Morphological and developmental characteristics of Echinococcus granulosusderived from sheep, cattle and camels in Iran

Echinococcus granulosus is widely distributed throughout iran, where a vari ety of animals act as intermediate hosts. Ln this study, the development an d morphological characteristics of E. granulosus of sheep, cattle and camel origin were compared and, overall, the characteristics of larval and adult isolates from sheep and cattle, although similar, showed significant diffe rences from those of the camel isolates, especially with respect to the siz e of rostellar hooks. Differences in the fertility rates of hydatid cyst in sheep, cattle and camel were recorded as 88%, 19% and 70% respectively. In dogs experimentally infected with the three 'strains' of E. granulosus, the rate of development was more rapid in the camel than in the sheep and c attle 'strain'. in addition, adult E. granulosus derived from the camel dem onstrate differences in worm length, segmentation and size, shape, number a nd arrangement of the genitalia when compared with worms derived. from shee p and cattle. The epidemiological significance of these findings is discuss ed in relation to human hydatid infections in Iran.