[The effect of temperature on the infective activiey oncospheres of Diorchis stefanskii hymenolepididae].

Heterocypris incongruens (RAMD.) was selected as an intermediate host, having emerged as the main host for Diorchis stefanskii Czapl. in experimental conditions. It was found that the index of infective activity for larvae of D. stefanskii was high on the first day, amounting to 50-54%, with an extensity of infection of 100%. The infective activity of larvae declined slowly but steadily at the low temperature (5 degrees C). Oncospheres retained their infective activity for more than 2.5 months. In contrast, in culture at 18-20 degrees C and 25 degrees C, the infective activity of larvae had declined rapidly only a few days into the experiment. The irrevocable loss of tapeworm infectivity occurred at temperatures of -5 degrees C and +38 degrees C, at which 100% of oncospheres died.