Case Study Emergencies/Illness Health Issues Necropsy

Case Study: Trichomonosis (Canker)

Avian Trichmonosis, often called canker (and not to be confused with ear canker) is a disease caused by one-celled protozoa, mostly affecting young birds. It primarily affects the chicken’s upper gastrointestinal system and causes them to develop lesions, or cankers, inside the mouth and the esophagus. As the disease progresses, the lesions get bigger and often interfere with the chicken’s ability to eat and drink. In severe cases, the lesions might block the esophagus causing suffocation.

Its severity depends on a bird’s vulnerability and on the virulence of the parasite’s strain. Adult birds that recover may become carriers, although asymptomatic and are resistant to re-infection.

Simon, Appenzeller Spitzhauben x Polish Rooster, 4 years old

I hatched my rooster in June 2017. In spite of other health issues that have affected my flock he’s always been healthy. He’s never been aggressive, but like many crested birds Simon’s a bit flighty and resists being touched so I’ve rarely picked him up.

Recently I noticed saliva coming out of his beak while he was on the roost bar. The next day he seemed okay, but a few days later I saw it happen again. He didn’t have other symptoms and I had seen him eating and drinking, but I thought I should do a health check on him.

Day 1: Simon was in the yard, beak open with some saliva coming out. That must have been happening for a bit because the feathers on his neck were matted. He was shaking his head, scratching his face and making a high pitched staccato squeak once in a while. I found a small hard lump in his neck, the size of a walnut, at the top of his throat (not his crop) and was unsure if it was an obstruction or an organic mass.

His crop was empty, meaning he hadn’t been eating or drinking. I attempted to look in his mouth with a flashlight and didn’t see anything like canker (trichomonosis).

I set him up in a sick bay in the living room with scrambled egg/cat food and water. I don’t think he touched either. He was preoccupied by the congestion in his throat and the mucous coming out of his beak – long gooey strands of it. Simon repeatedly swiped his beak on the shavings to remove it. No coughing or sneezing, but a bit of a wheeze as he was having difficulty breathing.

Day 2: Copious amounts of saliva coming out of his beak. His face and neck were wet with really pungent smelling mucous. The lump was unchanged. I had been attempting to massage the mass thinking it was an obstruction. I could manipulate it somewhat under the skin, but it didn’t change shape or move.

Day 3: He was drinking, but hadn’t eaten since I brought him inside. In 48 hours he only produced one small green, watery poop. Simon continued to drool. I looked in his mouth again, and this time I was able to see a small yellow plaque at the base of his mouth but out of my reach. I did a little research and found that canker can appear in either the throat or crop and not in the mouth.

“Older youngsters or mature birds with a reasonably strong natural immunity will often try to localize a canker infection, leading to nodule formation. If in the throat, these nodules can usually be seen or if in the crop wall can usually be felt as firm mobile lumps ranging in size from 0.5 cm to 4 cm in diameter. Affected birds are treated daily with Spartrix or Flagyl tablets. Once localized (usually 1 – 4 days), throat lesions can usually be teased free with a cotton bud or crop lesions pinched free into the crop. Occasionally, surgical removal is necessary. Premature attempts at removal usually result in excessive bleeding.” – The Poultry Site

As you can imagine this was bad news. Even with medication, treatment would be required to remove the mass in his throat.

Day 4: I called my veterinarian and as I feared this procedure wasn’t in his skill set. I could search for an Avian Veterinarian elsewhere, but felt that multiple visits, medications, and an invasive procedure weren’t practical – especially if it didn’t ensure his survival. I made the sad decision to have him euthanized.

I asked my friend Thomas to help and directed him to do it in such a way as not to damage the mass. He complied and we set about cutting open Simon’s neck. (NB: I wear gloves and encourage you do as well, Thomas opts not to).

On one side was a large lump visible under the skin. When we opened the area up there was a round spongy yellow ball located at the top of his neck. When extricated it left a deflated pouch of skin. Surprisingly, it didn’t smell.

The size of the mass was impressive and scary, in that, it was located at the top of his trachea and esophagus cutting off both his airway and ability to eat and drink. His fate would have been to suffocate or to starve to death. This was a sad decision, but a necessary one as I don’t think there was a way to save him.

We were short on time, so I opted not to necropsy the rest of his body, satisfied that we found the cause of his illness.

I’ve never experienced Trichomonosis in my flock and had some questions that I hadn’t found the answers for online. I sent a series of questions to Avian Veterinarian Dr Jeanne Smith.

At first she was reticent to agree my diagnosis: “I’ve been seeing backyard poultry for 33 years and have only seen a handful of cases in that time – it’s really rare in chickens. Did you look for the organisms under a microscope? If you saw trichomonads the lump would be from ‘canker’. There are mimics of canker: tumors if he was older than 3 years of age or Candida yeast infections. If the lump was found inside the esophagus or crop it could be due to Candida yeast which can cause lumps like that and plaques in the mouth. If the lump was under the skin on the neck or throat outside of the GI tract it could be caseous pus from an abscess or tumour.”

“The definitive test for trichomoniasis is looking at a fresh direct smear of the lesions or the esophagus or crop mucosal lining and seeing the organism swimming around. It can also be definitively diagnosed by histopathology of the tissues fixed in formalin. When I do a necropsy and see lesions like you’ve described I do a direct smear.”

I then sent her the photos that are included in this post to see if she could come up with an alternate diagnosis. “It does look like canker, especially if he also had plaques elsewhere. The lump was in his neck and the mucosa was normal once you removed the lump. The plaques are hard to see, but I think the two together look most like Trichomonas. I can rule out a tumour or abscess. Yeast usually would also cause a “Turkish towel” appearance to the esophagus/crop wall.”

How did he get infected? “It’s most often spread by pigeons, doves or infected chickens that have been introduced to the flock”. I live on a small island off the west coast of Canada where we have no pigeons, very few native doves and I haven’t added new members to the flock since October 2019. I’m also vigilant about biosecurity. It remains a mystery how Simon got it.

How long would it have taken for the mass to reach that size?: “4-6 weeks”.

What can I do to protect my flock?: “10% ronidazole powder put in drinking water – 2 tsp per gallon/water for 7-10 days. There is a 30 day egg withdrawal so you can’t eat the eggs during treatment or for 30 days after treatment. Treating with ronidazole will kill existing trichomonads, but won’t protect them from reinfection.”

Amazon was sold out of ronidazole. I asked my local vet and they weren’t aware of that product and couldn’t find it by that name in their compendium of pharmaceuticals. They did do some research and found that it is not recommended for use in animals designated for human consumption due to the carcinogenic risks. I’m currently looking for effective, but safer options. If you’re interested in more natural options Thyme oil extract has been shown to be effective. Both apple cider vinegar and crushed garlic added to their water once/month are considered a preventative.

Many thanks to Thomas for his unflagging willingness to help out when it comes to the not-so-pleasant side of keeping chickens.

I’m curious as to how ‘rare’ Trichomonosis is in chickens. If you’ve had experience with it please leave a comment or contact me.

Credits: Dr Jeanne Smith DVM; Poultry Site. Featured Photo: Simon, Aurora and their chick in the coop, 2019.

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