There are two types of tapeworms of concern. Both can live as adults in the fox gut and pass eggs. Eggs are picked up by a second host. In one, Dipylidium caninum, this host is the flea larvae. Infected adult fleas are accidentally swallowed by foxes, this tapeworms develop in the gut. The second one, Taenia pisiformis, has a similar cycle except the second host is different. Eggs are picked up by rabbits and then form cysts around the liver. Once these cysts are eaten by foxes, the adult tapeworm develops in the guts.