Giardia are protozoa (one-celled organisms) that live in the small intestine of dogs and cats.
Giardia are found throughout the United States and in many other parts of the world.
Infection with Giardia is called 'giardiasis.'
There are many things we do not know about this parasite. Experts do not agree on how many species of Giardia there are and which ones affect which animals. Veterinarians do not even agree on how common Giardia infections are and when they should be treated. Generally, it is believed that infection with Giardia is common but disease is rare. There is much about the life cycle we do not know either. Some experts believe Giardia is shed when the mom is stressed with labor.
Even very clean kennels have Giardia present.
How do Giardia reproduce and how are they transmitted?
A dog becomes infected by eating the cyst form of the parasite. In the small intestine, the cyst opens and releases an active form called a trophozoite. These have flagella, hair-like structures that whip back and forth allowing them to move around. They attach to the intestinal wall and reproduce by dividing in two. After an unknown number of divisions, this form develops a wall around itself (encysts) and is passed in the feces. The Giardia in the feces can contaminate the environment and water and infect other animals.
What are the signs of a Giardia infection?
Most infections with Giardia are asymptomatic. In the rare cases in which disease occurs, younger animals are usually affected, and the usual sign is diarrhea. The diarrhea may be acute, intermittent, or chronic. Usually the infected animals will not lose their appetite, but they may lose weight. The feces are often abnormal, being pale, having a bad odor, and appearing greasy. In the intestine, Giardia prevents proper absorption of nutrients, damages the delicate intestinal lining, and interferes with digestion.
This is another unknown. There are many species of Giardia, and experts do not know if these species infect only specific hosts. Sources of some human infections have possibly been linked to beavers, other wild animals, and domestic animals. Until we know otherwise, it would be wise to consider infected animals capable of transmitting Giardia to humans.
Most experts believe the human strand of Giardia is a different type....
How do we diagnose giardiasis?
Giardiasis is very difficult to diagnose because the protozoa are so small and are not passed with every stool. Tests on serial stool samples (one stool sample every day for three days) are often required to find the organism. Special diagnostic procedures, beyond a routine fecal examination, are necessary to identify Giardia. The procedures we use to identify roundworms and hookworms kill the active form of Giardia and concentrate the cyst form.
To see the active form, a small amount of stool may be mixed with water on a microscope slide and examined under high magnification. Because these forms have flagella, you can see them move around on the slide. The active forms are more commonly found in loose stools. If you ever have the opportunity to see the active form of Giardia under the microscope, take it! It is an interesting-looking creature. It is pear-shaped and its anatomy makes it look like a cartoon face, with eyes (which often look crossed), nose, and mouth. Once you see it, you will not forget it.
Cysts are more commonly found in firm stools. Special solutions are used to separate the cysts from the rest of the stool. The portion of the solution that would contain the cysts is then examined microscopically.
In spring, 2004, a diagnostic test using ELISA technology became available. This test uses a very small fecal sample, and can be performed in 8 minutes in a veterinarian's office. It is much more accurate than a fecal examination.
We have done the tests, now what?
Now we come to how to interpret the test results. It can be a dilemma for your veterinarian. What you see (or do not see) is not always a correct indication of what you have. A negative test may mean the animal is not infected. However, few, if any, laboratory tests are 100% accurate. Negative test results can also occur in some infected animals. If a negative test occurs, your veterinarian will often suggest repeating the test.
What about a positive test? That should not be hard to interpret, right? Wrong. Giardia can be found in many dogs with and without diarrhea. If we find Giardia, is it the cause of the diarrhea or is it just coincidence we found it? The animal could actually have diarrhea caused by a bacterial infection, and we just happened to find the Giardia. Test results always need to be interpreted in light of the signs, symptoms, and medical history.
If we find Giardia, how do we treat it?
Here we go again; treatment is controversial too. There is a question about when to treat. If Giardia is found in a dog without symptoms should we treat the animal? Since we do not know if G. canis can infect man, we often err on the side of caution and treat an asymptomatic infected animal to prevent possible transmission to people.
If we highly suspect infection with Giardia, but can not find the organism, should we treat anyway? This is often done. Because it is often difficult to detect Giardia in the feces of dogs with diarrhea, if there are no other obvious causes of diarrhea (e.g.; the dog did not get into the garbage several nights ago) we often treat the animal for giardiasis. Since all puppies stress from shipping, we choose to treat as if they have Giardia. Seven pills for seven days is a much easier solution than trying to clean up a full blown attack.
There are several treatments for giardiasis, although some of them have not been FDA-approved for that use in dogs. Fenbendazole or Panacur is an antiparasitic drug that kills some intestinal worms and can help control giardia. It may be used alone or with metronidazole. Metronidazole can kill some types of bacteria that could cause diarrhea. So if the diarrhea was caused by bacteria, and not Giardia, the bacteria can be killed and the symptoms eliminated. Unfortunately, metronidazole has some drawbacks it has a very bitter taste and many animals resent taking it – especially cats. Our vet believes Metronidazole is the best solution...and also cures other bacteria as well. WE SEND PILLS WITH EVERY PUP WE SELL.....please give the pills for seven days...and we should not have to deal with Giardia.
Quinacrine hydrochloride has been used in the past, but is not very effective and can cause side effects such as lethargy, vomiting, anorexia, and fever.
But now we come to yet another unknown. It is possible these treatments only remove the cysts from the feces but do not kill all the Giardia in the intestine.
How can I prevent my pet from becoming infected with Giardia?
The cysts can live several weeks to months outside the host in wet, cold environments. So lawns, parks, kennels, and other areas that may be contaminated with animal feces can be a source of infection for your pet. You should keep your pet away from areas contaminated by the feces of other animals.
This is not always easy.
As with other parasites of the digestive system, prevention of the spread of Giardia centers on testing and treating infected animals and using sanitary measures to reduce or kill the organisms in the environment. Solutions quaternary ammonium compounds are effective against Giardia.
Clean the Animals: Cysts can remain stuck to the haircoats of infected animals. So during treatment and before moving the treated animals to the clean area, they should be regularly shampooed and rinsed well. Especially concentrate on the perianal area. WASH THE BOTTOM VERY WELL
A study at Kansas State University showed that bathing the pet at least 1-2 times per week to remove Giardia cysts clinging to the fur can help prevent reinfection. We also recommend wiping the area
under the tail with a baby wipe each time the pet defecates. In long haired dogs, trimming the fur under the tail can also help prevent oocysts from clinging to the area and causing reinfections.
While not always possible, it is best to avoid letting the pet out in areas where they have previously defecated. Always pick up feces daily and dispose of appropriately. It is important to have your pet's stool recheck after treatment is completed to ensure that the giardia have been removed.
Most commonly, this is done 3 weeks after treatment, but this may vary in some cases
SOME TESTS DONE TOO SOON, WILL SHOW DEAD GIARDIA …..IT IS HARD TO KNOW IF THEY ARE DEAD OR ALIVE....SO YOU COULD BELIEVE YOU ARE STILL INFECTED.
The most common drug used to kill Giardia is called fenbendazole ("Panacur").
It is normally given daily for 6 days.
Another medication, metronidazole, given for five to seven day is potentially useful.
Sometimes in difficult cases metronidazole is used in with fenbendazole. Supportive treatment with other drugs may be needed as supplemental therapy if dehydration or severe diarrhea is present. Some dogs may require prescription diets that are very high in fiber, such as Science Diet W/D.
IT CAN BE A GOOD IDEA TO GIVE PROBIOTICS WHILE TREATING THE PUPPY TO HELP BOOST THE IMMUNE SYSTEM.
Remember, Giardia of dogs although it has not been proven, may infect people, so good, personal hygiene should be used by adults when cleaning kennels or picking up the yard, and by children who may play with pets or in potentially contaminated areas.
Veterinary & Aquatic Services Department, Drs. Foster & Smith
References and Further Reading
Barr, SC; Bowman, DD. Giardiasis in dogs and cats. Compendium on Continuing Education for the Practicing Veterinarian. 1994;16(5):603-614.
Barr, SC; Bowman, DD; Frongillo, MF; Joseph, SL. Efficacy of a drug combination of praziquantel, pyrantel pamoate, and febental against giardiasis in dogs. American Journal of Veterinary Research. 1998;59(1):1134-1136.
Georgi, JR; Georgi, ME. Canine Clinical Parasitology. Lea & Febiger. Philadelphia, PA; 1992;59-61.
Griffiths, HJ. A Handbook of Veterinary Parasitology. University of Minnesota Press. Minneapolis, MN; 1978;21-22.
Hendrix, CM. Diagnostic Veterinary Parasitology. Mosby, Inc. St. Louis, MO; 1998;19-20.
Meyer, EK. Adverse events associated with albendazole and other products used for treatment of giardiasis in dogs. Journal of the American Veterinary Medical Association. 1998;213(1):44-46.
Sherding, RG; Johnson, SE. Diseases of the intestine. In Birchard, SJ; Sherding, RG (eds.) Saunders Manual of Small Animal Practice. W.B. Saunders Co. Philadelphia, PA; 1994;699-700.
Sousby, EJL. Helminths, arthropods and protozoa of domesticated animals. Lea & Febiger. Philadelphia, PA; 1982;577-580.
Zajac, AM; LaBranche, TP; Donoghue, AR; Chu, Teng-Chiao. Efficacy of fenbendazole in the treatment of experimental Giardia infection in dogs. American Journal of Veterinary Research. 1998;59(1):61-63.
in conclusion, as indicated above....
We test all pups before they ship....because shipping will cause a drop in the immune system, and they are more likely to get sick the first seven days after shipping.