The likely role of protozoa in the maintenance of the environmental circulation of enteroviruses

: The purpose of the study was to define the likely role of protozoa as a possible natural reservoir for enteroviruses and their involvement in enterovirus-induced serous meningitis morbidity. Samples were taken from the running and standing water reservoirs of the Orenburg Region in the summer-autumn period and those of wastewaters were collected at all purification stages. Enteroviral RNA in the protozoan cultured was detected by the reverse-transcription polymerase chain reaction (PCR). The Ural River was found to contain 72 protozoan species; there were 15 and 38 protozoan species in the lakes and wastewaters, respectively. With PCR, enteroviruses were detected in 61.8% of the cultures of protozoa which belonged to 23 species of flagellates, amoebas, and infusoria isolated from the natural water reservoirs exposed to an anthropogenic load, as well as from the wastewaters at all purification stages. The predominant localization of enteroviruses was observed in the dominant taxons of the protozoa Paraphysomonas sp., Spumella sp., Petalomonas poosilla, Amoeba sp.