Paragonimiasis is one of the most important endemic diseases in Korea. However, recognition of the limitation of microscopic examination of sputum and feces for Paragonimus eggs has led to the investigation of immunoserological techniques for paragonimiasis.

The other hand, bithionol preparation has been used as a drug of choice in paragonimiasis but recently niclofolan preparation has introduced as a new agent. By the time, the authors attempted the evaluation of above both agents against experimental rat paragonimiasis by immunoelectrophoresis and Ouchterlony test.

The immunoeletrophoresis and Ouchterlony tests were performed according to the method Tsuji and Grabar et Williams respectively, with antigen extracted from lyophilized worm of P. westermani with 0.1 per cemt saline solution. Meanwhile, rats were infected with per os 20 metacercariae of P. westermani above two kinds of serologic tests and were undertaken at biweekly intervals.

Then, bithionol was administered every other day for 5 successively for 2 weeks or 6 weeks after infection. Another groups, niclofolan was administered per os single dose same as above.

1. The sera from the rats infected with P. westermani, after treatment with bithionol or niclofolan preparations began to show the precipitin bands against P. westermani antigen 8 weeks after the infection in immunoelectrophoresis and Ouchterlony test, but from 10 or 12 weeks after infection, the number of bands were decreased or disappeared gradually.

2. In general, the sera from the rats treated with bithionol or niclofolan showed the precipitin bands delaying 2 weeks than control rat groups.

3. The sera from the rats administered with hydrocortisone showed precipitin bands neither in immunoelectrophoresis nor in Ouchterlony test.