By ingesting food, water or soil contaminated with stool from infected dogs. This might include grass, herbs, greens, or berries gathered from fields.

By petting or handling dogs infected with the Echinococcus granulosus tapeworm. These dogs may shed the tapeworm eggs in their stool, and their fur may be contaminated.

"Pork Tapeworm"

Not commonly found in U.S. but the rate of cases is increasing. "Prevalent in broad regions of Eurasia, several South American countries, North and Central America, and Africa" - typically if it is seen in the United States it is present in immigrants or refugees.

CDC Information on Dipylidium caninum

"Most infections with Dipylidium caninum are asymptomatic. Pets may exhibit behavior to relieve anal pruritis (such as scraping anal region across grass or carpeting). Mild gastrointestinal disturbances may occur. The most striking feature in animals and children consists of the passage of proglottids."