Preliminary observation of the susceptibility of some freshwater snails to the infection with Varestrongylus sagittatus (Nematoda: Protostrongylidae).

Under laboratory conditions, the freshwater snails Galba truncatula Müll.), Radix peregra (Müll.) and Planorbarius corneus (L.) have been successfully infected with the first stage larvae of the protostrongylid nematode Varestrongylus sagittatus (Mueller, 1890) Dougherty, 1945. The net rate of the infection (mean number of larvae per snail examined - l/s) was 6.2 l/s in R. peregra and 3.5 l/s in P. corneus. G. truncatula was susceptible to the infection too (36.3 l/s). However, this result can be considered as pilot only, because of the low number of the specimens of this species examined. At 25 degrees C 50% of V. sagittatus larvae reached the 3-rd stage of development by 12.5 days post infection (DPI) in R. peregra and by 17.8 DPI in P. corneus. It was confirmed that the snail species of the Basommatophora that were studied can act as intermediate hosts of the nematode V. sagittatus under laboratory conditions.