[Survival of the third stage larvae of anisakis simplex in various conditions and experimental infection in rats].

UNLABELLED: OBJECTIVE To observe the characteristics of biology and pathogenicity of the third stage Anisakis simplex larvae (L3).

METHODS

The survival time of the L3 in various conditions was observed and the pathological change after experimental infection in rats was examined.

RESULTS

The results showed that the L3 frozen at -20 degrees C for 10 - 12 h can be killed. In the temperature range of 4 - 10 degrees C, the L3, can survive for over 8 months. The L3 was very active at 37 degrees C, and was killed at the high temperature over 40 degrees C in a very short time. The ingredients for sashimi cannot kill the L3. The experiment of rats infected by the L3 showed that about 15% -25% of the L3 penetrated into the gastrointestinal wall or migrated into the peritoneal cavity in 2 days. After 3d the L4 was not infectious, and died automatically in 7 - 10 days and could not develop into adults. The animals can be easily infected when the stomach was empty. The pathological study showed that the primary infection was a kind of reaction to foreign body, while that of the re - infection was allergic.

CONCLUSION

The L3 has a strong resistance to low temperature and to ingredients, it can be killed by freezing at -20 degrees C in 24 hours. The L3 can not mature in the body of terrestrial mammals but causes pathological change in the stomach and allergy.