Human exposure to larvae of processionary moths in France: study of symptomatic cases registered by the French poison control centres between 2012 and 2019

Abstract

Context

Contact with the setae of larvae (caterpillars) of pine or oak processionary moths could induce urticarial or allergic reactions in humans. These species are present in France and presently expanding towards highly populated areas due to climate change and/or human-mediated translocations. We aimed to describe the symptomatic cases of exposure to processionary larvae in France.

Methods

We conducted a retrospective study of symptomatic cases of exposure to processionary larvae registered by the French poison control centres between 1 January 2012 and 31 July 2019. We reviewed all medical records coded with the agent “larvae”.

Results

Of the 1274 included cases, 59% and 27% corresponded to pine and oak processionary larvae, respectively; the 14% remaining cases concerned unspecified processionary larvae. While the annual number of cases due to pine processionary larvae fluctuated during the study period, cases associated with oak processionary larvae increased steadily. Most of the annual cases occurred between January and May for pine processionary larvae, and April and August for oak processionary larvae (with a peak in March or June, respectively). Among the 1022 cases for which information was available, the sex ratio was 1.2 and the median age was 11 years old. Skin symptoms were reported by 96,3% of the cases, such as pruritus or urticaria. The severity was mild in 96.3% of cases, moderate in 3.5%, and severe in 0.2% (two cases). Ocular or oral exposures led more frequently to severe symptoms than dermal ones (respectively 31% and 18% vs. 2% of cases, p < 10⁻³).

Conclusion

Since processionary moth larvae exposure is a growing health concern, which can cause severe injuries particularly after ocular or oral exposures, the population, and the professionals should be informed of existing recommendations to avoid exposure and measures to be taken after being exposed.

Keywords:

• Processionary caterpillar
• envenomation
• poison control centres
• toxicovigilance

Acknowledgements

The authors would like to thank the French poison control centers research group members: Luc de Haro, MD, PhD (Marseille), Emmanuel Puskarczyk, MD, and Christine Tournoud, MD (Nancy), Wenico Caré, MD, Laurène Dufayet, MD, Hervé Laborde-Castérot, MD, PhD, and Dominique Vodovar, MD, PhD (Paris), Fanny Pelissier, MD, and Nicolas Franchitto, MD (Toulouse), Camille Paradis, PharmD (Bordeaux), Nicolas Simon, MD (Marseille), Patrick Nisse, MD (Lille), Nathalie Paret, PharmD, and Anne-Marie Patat, MD (Lyon), Marie Deguigne, MD, Marion Legeay, PharmD, and Gaël Le Roux, PharmD (Angers).

Disclosure statement

No potential conflict of interest was reported by the author(s).