Epidemiological risks of endoparasitoses spread by municipal waste water

Abstract

The occurrence of developmental stages of endoparasite germs (cysts, oocysts, protozoa, and helminth eggs) as an indirect detection factor of endoparasitoses circulation in the environment, was examined in raw municipal wastewater, sludge and biologically cleaned waste water. Examination of municipal wastewater and sludge from five monitored wastewater treatment plants (WWTPs) in east Slovakia, from various fractions of municipal wastewater, confirmed 35.87 % positivity of samples for the endoparasitic germs. Among of all analysed samples 11.09 % were protozoan oo(cysts) and 20.87 % were helminth eggs. 3.91 % of samples showed positivity to both the helminth eggs and protozoan oo(cysts). In the raw wastewater the protozoa comprised of Giardia spp. (1.08 %) and Entamoeba spp. (1.08 %). The helminth eggs primarily consisted of Ascaris spp. (4.35 %) and strongyle-type eggs (3.26 %). No germs of protozoa or helminths were found in the treated wastewater. However, the highest presence of the germs was found in drained stabilised sludge. The average number of oo(cysts)/kg was 2.86±0.24 and the average number of helminth eggs/kg was 5.77±0.09. In all kinds of sludge, obtained during the process of wastewater treatment, there were protozoan (Giardia spp., Cryptosporidium spp., Entamoeba spp.) and helminths eggs (Ascaris spp., Trichuris spp., Taenia spp., Hymenolepis spp., or strongyle-type eggs) presented. In drained (condensed) stabilised sludge the eggs of Capillaria spp. and Toxocara spp. were also detected. From the epidemiological aspect the sewage sludge, due to high concentration of protozoal oo(cysts) or helminth eggs, represents a significant epidemiological risk for the endoparasitoses dissemination.