Efficacy and safety of afoxolaner (NexGard®) in a collection of captive-bred lizards for the treatment and control of mite infestation

Lizards and other reptiles are increasingly gaining popularity as pets worldwide. These animals may be commonly parasitized by species of mites such as Ophionyssus natricis, which are deleterious, also because of their role as vectors of pathogens, including zoonotic ones. Treatment options are limited and may not be completely resolutive or safe. The aim of the present study was to assess the efficacy of afoxolaner (NexGard®; Boehringer Ingelheim, Germany) in a collection of mite-infested captive-bred lizards that were housed in mixed enclosures with other reptile classes, in a zoological park located in southern Italy. Lizards were clinically examined and weighed, and mite infestations were assessed on the animals and in their enclosures (environment). All animals were treated with a dose of 2.5 mg afoxolaner per kilogram body weight (2.5 mg/kg) administered orally. All animals were examined pre-treatment (T0) and at various time points post-treatment (T1, 24 h; T2, 14 days; T3, 28 days). The collected mites were morphologically identified at the species level and the species identity also confirmed molecularly and phylogenetically. Animals were morpho-molecularly screened for hemoparasites, endoparasites and vector-borne pathogens. Overall, 28 lizards were screened, and Leishmania infantum was detected in a Sudan plated lizard. Moreover, 6 (21.4 %) lizards had at least one mite. Mites were identified as O. natricis and Pterygosoma inermis infesting Indonesian blue-tongued skinks and Roughtail rock agamas, respectively. No mites were found on hosts after T1, and at T3 no mites were observed in the environment. No side effects were observed in the treated lizards. A single oral administration of afoxolaner at 2.5 mg/kg was a safe treatment in lizards and 100 % effective for the treatment and prevention of common mite species infestations.