Abstract
Increased mortality (1.5% per week) and low egg production (5–10% lower than normal) were observed in a flock of domestic breeding Pekin ducks (Anas platyrhynchos). At necropsy, salpingitis and peritonitis were the most significant findings. Histologically, there was accumulation of necrotic debris in the lumen of the oviduct. Numerous bacteria and trichomonads were observed histologically in the lumen of the vagina and occasionally in the shell gland. Escherichia coli and a trichomonad were isolated from the oviduct. The trichomonads were oval (6–8 μm long, 4.5–6 μm wide) and had 4 anterior flagella and an undulating membrane extending over the entire length of the body, finishing in a long posterior flagellum. Morphology was consistent with trichomonads of the genus Tetratrichomonas. Comparative sequence analysis of the 5.8S ribosomal RNA gene and the flanking internal transcribed space regions of the trichomonad isolate did not closely match with available sequences of the same region of other trichomonadid protozoa.