Detection of Giardia spp. cysts and Cryptosporidium spp. oocysts in untreated water collected from treatment plants in Blumenau, Santa Catarina State, Brazil.

Abstract Giardia spp. and Cryptosporidium spp. are water-borne pathogenic protozoans spread through fecal-oral transmission which cause several health problems, to include gastrointestinal diseases associated with the consumption of contaminated water. There are limited data regarding the occurrence of these protozoans in surface waters in southern Brazil. The aim of this study was therefore to investigate the presence of cysts and oocysts in untreated water collected from water treatment plants in Blumenau, Santa Catarina State, Brazil. The methodology employed to study the protozoans was filtration through mixed cellulose ester membranes followed by the immunofluorescence reaction using the Merifluor(r) kit. Microbiological analysis was conducted using the Standard Methods for the Examination of Water and Wastewater and multi-parameter probes were used for the physico-chemical analysis. Cysts of Giardia spp. were found in 23.19% of the samples and oocysts of Cryptosporidium spp. in 7.24% of the samples (n=67). All of the samples analyzed were contaminated with Escherichia coli and 11.76% of the untreated water samples had turbidity values higher than the recommended limit. In the case of the treated water samples, 23.52% had turbidity values above the limit established by legislation (Portaria MS 2914/2011). The detection of pathogenic protozoans in the untreated water at the treatment plants highlights the importance of adopting preventative measures, such as the protection of areas where water is present and adequate treatment of domestic sewage, in order to reducing the risk of protozoan transmission via potable water.