SURVEY ON SARCOPTIC MANGE IN IBEX (CAPRA IBEX L. 1758) OF THE FRIULIAN DOLOMITES REGIONAL NATURE PARK

INTRODUCTION: The establishment of the ibex (Capra ibex) colony within the Friulian Dolomites Nature Park dates back to 1985-87 and it started with the release of 26 specimens sourced from the surviving population of the western Alps. Initially, the colony experienced steady growth, but in 2011, the onset of sarcoptic mange led to a progressive decline in population numbers. In fact, the inherent coevolutionary dynamics between the parasite and its host gives rise to a cyclical pattern characterized by periodic epidemic outbreaks, although with reduced incidence rates affecting the population. This study aimed to determine the current population size and the trend of the sarcoptic mange epidemic within the ibex colony of the Friulian Dolomites Nature Park. MATERIALS AND METHODS: The study began with a retrospective analysis of data collected from annual censuses between 2012 and 2023. Additionally, it involved a longitudinal survey conducted from February to October 2023 in the Salta-borgà area, located in the southwest sector of the Park. This survey is the result of monthly monitoring of ibex through direct observation aided by optical instruments along established transects. These observations were carried out daily for several consecutive days, spaced one month apart. Each observation session included photographic documentation for subsequent health analysis of the animals, resulting in classification into four degrees of mange severity based on skin lesions. During the survey, biological samples were collected from the environment and from carcasses exhibiting mange-related lesions. These samples underwent laboratory analysis to detect Sarcoptes scabiei using a maceration in sodium hydrate followed by a flotation technique. RESULTS AND CONCLUSIONS: The findings confirmed the presence of a second sarcoptic mange outbreak, commencing in 2019 within the Salta-borgà area. while resulting in a reduced demographic decline compared to the initial outbreak, this recovery failed to facilitate a positive population trend. Laboratory analysis of samples revealed Sarcoptes scabiei presence both in carcasses and environmental samples, indicating potential transmission through various indirect sources. Despite milder cutaneous lesions, this secondary wave of sarcoptic mange propagated throughout the Park’s ibex colony. Considering the population´s characteristics - relatively young, genetically restricted and territorially isolated, future cyclical waves with low incidence can be foreseen due to the disease´s natural evolution. Hence, the recommendation from this study is to enhance genetic variability through reintroducing individuals from colonies with prolonged exposure to sarcoptic mange, potentially exhibiting an efficient coevolutionary response to the parasite.