Ecological niche and distribution patterns of snails that host Fasciola hepatica across South America: Unveiling the hidden landscapes

Abstract

In South America, Pseudosuccinea columella, Galba cubensis, Galba schirazensis, and Galba truncatula snails serve asvectors of Fasciola hepatica, posing significant challenges to public and animal health. This study identifiedenvironmentally suitable areas for these species using ecological niche models, including Maxent, RandomForest, and Support Vector Machine (SVM) models. Occurrence points (n =797) were compiled from the internationalliterature, following the PRISMA protocol, and the malacological collection of the FIOCRUZ Institutein Rio de Janeiro, Brazil. P. columella (51 %) and G. truncatula (18 %) had the highest records. The distribution ofPseudosuccinea columella and G. cubensis was influenced by precipitation, exhibiting a broad potential acrossSouth America. In contrast, the distribution of G. schirazensis and G. truncatula was influenced by temperatureand was limited to high-altitude areas. An ecological niche overlap was observed between P. columella andG. cubensis and G. schirazensis and G. truncatula. Moreover, suitable areas for these species were identified inArgentina, Peru, Bolivia, and Brazil. In Brazil, P. columella has demonstrated significant environmental suitabilityin the Cerrado and Amazon Forest biomes, which have been impacted by land-use changes, including pastureexpansion and deforestation resulting from unsupervised cattle production. Therefore, predicting the contaminationof new areas is critical to mitigate future liver fluke infections in suitable hosts (natives and rural communities,capybaras, etc.) from regions affected by large livestock movements on the continent. As we faceclimate change threats to vector-borne diseases, these modeling data highlight the need for significant preventivestrategies aimed at the welfare and social impact of all South American countries.