Canker - Trichomoniasis - Roup

Trichomoniasis

Trichomoniasis is a disease of the upper digestive tract, seen in pigeons, doves, raptors, turkeys, chickens as well as many other wild birds.

Occurrence
Trichomoniasis (Trich. For short) occurs frequently in pigeons and doves, as well as raptors which feed upon them. The disease is called canker in pigeons and frounce in falcons. With the current improved management practices in the poultry industry trichomoniasis is not common in turkeys and chickens. Outbreaks usually occur in warm climates or during warm weather.

Etiology
The etiological agent of trichomoniasis is Trichomonas gallinae (Tg). Tg is a pear-shaped flagellated protozoan with 4 anterior flagella and an undulating membrane to provide motility. The life cycle of Tg is very simple; it divides by longitudinal binary fission.

Transmission
Nearly all pigeons are carriers of Tg. The pathogenicity of the different strains of Tg is very variable. Adult pigeons transfer the organism to squabs via the "pigeon milk". Raptors often contract trichomoniasis by eating infected pigeons and doves. Turkeys and chickens contract the disease by drinking stagnant surface water containing T. gallinae . Pigeons are believed to be the most common vector by which the water supplies are contaminated.

Clinical signs
Affected birds may have difficulty closing their mouths and may drool and make repeated swallowing movements. Severely affected birds will stop eating, become depressed, ruffled in appearance, and emaciated before death.

Lesions
Lesions are seen in the mouth, sinuses, pharynx, esophagus, crop, and proventriculus. Typical lesions are white to yellow plaques or raised masses.

Diagnosis
Gross lesions are very suggestive of trichomoniasis but are not unlike those seen with visceral pox, candidiasis, and hypovitaminosis A.
histopathology of the lesions will help distinguish trichomoniasis from the above diseases. The presence of large numbers of trichomonads in the oral fluids is usually considered confirmatory. A wet mount of fresh oral fluids will reveal the motile trichomonads when examined microscopically.

Prevention
Eliminate any carrier birds as they will contaminate the waterers with Tg. Provide clean fresh water and eliminate sources of stagnant water.
Avoid contact between pigeons and doves and susceptible poultry. A low preventative level of protozoacide can be fed in the ration or in the drinking water. Agents that have been used are dimetridazole (Emtryl), nithiazide (Hepzide) and Enheptin.

Treatment
Several drugs have been used to treat trichomoniasis including Emtryl (dimetridazole), aminonitrothiazole, and Enheptin. These drugs are no longer available for use in the U.S.A. Back yard flocks or pigeons not used for food production may be effectively treated with dimetridazole by prescription of a veterinarian (1000 mg/L in drinking water for 5-7 days).

The only references I can find re a dose of Flagyl - is 50mg for a pigeon for 3 days and 60mg/kg for a bird for 5 days
Birds often do need much higher doses of antibiotics than other species. So for a 2kg chook I would give 1/4 of a 400mg flagyl daily, if its 3kg + then 1/2 tablet daily.

The with-holding period of Emtryl is 5 days.
Not sure about the flagyl but I would do 7 days.



Lesion removed a bird in another thread:


Some medication information quoted from Dr Colin Walker:

Any one of a group of medications called nitro imidazoles are effective against trichomonads. There are four commonly in use:

1. Dimetradazole - The common brand name here is Emtryl, available as a water-soluble powder. Dimetradazole was the first nitro imidazole available and is still an effective drug, although trichomonad resistance to it in some areas is a problem because it has been used for the longest. It must be used with care as it has a narrow safety margin. Overdose leads to a reversible loss of balance and coordination and, in high doses, death. The medication can interfere with sperm production in cocks, leading to a temporary infertility, and so is not recommended for use during breeding. The usual dose is 1 teaspoon (3 grams) to 4½ - 8 litres of water. Lower dose rates should be used in stock birds feeding youngsters and during hot weather when water intake increases and evaporation occurs from drinkers, increasing the concentration of the medication.

2. Carnadazole - The common brand name here is Spartrix. It is only available in tablet form. It has a wide safety margin and is very useful for individual bird dosing, particularly youngsters in the nest. The dose is one 10-mg tablet daily.

3. Metronidazole - The common brand name is Flagyl. This is available as a water-soluble syrup and as tablets in a variety of strengths. It is very economical, with the tablets being useful to dose individual birds. Individual birds are given ¼ of a 200-mg Flagyl tablet once daily. Flagyl syrup is water soluble and is given at the dose of 5 - 10 ml per litre but is very sugary and not very palatable to the birds.

4. Ronidazole - This is available as a water-soluble powder under a number of brand names world-wide, including Ridsol-S, Turbosole, Tricho-Plus and Ronivet. The usual strength used is 10%. The dose at this strength is ½ teaspoon per litre. Weaker preparations are available but the birds need to be treated longer with these. The drug is very bitter so preparations stronger than 10% tend to be unpalatable to the birds. It has a very wide safety margin and is safe to use during breeding, racing and moulting. World-wide, ronidazole is the current medication of choice to treat canker. However, in some countries it is not available for use in pigeons, authorities being concerned that resistant organisms may develop. As the drug is used in food-producing animals such as pigs, its use is reserved for these.

In any canker-control program, it is often best to rotate between at least two of these medications in order to decrease the chance of a resistant trichomonad strain developing. Currently, ronidazole-based preparations are used as the primary treatment because of their effectiveness and wide safety margin, but it is a good idea to swap to one of the other available drugs every third or fourth treatment.

Sources:
Damerow, G (1994) [i]The Chicken Health Handbook