The detection of Entamoeba histolytica and Toxoplasma gondii in wastewater

To increase current knowledge on the epidemiology of protozoan parasites in wastewater treatment plants (WWTP), the occurrence of Entamoeba histolytica and Toxoplasma gondii in raw and treated wastewater was investigated. Samples were collected from WWTP twice a month over a period of 8 months. Determination of protozoa was performed using polymerase chain reaction (PCR) and light microscopy. After concentration and purification of wastewater samples, DNA extraction was conducted followed by PCR amplification of small subunit ribosomal RNA (SSU rRNA) gene sequences of E. histolytica and B1 gene of T. gondii. Loop-Mediated Isothermal Amplification (LAMP) primer set was designed from E. histolytica hemolysin gene HLY6. Amplification of DNA in the LAMP mixture was monitored by naked eye as a blue color solution after addition of, hydroxynaphthol blue (HNB) to the reaction tube. Light microscopy revealed the presence of Entamoeba in all raw wastewater samples and treated water samples. PCR amplification of DNA products revealed that all, (9/9) wastewater samples were positive for Entamoeba. None was positive for Toxoplasma. These findings, which corroborate recent observations, indicate that E. histolytica may pose a public health risk.