Terrestrial Edible Land Snails as Vectors for Geographic Dissemination ofBrachylaimaSpecies

Abstract

Cornu aspersum (= syn. Helix aspersa ) snails imported into NE Spain from Algeria and South Africa, and intended for human consumption via sale in public markets, were analyzed to assess their contribution to geographic dissemination of Brachylaima species. Prevalence and viability studies of metacercariae were performed on Algerian and South African Brachylaima adults. Morphometric studies were performed by measuring 16 variables in metacercariae and 18 variables in adults. Principal component analyses (PCA) were performed to assess the contribution of each variable in the separation of the different groups. A MANOVA test performed on morphometric data from Brachylaima llobregatensis and Brachylaima mascomai Algerian and South African adults, revealed a significant multivariate main effect (P < 0.001) and univariate effects in 13 variables (P ≤ 0.001). Pairwise comparisons revealed significant differences in 13 variables between B. mascomai and Algerian adults, as opposed to 3 variables (testis I width, testis II width, and egg width) when compared with B. llobregatensis. South African adults had significant differences in 5 variables (body length, oral sucker length, oral sucker width, egg length, and egg width) when compared with B. llobregatensis, as opposed to 1 variable (testis II width) when compared with B. mascomai. Results from PCA showed 2 different groups: B. llobregatensis/Algerian adults (overlapped) and B. mascomai/South African adults (overlapped). Imported edible C. aspersum specimens can contribute significantly to the geographic spread of Brachylaima species by harboring infective metacercariae which could easily infect animals, given their heteroxenous character. Brachylaima llobregatensis has previously been detected in NE Spain only, and now this species appears to be parasitizing C. aspersum in Algeria (North Africa). This geographic dispersion could be favored by commerce in terrestrial snails such as C. aspersum.