[Distribution of Biomphalaria tenagophila and B. occidentalis in the State of São Paulo (Brazil)]. / Distribuição de Biomphalaria tenagophila e B. occidentalis no Estado de São Paulo (Brasil).

The geographical distribution of Biomphalaria tenagophila (d'Orbigny, 1835) and B. occidentalis Paraense, 1981 in S. Paulo State, Brazil, is described. The first species being the most important intermediate host of Schistosoma mansoni Sambon, 1907. The second species is unsusceptible to transmission. The two species inhabit the limnic environments of great areas of S. Paulo, occasionally in simpatria. The 3,160 samples of mollusks collected between September 1981 and March 1986 were examined. B. tenagophila were identified in 1,062 of these samples from 203 municipalities and B. occidentalis in 255 samples from 97 municipalities. Biogeographical circumstances related to the distribution of the planorbids species are commented on.

[Distribution of Biomphalaria straminae in the southern neotropical region of Brazil]. / Distribuição de Biomphalaria straminea ao sul da região neotropical, Brasil.

A careful anatomical revision of 10,616 preserved specimens of snails from 76 localities of the State of S. Paulo, Brazil, was made with a view better to determining the geographical distribution of Biomphalaria straminea in the Neotropical Region of Southern Brazil. The analysis has shown that previous determinations were correct. The study was then complemented with a survey of information from the literature about distribution of the species. The distribution pattern of the species has expanded greatly over the last few years, perhaps an account of the construction of new dams, and the navigation system in the upper Paraná Basin. Epidemiological data have shown that B. straminea is a good host to S. mansoni. Continuous schistosomiasis control must be exercised so as to prevent the further expansion of the disease.

[Estivation of Biomphalaria tenagophila (Pulmonata, Planorbidae)]. / Estivação de Biomphalaria tenagophila (Pulmonata, Planorbidae).

This study reports the finding of Biomphalaria tenagophila naturally aestived in two municipalities of the State of S. Paulo (Brazil): Ubatuba and Conchas. This ethological characteristic was discovered in 15 specimens collected in Ubatuba, and in 6 specimens collected in Conchas. The snails aestived showed vitality after being placed in water.

[Lymnic molluscs from an Alto Araguaia area (Brazil)]. / Moluscos límnicos de uma área do Alto Araguaia (Brasil).

An analysis was carried out to determine the natural population of freshwater molluscs from 5 municipalities within the area of influence of the Couto Magalhães hydroelectric project. These municipalities cover a large area of the State of Goiás and Mato Grosso do Sul (Brazil). In this study 624 molluscs of the following species were examined: Drepanotrema anatinum, D. lucidum, D. depressissimum, Biomphalaria straminea, D. schrammi, Physa marmorata, Lymnaea columella, Pomacea and Eupera. One to their importance in public health, the discovery of Biomphalaria straminea and Lymnaea columella, intermediate hosts, respectively, of Shistosoma mansoni and Fasciola hepatica, deserves special mention.

[The distribution of Biomphalaria (Gastropoda, Planorbidae) in the states of Rio Grande do Sul and Santa Catarina, Brazil]. / Distribuição de Biomphalaria (Gastropoda, Planorbidae) nos Estados do Rio Grande do Sul e Santa Catarina, Brasil.

An analysis to determine new localities colonized by the intermediate snail hosts (B. straminea, B. tenagophila and B. tenagophila tenagophila) of Schistosoma mansoni from Rio Grande do Sul and Santa Catarina States (Brazil) was carried out. As regards the geographical distribution of the schistosomiasis vector, the possible extension of the endemic disease to Southernmost Brazil is commented on.

[Occurrence of Achatina fulica Bowdich, 1822 (Mollusca, Gastropoda) in Brazil: intermediate snail host of angiostrongyliasis]. / Registro de Achatina fulica Bowdich, 1822 (Mollusca, Gastropoda) no Brasil: caramujo hospedeiro intermediário da angiostrongilíase.

Achatina fulica, the intermediate snail host of angiostrongyliasis and also an agricultural pest, is being bred in Brazil for human consumption as "escargot". The snail has escaped from its artificial breeding sites and its dispersal in Itariri country, State of S. Paulo, is reported here for the first time. A. fulica is a transmitter of the rat lungworm Angiostrongylus cantonensis, nematode which causes meningoencephalic angiostrongyliasis; the risks of human contamination are commented on.

Biomphalaria tenagophila/Schistosoma mansoni interaction: premises for a new approach to biological control of schistosomiasis.

Biomphalaria tenagophila is very important for schistosomiasis transmission in Brazil. However its mechanisms of interaction with Schistosoma mansoni are still scantly studied. Since this snail displays strains highly susceptible or completely resistant to the parasite infection, the knowledge of that would be a useful tool to understand the mechanism of snail resistance. Particularly, the Taim strain consistently shows absolute resistance against the trematode, and this resistance is a dominant character. A multidisciplinary research group was created aiming at studying B. tenagophila/S. mansoni interaction. The possibility for applying the knowledge acquired to obtain a biological model for the control of S. mansoni transmission in endemic areas is discussed.

Biomphalaria tenagophila/Schistosoma mansoni interaction: premises for a new approach to biological control of schistosomiasis

Biomphalaria tenagophila is very important for schistosomiasis transmission in Brazil. However its mechanisms of interaction with Schistosoma mansoni are still scantly studied. Since this snail displays strains highly susceptible or completely resistant to the parasite infection, the knowledge of that would be a useful tool to understand the mechanism of snail resistance. Particularly, the Taim strain consistently shows absolute resistance against the trematode, and this resistance is a dominant character. A multidisciplinary research group was created aiming at studying B. tenagophila/S. mansoni interaction. The possibility for applying the knowledge acquired to obtain a biological model for the control of S. mansoni transmission in endemic areas is discussed.