Giardia is a protozoa, or one-celled organism (similar to coccidia) that attaches to the intestinal wall. Giardia is an intestinal parasite but is not a parasitic worm. They are microscopic and can not be seen with the naked eye.
Many pets may be infected with giardia but show no symptoms. In other animals giardia can cause severe watery diarrhea, dehydration, lethargy, abdominal discomfort, weight loss, poor hair coat and vomiting. Giardia usually affects kittens, puppies and debilitated animals most severely. Treatment is usually encouraged for all animals who are found to have giardia in order to reduce potential transmission to other animals.
Giardiasis in dogs and cats occurs when they ingest microscopic cysts that are shed in the stool of already infected animals. These cysts can survive for several months in the environment, especially in water or very damp areas. Ingestion of dirt or fecal material through grooming occurs regularly in both dogs and cats. Infection can also occur through drinking water that contains the infective cysts.
Giardia can be diagnosed in a variety of ways. The giardia organisms are occasionally seen on a routine fecal examination where a fresh fecal sample is mixed with a special solution that encourages parasite eggs to float to the top and adhere to the slide. The slide is then examined under a microscope and the organisms are identified by a veterinary technician. In many cases, however the organisms are not seen using this method since they are very small and do not always float to the top and adhere to the slide. A direct fecal examination can also be performed where a very fresh sample of feces is placed on a slide and examined under a microscope. The most accurate way to diagnose giardia, however is to send a fecal sample off to the lab where they will test for antigens of the giardia organism.
Treatment for giardia usually consists of an oral antibiotic called Metronidazole. This medication comes in pill form and is usually given twice daily for 5-10 days. Repeat treatment can be necessary in some cases. Treating your pet’s environment is equally as important as treating your pet since giardia cysts are able to survive in the environment and reinfect your pet. Thoroughly cleaning all surfaces in your home with a dilute bleach solution and picking up all feces outside will help to minimize the possibility for reinfection. Giardia are very sensitive to being dried out so all wet areas of your yard should be thoroughly dried
Giardia is a zoonotic disease that can affect people as well as cats and dogs. Most people contract giardiasis by drinking contaminated water. It is very common in areas where clean drinking water is not readily available.