[Effect of freezing, high temperatures and drying on the eggs and larvae of Nematodirus spathiger Railliet, 1896].

A series of laboratory experiments were carried out to test the effect of freezing (--8 to --10 degrees C), high temperatures (15 to 20 degrees C, 26--28 degrees C, 36--37 degrees C, and 58--60 degrees C) on the eggs and larvae of N. spathiger in water, in a dry state, and in the faces. It was found under freezing the eggs retained their viability in water up to 260 days (5.4%), in a dry state up to 330 days (2.8%), and in the feces up to 373 days (5.3%). Embryonated eggs at --8 to --10 degrees C retained their viability up to 440 days. Infective larvae under freezing remained viable in water up to 150 days (4.6%), in a dry state up to 195 days (3.3%), and in the fecal mass up to 230 days (5.2%). Live larvae were detected in the fecal mass on the 450th day (4.6%) when kept at room temperature, on the 395th day (3.5%) at 26--28 degrees C, on the 186th day (5.5%) at 36--37 degrees C, and at the 180th minute (0.8%) at 58--60 degrees C. Frequent wetting and drying of larvae did not produce any unfavourable effect on their viability. A bioassay revealed that infective larvae frozen at --8 to --10 degrees C in the course of 150 days as well as dried at 15--20 degrees C for 166 days remained intact.