2.2. Selection and Exclusion Criteria
The screening focused essentially on the title and then on the abstract of the articles. All retrieved articles written in English (reporting primary data), with accessible full text, dealing with the presence of free-living amoebae in swimming pools and human recreation waters were selected. Studies whose data were insufficient, unclear or duplicated were excluded. Case studies that do not report the prevalence of FLA in swimming pools and human recreation waters were also excluded.