The production demand of edible snails in the Mediterranean area is very high and the attention to snail borne diseases is increasing. Following mass mortality events, we have analyzed 240 samples of Cornu aspersum collected from farms across Italy. Anatomopathological examination showed the presence of alterations of the gastro-intestinal apparatus and of the digestive gland, while histopathological examination revealed the presence of Rickettsia-like organisms (RLOs) in 70% (168/240) of cases and Giemsa positive amoebae in the remaining 30% (72/240) of cases. RLOs were localized mainly at the level of the DG, where regressive changes or nodular inflammation was observed. TEM examination of RLOs samples revealed the presence of many rod-shaped electron dense microorganisms. Amoebal infection occurred in the kidney, intestine, lung, the DG and were associated to regressive events or infiltrative/nodular and encapsulation like inflammation. To date it is still unclear if the pathogens detected could represent a risk for humans and animals, therefore further studies are needed to better elucidate this point.

This study investigated the influence of stress on release of Angiostrongylus cantonensis larvae from a snail host, Parmarion martensi. We subjected 140 infected, wild-caught P. martensi to three stress-inducing treatments (heat, molluscicide, physical disturbance) and an unstressed control treatment for 24 h, after which larval presence and abundance in the slime were quantified by qPCR targeting the ITS1 region of the parasite\'s DNA, and compared among treatments. The significance of stress and host infection load on larval release was determined by generalized linear mixed models and permutation tests. The results indicated that stress significantly increased the probability of larval presence in slime and the number of larvae released, and highly infected snails were also more likely to release larvae. Among stressed snails, 13.3% released larvae into slime, the number of larvae present in the slime ranging from 45.5 to 4216. Unstressed controls released no larvae. This study offers a partial explanation for conflicting results from prior studies regarding A. cantonensis presence in snail slime and sheds light on the broader One Health implications. Stress-induced larval release highlights the potential role of slime as a medium for pathogen transmission to accidental, paratenic, definitive and other intermediate hosts. These findings emphasize the importance of considering stress-mediated interactions in host-parasite systems and their implications for zoonotic disease emergence. As stressors continue to escalate because of anthropogenic activities and climate change, understanding the role of stress in pathogen shedding and transmission becomes increasingly important for safeguarding human and wildlife health within the One Health framework.