Fate of Cryptosporidium and Giardia through conventional and compact drinking water treatment plants

Abstract During the past thirty years, there has been a significant increase in the contamination of drinking water by enteric pathogenic protozoa, particularly Giardia and Cryptosporidium spp. Such microbial contamination has been responsible for disease outbreaks and increased background rates of disease in developed and developing countries worldwide. As such, controlling waterborne diseases is a critical aspect of public health policy and the primary objective of drinking water treatment plants (DWTPs). Limited studies applied real-time PCR (qPCR) and/or Immunofluorescence assay (IFA) for monitoring Giardia and Cryptosporidium spp., particularly in developing countries like Egypt. Samples of water from two conventional drinking water treatment plants and two compact units (CUs) were analyzed using both IFA and qPCR methods to detect Giardia and Cryptosporidium. The conventional DWTPs showed complete removal of Giardia and Cryptosporidium gene copies, whereas Mansheyat Alqanater and Niklah CUs achieved only partial removal. Specifically, Cryptosporidium gene copies removal rates were 33.33% and 60% for Mansheyat Alqanater and Niklah CUs, respectively. Niklah CU also removed 50% of Giardia gene copies, but no Giardia gene copies were removed by Mansheyat Alqanater CU. Conventional DWTPs were more effective than CUs in removing enteric protozoa. The contamination of drinking water by enteric pathogenic protozoa remains a significant issue globally, leading to increased disease rates. Infectious disease surveillance in drinking water is an important epidemiological tool to monitor the health of a population.