Histomonas meleagridis is a trichomonad parasite, which is capable to cause severe inflammations of ceca and livers in gallinaceous birds. It rarely can be satisfactorily explained, how the parasite was introduced into the flock. The role of wild birds as possible reservoir or as vectors has not been explored sufficiently. In the present study two experiments were done to determine if pigeons are susceptible to intracloacal infections with H. meleagridis and have the potential to act as vectors. In a first experiment nine racing pigeons (Columba livia forma domestica) were infected intracloacally with 400,000 living histomonads. Three further pigeons were kept as contact birds. Histomonal DNA was detected in cloacal swabs until one week after infection, but reisolation was not possible. In a second experiment 24 racing pigeons were either infected intracloacally with 250,000 viable histomonads or with the same culture, which had been inactivated. Histomonal DNA was detected in cloacal swabs of both groups until five days after infection, but reisolation was not possible. In both experiments neither clinical signs nor gross lesions were observed in any bird and in the ceca no histomonal DNA was detected. It was concluded that pigeons do not act as vectors for H. meleagridis after intracloacal infection.

Key words: Blackhead disease, Histomonas meleagridis, Pigeons, Transmission, Vector