Helminth diversity and seasonality of Angiostrongylus cantonensis in hedgehogs from Mallorca

Sentinel surveillance plays a critical role in monitoring pathogen circulation, assessing potential threats for species conservation, and evaluating the risk of spillover to human populations. This study provides a comprehensive exploration of helminth parasites in the Mediterranean-distributed hedgehog species Atelerix algirus in Mallorca, Balearic Islands. Using an integrated approach that combines necropsies and morphological and molecular identifications using the COI gene, we identified 11 helminth taxa in 135 hedgehogs, representing half of those that died at the local wildlife hospital in Mallorca between 2019 and 2022. We report an overall A. cantonensis prevalence of 11.5% and confirm the first case of a subclinical neuroangiostrongyliasis infection in a wildlife host. Infection prevalences over the year revealed that only two species, the nematode A. cantonensis and the cestode Mathevotaenia sp., had a seasonal pattern, with most A. cantonensis cases occurring in autumn and, to a lesser extent, Mathevotaenia sp. cases in winter. This pattern is probably due to the higher abundance and greater activity of snails and slugs (intermediate hosts) during these seasons, with important implications for public health and strategies for prevention of neuroangiostrongyliasis. Other key findings include a high prevalence (88.1%) of the lungworm Crenosoma striatum and detection of the acanthocephalan Moniliformis saudi for the first time in A. algirus. We anticipate that our study will facilitate surveillance efforts and clarify species identities in future studies. Given the lethal effects of A. cantonensis infection in hedgehogs, further studies are needed to evaluate the threat this parasite represents to European wildlife.