The infectivity of a camel strain of Echinococcus granulosus experimentally raised in dogs for domesticated food and burden animals was investigated. Of the animal species that were inoculated orally with gravid segments, hydatid cysts developed poorly in goats and sheep, less well in cattle and not at all in donkeys by six month post-inoculation. Cysts were most frequently found in the lungs, although other organs such as liver and spleen also contained cysts. Histological examination of affected organs in these animals revealed the cysts surrounded by a granulomatous cellular reaction. Protoscolices and brood capsules were lacking at the time of examination. Thus it appears that although hydatid cysts could develop in some of these animal species within six months, the cysts were immature.