Environmental surveillance of Cryptosporidium and Giardia in surface supply water and treated sewage intended for reuse from an urban area in Brazil

• Published in: Environmental pollution (1987) 2024-12, Vol.363 (Pt 1), p.125089, Article 125089
• Main Authors: Araújo, Ronalda Silva de, Barbosa, Mikaela Renata Funada, Dropa, Milena, Araujo de Castro, Vanessa Cristina, Galvani, Ana Tereza, Padula, José Antônio, Bruni, Antônio de Castro, Brandão, Carlos Jesus, Lallo, Maria Anete, Sato, Maria Inês Zanoli
• Format: Article
• Language: English
• Subjects: Brazil; Cities; Cryptosporidium; Cryptosporidium - genetics; Cryptosporidium - isolation & purification; decision making; Environmental monitoring; Environmental Monitoring - methods; fluorescent antibody technique; gene amplification; genes; Giardia - genetics; Giardia - isolation & purification; Giardia lamblia; humans; Oocysts; Phylogeny; pollution; Public health; qPCR; Reuse water; Sewage - parasitology; sewage treatment; species; surface water; United States Environmental Protection Agency; urban areas; Water Supply; Waterborne protozoan
• ISSN: 0269-7491; 1873-6424; 1873-6424
• DOI: 10.1016/j.envpol.2024.125089

Environmental monitoring of protozoa, with the potential to trigger diseases, is essential for decision-making by managing authorities and for the control of water surveillance. This study aimed to detect and quantify Cryptosporidium oocysts and Giardia cysts in surface water for drinking water supply and treated sewage for reuse in the city of São Paulo. Samples collected bimonthly for one year were concentrated using the USEPA 1623.1 and 1693 methods for surface water and treated effluents, respectively. Immunofluorescence and nucleic acid amplification techniques were used to detect and quantify (oo)cysts. The cloning technique followed by sequencing and phylogenetic analyses were performed to characterize species and genotypes. The immunofluorescence detected Cryptosporidium spp. and Giardia spp. in 69.2% (9/13) and 100% (13/13) of the surface water samples (0.1–41 oocysts/L and 7.2–354 cysts/L, respectively). In the reuse samples, 85.7% (12/14) were positive for both protozoa and the concentrations varied from 0.4 to 100.6 oocysts/L and 1.2 and 93.5 cysts/L. qPCR assays showed that 100% of surface water (0.1–14.6 oocysts/L and 0.3–639.8 cysts/L) and reused samples (0.1–26.6 oocysts/L and 0.3–92.5 cysts/L) were positive for both protozoa. Species C. parvum, C. hominis, and C. muris were identified using the 18S rRNA gene, demonstrating anthroponotic and zoonotic species in the samples. Multilocus SSU rRNAanalyses of the SSU rRNA, tpi, and gdh genes from Giardia intestinalis identified the AII, BII, and BIV assemblages, revealing that contamination in the different matrices comes from human isolates. The study showed the circulation of these protozoa in the São Paulo city area and the impairment of surface water supply in metropolitan regions impacted by the discharge of untreated or inadequately treated sewage regarding the removal of protozoa, emphasizing the need to implement policies for water safety, to prevent the spread of these protozoa in the population. [Display omitted] •Cryptosporidium and Giardia were detected in high concentration in water sources.•QPCR technique detected both protozoa in 100% of surface water and reuse samples.•Cryptosporidium species and Giardia AII, BIII, BVI were identified by sequencing.•Implementing water and sewage safety plans is urgent to minimize human health risks.