A METHOD FOR ASSESSING THE VIABILITY OF NEMATODE EGGS IN SLUDGE

Helminth eggs are found in urban sludge used in agriculture. Then, to evaluate the parasitic risk, a method was developed to estimate the vi ability of these eggs. The extraction of these eggs was performed with a diphasic treatment (SDS 0.01 % - Ethylacetate) coupled with a filtr ation on 500 mu m and 100 mu m sieves followed by concentration using two flotations with NaCl (d = 1.19). For the culture, 3 parameters tes ted showed a faster egg development at 30 degrees C in deionized water with continuous aeration, whereas organic compounds reduced this deve lopment. This culture was performed during respectively 13, 10 and 8 d ays to obtain Ascaris suum, Toxocara canis and Capillaria sp larva, an d 16 days for Trichuris vulpis which presented a slower development. T he quantification was realized by microscopic examination (100 X) afte r sonication and sodium hypochlorite (0.5 degrees Chl) treatment. The eggs reaching the larva stage were considered as viable and the percen t of viability was expressed by the ratio: nematode eggs at the larva stage/total of Nematode eggs counted.