title: Development of resistance to reinfection by Clonorchis sinensis in rats.
abstract: We investigated the induction of resistance to Clonorchis sinensis infection by prior infection in rat and hamster models. Animals were challenged with C. sinensis metacercariae, then treated with praziquantel and reinfected. Worm recovery rate in reinfected animals was used to estimate resistance to reinfection. The determined resistance rates to reinfection in rats and hamsters were 97.7% and 10.3%, respectively. In rats, cure from the primary infection of C. sinensis increased resistant to reinfection, and the greater the worm burden and the longer the duration of primary infection, the higher was the resistance rate. For primary infection doses of 10, 40 and 100 metacercariae per rat, the resistance rates were 87.4%, 93.8% and 98.4%, respectively. The resistance rates in rats after 2 or 8-week primary infection were 78.7% and 95.3%, respectively. All worms recovered from reinfected rats were immature. When cured rats were administered with methylprednisolone, resistance to reinfection became impaired. These findings indicate that rats develop a high degree of resistance to reinfection by C. sinensis after cure. The growths and maturations of reinfected worms were also impaired.
authors.affiliation: Department of Parasitology and Tropical Medicine, Institute of Endemic Diseases, Seoul National University College of Medicine, Medical Research Center, Seoul 110-799, Republic of Korea.
authors.forename: Byung-Suk
authors.initials: BS
authors.lastname: Chung
authors.forename: Hongman
authors.initials: H
authors.lastname: Zhang
authors.forename: Min-Ho
authors.initials: MH
authors.lastname: Choi
authors.forename: Deogkyu
authors.initials: D
authors.lastname: Jeon
authors.forename: Shunyu
authors.initials: S
authors.lastname: Li
authors.forename: Mejeong
authors.initials: M
authors.lastname: Lee
authors.forename: Sung-Tae
authors.initials: ST
authors.lastname: Hong
mesh_terms: D000818:Animals; D000871:Anthelmintics / Q000008:administration & dosage / Q000627:therapeutic use; D000893:Anti-Inflammatory Agents / Q000008:administration & dosage; D003003:Clonorchiasis / Q000276:immunology* / Q000469:parasitology / Q000473:pathology*; D003004:Clonorchis sinensis / Q000472:pathogenicity*; D006224:Cricetinae; D004195:Disease Models, Animal; D005260:Female; D007121:Immunocompetence; D007165:Immunosuppression Therapy; D008297:Male; D008647:Mesocricetus; D008775:Methylprednisolone / Q000008:administration & dosage; D011223:Praziquantel / Q000008:administration & dosage / Q000627:therapeutic use; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D000871:Anthelmintics; D000893:Anti-Inflammatory Agents; D011223:Praziquantel; D008775:Methylprednisolone