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Canker (trichomonosis)

Other Names: Canker, Frounce, Trichomoniasis

Avian trichomonosis (also known as 'canker' or 'frounce') is an infectious disease of birds caused by the flagellate protozoan parasite Trichomonas gallinae. The disease is extremely common in domestic and wild pigeons and doves (approximately 80-90% are carriers) worldwide.

Chickens usually become infected through sharing a water or feed source with domestic or wild pigeons and doves. T. gallinae can remain infectious for at least 5 days in moist grains and from 20 minutes to several hours in water.

Avian trichomonosis primarily affects the upper gastrointestinal system. Birds will develop 'canker'-like sores inside the oral cavity and esophagus.
appearance of canker lesions in chickens
As the disease progresses, and the lesions grow in size, they often start to interfere with the chicken's ability to swallow feed and water. In severe cases, the lesions that develop in the esophagus might grow so large that they completely block its opening, causing the chicken to suffocate. There have also been rare cases where the lesions inside the oral cavity have grown so large that they penetrated through the base of their skull into the brain.

Canker Vs Thrush

Candidiasis (Thrush)Canker
Body areas affectedOral cavity, esophagus, and cropOral cavity, esophagus, and crop
Pathogen typeYeastProtozoan parasite
Pathogen speciesCandida albicansTrichomonas gallinae
Oral lesion appearancePatches of raised, whitish, dead epithelial debris. The top white pseudomembranes can be wiped off. Sticky, yellowish-white 'canker-like' masses of caseous, necrotic material.
More likely to occur followingProlonged antibiotic therapy, concurrent disease, infestation with internal or external parasites, or stressful event.Pigeons and doves sharing the same water or feed source.
TreatmentNystatin, copper sulfateMetronidazole, thyme extract

Clinical Signs

White or yellow caseated plaques inside mouth
Difficulty swallowing
Weight loss


  • History - of pigeons and doves drinking or eating from the same sources as chickens.
  • Clinical signs
  • Physical exam
  • PCR testing

Reported Cases

  • Case 1: Esophageal trichomoniasis in a Chickens At the California Veterinary Diagnostic Laboratory System-Turlock Branch, esophageal trichomoniasis was diagnosed in two cases submitted from backyard chicken flocks. The esophageal lesions observed were similar to those seen in several other important diseases of chickens. The causative trichomonad organisms were readily demonstrated on wet smears and by histologic studies. In both cases, the investigated flocks were afflicted with several concurrent diseases. California has experienced an increase in the number of small nontraditional chicken production operations. These facilities are sometimes in close proximity to commercial poultry operations and biosecurity barriers occasionally fail. The poor husbandry practices often used in these small flocks make them a potential reservoir for rare diseases such as trichomoniasis and also for disease organisms that are devastating to commercial poultry. Ref

  • Case 2: Trichomoniasis in a Parakeet Trichomonas spp. infection of the crop and esophagus, and bacterial pneumonia caused the death of 15 budgerigars over a period of two months in a flock of 30 birds housed in an outdoor aviary of a rural area. Clinical signs included respiratory dyspnea and difficulty in swallowing. Large numbers of wild doves in the area and dusty conditions around the aviary might have been the source of Trichomonas spp. and bacteria, respectively. Ref

  • Case 3: Systemic trichomoniasis in a Pigeon Systemic trichomoniasis was diagnosed in a 7-day-old pigeon squab submitted from a commercial squab operation, which was undergoing high mortality in birds 2- to 10-days-old. Gross lesions indicative of omphalitis, yolk sac infection and peritonitis were seen at necropsy. Microscopically, organisms that were positive for Trichomonas spp. by immunohistochemistry were identified in affected tissues. Ref

  • Case 4: Trichomoniasis and systemic amyloidosis in a Finches Trichomoniasis and systemic amyloidosis were diagnosed in three finches submitted for necropsy from an aviary experiencing high mortality. The three finches had chronic, variably severe esophagitis and/or ingluvitis (inflammation of the crop) with trichomonads that were confirmed by IHC within the lesions. The three finches also had variably severe amyloidosis involving the liver, spleen, kidneys and/or intestinal tract. Ref

  • Case 5: Systemic trichomoniasis in a Pigeons Systemic trichomoniasis was diagnosed in two young pigeons. Clinical signs seen in the flock included increased mortality, greenish diarrhea, and emaciation. At necropsy the birds exhibited large masses of a solid, yellowish caseous material at the base of the heart and in the liver. Histologically, extensive areas of necrosis associated with large numbers of trichomonads were seen in the heart and liver. Trichomoniasis was confirmed by immunohistochemistry. Ref


Supportive careIsolate the bird from the flock and place in a safe, comfortable, warm location (your own chicken "intensive care unit") with easy access to water and food. Limit stress. Call your veterinarian.
SurgeryDiphtheritic plaques in the chicken's mouth may need to be removed by debridement.
CarnidazoleGiven once orally at 50 mg/kg.B Speer
MetronidazoleGiven twice a day orally at 10-30 mg/kg or added to flock drinking water at 100-200 mg/L for 7 days.B Speer
ToltrazurilGiven once orally at 50 mg/kg or added to flock drinking water at 25 mg/L for 2 days.B Speer
Thyme extractAdministered orallyNT Nasrabadi et al., 2012
Aqueous water extract of garlicAdministered in drinking water (200 mg/kg, once a day for one week)Seddiek ShA et al., 2014
BerimaxA highly effective alkaloid nutraceutical derived from purified plant extracts by a Norwegian veterinarian.
AntibioticsMay be required in cases of secondary infections.



  • Don't allow doves or pigeons access to the chicken feeders and waterers.
  • Don't let chickens drink from water sources that wild birds drink from
  • Maintain sanitary conditions
  • Provide apple cedar vinegar in drinking water (1 tablespoon per gallon (15 ml per 4 L) periodically (once a month or so).

Scientific References

Good Overviews


Age Range

Usually younger chickens are more susceptible to infection.

Risk Factors

  • Pigeons and doves drinking or eating from the same water or feed source.