|
KMID : 0383919770140000203
|
|
Report of National Institute of Health
1977 Volume.14 No. 0 p.203 ~ p.218
|
|
|
Effect of NaCl on mortality of metacercariae of Paragonimus westermani with reference to the metacerariae in crabs soaked in soy-bean sauce, Gejang
|
|
Nam Sang-Yul
|
|
|
Abstract
|
|
|
In order to obtain base line data to be used for the prevention of paragonimiasis, a study was conducted on the effect of NaCl on the mortality of metacercariae of P. westermani in crabs soaked in soy-bean sauce, Gejang, which is a traditional side dish eaten by Koreans.
This study consists of three parts: (1) the level of concentration of NaCl which penetrated each part of the muscle and viscera was determined periodically during the soaking period ;(2) the survival of the metacercariae in the tissues of the crabs soaked in soy-bean sauce and those soaked in brine was determined in relation to the level of NaCl concentration : and (3) the effect of different concentration levels of NaCl on the mortality of the metacercariae was tested in vitro in comparison with the degeneration and death of the metacercariae in the tissues of the crabs.
The results of the study are as follows:
1. In the tissues of the crabs, Gejang, which revealed a NaCl concentration level less than 6.0%. there was a possibility of the survival of the metacercariae. Up until the seventh day of soaking, such a concentration could be seen particularly in the middle part of the palm muscle of chelipeds and of the merus muscle of ambulatory legs and, in the case of large sized crabs, also in the liver.
2. The NaCl concentration reached high levels fastest in the gill, slowest in the middle palm of cheliped and middle merus of ambulatory leg muscles. The penetration of NaCl into deep muscles and the liver took longer in the large size crabs tan the small ones. The NaCl most easily penetrated through the gaps into the gill chamber, joint membranes, and the openings and parts of each organ which is exposed to the surface of the body
3. In comparison with the NaCl concentration among the 3 groups of crabs soaked in different ways, no significant difference was found in the NaCl concentration. However, it was slightly higher in crabs soaked in soy-bean sauce without seasoning, next highest in crabs with seasoning in the same sauce, and lowest in those crabs soaked in brine.
4. Metacercariae exposed to a series of NaCl solutions in vitro at 20℃ survived more than 30 days at low concentration levels. However, the mortality level increased in proportion to the NaCl concentration. Metacercariae died within 10 days in 3.0% solution, within 2 days in 5.0% solution, and within 6 hours in over 7.0% solutions.
5. In low NaCl concentration, the survival time of the metacercariae soy-bean sauce than in brine solution.
6. The temperature greatly effected the mortality of the metacercariae, the survival time being shorter at 20℃ and much longer at 4℃.
7. The preservatives sodium benzoate and buthyl-p-oxybenzoate, present in the soy-bean sauce at low concentration levels, did not show any adverse effect on the survival level of the metacercariae.
8. According to the results of this study, it may be inferred that crabs soaked in soy-bean sauce, Gejang, for less than 10 days still early a risk of infection from P. westermani.
|
|
|
KEYWORD
|
|
|
|
|
|
FullTexts / Linksout information
|
|
|
|
|
|
Listed journal information
|
|
|
|
|