Studies On The Morphology Of Pagumogonimus Cheni And The Adaptation To Two Kinds Of Host

[objectives] To observe the morphologic features of P.cheni and find the morphological differences between P. cheni and P. skrjabini.[methods] The metacercariae are obtained from crabs in epidemic area of P. cheni and are inoculated to experimental animals,a cat and twenty rats, after observing morphologic features. The cat is infected orally and the rats are infected through mouth and abdomen respectively. The eggs in feces are checked from the forth day to observe the egg positive time. These animals are dissected in 90-112 days for collecting the imagoes. The worm and the imago rates are calculated. The morphologic features are studied and described.[results] The morphologic features of P. cheni s metacercaria, excyted metacercaria, imago and egg are described as follows:The layer of metacercaria is single and it's side is 0. 445×0. 440mm. The shape of excretory bladder is like a long pocket. The side of imago is 10. 12 ± 0. 88×3. 34±0. 65mm.and the breadth length ratio is 1:2. 44 -1:3. 2. The ventral sucker is larger than the oral sucker. The ovary has centriol ,it's branchs are 4-6, it's shape is like fingers and it's place is near the ventral sucker. The spermary is long, it's branchs are 4-6 and it's length is about 1/6 of the body length. The skin spines are mixed. Most of eggs are not symmetric. The egg positive time of cat is the 50th day. The number of positive rats is 4 and their eggs positive time is the 68,68, 70, 70th day respectively. The worm rate of cat is 20%, imago rate is 17. 5%. The worm rate of rats is 6. 67%, imago rate is 43.75%. [conclusions]Morphologic features of metacercaria and imago of P. cheni are special. P. cheni can be identified according to the layer and the thickness of metacercaria and the shape of ovary and the arrangement of skin spines from P. skrjabini. Cat and rat are suitable for P. cheni. Both of them are the experimental host of P. cheni.