Observations on the possible development of resistance to reinfection in Oriental schistosomiasis among experimental animals

ABSTRACT

Observation made on the egg output of some experimental monkeys and pigs infected with Schistosoma japonicum cercariae show that after a certain period of time from the date of non-overwhelming initial infection, sufficient resistance may be induced against S. japonicum reinfections. This was noted after 31 months in monkeys and a relatively shorter period of time in pigs after their initial infections. It could, therefore, be surmised that in order to resist to a sufficient degree a big dose of cercarial infections, a longer time interval between initial and challenge infection is necessary. Inasmuch as the data presented are limited, it is felt that further investigations along this line should be carried out. (Authors)