Candida Infections in Birds

By Rick Axelson, DVM, updated by Laurie Hess, DVM

What is Candida?candida-1

Candida albicans is a common environmental fungus that can infect the digestive tracts of birds. It is a common cause of 'sour crop' or a crop infection (ingluvitis), especially in young birds. It may be spread from an adult bird feeding a young one; from a contaminated environment or contaminated water; or hand-feeding formulas.

People with yeast infections in their mouths (thrush) actually have Candida. Candida can be a primary or secondary cause of crop infections. Candida, in small numbers, is usually considered a normal resident of a bird's digestive tract. A disruption or imbalance of normal bacterial populations in the digestive tract may lead to a secondary overgrowth of Candida. Excessive sugar or carbohydrates in the diet may contribute to Candida overgrowth, as fungus grows well in sugary environments. Often, other diseases compromise the bird's immune system and predispose a bird to secondary Candida infection (candidiasis). Steroid use, long-term antibiotic use, excessive stress, poor husbandry or hygiene, viral infections, and other chronic infections can all cause immune suppression and lead to secondary candidiasis.

"Often, other diseases that have compromised the bird's immune system can predispose a bird to secondary Candida infection."

In its advanced stages, Candida can affect a bird systemically, as it goes outside the gastrointestinal tract and invades the rest of the body, but this is rare. With a systemic infection, it can be found in the blood, certain body organs, and bone marrow.

How do I know if my bird has Candida?

Common clinical signs include lethargy, fluffed feathers, little to no appetite, vomiting or regurgitation, delayed crop emptying, a distended crop full of mucus, and occasionally a crop impacted with dry food, mucus, or other debris. A veterinarian familiar with birds will start with a complete history, a body weight and a physical examination. Since the clinical signs of candidiasis occur with many different diseases and are not specific to candidiasis, your veterinarian will likely advise a series of diagnostic tests to determine the actual cause of disease.

What tests can be done?

Candida is diagnosed by fungal culture and/or by cytology (microscopic analysis) of a specially stained sample from either the crop or feces. Since Brewer's yeast may be added to hand feeding formulations and may be present in many baked goods, specific fungal culturing is recommended for differentiation, as Brewer's yeast and Candida can look similar under the microscope . If a bird has eaten baked goods or other yeast-containing foods during the day before the sample was taken and the bird isn’t severely ill, a veterinarian may suggest holding the bird off all potentially yeast-containing foods for a few days and then rechecking a sample under the microscope. Severely affected birds should be treated regardless of whether they’ve eaten yeast-containing products. The quality of the sample also is very important. If a sample does not demonstrate yeast, especially in a sick bird, it may be that deeper samples or tissue scrapings are needed.

"Brewer's yeast and Candida can look similar under the microscope."

It is common for candidiasis to develop secondary to other disease processes; therefore, other tests should be performed to determine whether there are other problems predisposing the bird to secondary infection. Early diagnosis generally leads to faster resolution of underlying problems.

Can my bird be treated?

Yes, once diagnosed, Candida is treated with antifungal medications. There are a number of different medications available. In addition to treating the Candida, your veterinarian should diagnose and treat all predisposing factors or diseases. Good hygiene, a clean environment, and fresh, clean food and water is essential in managing this problem and in maintaining your bird's health.

If your bird is diagnosed with candidiasis, closely follow your veterinarian’s recommendations in administering prescribed medications and ensuring your pet’s environment is disinfected properly.

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