An adaptation of concentration techniques for the enumeration of parasitic helminth eggs from sewage sludge

Abstract

A technique for the routine examination of sewage sludges for parasitic helminth eggs has been developed in this laboratory in response to a need for information on levels of parasitic eggs in sewage sludges disposed to land. Eggs of Taenia saginata heat-killed and eosin-dyed were used throughout the development of this technique to determine the efficiency of the isolation procedure. The basic technique which takes 2–3 h per sample has been used on a routine basis in this laboratory for approx. 4 years, isolating eggs of Taenia, Ascaris and Trichuris spp. A wide range of sludge types have been tested and levels of eggs have remained low. This method when used routinely would be expected to detect readily any increase in egg numbers in a particular sludge.