What is Avian Gastric Yeast?
Megabacteria, now known as Avian Gastric Yeast (AGY) is primarily seen in canaries, finches, lovebirds, cockatiels and budgies and sometimes in larger birds. It is an ascomycetous yeast that grows in the isthmus, or the narrow part of the stomach that is between the proventriculus and ventriculus. Although originally thought to be a bacterial infection, hence, the name Megabacteria, researchers have learned that fungal medications are highly effective in ridding a bird of the illness.
In a publication by Lucio J. Filippich of The University of Queensland, Queensland, Australia, he states that: “Megabacteria are large, gram positive, rod-shaped organisms that are being increasingly found worldwide in the proventriculus or droppings of several pet bird species, especially budgerigars and canaries.”
Due to the severity of the symptoms, fast diagnosis and treatment are important. In the acute state birds may exhibit the following symptoms:
- Regurgitate blood & food
- Bleeding in the droppings
- Severe lethargy
- Fast, severe weight loss
- Fluffed up feathers
- Undigested food
Dr. Speer reports that birds show signs of having a severe stomach ache. They have a fluffed appearance and may tuck their heads under a wing. Some birds will sit on the bottom of the cage with closed eyes or have a look of severe pain.
Recently, research has provided a reliable and safe diagnosis and treatment. You vet can test your birds fresh droppings on a wet-mount slide viewed at 400 power or higher to see the large rod shaped yeast. Due to the size of the yeast, the disease is relatively easy to diagnose for the experienced avian vet. Untreated, the course of the disease may take months and there may be intermittent periods of recovery and relapse. Differential diagnoses include proventricular dilatation disease (PDD), lead, zinc or copper toxicoses, trichomoniasis, bacterial, mycotic or parasitic infections, and neoplasia.
Currently, the most effective treatment is with the antifungal drug,oral Amphotericin B. It is believed that this medication attacks the cell membranes of fungi. Treatment is twice daily for 30 days. This medication is difficult to locate in an oral suspension so your vet may use a compounding pharmacy. It is available in several flavors.
Side effects of the drug include anorexia, vomiting (gastrointestinal irritation), hypokalemia, and fever. We’ve found that allowing our bird to feed prior to administering the medication reduces the side effects.