Two types of trichomoniasis, respiratory and intestinal, were found in
two duck farms. Based on the morphological features, the organism was
identified as Tetra-trichomonas anatis. In the first outbreak, main c
linical signs were bilateral swelling of infraorbital sinuses, sneezin
g and profuse diarrhoea with high fatality (300/400) in young ducks. H
istological lesions were confined to the upper respiratory tract and l
ower small intestine and consisted of mucofibrino-purulent sinusitis a
nd catarrhal rhinitis, tracheitis and enteritis. The protozoa appeared
frequently in the infraorbital sinuses, the respiratory region of the
nose, and the lower small intestine, but rarely in the trachea. In th
e second outbreak, the lesions were limited to the lower small intesti
ne with catarrhal enteritis in adult ducks clinically showing profuse
diarrhoea and low mortality.