Giardia & Giardiasis
Giardia is a parasitic protozoan that can cause an intestinal infection in dogs referred to as giardiasis. Giardia clings to the intestines and interferes with normal digestion and causes diarrhea. Many dogs carry this parasite and have no symptoms. Certain dogs, particularly puppies or dogs with compromised immune systems, are more prone to this infection. It can be difficult to diagnose.
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Features
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Giardia is found in the intestines of many dogs. Most of the time giardia does not lead to infections or complications. Puppies and dogs with compromised immune systems are more susceptible to Giardia infection, or Giardiasis. Giardia occurs in two forms. The first form is the active stage of the organism. It is called the trophozoite stage. This is the stage where the organism attaches to the intestines, divides, and multiplies. The second stage is the inactive stage of this organism. This is where the organism passes out of the dog's body in the form of a cyst. The cyst is very resistant and can survive in the enviroment for months. The cysts contaminate food and water and can be ingested by another dog. During the digestion process, the cyst breaks down and begins the trophozoite stage in the newly infected dog.
Effects
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In some dogs, Giardia multiplies rapidly and invades the tissues of the intestines. This is referred to as giardiasis. The multiplying giardia blocks normal digestion and causes a number of symptoms.
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Symptoms
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Most dogs are asymptomatic carriers of giardia. They may occasionally shed cysts in their stool, yet exhibit no symptoms. When giardiasis does occur, symptoms typically begin one week after infection. Symptoms of giardiasis include diarrhea, weight loss, anorexia, fatigue, and blood or mucous in the stools.
Diagnosis
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It can be difficult to diagnose giardiasis. Many conditions can causes diarrhea. Cysts are not shed in every stool, so a routine fecal sample is not always effective. A negative result does not rule out giardiasis. It is necessary to collect all stools for 48 to 72 hours. The cysts may be visible under a microscope. The second way to diagnose giardiasis is with an antibody based test called ELISA. This is also used to detect the cysts in the stools, but is more accurate and quicker.
Treatment
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Two medications are used to treat giardiasis. Metronidazole kills giardia and strengthens the immune systems. It can cause liver toxicity in some dogs so careful monitoring is necessary. Fenbendazole is an anti-parasitic medication that is commonly used to control the amount of giardia in the dog's digestive system.
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References
- Photo Credit puppy image by Karol Grzegorek from Fotolia.com
