Oral Canker or Trichomoniasis causes a cheesy substance to form in the mouth and throat of affected peafowl. It is a disease of the upper digestive tract and also affects pigeons, turkeys, chickens and other wild birds.
With the current preventative measures in the poultry industry, trichomoniasis is uncommon in food industry turkeys and chickens. However, outbreaks can still occur in warm climates or during warm weather.
The Aetiology of Oral Canker
The aetiological agent of Trichomoniasis in birds is Trichomonas gallinae (Tg). Tg is a pear-shaped flagellated protozoan with four anterior flagella and an undulating membrane to provide its motility. The pathogenicity of the different strains of Tg is very variable.
Nearly all pigeons carry Tg; the adults transfer it to their squabs via “pigeon milk”. In turn, raptors contract the disease by eating infected pigeons and doves. Turkeys and chickens, on the other hand, pick up the organism by drinking stagnant surface water containing it. Again pigeons are the most common vector by which that water is contaminated.
Signs and Symptoms
Affected birds can have difficulty closing their mouths and may drool and make repeated swallowing movements. Severely affected birds will stop eating, become depressed, ruffled in appearance, and emaciated before death. You will see canker lesions in the mouth, sinuses, pharynx, oesophagus, crop, and proventriculus. At the back of an affected bird’s throat they look like white to yellow plaques.
The plaque lesions are very suggestive of trichomoniasis but are not unlike those seen with visceral pox, candidiasis, and hypovitaminosis A. Histopathology of the lesions helps distinguish trichomoniasis from other diseases. The presence of large numbers of trichomonads in oral fluid is usually considered confirmatory – a wet mount swab will reveal the motile trichomonads when examined microscopically.
Prevention is always better than cure. Minimise contact with carrier birds such as pigeons and doves, provide clean fresh water, and eliminate sources of stagnant water. A prophylactic dose of a Protozoacide can be fed in the ration or added to drinking water.
Several drugs are used to successfully treat Trichomoniasis including Emtryl (Dimetridazole), Aminonitrothiazole, and Enheptin, however these drugs are no longer available over the counter in the UK. Backyard flocks or pigeons not in the food chain are commonly treated with Dimetridazole by veterinary prescription.