Trichomoniasis is a parasitic protozoan disease that affects domestic fowl, pigeons, doves, and hawks. It occurs in the digestive as either the ‘lower’ form, which is characterised by depression, weight loss and watery yellow diarrhoea or the ‘upper’ form, which is characterised by depression, drooling and repeated swallowing movements, sunken and empty crop, open-mouth breathing and bad odour. The upper form is rare in turkeys and chickens. Most caged, domestic and game birds (except waterfowl) are susceptible but the disease is more serious in young birds. Recovered birds remain carriers for life.
Trichomoniasis is caused by infection with the parasitic protozoa Trichomonas gallinae. This protozoan has variable pathogenicity (ability to cause disease). Transmission of the protozoa is by bird to bird contact or by contact with infected litter, feed or water. The protozoa are shed in the faeces of infected birds and can be regurgitated in crop milk.
Treatments are available that will control the disease but there may be restrictions on their use in commercial flocks. Prevention requires good biosecurity and management practices to eliminate the sources of infection. Drain water pools on ranges, screen out wild birds, separate young birds from adults as well as susceptible birds from recovered (carrier) birds.
Poultry Health Handbook 4th Ed, 1994. L. D. Schwartz, Pennsylvania State University.