The malacological studies by Adolpho Lutz were preceded by research on schistosomiasis since 1916, nine years after Sambon proposed the name Schistosomum mansoni for the agent of the intestinal form of the parasite, and eight years after its identification, in Brazil, by Pirajá da Silva. It is worth noting that Lutz studied the subject during the First World War, when he knew little about the research done by Leiper in Egypt and published between 1915 and 1918. Lutz only read Leiper's articles when his own research was well advanced and he had already reproduced the whole life cycle of the parasite. Lutz and Oswino Pena conducted observations in endemic regions in Northeast Brazil and studied almost every species of Brazilian planorbids. The malacological section of Lutz’ scientific production was the subject given to me in this edition of his Obra Completa.
Malacology, according to Lutz, is condensed in the article “Caramujos de água doce do gênero Planorbis, observados no Brazil” (“Fresh water snails, gender Planorbis observed in Brazil”), published in 1918 in Memórias do Instituto Oswaldo Cruz. Fourteen nominal species from seven States, from Pará to Rio de Janeiro, are described and discussed. Besides these species, the article contains a list of the planorbids found in other South-American countries (Argentina, Bolívia, Equador, Peru, Uruguay, and Venezuela) and mentioned in current literature, and an appendix with the original descriptions of 14 nominal species copied from Orbigny (9), Lesson (1), Moricand (1), Dunker (2), and Martens (1).
Lutz’ monograph is here carefully illustrated, with drawings by Castro Silva and Rudolf Fischer, showing the front and both sides of shells in diametric cut, and the surface of the soft parts seen through the shell. The presentation of diametric cuts is an innovation that shows the contours of the shell's spirals and their arrangement. Unfortunately, he did not adopt anatomic investigation especially for the reproductive system, as already done by some important authors of the time. Nonetheless, the detailed description of shells and the figures allow for the recognition of almost all of the species he mentioned, particularly of two of the three transmitters of Schistosoma mansoni: Biomphalaria glabrata and B. tenagophila.
Six of the 14 nominal species in this work were described by Lutz and are nowadays considered as synonyms: Planorbis centimetralis = Biomphalaria straminea; Planorbis confusus, after (Lutz 1923) emended to Planorbis immunis = Biomphalaria tenagophila; Planorbis nigrilabris and Planorbis incertus = Biomphalaria schrammi; Planorbis melleus and Planorbis nigellus = Drepanotrema anatinum.
As a guest of the Venezuelan government, Lutz studied important aspects of zoology and parasitology in that country, with emphasis on molluscs and trematodes (Lutz, 1928). Except for the Biomphalaria prona, which does not transmit the Schistosoma, he found other species of molluscs that also occurred in Brazil.
Besides his malacological research, Adolpho Lutz studied the relationships between molluscs and trematodes, describing more than 20 species of cercaria (e.g. Lutz, 1933).
Well-acquainted with Brazilian malacological fauna as he was, he confirmed Leiper's results from Egypt with planorbids in Brazil. Lutz studied the egg and the miracidia with detail, and observed their penetration in several fresh water molluscs and development through sporocyst stages until the formation of cercaria with bifurcated tails. He also recognized Planorbis olivaceus and P. guadaloupensis (both being synonyms for Biomphalaria glabrata), and P. centimetralis (synonym of Biomphalaria straminea) as intermediary hosts, signalling the main lesions produced by their parasites. Lutz described the cercaria he identified as Cercaria blanchardi discovered by Pirajá da Silva (1912), by observing the conditions they were released from the mollusc body and their penetration in laboratory animals. He confirmed the characterization of adult warms made by Pirajá da Silva and Leiper. Finally, he occupied himself with human and experimental infection in the symptomathological, pathogenic, anatomopathological, therapeutic, and prophylactic aspects.
As a curiosity, I would like to refer to the technique recommended by Lutz for the research on eggs of Schistosoma in feces. In his 1919 work on the Schistosoma mansoni, the following is in parenthesis:
"(The exam becomes easier after the repetitive washing of the feces, followed by simple sedimentation or centrifugation. To these we combine the use of wire tissue and miller's gauze to retain all of the coarser bodies. This way we obtain a sediment containing almost exclusively amylaceous corpuscles and parasite eggs that are easy to examine)."
This process is usually mentioned in the literature as the Hoffman, Pons and Janer method.
W. Lobato Paraense
Head of Malacology Laboratory
Instituto Oswaldo Cruz / Fundação Oswaldo Cruz
Lutz, A. Caramujos de água doce do gênero Planorbis, observados no Brazil. Mem. Inst. Oswaldo Cruz, v.10, p.65-82, 1918.
Lutz, A. O Schistosomum mansonie a schistosomatose segundo observações feitas no Brasil. Mem. Inst. Oswaldo Cruz, v.11, p.121-55, 1919.
Lutz, A. Planorbis immunis n.n. Nautilus, v.37, p.36, 1923.
Lutz. A. Moluscos de agua Dulce recogidos y observados en Venezuela. In. In: Estúdios de zoologia y parasitologia venezolanas. Rio de Janeiro, 1928, p.75-89
Lutz, A. Notas sobre Dicranocercarias brasileiras. Mem. Inst. Oswaldo Cruz, v.27, p.349-76, 1933.
Pirajá da Silva, M. A. Cercaire brésilienne (Cercaria blanchardi) à queue bifurquée. Archives de Parasitologie v. 15, p.398-400, 1912.