Candidiasis,Thrush of poultry

Introduction

A disease of the alimentary tract of chickens, turkeys, and sometimes other birds and mammals, characterised by thickening and white plaques on the mucosa, especially in the crop but sometimes in the proventriculus, intestine and cloaca, and associated with gizzard erosion.

The cause is a fungal yeast, Candida albicans and the condition is seen worldwide. Morbidity and mortality are usually low.

The route of infection is normally oral and the organism is often present in healthy animals with disease occurring secondary to stress and poor hygiene. The fungus is resistant to many disinfectants.

Signs

• Dejection.
• Poor appetite.
• Slow growth.
• Diarrhoea, possibly confused or masked by signs of the primary disease.

Post-mortem lesions

• White plaques in mouth, oesophagus, crop, occasionally proventriculus and intestine.
• Raised focal lesions may slough into lumen as caseous material.

Diagnosis

Lesions, histopathology, microscopic examination of a digested smear (heat in 10% potassium hydroxide) to demonstrate the hyphal forms of the yeast in the tissues. Colonies of this fungus appear as white to ivory colour, smooth and with a yeasty smell.

Treatment

Nystatin (100 ppm in feed) for 7-10 days, copper sulphate (1 kg/tonne feed) for 5 days, or copper sulphate 1gm/2 litre water for 3 days if approved locally.

Prevention

Avoid excessive use of antibiotics and other stressors. Ensure good hygiene, proprionic acid, sodium or calcium proprionate at 1 kg per tonne continually. A finely divided powder of copper sulphate (where approved) at 200gm/tonne continually or to 14-16 weeks in replacement pullets.

Control of Candida through drinking water is sometimes practised with chlorination (e.g. Chlorox, sodium hypochlorite) at 5 ppm. This is economical and effective. It should be repeated periodically. Take care to provide fresh clean feed and water, uncontaminated by fungi.