Echinococcus Granulosus in Dogs

Echinococcus granulosus is a parasite in the Cestoda class from the Taeniidae family which is one of the most important and most oft diagnosed parasitic infestations in dogs and cats in the United States.  The eggs of this parasite are ingested by the host in various mediums, i.e. consumption of any portion of birds, fish, reptiles and rats or from consumption of fleas or lice in the natural process of grooming themselves. They then inhabit the small intestine of the host and, without appropriate treatment, can flourish exponentially.

Echinococcus granulosus, more commonly referred to as tapeworm, is a parasite which, after being ingested by the host, inhabits and flourishes in the small intestine of dogs and cats.

Echinococcus granulosus in dogs generally doesn’t present with specific symptoms. There are, however, some signs which may suggest the possibility of a tapeworm infestation in your pet:

• Itching around the anus
• Licking of the perianal and anal areas
• Butt scooting
• Weight loss when appetite is normal
• Increased appetite without the expected weight gain
• Less than desirable coat and skin conditions
• Swollen and painful abdominal area
• Diarrhea
• Lethargy
• Irritability

If you notice these symptoms, it would be a good idea to inspect the anal and perianal areas of your canine family member as well as the droppings, looking for pieces of the tapeworm (proglottids) which will be shed in the feces.

Types  

The types of echinococcus granulosus are related to the afflicted host.  Being a zoonotic disease (can be passed between humans and animals), humans can be afflicted as well.

• Cystic echinococcosis (CE) - Also known as Hydatid disease, this can cause cysts which grow slowly in the liver and lungs as well as other organs, going unnoticed for years
• Alveolar echinococcosis (AE) - Cysts can form in same areas as the cystic variety in humans but is more serious than CE (can be fatal if not treated)
• Echinococcus granulosus - Parasitic infestation in the small intestine of the canine species, eggs of parasite are shed in feces which can then be picked up by both animals and humans

The parasite has a life cycle that can begin in an intermediate host (usually herbivores like sheep, horses, camels, and pigs) and is passed along to the definitive host (dogs, coyotes, wolves and other canids) where is proliferates and prospers (usually within 47 days). 

• The parasite is picked up by the host accidentally as it eats from contaminated soil, water, fleas or lice which contain the eggs, cysts or proglottids (pieces of tapeworm which are ready to reproduce
• The eggs, cysts or proglottids get into the intestinal system of the host (whether animal or human) and attach themselves to the mucosal walls and set up housekeeping
• They reproduce and shed the eggs, cysts or proglottids in the feces of the host
• The life cycle begins anew in both the host as well as any other species who ingests the pieces and parts which now will be found in the soil, water, fleas and lice for the next host (whether intermediate or definitive) to harbor, being able to survive in the ground (outside the body) for up to a year
• The shedding process can begin as early as 2 to 3 weeks after initial infestation or up to 1 to 2 months later
• Once established in the intestinal system of the host, the worm feeds slowly on blood and nutrients from the host; this prevents much of the nutritional elements being fed to the host from being utilized by the host
• The hatched larvae eat through the gut wall and get into the bloodstream where they can travel anywhere and everywhere in the body, resulting in cysts in places like the liver and lungs of the host, whether animal or human

Diagnosis of echinococcus granulosus in dogs can be done in various ways.  First, your veterinary professional will need a complete history from you in which you note the symptoms, whether you saw the typical “grains of white rice” in the stools of your pet, if your examination of the animal’s rear end revealed any traces of pieces of the worm, eating habit changes, and unusual behaviors noted in your pet.  He will also do a physical examination in which he will be looking for some of the same physical manifestations.  

He will also need a stool sample for testing.  He may have to utilize a couple of different methods of analysing the stool sample if eggs, cysts or proglottids are not immediately noted in the sample (as is quite possible for this parasitic infection).  Once he has collected all of this information, he will develop an appropriate treatment plan for your doggy family member.

There are several medications which have been approved for use in the treatment of intestinal parasites such as echinococcus granulosus.  A treatment plan utilizing fenbendazole, praziquantel, epsiprantel and nitroscanate, either individually or in some appropriate combination, may be recommended, with repeated regimens as needed to rid your pet of this persistent parasite.  

Your veterinary professional will review the information you have provided and may recommend dietary changes, changes in hygiene for your animals and appropriate cleaning and sanitizing of the bedding, eating and living areas occupied by your doggy family member. It is important to take all necessary steps to prevent infection in other animals in your household or kennel since the disease is so easily transmitted to other species.  Also, since this is a zoonotic disease and can be passed between humans and animals, he will likely caution and instruct you on the steps needed to prevent the infection of the parasite in you and other human family members.

Transmission of this parasitic infestation is quite easy.  And, because the disease doesn’t always present with specific or acute symptoms, knowing that echinococcus granulosus has taken up residence in the intestines of your canine family member makes diagnosis as well as appropriate and timely treatment of the parasite difficult.  This will be dependent upon your close observation of your pet on a regular basis.

If you note any of the above mentioned symptoms or, if you notice any unusual behavior in your canine, be sure to get medical advice as soon as possible.  While the growth and damage caused by this parasite take place quite slowly as a rule, because it is so easily transmitted to humans as well as other canines, your vet will want to treat it as early as possible. Except in the case of an intestinal blockage which can rarely be caused by the parasitic infestation, the prognosis of your pet is very good with treatment and continued monitoring.  In the event of an intestinal blockage, do not hesitate to get medical care for your pet on an emergent basis as this is a life-threatening situation for the host.