Sarcoptic Mange in Wild Caprinae of the Alps: Could Pathology Help in Filling the Gaps in Knowledge?

Abstract

Sarcoptic mange represents the most severe disease for wild Caprinae individuals and populations in Europe, raising concerns for both conservation and management of these ungulates. To date, this disease has been investigated in different wild caprine species and under many different perspectives including diagnostics, epidemiology, impact on the host populations, and genetics of both hosts and parasite, with the aim to disentangle the host-Sarcoptes scabiei relationship. Notwithstanding, uncertainty remains and basic questions still need an answer. Among these are the effect of immune responses on mange severity at an individual level, the main drivers in host-parasite interactions for different clinical outcomes, and the role of the immune response in determining the shift from epidemic to endemic cycle. A deeper approach to the pathology of this disease seems therefore advisable, all the more reason considering that immune response to S. scabiei in wild Caprinae, generally classified as a hypersensitivity, remains poorly understood. In this paper, we reviewed the pathological features associated to sarcoptic mange in wildlife, exploring different kinds of hypersensitivity and outcomes, with the objective of highlighting the major drivers in the different responses to this disease at an individual level and proposing some key topics for future research, with a particular attention to Alps-dwelling wild caprines.

Sarcoptic mange in the wild boar, Sus scrofa, in Sweden

“…Presence of S. scabiei has been reported in a large variety of wild animals including the red fox ( Vulpes vulpes ), Pyrenean chamois ( Rupicapra pyrenaica ), and Iberian ibex ( Capra pyrenaica ) where endemic outbreaks occur with devastating mortality, e.g. the Scandinavian red fox population, which was severely affected in the mid-1980s, and the Iberian ibex in Spain, which has suffered substantial losses in the past decade ( Borg, 1987 ; León-Vizcaíno et al, 1999 ) and recently in the Alpine chamois and Alpine ibex in the Eastern Alps ( Turchetto et al, 2020 ). In Swedish wildlife, sarcoptic mange has, apart from in the red fox, also been diagnosed in the pine marten ( Martes martes ), Artic fox ( Vulpes lagopus ), Eurasian lynx ( Lynx lynx ), and wolf ( Canis lupus ) ( Mörner, 1992 ; Ryser-Degiorgis et al., 2002 ; Mörner et al., 2005 ; Oleaga et al., 2008 ; Collins et al., 2010 ).…”

Development of resistance to sarcoptic mange in ibex

“…Mortality induced by sarcoptic mange varies between host Caprinae species and populations (Pérez et al 2021), but it is probably still the most severe disease affecting wild Caprinae in Europe (Rossi et al 2019, Turchetto et al 2020). Despite being intensively studied in recent decades, several aspects of the disease remain unclear (e.g., its effect on host behavior and its detection probability during field surveys).…”

Host gene expression in wildlife disease: making sense of species‐level responses

“…Sample timing can be informed by baseline disease data, either on symptoms and clinical course from captive animals or, potentially, longitudinal sampling of wild hosts. Further, animals possess a diverse suite of immune defences, and distinct pathogen threats may be met with different types of immune responses over varying timescales (Rollins‐Smith, 2020; Rollins‐Smith et al, 2011; Spellberg & Edwards, 2001; Sutherland et al, 2014; Turchetto et al, 2020; Viney et al, 2005). Ideally, prior information about the specific host responses likely to be at play will help guide decisions about how sampling effort can be best allocated in any gene expression study with a time‐course design.…”