Initially, I wish to express my sincere appreciation for the opportunity to give this talk, for two reasons. First of all, because talking to you in this wonderful baroque church is a privilege. This was possible for me only due to the Ecumenical Council II, which was held on the 1960s, therefore only a few decades ago, convoked by the eminent Pope Johannes XXIII of memorable remembrance. Secondly, because it is with great pleasure that I speak after another important "Pope": Dr. Lobato Paraense, who is admired by all of us, worthy of respect, applauded, and copied. His solid scientific formation and the accuracy he considers the scientific subjects, can explain why his works have so much contributed for Malacology to which he is really the Pope.Therefore, I would like to thank Dr Omar dos Santos Carvalho, President of this Symposium, for this unique opportunity, which could be only offered to me by a friend and colleague of so many years. To Dr Omar must be credited a great part of the success attained by the Schistosomiasis Programme at Fiocruz.