Effect of Temperature on Embryonation of Ascaris suum Eggs in an Environmental Chamber

Abstract

The influence of temperature on the development and embryonation of Ascaris suum eggs was studied using coarse sand medium in an environmental chamber with 50% humidity. The time required for development and embryonation of eggs was examined under 3 different temperature conditions, 5 degrees C, 25 degrees C, and 35 degrees C. A. suum eggs did not develop over 1 month at the temperature of 5 degrees C. However, other temperature conditions, 25 degrees C and 35 degrees C, induced egg development to the 8-cell-stage at days 5-6 after incubation. All eggs examined developed to the 8-cell stage at day 6 after incubation in the sand medium at 25 degrees C. The higher temperature, 35 degrees C, slightly accelerated the A. suum egg development compared to 25 degrees C, and the development to the 8-cell stage occurred within day 5 after incubation. The formation of larvae in A. suum eggs at temperatures of 35 degrees C and 25 degrees C appeared at days 17 and 19 after incubation, respectively. These findings show that 35 degrees C condition shortens the time for the development of A. suum eggs to the 8-cell-stage in comparison to 25 degrees C, and suggest the possibility of accelerated transmission of this parasite, resulting from global warming and ecosystem changes.