Abstract
Echinococcus multilocularis has been maintained in the cyst stage in gerbils and cotton rats over a period of 3 years by means of 9 serial transfers of viable cyst tissue suspensions inoculated into the peritoneum of the rodents. Masses of cysts containing motile scolices and relatively free of host tissue, are produced in 4 to 6 months. Mice and weanling rats are slightly susceptible to secondary echinococcus infection with E. multilocularis, but guinea pigs, rabbits, and hamsters are refractive to infection.