OCCURRENCE OF NEMATODES IN TERRESTRIAL GASTROPODS FROM FUNDÃO ISLAND, RIO DE JANEIRO, BRAZIL

Terrestrial gastropods play an important role as intermediate hosts of nematodes of veterinary and medical relevance, particularly in urban environments where human–animal interactions are frequent. This study reports the occurrence of nematode infections in terrestrial gastropods collected from selected sites on the campus of the Federal University of Rio de Janeiro (UFRJ), Ilha do Fundão. Gastropods were collected at nine predefined sites and examined through taxonomic identification and parasitological analysis using artificial tissue digestion. Larvae morphologically compatible with Metastrongyloidea were isolated and molecularly identified by sequencing a fragment of the mitochondrial cytochrome c oxidase subunit I (COI) gene. Three gastropod species were selected: Achatina fulica (Bowdich, 1822), Bradybaena similaris (Férussac, 1821), and Sarasinula linguaeformis (Semper, 1885). A. fulica was the most abundant species and showed the highest infection rate. Three nematode groups were identified—Metastrongylidae, Rhabditidae, and Kathlaniidae—with coinfections detected, including Angiostrongylus cantonensis and Cruzia tentaculata. Infection patterns varied spatially and seasonally, with higher prevalence during fall and summer. These findings document the occurrence of infected gastropods in areas with intense human circulation at UFRJ.