In order to judge appropriately the suitability as the second intermediate host of @entity2440 , the present experiments were proposed to survey the metacercaria of @entity2441 in the fish host, Cultriculus eigenmanni, in the field, and to observe, by experimental @entity281 of the fish with @entity2440 cercaria, the penetrating ability of the cercaria, @entity2175 , the process of degeneration and extinction, and infectivity of the metacercaria. The following is a brief summary of the leading facts gained through the experiments. All the ten fish (mean body weight 13.4 +/- 3.43g) which were caught in Ok-ku irrigation reservoir were infected with the metacercariae and the average number of the metacercariae found in the fish body/gram was 4.55. The fish was easily subject to invasion of the cercaria, and the examination of the cercariae after having the fish infected disclosed that 24 hours after the @entity281 , all of the cercariae formed their cysts in muscle and the metacercariae kept growing, that 7 days later the metacercariae were found folding their bodies twice, and that in 15 days the characteristic structure of the metacercariae was complete and made a @entity717 intermittently. In the case of control fish, @entity12109 , both penetrating ability of the cercariae and the infective degree of the metacercariae to control host were stronger as compared with the fish host because that the control fish had higher suceptibility to @entity2441 . Afterwards, the metacercariae in the fish host came to a state of @entity2175 and beyond this stage some metacercariae started the process of degeneration and extinction in as early as 30 days, and as more days elapsed, mortality of the metacercariae was not uniformly increased but difference of mortality appeared to be according to the individual of fish host. That is, in 390, 540 and 586 days, all of the metacercariae in the fish hosts became dead, meanwhile almost all of those found in the fish host of 596 days after the @entity281 survived (mortality; 8.51 percent). Percentage of orally administered metacercariae developing to @entity2175 in @entity95 is 10.46 percent in the last case. As the days were progressed the shapes of the metacercariae in the fish host tended to change from ellipsoid to almost round shapes, the length became shorter while the width was wider. The results shown above revealed that C. eigenmanni was, though it could not be proper host than @entity12109 , suitable as the second intermediate host in addition to our previous observation results.

[Experimental studies on the second intermediate hosts of @entity2440 IV. Observations on the fate of metacercariae of XXXX in the fish host, Cultriculus eigenmanni]

@entity2175 :: ('MESH:D003924', 'Disease') :: ['maturity'] @entity95 :: ('9986', 'Species') :: ['rabbit'] @entity2441 :: ('143401', 'Species') :: ['C. sinensis'] @entity281 :: ('MESH:D007239', 'Disease') :: ['infection'] @entity2440 :: ('79923', 'Species') :: ['Clonorchis', 'Clonorchis sinensis'] @entity717 :: ('MESH:D009069', 'Disease') :: ['vigorous rotary movement'] @entity12109 :: ('51549', 'Species') :: ['Pseudorasbora parva', 'P. parva']
@entity2440 :: (79923,Species) :: ['Clonorchis sinensis']
