most common tapeworm species in the United States is Dipylidium
caninum. Animals including dogs, cats and
humans get the tapeworm by consuming often
inadvertently infected adult fleas. The flea
contains an infectious cysticercoid which emerges in the small
intestine, and attaches itself to the wall. It is here
the adult tapeworm forms. Within 2 or three weeks the
tapeworm sheds egg filled proglottids which are passed in the
dogs feces. These are ingested by flea larvae
which eat dog feces as well as flea feces! The tapeworm
egg matures with the flea.
and eggs are not evenly spread through the feces, and the odds
of finding them on a single fecal exam are small. If you
have abundant fleas it is probable that your dog has Dipylidium
infection. The monthly heartworm treatments do not treat
tapeworms. Praziquantel found in Droncit or Drontal
does effectively kill tapeworms. Reinfection is common
and a second dose should be given two weeks after the initial
one. Some veterinarians recommend adding praziquantal to
the monthly preventative regimen. However, nasty though
they may sound, tapeworms produce little effect on the animal.
There have been reports of impaction sometimes fatal in puppies.
other species of tapeworm that can infect out dogs is Taenia.
Proglottids are shed as with Dipylidium, but the eggs
are ingested by other mammals. There they hatch and
migrate into other organs, usually the liver. There the
larvae form large fluid filled cysts. Consumption of the
infected liver introduces the larvae into the dog, and they also
attach to the small intestinal wall and mature and produce
proglottids. Consuming infected mice (Taenia
taeniaeformis) or rabbits (Taenia pisiformis) is
the normal cause of infection, although other species of Taenia
have been reported, as have Echinococcus spp.
Treatment is the same as for Dipylidium.
they rarely cause significant problems in dogs, their zoonotic
ability to infect humans is often of concern.