Larvicidal action of liquid nitrogen against metacercariae of <i>Clonorchis sinensis</i>

, Song, Soo Bok

doi:1987.25.2.123

Korean J Parasito > Volume 25(2):1987 > Article

Original Article


Korean J Parasitol. 1987 Dec;25(2):123-128. English. Published online Mar 20, 1994. http://dx.doi.org/10.3347/kjp.1987.25.2.123
Copyright © 1987 by The Korean Society for Parasitology


Larvicidal action of liquid nitrogen against metacercariae of Clonorchis sinensis
Soo Bok Song
Department of Parasitology, College of Medicine, Pusan National University, Pusan 600, Korea.



Abstract
The author investigated the larvicidal action of liquid nitrogen against the metacercariae of Clonorchis sinensis, with an observation on the freshness and change of taste in the flesh of fishes. The results obtained were as follows: The metacercariae in the flesh of Pseudorasbora parva, which were treated with liquid nitrogen (-192℃), were not killed within 10 seconds, but completely killed over 30 seconds. In comparison, the metacercariae in the flesh of P. parva kept in a refrigerator (-12℃) were killed only in 84 percent in 10-hour exposure group. The freezing speed of fishes by liquid nitrogen was 4 min. (') and 15 seconds(") for Cyprinus carpio, 1'22'' for Carassius carassius and only 30'', for Pseudorasbora parva. As for the freshness and taste of raw fresh water fishes, they were not deteriorated after the treatment with liquid nitrogen. In animal infection experiment of C. sinensis metacercariae after freezing, they were found not infective after they were treated with liquid nitrogen. From the results, it is inferred that the treatment of fresh water fishes for longer than 30 seconds with liquid nitrogen is helpful to reduce the possibility of C. sinensis infection without alteration of the freshness and taste of fishes.

Tables


	Table 1 Larvicidal effect of low temperatures on C. sinensis metacercariae encysted in Pseudorasbora parva


	Table 2 Movement of metacercariae according to action time in liquid nitrogen


	Table 3 Freezing time according to fish size with liquid nitrogen


	Table 4 Recovery of adult C. sinensis from rats infected with the metacercariae treated with liquid nitrogen


	Table 5 Survey on eating habits of fresh water fishes among Sunam Residents

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