Candidiasis in Animals

Candidiasis in Animals is also known as Moniliasis, Thrush, Crop mycosis and Oidiomycosis.

Candidiasis in animals is a fungal disease caused by an yeast, Candida albicans, and has been manifested by the development of mucocutaneous mycoses in skin, hair and nail.

More commonly superficial infection such as oral thrush, vaginitis and life threatening candidemia in animals and human as well.

Oesophageal or Crop Candidiasis occurs very frequently but clinical signs are rarely exhibited by the affected birds. Candida organisms mainly affect birds below 3 weeks of age but cause low to nil mortality.

Etiology

The genus candida comprises 150 various species. Candida albicans is the most pathogenic species followed by C.tropicalis, C.labrata, C.krusei, C.parapsilosis, C. dubliniensis in human.

Candida is a small, oval, thin walled dimorphic, budding type yeast like cells (blastospheres), measuring 2-6 mm, 3-5 mµm diameter, most frequently causes crop mycosis, found on epithelial surfaces and deeper tissues as a branching septate hyphae or pseudohyphae. Less frequently caused by Oidium pullorum and Candida krusei.

Candida species are ubiquitous in the environment.

Epidemiology

• Continued use of antibiotics, corticosteroids, vitamin A and B deficiency and high level of glucose in diet.
• External use of detergents or douches or internal disturbances by hormone can disturb the normal vaginal flora such as lactobacilli.
• Pregnancy and use of oral contraceptives are considered as risk factors in human.
• Diabetes mellitus, HIV, AIDS, mononucleosis, cancer therapy and stress.
• Wearing of wet swim wears also increases the incidence of yeast infections.

Transmission

• Infected feces loaded with organisms spread the disease.
• Man acquires the infection by eating contaminated meat and food.
• Human acquires the infection through in-utero and venereal contact.

Host Affected

• Chickens, turkeys, cattle, buffaloes, horses, goats, sheep, pigs, dogs, cats, including human are susceptible to infection.

Pathogenesis

In Animals

• The candida species produces the enzyme known as leucine amino peptidase which causes damage to the tissues and thereby induce the development of disease.
• The presence of high levels of antibiotics, maltose and dextrose cause cutaneous and systemic mycoses in pigs and candida endometritis in mares, panleukopenia in cats due to repeated use of antibiotics.
• The organism also invades the vital organs and set up diarrhoea, pneumonia, nephritis, endocarditis, mastitis, repeat breeding and abortion.
• The organism can be isolated from semen, aborted materials, uterine mucus of repeat breeders and mastitis milk and from the environment.

In Poultry

• The organisms lives in mouth, oesophagus and crop as a normal resident and also acquired by ingestion.
• Inhibition of normal microflora and immunosuppression allow the yeast to invade and proliferate on the superficial epithelial layers which results in development of epithelial hyperplasia, pseudo or diptheritic membrane formation.
• Crop appears to have a sticky and adhesive multifocal, confluent mats of white cheesy materials which may be found less in oesophagus and pharynx.
• Severely affected birds may have ulcers otherwise very mild inflammatory response will be seen in mucosal candidiasis.
• Inflammatory response to mucosal candidiasis is mild unless ulceration is prolonged.

Clinical Signs

Mucocutaneous form

• The tongue, gums, buccal mucosa of the infected animals are filled up with whitish creamy pseudomembranous exudate which contains yeast cells are known as thrush.

Cutaneous form

• Thrush in rumen, sub-clinical and acute mastitis, anorexia, lameness, and decrease milk yield may be developed in adult cattle.
• In calves, gastroenteritis, profuse watery diarrhoea, anorexia, dehydration and death noticed.
• Mycotic mastitis and abortion in cows and buffaloes are produced.
• In pigs, lesions from mouth, esophagus, skin and stomach may spread from vagina of pregnant and non pregnant sows.
• In Human, Both in children and adults lesions in interdigital space, intra-mammary folds, groins and axillae could be seen.
• The skin and nails of the whole body of the human are affected. In children and adult lesions found in interdigital space, intramammary folds, groins and axillae. Itching is a very important signs.

Systemic form

• Cattle and calves suffer from inflammation of the stomach and intestine and leads to profuse watery diarrhoea.
• In Poultry, Candidiasis is the most common infection, nevertheless, clinical signs seen in severely infected birds.
• Birds having infection in superficial region of oral cavity, oesophageal and crop become dehydrated and fail to gain body weight.
• Candida spp. invade into nervous system, renal, intestinal area but rarely shows symptoms.

Necropsy Findings

Pseudomembranes and diptheritic membranes in the crop, oesophagus and mouth are highly suggestive of candidiasis but can be produced after ingestion of caustic substances, trichothecare mycotoxicosis and in severe cases oral trichomoniasis.

Visualization of hyphae and pseudohyphae microscopically in hair and/or scrapings. Histological section will confirm diagnosis.

Diagnosis

• Based on clinical signs and necropsy findings.  
• Animal Inoculation: In mice and rabbit, One ml antigen in 15ml saline solution is suspended and injected intravenously or intra peritoneally causes death in a rabbit within 4-5 days of injection because of the abscess formation in kidney. The kidney smear show budding cells.
• Antigen and antibody detection by immuno-diffussion, counter immuno-electrophoresis, tube and latex agglutination test can be done to detect candidia antibody.
• Speciation require culture in Sabouraudes dextrose agar but many normal birds may be positive.

Sample Collection

Hair, pus discharges, swab from tissue lesions, blood and serum.

Differential Diagnosis

• Histoplasmosis
• Other mycotic infection

Treatment

Most candidial infections respond to the treatment with antibiotics. The commonly used antifungal drugs are topical Clotrimazole, Nystatin, Fluconazole and Ketoconazole.

Diflucan (Fluconazole): A single dose of 150mg tablet/oral give 90% control in a vaginal yeast infection. (It is also essential to take care of persons allergic for azole group of medicines. It is only useful for vaginal yeast infection.

In hospitalized patients, Amphotericin B, Caspofungin or voriconazole can be used. Local treatment with vaginal suppositories or medicated douches.

Gentian violet used for breastfeeding thrush, but when used large quantities it can cause mouth and throat ulcerations in nursing babies, and has been linked to mouth cancer in humans and to cancer in the digestive tract of other animals.