A NOTE ON BIOMPHALARIA STRAMINEA (DUNKER, 1848) FROM MANAUS, STATE OF AMAZONAS, BRAZIL

Frederico S. Barbosa

Biemphalaria straminea (— centime- for several days and none of them shed tralis), an important intermediate host of cercariae of the mansoni type. Schistosomiasis in Brazil, has large geo- Six snails were preserved and the animais graphical distribution. It is known from dissected. The morphology of the animais Venezuela, Guianas and Brazil, reaching dissected, particularly genitals, kidney and south to about 20° latitude. radula, was the same as compared with In Northeastern Brazil B. straminea is a typical specimens of B. straminea from most important vector of the disease. It is several places in Brazil. the only vector known it the State of Cea­ rá as well as in most of the territories of Crossing experiments were performed the State of Pernambuco, Paraíba and Rio between pigmented snails from Manaus Orande do Norte. and an albino strain of B. straminea from B. straminea is also known from North­ Quixeramobim (State of Ceará, North­ ern Brazil. It occurs in several areas of the eastern Brazil) according to techniques carboniferous formation of the Amazon previously described (Barbosa et al., 1). basin (Sioli, 4). This species was in- Two couples were used. Each couple (Ma­ criminated as the vector of Schistoso­ naus x Quixeramobim) was put to mate in miasis in a limited focus localized in Bel- a small glass Container for 30 days. After terra, Fordlandia, State of Pará. that period the albino snails were tsolatsd The material used in the current paper from its partners and followed during was received from Dr. Mario Morais of the another 30 days. Results of those expe­ "Instituto Nacional de Pesquisas àa Amazô­ riments show that the two snails are nia” in September 1965. It consisted of 56 conspecific. In both experiments pigment­ snails from which 42 were alive. Collected ed snails were produced exclusively. Couple outside the town of Manaus, State of Ama­ 1 produced 69 pigmented F1 snails while zonas, Brazil, the snails, were found in lake couple 2 produced 94 snails of the same Rei in center of Careiro and in a small type. No albino snails were obtained dur­ “igarapé” afluent of the “igarapé” Ca- ing the 30 days of observation. Hybrids choeirinha. obtained were fertile and produced pros- The snails, kept in tanks, were used perous colonies. for observations on morphology, Crossing Snails from Manaus were exposed to experiments and exposition to the infect- miracidia of a Northeastern strain of S. ion with a Northeastern strain of Schisto- mansoni. Each snail was exposed to 5 soma mansoni. miracidia, and examined daily for cerca­ Prior to the experiments ali the snails riae after the 20 th day of the infection were exposed to sun light during few hours Negative results were obtained of the

Centro de Pesquinas Aggeu Magalhães, Instituto Nacional de Endemias Rurais, Recife, Brasil. 78 Rev. Soc. Bras. MeBiomphalaria glabrata, was used as where the surface water is almost neutral control in the above experiment. He concluded that there is little danger of Other snail specimen from Manaus was the introduction of Schistosomiasis in the exposed to h gh unrecorded oumber of rest of the great area of the Amazon basin miracidia of S. mansoni. The snail was where waters are acid and the snails were fixed in Boun’s fluid after 24 hours of the not found. exposition and the anterior part of tne Negative attemps to infect the specimens animal sectioned and stained w.th haema- of B. straminea from Manaus do not toxilin-eosin. Tissue reactions were observ- exclude the poss;bility of those snails to ed around ali the penetrating miracidia become adapted to other strain cf S. man­ denotating the well known process of soni. Evidence of local adaptation of a destruction of the parasite in resistant snail of S. mansoni was recently producetí snails (Barbosa et al., 1). by Paraense & Correa (2) in Southern The possibíl.ty of introduction of Schis- Brazil.

BIBLIOGRAPHY 1 — BARBOSA, F.S. et al. Manual de Ma- 3 — SIOLI, H. Schistosomiasis and Lim* lacologia Médica — Fundação Gon- nology in the Amazon Region. Am. çalo Moniz, Salvador, Bahia, 1960. J. Trop. Med. and Hyg., 2 : 700-707, 1953. 4 — SIOLI, H. Limnologische Untersu- 2 — PARAENSE, W.L. & CC-RREA, L.R. chungen und Betrachtungen zur Susceptibility of Australorb s tenago- erstmaligen Entdeckung endemischer philus to infection with Sch.stosoma Schistosomiasis (Sch. mansoni) in mansoni. Rev. Inst. Med. Trop. São Amazonasgeb;et. Arch. F. Hydrobiol., Paulo, 5: 23-29, 1963. 48: 1-23, 1953.