For the fourth winter in a row, cases of eye disease have been reported in birds frequenting feeding stations in Quebec. Although we have not recently received specimens allowing us to confirm the diagnosis, the lesions observed are highly characteristic of an infection by Mycoplasma gallisepticum (a disease known as mycoplasmosis). We definitely can say that this condition, which first appeared in North America in 1994, is back. In Quebec, mycoplasmosis in wild birds seems to be especially prevalent; nearly 30 different reports, especially in house finches (Carpodacus mexicanus), American goldfinch (Carduelis tristis) and evening grosbeak (Coccothraustes vespertinus), have been documented so far this winter.
The geographic distribution of suspected and confirmed mycoplasmosis cases in Canada can be viewed on the following map: http://www.cwhc-rcsf.ca/mycoplasmosis_map.php.
A quick reminder of what mycoplasmosis is: This is an avian disease that affects both wild and captive birds, and caused by bacteria of the genus Mycoplasma. Among the different species of avian Mycoplasmas, Mycoplasma gallisepticum is the most pathogenic. It is transmitted between birds via ocular and nasal secretions. Since this organism is not very resistant in the environment, the transmission relies on close contact between birds, for example at gathering places such as feeding stations, either by direct contact or via the feeder. In addition, this disease has a high rate of contagiousness, and will therefore affect many individuals quickly. However, the mortality rate is not necessarily high. Affected birds will present respiratory and ocular clinical signs such as conjunctivitis, rhinitis, sinusitis. This results in swollen and red eyes, eye and beak secretions, soiled feathers stuck on the head. Some birds may also show depression, decreased appetite and weight loss. Death occurs when the animal can no longer eat properly.
In order to limit the spread of the disease, certain actions can be recommended:
- During a known outbreak of mycoplasmosis, temporarily remove feeders and birdbaths to reduce the risk of transmission.
- Clean your feeders and birdbaths regularly. A bleach solution (10% sodium hypochlorite) should be used.
- Avoid using tube feeders that birds have to stick their heads into, as infected individuals may leave discharge around the sides of the opening, which could easily be transmitted to healthy individuals.
- Treatment of infected wild birds is not recommended, as the use of antibiotics could lead to the development of an asymptomatic carrier state or resistant bacteria. It is also reported in farmed poultry that antibiotics reduce clinical signs and transmission, but do not eliminate the infection.
- Report birds found dead or sick to the Canadian Wildlife Health Cooperative. Find the nearest regional center at: http://www.cwhc-rcsf.ca/
Although the bacterium Mycoplasma gallisepticum cannot be transmitted to humans, wild birds can be affected by other diseases transmissible to humans and pets (such as Salmonella, Campylobacter and E. coli bacteria for example). It is therefore important to take precautions when cleaning feeders:
- All equipment used to clean bird feeders and baths should not be used for any other purpose. Keep them outside and away from food preparation areas.
- Wear rubber gloves when cleaning feeders and wash hands and forearms thoroughly with soap and water, especially before eating or drinking. Avoid handling sick or dead birds directly with bare hands.
For more information on this condition see the following links:
http://www.cwhc-rcsf.ca/docs/fact_sheets/Bird_Feeder_Strategies_Trifold.pdf
http://www.cwhc-rcsf.ca/docs/fact_sheets/Avian_Mycoplasmosis_Fact_Sheet.pdf
Submitted by CWHC – Quebec