Genomic characterization of Cryptosporidium spp. in Sludge Produced from Wastewater Treatment Plants in Gaza Strip: Environmental Health Impact

Background: Massive amounts of sludge created by wastewater treatment in the Gaza Strip that are not treated may pose a health risk due to the protozoa and other diseases prevalent in the sludge. The current work sought to identify the genetic characteristics of Cryptosporidium spp. and other protozoa found in sludge from wastewater treatment plants in the Gaza Strip.Materials Methods: Between December 2021 and August 2022, 72 sludge samples were collected from the Gaza Strip's three municipal wastewater treatment plants, each of which uses a different biological treatment procedure. Following transfer to the laboratory, materials were coded and microscopically examined using the modified Ziehl-Neelsen (MZN) method. The results were then validated using the Enzyme-linked Immunosorbent Assay (ELISA), PCR, and sequence analysis for Cryptosporidium spp.Results: The MZN stain identified 16/72 (22.2%), while the ELISA identified 9/72 (12.5%) of the Cryptosporidium spp. samples. Using the PCR technique, only 3/72 (4.2%) of the samples tested positive for Cryptosporidium spp. The three positive Cryptosporidium samples were identified as Cryptosporidium parvum by sequencing. The nucleotide sequences of Cryptosporidium spp. were found to be highly similar using Sanger dideoxy sequencing (more than 96% similarity). The sequences discovered in this work have been submitted to GenBank with the accession numbers OQ104414, OQ104415, and OQ104416.Conclusion: The sludge from sewage plants was found to be polluted and confirmed as Cryptosporidium parvum using several techniques.