Estimating the global burden of cystic echinococcosis

Objective: The global burden of numerous neglected tropical diseases, including cystic echinococcosis (CE), remains largely unknown. We conducted a systematic review of available CE literature worldwide, with the ultimate goal of estimating the number of disability adjusted life years (DALYs) associated with CE by region, age, and sex.

Methods: A systematic search was conducted in PubMed, Commonwealth Agricultural Bureau (CAB) Abstracts, and 22 international databases for literature related to CE epidemiology and clinical manifestations. Articles published from January 1, 1990 to June 1, 2008 were considered. Results from individual studies providing an overall prevalence or incidence rate of CE were reported. In addition, the distribution of clinical manifestations was reported for each eligible study. Meta-analyses were considered when appropriate.

Results: The titles and abstracts of 1,211 and 2,366 articles were reviewed to assess their eligibility for full article review for the epidemiology and clinical manifestations searches, respectively. Eligibility criteria included original data, human studies, correct agent and appropriate study dates. A total of 528 and 772 articles were eligible for quantitative and qualitative review for the epidemiology and clinical manifestations searches, respectively. Only a small percentage of the literature reviewed was found to be relevant to this study and certain endemic regions were found to be under-represented in the literature.

Discussion: This is the first systematic review of both CE epidemiology and clinical manifestations. The unequal distribution of the origin of published literature, in addition to poor official reporting, makes an accurate global assessment of the burden of CE difficult.