| Popis: |
The occurrence of epizo6tics of fascioliasis among sheep in the Rocky Mountain States has been responsible for an investigation to determine the intermediate hosts of Fasciola hepatica Linn. in that region. Several shipments of snails from Utah were negative when examined for liver fluke infections, possibly because they were taken in the spring months. In these shipments of snails, Succinea avara Say, Lymnaea (Galba) palustris Miill., and L. (G.) obrussa Say were identified by Mr. Wm. B. Marshall of the National Museum, and Fossaria modicella Say,1 the most abundant snail, was identified by Dr. F. C. Baker, University of Illinois. A number of Fossaria modicella was received from Utah on May 17, I932; of these, 70 were dissected; all were negative for trematode infections. Forty of the remaining snails of this lot were isolated in a watch glass and subjected to attack by many miracidia of Fasciola hepatica which had hatched from eggs collected April I5, I932, at Jeanerette, Louisiana. The miracidia promptly attached to the snails and worked their way into them. After 2 hours the miracidia, except for a few dead ones on the bottom of the container, had disappeared, and the snails were then transferred to a suitable container and fed on lettuce. Twenty-seven days later, 25 of the snails were dead; 4 had not disintegrated and examination showed these to contain many rediae of F. hepatica Linn. Four of the living snails were dissected the |
