Dr. Murai Éva szerk.: Parasitologia Hungarica 25. (Budapest, 1992)

worms. On the 20th day, most of the worms of lung origin had fully developed reproductive organs, while in the worms of liver origin the reproductive organs were not fully developed. The worms of lung origin were gravid on the 40th day, while the worms of liver origin attained this stage on the 42nd day p.i. (Fig.l A,B). Stages Fig. 2. Rate of segmentation and maturation of E. granulosus in dogs, infected with protoscoleces of buffalo liver and lung origin. The percentage of worms (liver and lung origin) at the most developed or mature stage attained at various time intervals are shown and compared (Stages -1: Protoscoleces, II: 1st Banding , III: 2nd Proglottid, IV: 3rd Proglottid, V: Testes and ovaries, VI: Uterus cells, VII: Unshelled eggs, VIII: Shelled eggs) DISCUSSION It is evident from the results that dogs are susceptible to protoscoleces originating from buffalo liver and lung cysts. Thus, the increased prevalence of buffalo hydatidosis may be due to a buffalo/dog cycle in this part of the country, and it may also be responsible for human hydatidosis due to the prevailing socio-economic conditions and the association of dogs with the human population (Irshadullah et al. 1989a,b). Some differences have been noted between protoscoleces derived from buffalo liver cysts and those originating from lung cysts in their pattern of development into the adult stage in dogs. The differences observed in growth rate between the two isolates may have been due to individual host variation as was also reported for the British horse and sheep strains (Thompson 1977). As far as the rate of segmentation and appearance of genitalia is concerned, only the results obtained for protoscoleces of lung origin are in agreement with those reported by Gill and Rao (1967) for buffalo/dog material, whereas they are contrary