The present study was undertaken to find the most susceptible laboratory host for secondary echinococcosis using Echinococcus granulosus protoscoleces obtained from hydatid cyst of sheep. For this, 36 male white mice (NMRI strain), 27 male white rats (NMRI strain), 27 mole hamsters (Albino variety) and 5 male rabbits (New Zealand white) all were injected intraperitonaelly with the protoscoleces. White mice, white rats, hamsters and rabbits each received 1000, 8000, 10000 and 100000 protoscoleces respectively. Four mice, 3 rats, 3 hamsters and 1 rabbit were killed each month during 9 months and their liver , lung, peritoneal cavity, kidney and spleen were examined for presence of hydatid cyst. Secondary hydatid cysts were found in some of the mice after 3 months post inoculation but in 9th month all the mice were found infected, Hydatid cyst developed in 2 of 5 rabbits and only in one rat but did not develop in hamsters. All the cysts found in mice rabbits and rat were sterile and unfertile.
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