Vertical distribution of Fasciola gigantica metacercariae on stems of rice plant grown in a water pot
Ueno, H.; Yoshihara, S.
National Institute of Animal Health Quarterly 14(2): 54-60
1974
ISSN/ISBN: 0027-951X PMID: 4444734 Document Number: 74536
The vertical distribution of F. gigantica metacercariae, emerged from Lymnaea ollula, was investigated on the stems of Oryza sativa grown in a transparent water pot under laboratory conditions simulating the paddy field. The results were compared with those from cysts on the submerged inside wall of the pot before and after transplantation of a stump of plant in it. Most of the metacercariae on the wall of the pot were found above 1.6 cm depth of water. Cercarial cyst formation was observed infrequently at 19.2 cm depth. Most of the cysts on the stems, however, were distributed more widely than those on the wall; that is, from the surface to 6.4 cm depth. Cysts decreased rapidly in number with an increase in depth of water. Cercariae from infected snails encysted more frequently on green stems than on brownish green or brown stems; the number per stem was 16.5, 7.7, and 2.6, respectively. It is suggested that the stems of rice plant may not always be objects suitable for the cyst formation of F. gigantica cercariae.