Histomoniasis is a commercially significant disease of poultry, particularly of chickens and turkeys, due to parasitic infection of a protozoan, Histomonas meleagridis.

[1][2] H. meleagridis resides within the eggs of H. gallinarum, so birds ingest the parasites along with contaminated soil or food.

Symptoms of the infection include lethargy, reduced appetite, poor growth, increased thirst, sulphur-yellow diarrhoea and dry, ruffled feathers.

[3] Poultry (especially free-ranging) and wild birds commonly harbor a number of parasitic worms with only mild health problems from them.

Thus, chickens can be infected carriers for a long time because they are not removed or medicated by their owners, and they do not die or stop eating/defecating.

Symptoms appear within 7–12 days after infection and include depression, reduced appetite, poor growth, increased thirst, sulphur-yellow diarrhoea, listlessness, drooping wings, and unkempt feathers.

However, outbreaks in chickens may result in high morbidity, moderate mortality, and extensive culling, leading to overall poor flock performance.

[6] A protozoan H. meleagridis is responsible for histomoniasis of gallinaceous birds ranging from chickens, turkeys, ducks, geese, grouse, guineafowl, partridges, pheasants, and quails.

Histomonads then gain entry into small veins of the blood stream from the cecal lesions and migrate to the liver, causing focal necrosis.

Good management of the farm, including immediate quarantine of infected birds and sanitation, is the main useful strategy for controlling the spread of the parasitic contamination.

[15] Nifurtimox, a compound with known antiprotozoal activity, was demonstrated to be significantly effective at 300–400 ppm, and well tolerated by turkeys.