Prevalence of free-living amoebae in swimming pools and recreational
waters, a systematic review and meta-analysis
Abstract
Free-living amoebae (FLA) are cosmopolitan microorganisms known to be
pathogenic to humans who often have a history of contact with
contaminated water. Swimming pools and recreational waters are among the
environments where the greatest human exposure to FLA occurs. This study
aimed to determine the prevalence of FLA in swimming pools and
recreational waters, through a systematic review and meta-analysis that
included studies published between 1977 and 2021. 71 studies were
included and an overall prevalence of FLA in swimming pools and
recreational waters of 40.89% (95% CI = 33.97–48.00) was found.
Considering the studies published up to 2010 (1977 - 2010) and after
2010 (>2010 - 2021) the prevalence were 51.54% (95% CI =
36.65-66.29) and 37.95% (95% CI = 30.34 – 45.86), respectively. The
highest prevalence were found in the American continent (59.52%), in
Malaysia (89.33%) and in indoor hot pools 52.27%. In studies that used
morphological methods, PCR and both methods simultaneously to identify
FLA, the prevalence was 56.41, 22.32 and 39.94%, respectively.
Considering only PCR-based studies, the prevalence of Naegleria
spp., Acanthamoeba spp., Hartmanella spp. and
Vermamoeba spp. was 10.01, 15.38, 16.40 and 16.06%,
respectively. There is considerable risk of AFL infection in swimming
pools and recreational waters. Recreational water safety needs to be
routinely monitored and, in case of risk, locations need to be
identified with warning signs and users need to be educated. Swimming
pools and artificial recreational water should be properly disinfected.
Photolysis of NaOCl or NaCl in water by UV-C radiation is a promising
alternative to disinfect swimming pools and artificial recreational
waters.