Suspected stonefish (Synanceia verrucosa) envenomation on Reunion Island

Envenomations induced by stonefish (Synanceia verrucosa) stings are among the most painful envenomations in the marine environment. Reunion Island in the Indian Ocean is not spared from these envenomations. The aim of this series is to characterize suspected cases of stonefish envenomation and to describe the associated clinical management.

This is a retrospective observational series of suspected stonefish envenomations recorded into the database of the Indian Ocean toxicovigilance Department between 1 January 2020 and 2 June 2024 on Reunion Island. Data on clinical characteristics were obtained from the patients' electronic medical records, and additional information was obtained during telephone conversations with the victims if necessary.

Between January 2020 and June 2024, 135 stonefish envenomations were recorded. Most victims were male, with a median age of 31.5 years. January recorded the highest number of cases. The majority of envenomations occurred on beaches, notably l'Ermitage (66 cases) and Saint-Pierre (39 cases), with the foot being the most affected area (94.8%). The pain was intense for most cases (Visual Analogue Scale 8-10), and skin symptoms included localized and extensive oedema, as well as necrotic halos in some instances. General symptoms like hypertension and paresthesia were rare. No fatalities occurred. Treatment involved opioids, paracetamol, and hot water immersion. Our findings demonstrated a statistically significant correlation between the number of stings and the extent of edema (p < 0.00003). However, no significant relationship was found between the number of stings and pain intensity (p = 0.86).

On Reunion Island, approximately 30 suspected stonefish stings occur annually, with a peak in January and frequent locations including l'Ermitage and Saint-Pierre. These envenomations mainly affect the foot and cause intense pain, sometimes accompanied by significant oedema correlated with the number of stings. While no deaths were recorded, emergency care is often necessary. In the absence of official guidelines, locoregional anaesthesia appears to be an effective strategy for pain relief.