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

TL;DR

This study found that the rat lungworm parasite is present in invasive snails across French territories in the Americas, with different snail species playing key roles in different regions.

Contribution

The study identifies Lissachatina immaculata as a new potential intermediate host for Angiostrongylus cantonensis in French Guiana.

Findings

Lissachatina fulica was the main carrier of A. cantonensis in Guadeloupe and Martinique.

Lissachatina immaculata was confirmed as a potential intermediate host in French Guiana for the first time.

Infection rates in snails were high, but human cases remain rare due to limited human-snail interaction.

Abstract

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.

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.

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.

We studied the presence of the parasite Angiostrongylus cantonensis, also known as the rat lungworm, which can cause eosinophilic meningitis in humans. This parasite usually lives in rats, but humans can become accidental hosts if they eat raw or undercooked snails or other small infected animals. First reported in the French West Indies in 2002, cases of A. cantonensis infections are emerging due to the spread of its intermediate hosts, particularly the invasive African giant snail (Lissachatina fulica), but very little was known about how widespread it might be in this region. To answer this question, we collected snails in Guadeloupe, Martinique, and French Guiana and tested them for the parasite. We found that L. fulica was the main carrier in Guadeloupe and Martinique, while another species, Lissachatina immaculata, played an important role in French Guiana. Infection rates in snails were high, but human cases remain rare, likely because people in these regions do not often eat raw snails. Our work shows that different snail species contribute to the spread of the parasite in different geographical regions, and that further studies into the dynamics of transmission are therefore important for protecting human health.

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