First Report of Cutaneous Lepidopterism by Hylesia invidiosa (Lepidoptera: Saturniidae): Outbreak Description and Review of the Literature.

Cutaneous lepidopterism associated with exposure to setae from Hylesia moths has been frequently reported in the Americas. Despite efforts to understand its pathophysiology, little is known about the biology of the implicated species, treatment approaches, and outbreak prevention and control. This affects the direction of clinical management and exacerbates the social and public health implications of lepidopterism. In March 2024, the Ministry of Health of Costa Rica was alerted about human cases of dermatitis in the Tucurrique District, Cartago Province, which residents attributed to moths. Fifteen adult moths were collected in the surroundings of a school in the affected community. The specimens were morphologically identified as Hylesia invidiosa (H. invidiosa). A fragment of the cytochrome c oxidase subunit I (cox-1) gene was amplified and sequenced from one specimen for molecular confirmation of the species, yielding complete homology with reference DNA sequence data (GenBank accession number JQ569633.1). Moreover, in March 2025, a second outbreak with the same characteristics was reported in the Tuis District, Cartago Province. To the best of the authors' knowledge, this is the first published report of lepidopterism outbreaks associated with H. invidiosa. Herein, a historical overview of Hylesia lepidopterism in Latin America is provided, and previously reported treatment approaches, control actions, and measures to prevent and mitigate the effects of Hylesia outbreaks are discussed.