Molecular characterization of waterborne protozoa in surface water and sediment in Brazil: a taxonomic survey of ciliated protozoa and their correlation with Giardia duodenalis and Cryptosporidium spp.

Abstract

The detection of Giardia duodenalis and Cryptosporidium spp. was performed, along with the identification of the ciliated protozoa biodiversity, to evaluate the correlation between these protozoa in freshwater quality monitoring. Water and sediment samples from two sites in the Atibaia River (Campinas, São Paulo, Brazil) were collected monthly for two years (n = 96). Pathogenic protozoa in water and sediment were detected by using immunomagnetic separation, followed by visualization by immunofluorescence assay (IFA). All positive aliquots in IFA were subjected to DNA extraction and subsequently nested PCR. Qualitative (in vivo observation and silver impregnation) and quantitative (in vivo enumeration) analyses were performed for the ciliated protozoa. Giardia cysts were detected in 62.5% of the surface water samples and Cryptosporidium spp. in 25.0%. In the sediment, cysts were detected in 35.4% samples and oocysts in 16.6%. A total of 57 samples positive for Giardia cysts were subjected to sequencing, 40 of which were harboring G. duodenalis (24 were characterized as sub assemblage AII). For ciliated protozoa, 73 taxa belonging to 53 genera were identified over the period of the study. These results revealed a high degree of contamination by waterborne protozoa in the main water source which supplies drinking water for more than one million people in Campinas (São Paulo), highlighting the need for continuous monitoring of this catchment site. In addition, the present study provides important data regarding the sources of the water body degradation, i.e., fecal contamination of human origin, in addition to the survey of the ciliated protozoa.

Free-living protozoa (ciliophora, excavata and amoebozoa) in two water sources for human supply in the municipality of Blumenau, SC

“…The inventory of free-living protozoan species identified at points P1 and P2 during the study and each species' occurrence over twelve months of sampling BONATTI et al, 2016).…”

“…Among the aquatic organisms used as bioindicators, free-living protozoa have received attention in recent decades (BONATTI et al, 2016;REGALI-SELEGHIM et al, 2011). These organisms are unicellular, eukaryotic, heterotrophic, or mixotrophic (GODINHO; REGALI-SELEGHIM, 1999), with a short life cycle, being sensitive to environmental changes (NORF et al, 2009;XU et al, 2015;XU, 2020).…”

“…Among the studies on freshwater protozoa in the country, which stand out for presenting surveys of species, we can mention the studies by Dias et al (2008), Pauleto et al, (2009), Regali-Seleghim et al, (1992, Colzani;Alves (2013), Velho et al, (2013), Bonatti et al, (2016, Debastiani et al, (2016), Segovia et al, (2016) and Souza et al, (2019). According to Regali-Seleghin et al, (2011), large surveys involving the protozoofauna have been carried out in Europe and North America; however, few studies focus on the Neotropical region.…”