The course of Trypanosoma brucei ssp. infection in domestic chickens.

Three unrelated stocks of Trypanosoma (Trypanozoon) brucei were tested for their ability to infect domestic chickens. One of them, Lugala/55/EATRO/459, regularly produced a chronic infection. This was characterized by a low parasitemia (3-100 mouse infective organisms per ml of blood) that lasted for nine months in pullets and over one year in cockerels. Advances and remissions of the parasitemia were detected during the course of the infection. There was no obvious impairment of the health of the birds and their growth rate was indistinguishable from that of uninfected chickens. A second stock of T. brucei produced a transient infection that lasted for a few days only and a third failed to infect. These observations, of persistent symptomless infections, raise the possibility that domestic chickens and other birds may act as reservoirs in the cycle of infection in nature, as do many game animals.