Viability and infectivity of protoscolices of Echinococcusmultilocularis stored at different temperatures

Survival of protoscolices of Echinococcus multiocularis removed from the intermediate host was studied at constant temperatures. The longest survival time was 16 days at 12°C when the protoscolices were stored within the cyst mass. The infectivity of the protoscolices in the decayed intermediate host was also studied. The carcasses harboring hydatid cysts were fed to dogs and a red fox on the 7th and 14th days after killing. Tapeworms were recovered from all these canines. The results indicate that the protoscolices in the decayed carcasses keep their infectivity for more than 2 weeks and suggest that the saprophagy of canines may be epidemiologically important for the transmission of E. multilocularis.