Because of their indirect life cycle and survival strategy, tapeworm eggs are capable of surviving outside of dogs for extended periods. Once in the environment, the eggs must remain viable until their intermediate hosts -- larval fleas -- eat them. Most tapeworm eggs last for months while waiting for their intermediate hosts; however, scientists have documented that the eggs of some tapeworms are capable of surviving up to eight months, Animal Diversity Web reports.
Tapeworms of Dogs
Most mammals can be afflicted with at least one species of tapeworm. Dogs are susceptible to several different tapeworm species, including Dipylidium caninum, and others of the genera Mesocestoides and Echinococcus. Because fleas are important intermediate hosts for tapeworms, and tapeworms may be passed to humans, it is important to keep pets free of fleas.