• Cause: infection with the mycelial yeasts of the genus Candida, principally Candida albicans.
• Signs: non-specific.
• Diagnosis: history and clinical signs, yeast culture, direct microscopy of tissue samples or crop wash.
• Treatment: powdered copper sulfate, nystatin, parconazole.
• Prognosis: good.
• Candida species constitute part of the normal microflora of the digestive system and can be readily isolated from the intestines and mucocutaneous surfaces of clinically normal birds, humans, and other animals.
• Birds are particularly susceptible to oral and crop candidiasis, which resembles thrush in humans.
• Crop mycosis is the most commonly used term for infection in birds but stomatitis oidica, muguet (French), soor (German), moniliasis, oidiomycosis, and sour crop are other terms for the disease. Thrush is often used for Candida infections of the upper digestive tract in humans and other animals.

• Non-specific.
• Unthrifty.
• Sour crop.

• Young birds are more susceptible than older birds to mycosis of the digestive tract.
• As infected birds grow older, they tend to recover from the infection.
• In one outbreak, losses amounted to 10,000 of 50,000 chicks younger than 60 days of age.
• Also, turkeys younger than 4 weeks of age succumbed rapidly to infection.
• In contrast, a high percentage of recoveries occurred when birds were older than 3 months of age.

• Candidiasis affects chickens, turkeys, geese, pigeons, guinea fowl, pheasants, quail, and other avian species.

• Occurrence of avian candidiasis is sporadic, but outbreaks can be costly.
• The first major reported outbreak resulted in mortality up to 20% in young turkeys, and another report the following year described the loss of 10,000 chicks because of candidiasis.

• Candidiasis is a mycosis caused by infection with the mycelial yeasts of the genus Candida, principally C. albicans, although other Candida species have been isolated from both healthy and diseased birds.
• In a mycological survey of crops from broilers, C. albicans comprised 95% of isolates but other species included C. ravautii, C. salmonicola, C. guilliermondii, C. parapsilosis, C. catenulata, and C. brumptii.
• Only C. albicans, C. parapsilosis, and C. rugosa have been associated with crop mycosis.
• An outbreak of candidiasis in turkeys yielded isolates of C. albicans, C. rugosa, C. famata, C. tropicalis, and C. guilliermondii from the crop suggesting that the conditions can favor growth of a broad diversity of Candida species.
• Candidiasis is an opportunistic endogenous mycosis that results from a disturbance of the microflora or other debilitation of the host, rather than dissemination of a pathogenic strain.
• Extremes of age and concurrent disease are often implicated when immunosuppression is suspected to be the underlying problem.
• Prolonged or otherwise inappropriate antimicrobial therapy that upsets the ecology of the microflora can initiate candidiasis, although feed additives may also contribute.
• Broad‐spectrum antibiotic treatment in turkeys.

Specific

• Antibiotic treatment.

Refereed papers

• Recent references from PubMed and VetMedResource.

Other sources of information

• Morishita T Y & Porter R E Jr (2021) Gastrointestinal and Hepatic Diseases. In: Backyard Poultry Medicine and Surgery. A Guide for Veterinary Practitioners. 2nd edn. Wiley-Blackwell, USA. pp 289-312.
• Arne P & Lee M D (2020) Fungal Infections. In: Diseases of Poultry. 14th edn. Eds: Swayne D E, Boulianne M, Logue C M et al. Wiley-Blackwell, USA. pp 1111-1129.

_{Reproduced with permission from Cheryl B Greenacre & Teresa Y Morishita: Backyard Poultry Medicine and Surgery. A Guide for Veterinary Practitioners. © 2021, and David E Swayne: Diseases of Poultry. © 2020, published by John Wiley & Sons.}