The seroprevalence rate and population genetic structure of human cystic echinococcosis in the Middle East: A systematic review and meta-analysis

Abstract

Cystic echinococcosis (CE) represents an increasing public health concern in many parts of the world, including the Middle East. The present study is the first systematic review and meta-analysis to assess the seroprevalence rate and population genetic structure of human CE in the eastern Mediterranean region. To estimate the population genetic structure, Echinococcus sequences of the cytochrome oxidase subunit 1 (cox1) gene isolated from countries from this geographical area were retrieved from the GenBank database. An electronic search for articles from 1990 until 2015 was performed using databases PubMed, ScienceDirect, and Scopus. A total of 53 articles reporting on CE seroprevalence and genotyping data met our eligibility criteria and were included in a meta-analysis. The overall CE seroprevalence rates in the general population and in individuals at high risk of infection were estimated using the random-effect model at 7.4% (95% CI = 4.8-10.6) and 10.7% (95% CI = 7.6-14.3), respectively. Risk factors including age group (P < 0.001), dog ownership (P = 0.03), residence area (P < 0.001), and educational level (P = 0.04) showed a statistically significant association with CE seroprevalence. A pairwise fixation index (Fst), used as an estimation of gene flow, suggested a moderate level of genetic differentiation between members of the E. granulosus sensu stricto (G1-G3) complex from Iranian and Turkish metapopulations (Fst = 0.171). The finding of common haplotypes may represent an ancestral transfer of alleles among populations probably during the early stages of animal domestication. The high CE seroprevalence rates found highlight the necessity of implementing appropriate public education for preventive and control strategies, particularly in individuals at high risk of infection; furthermore, our genetic findings reveal novel molecular data concerning microevolutionary events of Echinococcus isolates among Middle East countries.

Keywords: Cystic echinococcosis; Echinococcus granulosus; Gene flow; Meta-analysis; Middle East; Systematic review.