The Laboratory Propagation of Spirometra mansonoides as an Experimental Tool. I. Collecting, Incubation and Hatching of the Eggs

Abstract

Methods are described for incubation of Spirometra eggs so that almost total, simultaneous hatching occurs, and massive concentrations of coracidia are obtained. Directions are given for laboratory maintenance of cats infected with the adult worms. These cats are fed pure horse meat, exclusively, for approximately 2 weeks when feces are processed for eggs. From the black tarry feces eggs almost completely free of foreign material are concentrated in massive quantities by a process of emulsification, sieving, and decanting. Massive numbers of eggs are incubated in water in a heavy walled Ehrlenmeyer flask, fitted with an air stone, and mounted on a shaking machine, at room temperature. Forced aeration and agitation (3 cycles/second) are continued constantly for 10 days, with only periodic stops to change water and check development. Contamination is controlled by adding iodine to the water. A special optical arrangement is figured for observing progress of hatching and concentration of oncospheres. Strong sunlight, change of water, and temperature shock stimulate hatching. Since coracidia resist centrifugation at high speeds, their specific gravity must be close to 1.0.