STUDIES ON A SMALL COLLECTION OF PLANORBID FROM SOUTHERN SOUTH AMERICA

F rederico S. Barbosa and Dalva A. Mello

Snails belonging to were collected from some regions of Southern South America as follows: Resistencia, province of Chaco, Argen­ tina; Assumpcion, Paraguay; Department of Maldonaão of Caneloni, Vruguay; anã Pôrto Alegre, Rio Grande do Sul, Brazil. The material was classified as (Orbigny) twice from Uruguay and o n ce in Brazil; B. tenagophila (Orbigny), from Argentina and Brazil; anã B. straminea (Dwnker) in Paraguay. Negative results were obtaineã from the exposition of the abon e refer- eã specimens to miraciáia of S. mansoni from Pernambuco, Brazil.

During the month of January 1969 the After 40 days the snails were crushed and junior Author travelling in Southern examined for infection. South America, made a limited number The temperature of the water, during of •ccllections of fresh-water snails belong­ the experiments, varied from 24 to 26°C. ing to the Planorbid genus Biomphala­ The following studies and observations ria. were made. Part of the snails was extended with menthol crystals and fixed locally in al- PARAGUAY cohol 70%, while some other specimens were brought alive to the laboratory in Twenty-one snails were collected in Recife where the present studies were drainage ditches in the streets of “Bair­ made. Upon arrival the alive snails were ro Capitalizador”, Assumption. The water put in tanks to breed. in the ditches was dark, highly polluted and the bottom was muddy. Aquatic plants Preserved snails were dissected for were not present. The habitat was not classif ication. Alive snails were each permanent since the water was mainly exposed to ten miracidia of a local strain originated from periodical rains fallen of mansoni. In ali the in- few days before. Snails of the genus Po- fection experiments a highly suseeptible macea (Ampulariidae) were seen thriving strain of , from along with the Biomphalaria. The shell Paulista (Pernambuco), was used as . and the anatomy of the snails collected control. correspond to the Biomphalaria Snails exposed to the infection were straminea (Dunker). That species in kept in tanks and examined for cercariae known from Venezuela, the Guianas and by exposition to a strong source of light Brazil, reaching to about 20°S. It was beginning the 20th day after the infection recently found in Colombia (1) . The

School of Medicine, Universlty of Pernambuco, Recife, Brazil Adress: I.B.T.M., Caixa Postal 1859. Rio, G uanabara. 266 Rev. Soc. Bras. Med. Trop. Vol. III — N.° 5 species is for the first time recorded in ed from Ecuador, Bolivia, Chile, Brazil, Paraguay. Paraguay, Uruguay, and Argentina west The exposition of 17 specimens of the of the Andes from about the Equator to Paraguay strain of B. straminea to mir- 42.° S, and east of the Andes from about acidia of S. mansoni resulted negative: 15.° to 41.°S (8) . none of the snails got the infection. Negative results were obtained from the exposition of 17 snail specimens of B. pe­ ARGENTINA regrina from Maldonado and 1 specimen from Caneloni to miracidia of S. mansoni. A collection of snails was made in the town of Resistencia, capital of the prov- BRAZIL ince of Chaco, northern Argentina. Snails were collected in a large swamp at the end One collection was made in the Southern of Street Brazil in the outskirts of the Brazilian state of Rio Grande do Sul. town. The habitat seemed to be perman- The place collected was near the airport ent: the water showed high turbidity and of Porto Alegre where two species of several aquatic plants were present. Biomphalaria were found. The habitat is Other snails found were specimens of an extensive permanent swamp located at Drepanotrema sp. () and of the edgde of the highway leading to the sp (). The spec­ airport. The water showed some turbidity, imens of Biomphalaria collected were clas- the bottcm was muddy and many aquatic sified as B. tenagophila (Orbigny). This plants were present. Snails of the families species was already known from Argentina, Physidae and Ampullariidae were found. Paraguay, Uruguay, Brazil (about 15.° Numerous empty shells of Biomphalaria southward), Bolivia and Peru (7). tenagophila (Orbigny) plus 3 alive specim­ The exposition of 18 specimens of the ens of B. peregrina were collected. Of Argentina strain of B. tenagophila to those only one specimen was alive when miracidia of S . mansoni gave negative arrived in Recife. This specimen was ex- results. posed to miracidia of S. mansoni and was found dead few days latter. Obviously the classification of both species was made URUGUAY by shell features. Two collections were made in this coun- try: one in the town of San Carlos (De­ COMMENTS partamento de Maldonado) and other about 20 km northern of Montevideo (De­ Two species represented in the small partamento de Caneloni). The specimens collection of planorbid snails studied in of Maldonado were collected in a small the present paper are well known as vec- ditch in a Street near the center of the tors of mansoni: B. stra­ small town of San Carlos. The snails minea chiefly in northeastern Brazil and were living in a small temporary pooJ B. tenagophila in the southem part of without aquatic plants and with no other this country. B. peregrina can be con- snails. The bottom was clayey. The snails sidered as a potential vector of Schis­ from Caneloni were found in a permanent tosomiasis according to laboratory infec­ stream known as Toledo Chico. The water tion data given by Barbosa, Barbosa & was clear, the bottom muddy and many Rodriguez (5) for specimens from Ecuador, aquatic plants were present. One specimen by Richards (9) for specimens from Puer- of Lymnea sp. was found among the to Rico, and by Paraense & Correa (7) for planorbids. Snails from both places in specimens from Paraná, Brazil. Uruguay were classified as Biomphalaria peregrina (Orbigny): 22 specimens were Other potential intermediate hosts of collected in Maldonado and 56 specimens S. mansoni are known to occur in regions in Caneloni. The species has large geo- where the human infection has never gaphical distribution. It has been record­ become established (3, 4, 6). Set.-Out., 1969 Rev. Soc. Bras. Med. Trop. 267

Results presented in the current paper Brazil, behave differently in northern do not exclude the possibility that the snail South America when submitted to labor- strains used for the infection experiments atory infections. Barbosa (2) recently could serve as potential intermediate hosts showed that B. straminea from Manaus, for schistosomiasis. Brazil, was fully resistant to the infection with S . mansoni from Pernambuco and The capability of a snail to act as a that the strain of the same snail species suitable host depends on both snail and from Cali, Colombia, (1) could be hardly parasite. B. straminea, the well known infected with S. mansoni from the same vector of schistosomiasis in northeastern origin.

RESUMO

Caramujos do gênero Biomphalaria (Planorbidae) foram coletados ao sul da América do Sul, nos seguintes locais: Resistência, 'província do Chaco, Argentina; Assunção, capital do Paraguai; províncias de Maldonado e de Ca­ neloni, Uruguai; e Pôrto Alegre, capital do estado do Rio Grande do Sul, Brasil. O material foi classificado como se segue: Biomphalaria peregrina (Or­ bigny)i, duas coletas no Uruguai e uma no Brasil; Bi. tenagophila (Orbigny), na Argentina e no Brasil; e B. straminea (Dunker), no Paraguai. i Resultaram negativas tôãas as tentativas feitas em laboratório para in­ fectar as espécies acima mencionadas com a cêpa de de Pernambuco.

RESUMO

1. BARBOSA, F.S. — Biomphalaria termediate host of Schistosoma man­ straminea (Dunker) en Colombia. soni in Ecuador. Jour. Parasitol., Antioquia Medica, 18: 753-758, 1968. 44: 622, 1958. 2. BARBOSA, F.S. — A note on Biom­ 6. CRAM, E. B., JONES, M. F. & phalaria straminea (Dunker, 1848) WRIGHT, W. H. — A potencial inter­ from Manaus, state of Amazonas, mediate host of Schistosoma manso­ Brazil. Rev. Soc. Bras. Med. Trop., ni. Science: 101: 302, 1945. 2: 77-78, 1968. 7. P.A.H.O. — A Guide for the Iden­ 3. BARBOSA, F.S. & BARBOSA, I. — tification of the Snail Hosts of Schis­ Tropicorbis chilensis from Santiago, tosomiasis in the Américas. Scientific Chile, a potential intermediate host Publication N.° 168. Washington. of Schistosoma mansoni. Boi. Chile­ no Parasitol., 13: 7-9, 1968. D.C., U.S. ., 1968. 4. BARBOSA, F. S., BARBOSA, I. & 8. PARAENSE, W.L. — The synonymy CARNEIRO, E. — Description of Aus- and distribution of Biomphalaria pe­ tralorbis sericeus (Dunker), a pos- regrina in the Neotropical region. sible intermediate host of Schistoso- Rev. Brasil. Biol., 26: 269-296, 1966. ma mansoni in Ecuador. Ann. Trop. Med. Parasitol., 57: 52-58, 1963. 9. RICHARDS, C.S. Infectivity of Schistosoma mansoni for Puerto 5. BARBOSA, F. S. BARBOSA, I. & Rican mollusks, including a new RODRIGUEZ, J. D. — Tropicorbis potential intermediate host. Am. J. philippianus (Dunker) a potential in­ Trop. Med. Hyg., 12: 26-33, 1963.