Infectious Diseases (Impact Factor: 6). 12/2012; 206 Suppl 1(S1):S41-5. DOI: 10.1093/infdis/jis531
Source: PubMed


Ethiopia launched influenza surveillance in November 2008. By October 2010, 176 patients evaluated at 5 sentinel health facilities in Addis Ababa met case definitions for influenza-like illness or severe acute respiratory illness (SARI). Most patients (131 [74%]) were children aged 0-4 years. Twelve patients (7%) were positive for influenza virus. Most patients (109 [93%]) were aged <5 years, of whom only 3 (2.8%) had laboratory-confirmed influenza. Low awareness of influenza by healthcare workers, misperceptions regarding case definitions, and insufficient human resources at sites could have potentially led to many missed cases, resulting in suboptimal surveillance.

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    • "This corroborates the sentinel data in Egypt and Morocco [30], which confirmed that the peak of A(H1N1)pdm09 incidence occurred between November 2009 and January 2010. Similarly, to Djibouti’s neighbour, Ethiopia, which reported its first two cases in June 2009 (first wave), followed by a lapse until early 2010 (second wave), when more cases were noticed [31]. Although this scenario was acceptable to the regional WHO EMR office, it should be considered carefully since countries with functional surveillance systems were likely to detect and report the pandemic circulation earlier than those without these surveillance systems. "
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    ABSTRACT: Following the 2009 swine flu pandemic, a cohort for pandemic influenza (CoPanFlu) study was established in Djibouti, the Horn of Africa, to investigate its case prevalence and risk predictors' at household level. From the four city administrative districts, 1,045 subjects from 324 households were included during a face-to-face encounter between 11th November 2010 and 15th February 2011. Socio-demographic details were collected and blood samples were analysed in haemagglutination inhibition (HI) assays. Risk assessments were performed in a generalised estimating equation model. In this study, the indicator of positive infection status was set at an HI titre of >= 80, which was a relevant surrogate to the seroconversion criterion. All positive cases were considered to be either recent infections or past contact with an antigenically closely related virus in humans older than 65 years. An overall sero-prevalence of 29.1% and a geometrical mean titre (GMT) of 39.5% among the residents was observed. Youths, <= 25 years and the elderly, >=65 years had the highest titres, with values of 35.9% and 29.5%, respectively. Significantly, risk was high amongst youths <= 25 years, (OR 1.5-2.2), residents of District 4(OR 2.9), students (OR 1.4) and individuals living near to river banks (OR 2.5). Belonging to a large household (OR 0.6), being employed (OR 0.5) and working in open space-outdoor (OR 0.4) were significantly protective. Only 1.4% of the cohort had vaccination against the pandemic virus and none were immunised against seasonal influenza. Despite the limited number of incident cases detected by the surveillance system, A(H1N1)pdm09 virus circulated broadly in Djibouti in 2010 and 2011. Age-group distribution of cases was similar to what has been reported elsewhere, with youths at the greatest risk of infection. Future respiratory infection control should therefore be tailored to reach specific and vulnerable individuals such as students and those working in groups indoors. It is concluded that the lack of robust data provided by surveillance systems in southern countries could be responsible for the underestimation of the epidemiological burden, although the main characteristics are essentially similar to what has been observed in developed countries.
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