The term “ear canker” is a bit misleading because it has nothing to do with the protozoan parasite Trichomonas gallinae, the organism that causes canker. Since I started doctoring chickens some fifty-plus years ago, I have investigated over two hundred cases of ear infections, or otitis, and none of them have been caused by Trichomonas gallinae. I've collaborated with many laboratories on this subject, and none of them have seen an ear infection caused by Trichomonas gallinae, either. I recently checked some statistics from one of the leading state diagnostic laboratories in the country, and their listing for ear infections identified bacterial sources—not protozoa.
Canker caused by the protozoa Trichomonas gallinae typically resides in the mouth, esophagus, and intestinal tract. Lesions are commonly found in the mouth cavity and appear as a pale, cheesy-looking, white-to-bleached-yellow lesion. Removal of the lesions can easily be accomplished with a pair of forceps. Some bleeding will occur because the lesion is attached to the mucosal surface tissue of the mouth. Lesions may appear anywhere in the oral cavity but usually are easily seen on the tongue, edges of the beak, the opening of the esophagus, and can also cover the glottis (airway opening) as well.
Medication is required to clear the infection from the affected birds. Failure to properly recognize and treat this disease can be fatal. Trichomonas gallinae is spread through bird-to-bird contact, contaminated feed and water sources, and consumption of the carcasses of infected birds. Medications that are used for canker target protozoa, although not all medications that have activity against protozoa will work for Trichomonas gallinae. Sulfa drugs will not work, nor will amprolium-based products. Many of the medications that are active against this organism have, for one reason or another, been removed from the marketplace. Today, the standard medication for treating this is metronidazole.
The ear infection that is commonly called ear canker can be caused by one of the following bacteria:
Since not all bacteria strains are resistant to antibiotics, the choice of which medication to use depends on antibiotic sensitivity testing. Some medications that may help are gentamycin, amoxicillin, and the fluoroquinolone class of medications.
Antibiotic sensitivity testing should be performed if possible to select the most effective medication as this organism is highly resistant to many common antibiotics.
The three bacteria that are primarily responsible for the ear infection that we call ear canker appear to infect the ears through a small opening in the roof of the mouth called the infundibular cleft. This opening is located in the roof of the mouth caudally (to the rear) in relation to the larger opening that we commonly call the nasal cleft, or choana, which opens directly to the sinus cavities.
The infundibular cleft opens directly into the auditory canals of the ears. The canals are semi-circular in shape and lead to the external ear opening. It is in these canals that the infection takes hold. If left unchecked, it will eventually protrude from the external ear opening.
All of the ear infections that I have observed over the years have been mitigated through the use of antibiotics appropriate for the bacterial organism that was present. None of the Infections responded to an Initial dosing with any anti-protozoal medication.
Active prevention is critical in ensuring your chickens avoid the chance of infection. Learn how to prevent another common infection in our article about Mansons Eyeworm.: