Occurrence of Angiostrongylus cantonensis in invasive snails in the French territories of America, French Guiana, Guadeloupe, and Martinique

BACKGROUND: Angiostrongylus cantonensis is the primary etiological agent of eosinophilic meningitis, transmitted through rats (definitive hosts) and molluscs (potential intermediate hosts). Human infection occurs accidentally through the ingestion of contaminated hosts. First reported in the French West Indies in 2002, cases of A. cantonensis infections are emerging due to the spread of its hosts, particularly the invasive African giant snail (Lissachatina fulica). This study aims to assess the prevalence of A. cantonensis in gastropods across Guadeloupe, Martinique, and French Guiana, providing insights into its transmission dynamics. METHODOLOGY/PRINCIPAL FINDINGS: Terrestrial gastropods were collected in 2017 from residential areas with prior human cases and other selected sites with no reported case. The gastropods" species were identified by a malacologist and processed for DNA extraction. Molecular diagnosis of A. cantonensis was performed using quantitative PCR. Prevalence rates were analyzed by Chi-square and Kruskal-Wallis tests, while correlations between weight and level of A. cantonensis DNA detected were assessed via Spearman's rank correlation. A total of 430 gastropods, representing nine species, were collected: 103 from Guadeloupe, 161 from Martinique, and 166 from French Guiana. The highest prevalence of A. cantonensis was observed in Guadeloupe (38.8%), followed by Martinique (27.6%) and French Guiana (15.7%). Sampling in Martinique included a wider diversity of gastropod species, whereas collections in French Guiana and Guadeloupe were limited to Lissachatina spp. In Martinique, eight species were identified, five of which were infected. The prevalence was positively correlated with weight in the primary intermediate host, L. fulica. Interestingly, Lissachatina immaculata in French Guiana was confirmed as a potential intermediate host for the first time. CONCLUSIONS/SIGNIFICANCE: The study highlights L. fulica as the predominant host in Guadeloupe and Martinique, while L. immaculata plays a significant role in French Guiana. Gastropod diversity and prevalence varied across territories, influenced by collection methods and ecological factors. Despite high infection rates in gastropods, human cases remain relatively rare, likely due to limited human-gastropod interaction and local culinary practices. These findings underscore the need for further investigation into transmission dynamics and phylogenetic studies to inform public health strategies.