Motile Flagellate Protozoa

Causes

There are a variety of different types of motile flagellate protozoa that can infect finches, including Trichomonas, Cochlosoma, Giardia, and Hexamita. The two I hear most about in finches are Trichomonas and Cochlosoma. Giardia comes up occasionally. I have yet to hear anyone talk about a Hexamita infection, although I believe it is a possibility. These protozoal infections are usually passed on by ingesting either the organism themselves, shed in droppings of other birds (frequently ingested via contaminated water), or, for some organisms, by ingesting the cysts shed by the organism. Water contaminated with droppings is a frequent method of spread. Giardia can be spread via the cysts, and the cysts can frequently survive for many months and are resistant to many disinfectants - even bleach may not be 100% effective (although it is the best choice for this particular organism).

Symptoms

I occasionally find new birds infected with motile flagellate protozoa. These birds were carrying the organism but not showing symptoms. I did have one bird die with a very bad protozoal infection. It died before I could get to a vet or get my hands on Ronivet-S (they always pick the weekend to come down with the bad stuff). I do not know for sure if the protozoa was the cause of the bird's death or if there was another concurrent problem. The bird that died had trouble hitting the perch and would easily fall off the perch to the bottom of the cage/aviary. The droppings had a bright yellow cast to them and were somewhat runny and sticky. Because the bird couldn't perch well, it would sit on the floor of the hospital cage and its droppings would become caked to the vent. I had to constantly clean the vent so it would not become clogged. I am not sure which protozoa this bird was infected with, but my best guess based on the random, bumper car motion of the protozoa is Trichomonas.

Prevention

I like to scan for this protozoa under the microscope when i purchase new birds. If found, I treat for it right away. Some sources seem to imply that treatment of some protozoa like Cochlosoma may be only temporary (once certain carrier birds are infected, you can only control it and not get rid of it). I haven't been able to confirm or contradict this.

Keeping a clean, dry environment will help prevent its spread. Limiting the time bath water is available and offering water in drinkers that make it difficult to soil the water will also help contain the spread. If I find an infected bird in the aviary, I treat everyone just to be on the safe side, and I disinfect the aviary with bleach to try to kill off any remaining organisms or cysts. It is my understanding that Trichomonas organisms will not survive long in the environment (especially in dry conditions), but Giardia cysts may survive for many months.

Identification

In a severely infected bird, protozoa are easier to identify under the microscope because there is so much movement on the slide that you know something is going on. When only a few protozoa organisms are present, it takes some experience to distinguish it from Brownian motion.

Based on videos on the Internet (ExoticDVM website), it appears that Trichomonas moves in a random bumper car type fashion. They zig zag about hitting and disturbing urate crystals and background material. I have occasionally seen the flagella, but only in a smear that has nearly cooled, where the organism is still moving the flagella but is no longer moving in space. Giardia is supposed to either roll or move in smooth circles. Hexamita is supposed to move in straight lines, like little mice. I have not seen video of Cochlosoma, although I may have seen it under the scope. Cochlosoma is supposed to spin around and move like a top.

Treatment

Regardless of which type of protozoa is found, the treatment is usually the same. Vets will frequently prescribe Metronidazole (eg, Flagyl). However, Giardia is becoming more and more resistant to this drug. A popular choice among aviculturists is Ronidazole (eg, Ronivet-S). Ronidazole is supposed to be more palatable and better accepted by birds as well as being more effective at treating Giardia.

If I find protozoa, I treat with Ronivet-S for seven days. I increase the concentration by four times as the standard dosage may not be enough to get rid of the problem, depending on the causative organism. I have never had any problems at this dosage. I mix 1/8 teaspon of Ronivet-S with 125 mL of water to obtain this concentration. Note that Ronivet-S is 6% Ronidazole. Do not attempt to alter the dosage of other products with a different concentration in this way. I have safely given Ronivet-S with nystatin. I have also heard that it is safe to mix Ronivet-S and Amtyl in the water concurrently, although I have never tried this.