Also Known As: Canker — Frounce — Roup — Tetratrichomiasis — Trichomoniasis — Avian Trichomonosis
Caused by: Trichomonas gallinae
Introduction
Avian trichomoniasis is primarily an upper gastrointestinal disease of birds caused by the flagellate protozoal pathogen Trichomonas gallinae.
Columbiforms (pigeons and doves) are the primary hosts. Residing primarily in the crop, the parasite is passed from infected parents to offspring during “pigeon milk” feeding early in life. Adult columbiforms also transmit the protozoan during courtship displays. Infection can then persist for considerable time. Only young birds usually show signs of disease.
Domestic chicken and turkey infections are solely acquired from drinking water contaminated by wild birds, usually feral pigeons. There is no vertical transmission from parent to offspring. Birds of prey can also acquire the disease by ingestion of infected birds.
Distribution
Trichomoniasis is present worldwide and is a significant cause of economic loss in pigeons and turkeys. T. gallinae can survive a wide range of environmental conditions.
Clinical Signs
Presence of the parasite in the crop, oesophagus, mouth, throat and sinuses causes yellow lesions/masses that grow in size and become obstructive. Birds may not be able to close their mouths, causing dyspnoea, dysphagia and fluid accumulation within the oral cavity. Weight loss, ocular discharge, ataxia and blindness are also commonly reported.
Diagnosis
Presence of yellow vesicles, “buttons” or masses on the oral mucosa and oesophagus is highly suggestive.
Throat swabs can be used for laboratory culture and Giemsa staining achieving definitive diagnosis.
Pathology
Caseous lesions/masses are commonly present within the mouth, oesophagus, crop and glandular stomach.
The most frequently affected visceral organ is the liver, which can then occasionally cause distribution throughout the abdominal cavity.
In very young birds (squabs) the navel region may be affected, encasing many visceral organs in a caseous mass.
Treatment
2-amino-5-nitrothiazole is the drug of choice due to its lack of adverse effects and few resistance problems at present.
Carnidazole, dimetridazole, metronizadole and ronidazole have also been used successfully. All are administered in water or by force feeding.
Control
Prevention of wild birds' access to water sources, good sanitation protocols and quarantine of new birds are paramount to control of this disease.
Relevant links: Bovine Trichomonosis
References
Animal Health and Production Compendium. (2011) Trichomonas gallinae datasheet accessed online 03/06/2011 @ http://www.cabi.org/ahpc/
BonDurant, R.H., Honigberg, B.M., 1994. Trichomonads of veterinary importance. In: Kreier, J.P. (Ed.), Parasitic Protozoa, 2nd ed. vol. 9. Academic Press, San Diego, CA, 168–177.
Frank K. (2004). Canker [online] Available at: http://www.albertaclassic.com/trichomonas/trichomonas.php. [Accessed 12 May 2011]
Franssen, F. F. J., Lumeij, J. T.(1992) In vitro nitroimidazole resistance of Trichomonas gallinae and successful therapy with an increased dosage of ronidazole in racing pigeons (Columba livia domestica). J Vet Pharm Therap, 15(4):409-415; 20.
Levine N. D (1973) The Trichomonads Levine ND, ed. Protozoan Parasites of Domestic Animals and of Man. Burgess Publishing Company. Minnesota, USA , 88-110.
Samour J. H., Bailey, T. A., Cooper, J. E. (1995) Trichomoniasis in birds of prey (Order falconiformes) in Bahrain. Vet Record, 136(14):358-362.
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