Effects of temperature on the larval development of Angiostrongylus cantonensis in the intermediate host, Biomphalaria glabrata.

The effects of temperature on the larval development of Angiostrongylus cantonensis in Biomphalaria glabrata were studied under controlled conditions. When B. glabrata were maintained at different, constant temperatures, the first-stage larvae developed to third-stage larvae between 20 degrees and 31 degrees C. The velocity of development to the third-stage in the snail depended on the relationship, Y = -0.1281 + 0.0081 X (Y velocity of development; X rearing temperature). The "threshold of development" was 15.8 degrees C and the thermal constant 123 degree-days. It is concluded that there might be a possibility of A. cantonensis spreading to temperate regions in the world, if, in addition to the temperature, other factors allowed the completion of the life cycle of this worm.