Successful treatment of Lernaea sp. ectoparasites in a pet axolotl ( Ambystoma mexicanum ) using ivermectin

Abstract A pet axolotl ( Ambystoma mexicanum ) from Tuscany (Italy) presented with small, whitish, elongated structures attached to the neck region and abdominal flanks and was in poor general clinical condition. The structures were identified as belonging to the genus Lernaea (commonly called ‘anchor worm’), crustacean copepods that commonly parasitise freshwater fish species and, less frequently, amphibians. Ivermectin was administered orally, and the animal was transferred to another aquarium, with daily water changes. Previous reports of Lernaea spp. in axolotls are limited: after the first description of this parasite affecting this host in a farm in Uruguay, it was described in Mexico and in Italy. The described case report underlines the possible presence of Lernaea copepods that clinically affect axolotls, especially after contact with freshwater fish. Follow‐up showed that the animal fully recovered, supporting the efficacy of ivermectin in conjunction with sanitary measures to interrupt the life cycle of the parasite.