Journal of Water and Health Vol 5 No 4 pp 609–614 © IWA Publishing 2007 doi:10.2166/wh.2007.006
Comparison of two methodologies for detection of Giardia spp. cysts and Cryptosporidium spp. oocysts in activated sludge samples from a sewage treatment plant in the city of Campinas, São Paulo State, Brazil
Taís Rondello Bonatti, Regina Maura Bueno Franco and Romeu Cantusio Neto
Parasitology Department, Biology Institute, State University of Campinas, SP Brazil PO Box 6109, CEP:13083-970,
Parasitology Department, Biology Institute, State University of Campinas, SP Brazil PO Box 6109, CEP: 13083-970, Tel: +55 -19 - 3521-6285Fax: +55-19-3521-6285mfranco@unicamp.br.
Microbiology Laboratory, Society of Water Supply and Sanitation S/A, Campinas, SP Brazil
ABSTRACT
Giardia spp. and Cryptosporidium spp. are recognized worldwide as highly infectious protozoan parasites that can cause severe gastrointestinal disease in humans and animals. The detection of these pathogens in activated sludge samples becomes interesting since there is an increasing trend for the use of sewage sludge (biosolids) in agriculture. A total of 22 samples were collected and evaluated by means of Centrifugal – Concentration, followed or not followed by a purification process (ether clarification and sucrose flotation). Student t tests for comparison of the two procedures indicated a higher recovery rate of Giardia cysts with Centrifugal – Concentration; with regard to Cryptosporidium oocysts, no significant differences were found between the two methods, as only two samples were positive. The Centrifugal – Concentration procedure was shown to be the simplest and cheapest to perform, as emphasized by the efficiency recovery results.
Keywords: Centrifugal – Concentration; Cryptosporidium; Giardia; recovery; sewage sludge
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