Relata-se a introdução em nosso meio de Thiara (Melanoides) tuberculata possivelmente anterior a 1967, quando pela primeira vez foi coletada em Santos. Essa espécie pode comportar-se como primeiro hospedeiro intermediário de Paragonimus westermani e de Clonorchis sinensis. Somente o último trematódeo tem alguma possibilidade de vir a parasitar o homem, em nosso meio.

Resumo Exemplares de Achatina fulica foram experimentalmente infectados com larvas de Angiostrongylus costaricensis, agente etiológico da angiostrongiliase abdominal, mostrando-se susceptíveis ao parasita. Achatina fulica pode representar um risco para a urbanização da angiostrongilíase abdominal devido a sua alta prolificidade contínua dispersão e notável adaptação a ambientes urbanos. Palavras-chaves: Achatina fulica. Angiostrongylus costaricensis. Infecção experimental. Angiostrongilíase abdominal.Abstract Samples of Achatina fulica were experimentally infected with Angiostrongylus costaricensis larvae, etiological agent of abdominal angiostrongyliasis, showing that A. fulica is susceptible to the parasite. Achatina fulica may be a risk to urbanization of abdominal angiostrongyliasis presumably due to its high proliferation, continuous dispersion and remarkable adaptation in several Brazilian towns.

RESUMO Os conhecimentos sobre a distribuição geográfica das espécies dos caramujos transmissores de 'Orbigny, 1835), 3,402 lots (91.7%) -88,068 (81.4%) specimens and Biomphalaria straminea (Dunker, 1848), 85 lots (2.3%) -12,174 (11.2%)

Studies performed in the last 30 years demonstrated that a strain of B. tenagophila from the Taim Biological Reserve is completely resistant to Schistosoma mansoni infection. This resistance to parasite infection is a dominant characteristic during crossbreeding with susceptible B. tenagophila strains. These experiments also identified a 350 bp molecular marker that is exclusive to the Taim strain and does not occur in other geographic strains of this snail species. The Taim strain (Taim/RS) of Biomphalaria tenagophila was bred on a large scale, physically marked and introduced into a stream in which previous malacological analyses had revealed the presence of only parasite-susceptible B. tenagophila. Samples of offspring captured 4, 11 and 14 months after the introduction of the Taim strain were examined, and the susceptibility of the snails to S. mansoni infection dropped from 38.6–26.5% to 2.1% during the 14 months after the introduction of the Taim snail strain. A significant correlation was also observed between the absence of infection and the identification of the Taim molecular marker. These results demonstrate that the genetic marker from the Taim strain was successfully introduced into the wild snail population. In addition, a significant relationship exists between the marker and resistance to infection.

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