Preliminary observations on the removal of Taenia saginata eggs from sewage using various treatment processes

Cattle were grazed for four months on pasture irrigated by effluent from activated sludge plants, a trickling filter plant, from a lagooning process with raw sewage, and then killed and their heart, diaphragm, tongue, and muscles of their head and one forelimb were sliced and examined for Cysticercus bovis. None of the cattle grazed on pasture irrigated with effluent from lagooning were infected compared with 3.3% from the trickling filter plant, 9.0% and 12.5% from the two activated sludge plants and 30.0% of cattle on pastures irrigated with raw sewage. Of the 40 control calves killed at the time the test calves were placed on the various pastures, 2.5% were infected. It appears that modern sewage purification methods do not efficiently remove Taenia saginata from the final effluent and that prolonged settling is necessary before effluent is used to irrigate cattle pastures if C. bovis infection is to be reduced to very low levels.