USE OF A POLYURETHANE CARRIER FOR ASSESSI NG THE SURVIVAL OF HELMINTHEGGS IN LIQUID BIOLOGICAL SLUDGES

Soft expanded polyurethane (plastic foam) was used as an egg carrier. A carrier of helminth eggs and a method for their isolation were teste d. They proved applicable to evaluation of the survival of helminth eg gs in liquid biological substrates (sludges, liquid excrements). The i nside of the carrier was inoculated with 1,000 +/- 50 Ascaris suum egg s. After 21 days of incubation in an aerated medium at room temperatur e, 660.7 (66.1%) eggs were isolated on the average (n = 10, Tab. I). T he carriers incubated in the medium at 4 degrees C yielded 716.2 eggs (71.6%) on the average (Tab. II). The intactness of the carriers in he lminth eggs was proved during 21 days of incubation in aerated medium when the detected mean percentage of embryonated eggs was 80.5 % (Tab. I). From the carriers kept at 4 degrees C for 21 days and subsequentl y incubated 76.6% of embryonated eggs were recovered on the average (T ab. II). Control showed 80.95% of embryonated eggs on the average, whi ch is a statistically insignificant difference (P < 0.05). With the us e of the carrier more than a 13-fold increase in the viable eggs was r ecorded, compared with a 5% yield obtained at a direct inoculation int o liquid substrates. This method is rewarding for its optimization of experimental results and for reducing the number of eggs used in the e xperiments.