Trichomonosis Incidents in Atlantic Canadian Birds
Recent reports from Atlantic Canada suggest there are numerous potential incidents of trichomonosis causing disease and death of birds. Trichomonosis is a disease that regularly infects birds in the region.
What is Trichomonosis?
Trichomononsis (also commonly known as trichomoniasis, canker, or frounce) is an infectious disease among many species of birds caused by the microscopic parasite Trichomonas gallinae. The parasite often infects the upper digestive tract, as well as the liver, lungs, air sacs, internal lining of the body, pancreas, bones, and the sinuses of the skull. This parasite does not pose a health risk to humans or other mammals (e.g. cats and dogs), however, it does pose a risk to captive birds (e.g. domestic poultry and pet birds).
Liver of American goldfinch (Carduelis tristis) infected with Trichomonas sp.
Photomicrograph from Forzάn et al. (2010): Can. Vet. J. 51: 391-396.
Why is Trichomonosis Important?
Outbreaks of trichomonosis have resulted in significant population declines in greenfinches and chaffinches in the United Kingdom since 2005. This disease was identified for the first time in wild birds in Atlantic Canada in 2007 where it is regularly identified in purple finch (Haemorhous purpureus), American goldfinch (Carduelis tristis), and pine siskin (Spinus pinus) populations.
Healthy male American goldfinch.
Photo credit: Dwaine Oakley
Healthy male and female purple finches, respectively.
Photo credits: Dwaine Oakley
Healthy pine siskin.
Photo credit: Dwaine Oakley
What are the Symptoms?
Lesions within the mouth, throat, crop, and esophagus. Difficulty swallowing food and water, may drool, exhibit difficulty breathing, may exhibit wet/matted plumage around face/neck (possibly from regurgitation), and/or swollen neck. General signs of illness including lethargy, poor ability to fly, and fluffed up feathers.
American goldfinch exhibiting signs of infection.
Photo credit: Penny Clark
Purple finches exhibiting signs of infection.
Photo credits: Penny Clark and
Forzάn et al. (2010): Can. Vet. J. 51: 391-396, respectively .
How is it Spread?
Birds can be exposed to the parasite through food or water that has been contaminated by saliva, regurgitated food, or bird droppings from infected birds. Infected birds can also infect their nestlings when providing them with food. Feeders and baths represent potential sites where birds may be exposed to and contract trichomonosis.
How can we Help Prevent Spreading Trichomonosis?
Due to the potential risk that bird feeders and bird baths pose as transmission sites for Trichomonas it is recommended that these are emptied and taken down during outbreaks. Remove feeders and baths for at least two weeks to encourage birds to disperse from the area, reducing the potential for disease transmission. There is often plenty of other sources of food and water for birds during the summer months.
Clean and disinfect bird feeders and bird baths thoroughly and regularly. It is recommended that you use a weak solution of household bleach to disinfect feeders and baths. Be sure to rinse feeders and baths well and allow them to dry completely before returning them to use.
Recent research suggests that moist bird seed is a more suitable environment for hosting Trichomonas than dry seed, for this reason it is recommended that you only use bird feeders that prevent feed from becoming wet. Do not use table/platform feeders, these feeders can often expose seed to rain and also allow potentially sick birds to sit on top of the seed, potentially further increasing risk of disease transmission among birds.
American goldfinches and purple finch at bird feeder. Photo credit: M. Cockram
Please report any sick or dead birds to your nearest CWHC regional centre.
*This post has been revised. Previous photos have been replaced to avoid potential confusion.