GIARDIOSIS IN CANINE BREEDING
Biology of the parasite
Giardiasis is a parasitic disease that affects many mammal species, including Man and Dog. It is due to a unicellular parasite belonging to the Flagella family: Giardia duodenalis or intestinalis, also called Lamblia sp. Giardiosis is rather common in France, especially in humid areas where it is an endemic disease.
Dogs gets contaminated through the ingestion of eggs that can survive in the environment under encysted form. The cysts are very sensitive to dessication, so they are mostly present in damp areas (flower or vegetable gardens). In such conditions, they can resist up to several weeks in the environment: 2 months at 8°C, 1 month at 1°C, 4 days at 37°C.
Once ingested by the host, the eggs give birth to parasites that stick to the surface of the anterior parts of the small intestine. As the mucosa is lined with the parasites, it becomes irritated, and digestion/absorption are impaired. Within a week after the contamination, eggs start to be excreted in a intermittent way, inducing the contamination of the environment. Dissemination of the parasites occurs according different ways:
Diagnosis of giardiosis
- excretion by “ safe-carriers ”, i.e animals or men that do not present any symptom,
- passive vectors (breeder’s boots, dog’s hair),
- but mostly because of water or food contaminated by fecal materials.
Clinical signs of giardiosis in a canine breeding
In dogs from the weaning up to about 2 years old, giardiosis induces digestive disorders that look like very much those that are observed in case of exocrin pancreatic deficiency:
- augmentation of the volume and of the frequency of defecation,
- discolored stools, with a sticky, dungy and fatty aspect,
- rancid smell of the stools (pH often inferior to 6),
- weight loss, despite an increased appetite ant thirst.
Contrary to pancreatic deficiency, these symptoms are not constant but intermittent (alternance of diarrheic and non-diarrheic episodes), they have the appearance of a contagious disease, and moreover, the breeder and his family can be also affected (zoonosis). The general condition of the animals is not altered.
Observation of the parasite
The active forms of Giardia are difficult to find in the stools, except in case of direct examination of fresh stools (scotch-test in the anal area). It is easier however to observe Giardia cysts, providing that a collective coprologic examination is performed, mixing samples of stools from different suspected dogs.
Metronidazole (Flagyl NDH, Rozex NDH, Stomorgyl NDV), has been formerly used in the treatment of Giardiosis. Today, new molecules are preferred, because they are more efficient, better tolerated and less expensive.
Albendazole (Valbazen ovins NDV, Zentel NDH), weakly absorbed by the intestine, is efficient against Giardia, under the posology of 25 mg / kg during 2 consecutive days. This molecule proved to be 50 times more efficient than metronidazole in the treatment of human giardiosis.
Fenbendazole (Panacur 250 Dogs NDV) is also very active, using the same dosage as the one recommended by the laboratory for a classical anthelmintic treatment, i.e 25 mg / kg twice a day, 3 days in a row.
Practically, when a giardiosis is confirmed in a canine breeding, it is highly advised to treat all the dogs, except the pregnant bitches.
To be useful, the medical treatment has to be completed by some hygiene measures concerning the environment and the potential vectors.
Boxes will be cleaned with a detergent product (HD3 NDV type), then rinsed with boiling water, and disinfected with quaternary ammonium (ex: TH4+ NDV) during at least 3 days. (Bleach is not very active against Giardia cysts, neither on Coccidia cysts). The water supply will be carefully checked: rising up the bowls limits the risk of fecal contamination of the water.
At the beginning and at the end of the treatment, dogs that are likely to carry cysts in their hair will receive a shampoo, then rinsed with water added with a disinfectant product (ex: Stéricide NDV, 15 ml / 5l water), and finally blow-dried.
To get rid of giardiosis, the breeder must accept an extra-burden of work during about one week. Treatment failures are generally due to accidental recontamination because one element of the parasitic cycle has been neglected.
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