【摘要】 <正> 一、前言 环肠科(Cyclocoelidae Kossack,1911)吸虫是禽类呼吸器官的寄生虫。家鸭常因鸭嗜气管吸虫Tracheophilus cymbius(Dies.,1850)Skrjabin,1913(通常称鸭气管环肠吸虫)寄生而致营养不良、消瘦、甚至因虫体阻塞呼吸道发生窒息死亡,给家禽养殖带来一定的损害。本类吸虫虽然是一个不大的吸虫类群,但由于成虫生殖腺的形态、排列位置的变异幅度比较大,因此在属、种的名称上比较混乱,如鸭嗜气管吸虫虫种问题也长期未能肯定(Yamaguti,1971等)。本类吸虫的生活史虽曾经一些蠕虫学者的研究,但各期形态的观更多还原

【Abstract】 A survey on helminth parasites of domestic ducks and wild aquatic birds from Fuzhou was conducted during the winter of 1964.Totally 121 ducks and 425 aquatic birds were examined.Among other helminths 193 specimens of cycloeoelid trematodea belonging to sewn species,five genera and two subfamilies were collected from 16 species of birds.There are 3 new distributional records and 11 new host-records given in this paper.The cycloeoelid trematodes secured are as follows:Cyclocoelum mutabile (Zeder,1800);Cyclocoelum micrustomum (Creplin,1820) Kossaek,1911;Haematotrephus triangularum (Harrah,1922);Uvitellina adelpha (Johnston,1916) wit.,1923;Uvitdlina keri Yamaguti,1933;Ophthalmophagus magalhaesi Travassos,1925 and Tracheophilus cymbius (Dies.,1850) Skrjabin,1913.While general accounts were made on all above-mentioned species,special emphasis was laid on T.cymbius with regard to its epidemiology and life history.One hundred and four domestic ducks were examined in Fuzhou,with 20 (20.2%) of them infected with T.cymbius.The positive ducks were distributed in.6 localities from the vicinity of Fiizhou.The incidence of infection in the 6 localities were from 12:5% to 30%,and the intensity of infection was 1-7 tremadtodes in each positive duck.Of the 17 domestic ducks from Xian-you district were examined only one duck (5.8%) harboured a single specimen of T.cymbius in its trachea.On two occasions June 1965 and July 1974 in Fuzhou,dissections were made on freshwater snails collected from the roadside ditches near rice fields where domestic ducks were reared.Of 1082 Hippeutis cantori examined 7 (0.59%-0.85%) of them were found infected with T.cymbius.On the examination of snails from a pond where domestic ducks were reared during the March of 1974 in Chi-Bee near Amoy.One (1.3%) of 80 H.cantori was found to be infected with T.cymbius.During the summer of 1965,experiments were conducted to infect snails belonging to the species Hippeutis cantori Benson,Segmentina hemisphaerula (Benson) and Gyraulus convcxiusculus Hutton with miracidia obtained from the dissection of living T.cymbius and T.sisowi.The result showed that these three species of snails were all susceptible to the parasite.Our observations agreed in essentials with the accounts of Szidat (1932,1933) and Stunkard (1934) on the development of T.cymbius.While some details were added to the morphology of the various stages such as the miracidium,redia,cercaria and metaeercaria,new data were found on the parasitic location of these larvae and on their migration.The progenetie miracidium possesses a young redia in its body.When the swimming miracidia were placed together with the snail intermediaries in a small dish,they were attracted by the gastropods,began to attack them and held firmly on the body wall of the snail.The miracidium did not penetrate into the snail,but continued to hold on and through the opening of its proboscis-like terebra-torum at the cephalic end,the contained redia soon emerged and penetrated into the tissue of snail.Through the lymph space of body they migrated into the periear-dial cavity of the mollusc.Five hours after infection,actively moving rediae were found in the pericardium,each with head collar and one pair of posterior locomotor-appendages.The subsequent development resulted with various stages all occurred in the pericardium of the snail.There is no daughter redial generation,10-15 days after infection tha tailless cercariae become fully developed in the body of redia.The tailless cercaria possesses pyriform head organ and acetabulum.Near the dorsal surface of acetabulum five pairs of unicellular penetration glands were observed,each of which possesses a vesicular nucleus in the center of cell body.The ducts from these gland are grouped together in two bundles proceeding forward along the each side of oesophagus,terminating on the dorsal anterior margin of the head organ.All the subcuticular zone of cerearia are filled with the cystogenous gland cells,obscurring the internal structures as well as the penetration glands whichwere observed only w更多还原