[Gnathostoma larvae investigation in fresh water fishes in the valley of Chinese Chang River and the morphological characteristics of the larvae].
An investigations were carried out on the prevalence of larval gnathostomes in fresh water fishes in southeast area of the Yang-tze Valley, the people's Republic of China, from October to November. The fishes were collected from five districts which were from Shanghai, Chenchiang, Nanching, Chiuchiang and Nanchang, especially the Shanghai district involved Kunshan, Tienshanhu, Chingpu and Nanhui areas. Species of the fishes collected were Channa argus (110), Siniperca chuatssi (24) and Silurus asotus (39). A total number of fishes examined were 137. Muscles of the fishes were each dissected into small pieces and sliced. These slices were examined under a dissecting microscope. The fish viscera from 4-5 individuals were mixed, homogenized and digested by the artificial gastric juice at 37 degrees C overnight. As a result, four encysted larvae were recovered from the muscles of four fish of C. argus. 34 larvae in total were obtained by the digesting. Those larvae mainly recovered from the viscera. The morphological examination showed those 38 larvae could divide into three groups by their body lengths such as 0.58-0.86 mm (group A), 1.12-2.61 mm (group B) and 4.86 mm (group C). Group A consisted of 5 which belong to the early third-stage parasitologically which usually lives the first intermediate host. The majority (32) belongs to group B. Unfortunately, only one larva was obtained in group C which belongs to the advanced third-stage which usually lives in the second intermediate host. Light and scanning electron microscopy revealed that group A and B had the characteristics of G. hispidum and group C had those of G. spinigerum. Next, we investigated fishes near the tow big lakes, Hongtze-hu and Tai-hu situated along the river. In these lakes 12 genera, 12 species fishes (533 individuals) were captured. From these fishes 18 ganathostome larvae collected. Most of the larvae obtained from C. argus and Monopterus albus. All these larvae belongs group B which identified as G. hispidum. In conclusion, many fishes have only G. hispidum of stage of the early third in their viscera.
Koga
Masataka
M
Department of Parasitology, Faculty of Medicine, Kyushu University, Fukuoka 812-8582, Japan. sayadejp@yahoo.co.jp
Ishii
Yoichi
Y
D000818:Animals; D002681:China; D005399:Fishes / Q000469:parasitology*; D005618:Fresh Water; D006039:Gnathostoma / Q000302:isolation & purification* / Q000648:ultrastructure*; D007814:Larva / Q000648:ultrastructure*; D008855:Microscopy, Electron, Scanning; D051381:Rats; D045483:Rivers