Comparison among the bio-control effects on larval Schistosoma japonicum in Oncomelania hupensis with pre-infection by larval Exorchis trematodes at different intervals.

Larval Schistosoma japonicum could be blocked in infected Oncomelania hupensis snails which were pre-infected with 21 days interval by larval Exorchis trematodes.The present manuscript reports the result of comparison between the bio-control effects on larval S.japonicum in O.hupensis snails which were dually infected with larval Exorchis and S.japonicum with different intervals.The infection rates and larvae invader rates of S.japonicum at different interval O.hupensis snails as follows:At 21 days interval,75%(39/52)and 25.5%(398/1 560);at 37d,77.8%(21/27)and 35.6%(299/840);at 55d,44.4%(8/18)and 11.9%(19/160);at 70d,100%(15/15)and 10.6%(143/1 350);at 85d,43.3%(13/30)and 5.8%(66/1 140).The attack degrees on larval S.japonicum in experimental O.hupensis snails dually infected with longer intervals were stronger than that of shorter intervals.