Giardia Infections In Birds

By Gregory A. Rich, D.V.M.
Copyright © 1991 by NCS

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Giardia is a protozoa that can infect a variety of animals besides birds, including man, dogs, cats, rabbits, deer, and wild rodents. Protozoa are microscopic multicellular organisms. These organisms can cause severe gastreointestinal disease in man and other mammals. In birds, the clinical signs are varied and will be discussed later. Transmission of the organism is via ingestion of infected fecal material, contaminated food or drinking contaminated water. Research has been inconclusive whether giardia can be transmitted from birds to humans.

Giardia causes problems primarily in parakeets, cockatiels, grey-cheek parakeets and lovebirds. In California, it is reported that up to 50% of cockatiels and budgerigars are infected with the organism. Percentages may differ in other parts of the country. Not all infected birds will show clinical signs, so many potential spreaders go unchecked.

Clinical signs in parakeets include weight loss, soft lime green stools, dry flaky skin and unthriftiness. The disease in cockatiels usually manifests itself by feather plucking, which is where the name "cockatiel feather syndrome" was formulated by Dr. Alan Fudge of the California Avian Laboratory. Cockatiels exhibiting feather picking along the legs, flank area, or in the center of its back between the wings should be brought to the veterinarian for examination (see photo below).

Any type of weight loss that is unresponsive to traditional antibiotic/antifungal therapy should be checked for evidence of the organism. It has been documented by Dr. Greg Harrison and others that some of the clinical signs may be due to vitamin E/selenium deficiency, so a malabsorption of these vitamins may occur with giardial infections.

Diagnosis of this disease can be very difficult depending on the expertise of the veterinarian. Fresh fecal material is required to visualize the living organism under the microscope. Special stains can be used to identify the cysts of the organism under microscopic evaluation.

Treatment of the disease not only involves killing the organism, but also supportive care. As mentioned earlier, malabsorption may occur in some cases, so vitamin supplementation will aid in recovery for weak birds or birds with weight loss. Antihistamines therapy is suggested for those birds that have been frantically pulling feathers on their legs, flank or back. Several drugs are available for antigiardial therapy. Long term therapy is recommended, as treatment failures or reinfestations are common. New drugs will be tested and made available in the near future. The old standby, Emtryl, has been taken off the market and Flagyl tablets in drinking water has proven ineffective. Several veterinarians that have studied the problem in aviaries have implicated a genetic tendency towards a weakness in not being able to ward off the organism after or during treatment. Monitoring of breeders that frequently turn up shedders or diseased babies might back this theory up and consequently lead to improved genetics through new pairings.

In conclusion, any bird with an unknown weight loss, diarrhea or feather plucking disorder should be checked by an avian veterinarian. Since this disease may be contagious to humans, care should be taken when handling sick birds' fecal material. Consult your personal physician if you contract a severe gastrointestinal disorder.

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