Global Estimate of the Total Number of Human Strongyloidiasis Cases: A Systematic Review
Author(s): Heron Gezahegn
Background: The soil-dwelling nematode Strongyloides stercoralis is one of the most underestimated and neglected parasites in the Neglected Tropical Diseases (NTDs) group. All available data were systematically reviewed and summarized to better understand the problem's magnitude and estimate the total number of Strongyloidiasis cases in humans at best and worst.
Methods: A systematic electronic literature search was performed in the PubMed, WHOLIS, and ISI Web of Science databases for articles published between January 1990 and May 2017. Reports with quantitative data on prevalence, incidence, duration of infection, remission/cure, and mortality in humans were considered. After obtaining the raw data from the systematic review, correction for diagnostic accuracy, selection of the reference population, and adjustments for age and reference year 2017 were made as a prerequisite for estimating the total number of strongyloidiasis cases in humans worldwide.
Findings: A total of 166 community-based studies from 60 countries and all continents except Antarctica were identified to estimate the total number of infections worldwide. Overall, it was estimated that 159 542 655 people are infected with S. stercoralis worldwide in the best-case scenario and 260 710 055 in the worst-case scenario, with Asia and Europe having the highest and lowest numbers of strongyloidiasis cases, respectively.
Conclusions: This study revealed a high number of infections in both scenarios. Although there is still a need for more sufficient data on the epidemiology of strongyloidiasis, the current information emphasizes that S. stercoralis should not be neglected. Furthermore, the findings of this study can be used as a basis for Burden of Disease (BoD) calculation.