Protective immunity against multiple challenges of Brugia pahangi in Mongolian gerbils induced by drug-abbreviated infection.

Protective immunity against multiple challenge infections was examined in Mongolian gerbils after a drug-abbreviated infection with Brugia pahangi. The gerbils treated with mebendazole (MBZ) during the late prepatent period (7-9 weeks of postinfection) were challenged with 5 inoculations of 50 infective larvae of B. pahangi at 4-week intervals. The worm burden was significantly reduced 68.6% (19.0 in average number) to that of controls (60.6) and was accompanied with enhanced eosinophil responses 1 week after each challenge. MBZ-treated gerbils suppressed microfilaremia almost completely after the challenge infections.