Published on Tue, 06/16/2015 - 2:39pm
What you need to know
By Peter Brown, aka The Chicken Doctor
The term ear canker is a bit misleading because it has nothing to do with the organism that causes canker. Since I started doctoring chickens some fifty-plus years ago, I have never seen a case of true ear canker caused by Trichomonas gallinae. I have investigated over two hundred cases of ear infections, or otitis, over the course of time and none of them have been caused by Trichomonas gallinae.
Over the years, 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 was also from bacterial sources and not protozoa.
Symptoms and treatment
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 (air way) 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 carcass 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 have activity against this protozoa have for one reason or another been removed from the market place. Today, the standard medication for treating this is metronidazole.
The ear infection that is commonly called ear canker is caused by one of the following bacteria:
Pseudomonas aeuroginosa, is a gram-negative (unable to be stained on a slide) flagellate bacteria (meaning it is able to move on its own via little appendages). It is commonplace in nature and found just about anywhere you care to look. It is often found in rotting or spoiled vegetation, water, and soil and prefers a warm humid environment.
Pseudomonas aeuroginosa readily grows on warm moist surfaces. This bacteria is aggressive and difficult to treat due to it being extremely resistant to antibiotics. Common method of entry into the birds system is through the oral cavity (mouth) or open cuts and wounds. The antibiotic polymyxin B has been shown to be the medication of choice with this organism as it is highly effective against it.
Escherichia coli, or E.coli, is a gram negative bacteria that is also ubiquitous is nature and is also found in reasonable numbers in the lower intestines of the chicken. Not all strains of E.coli are pathogenic, hence the great number living in the lower intestines of poultry and other animals.
Since not all strains are resistant to antibiotics, the choice of which one to use depends on antibiotic sensitivity testing. Some medications that may help are gentamycin, amoxicillin and the fluroquinolone-class of medications.
Enterococcus faecalis is an opportunistic pathogen that takes advantage of certain conditions in the animal such as impaired immune system response. It is also prevalent in nature and has become highly resistant to most antibiotics. It is easily spread through contaminated feed and water as well as fecal contamination. Enterococcus faecalis is commonly found in the intestinal tract of poultry and other species of animals—even humans.
Antibiotic sensitivity testing should be performed if possible to select the most effective antibiotic as this organism is highly resistant to many common antibiotics.
How canker enters
The three bacteria that I have found to be responsible for the ear infection that we have called 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 all 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.
About the author
Peter Brown, aka The Chicken Doctor, has been caring for chickens for over 50 years and holds an AAS in poultry science. Peter is a regular on The Chicken Whisperer radio show and founder of First State Veterinary Supply.