Overview of waterborne protozoa in Latin American water samples, detection methods and water treatment

Waterborne protozoa are a public health concern worldwide, affecting mostly low- and middle-income countries. In Latin American (LA) countries, poor sanitation and inefficient water treatment increase the risk of waterborne outbreaks. In this context, this research evaluated 85 peer-reviewed papers, addressing the occurrence of waterborne protozoa in water samples in LA countries. This study aims to provide relevant information about the protozoa detected, their basic characteristics, detection methods used, and treatment techniques studied entirely within the LA background to support decision-making. According to the results, the presence of Cryptosporidium spp., Giardia spp., Entamoeba spp., Blastocystis spp., Toxoplasma gondii , Cyclospora spp., Cystoisospora spp. and Trichomonas spp. in raw, treated and recreational water was detected. Giardia spp. and Cryptosporidium spp. were addressed in 70.5% of studies, mainly in Brazil and Argentina. Among water samples assessed, raw water was the most evaluated (83.5%), followed by treated water (42.3%) and recreational water (4.7%). The steps for concentrating, purifying, and detecting protozoa varied among the LA research groups; however, most of them used membrane/cartridge filtration and immunofluorescence microscopy, and the purification step was applied in only 41% of studies. It was found that few LA research groups (11.7%) evaluated water treatment for protozoa inactivation, in which chlorine disinfection was the most commonly reported technique. Water samples from LA countries have revealed the presence of waterborne protozoa, underscoring the need for investments in water and sanitation services, as well as improved detection methods for surveillance and control. • Cryptosporidium spp. and Giardia spp. are the most studied protozoa in LA countries • Entamoeba spp., T. gondii and emerging protozoa have been identified in water samples • Waterborne protozoa were detected in raw, treated, and recreational water samples • Filtration and immunofluorescence microscopy are the most used detection methods • Urgent need for improving water and sanitation infrastructures and protozoa detection methods in LA countries