Real scale environmental monitoring of zoonotic protozoa and helminth eggs in biosolid samples in Brazil

• Published in: Journal of parasitic diseases Vol. 40; no. 3; pp. 633 - 642
• Main Authors: Bonatti, Taís Rondello, Franco, Regina Maura Bueno
• Format: Journal Article
• Language: English
• Published: New Delhi Springer India 01.09.2016; Springer Nature B.V
• Subjects: Activated sludge; Ascaris; Brazil; Cryptosporidium; Cysts; Eggs; Electron microscopy; Environmental monitoring; Giardia; Health Promotion and Disease Prevention; helminths; Infectious Diseases; Ionic strength; Medicine; Medicine & Public Health; Morphology; Oocysts; Original; Original Article; parasitoses; pathogens; pH effects; Protozoa; Scanning electron microscopy; Sewage sludge; sewage treatment; solar radiation; Sunlight; temperature; Temperature effects; Toxocara; Trichuris; viability; Brazil; Biosolid; Monitoring; Helminth eggs; Cryptosporidium; Giardia
• ISSN: 0971-7196; 0975-0703
• DOI: 10.1007/s12639-014-0549-9

Biosolid is the product of the activated sludge treatment system and its final disposition is subject of ongoing discussion as this residue can therefore harbor a great number and variety of pathogens. This study was aimed to (1) monitor the presence of Giardia and Cryptosporidium in biosolid samples from a treatment plant in Campinas, SP, Brazil, (2) observe Giardia cyst wall morphological integrity in treated samples using scanning electron microscopy (SEM) and (3) verify the presence and viability of helminth eggs. Cysts were present in 33.3 % of the samples, whereas oocysts were detected in 8.3 %. Viable Ascaris sp. Toxocara sp. and similar to Trichuris sp. eggs were found through the use of Mexican Official Norm. Results demonstrate the difficulties inherent in working with biosolid as factors such as temperature, ionic strength and pH influenced the recovery of cysts and oocysts. Pores and ruptures were not observed in cyst wall visualized by SEM following 45 days of exposure to sunlight, only minimal morphological changes. These observations emphasize both the importance of adequate treatment of sewage sludge and the need to develop appropriate techniques for the detection of Giardia and Cryptosporidium in this type of sample. This is the first time that a study was done in a real scale for biosolid samples in determining the presence of pathogenic protozoa as Giardia and Cryptosporidium in Brazil, and also observed minimal cyst wall damage after sunlight treatment.