Development of resistance to sarcoptic mange in ibex

Abstract

Sarcoptic mange affects mammal host species worldwide and, particularly, wild Caprinae throughout much of Eurasia. In the Iberian Peninsula, several outbreaks of sarcoptic mange in Iberian ibex (Capra pyrenaica) have been reported since the 1980s. Using data from a period of long‐term monitoring and a seasonal autoregressive integrated moving average (SARIMA)‐generalized autoregressive conditional heteroscedasticity (GARCH) model approach, we performed a time‐series analysis of the monthly prevalence of sarcoptic mange in the Iberian ibex population in Sierra Nevada Natural Space in southern Spain. In January 2003–March 2021, we documented a significant negative trend in sarcoptic mange prevalence, albeit with some interannual peaks. These findings can only be explained if a certain level of resistance to sarcoptic mange exists in hosts that, along with other factors, could provoke this reduced prevalence. Prevalence values varied seasonally, with maximum values in spring and minimum values at the end of summer, which may be due to factors linked to climate, host behavior, and endocrine activity. Our model predicts that the prevalence of sarcoptic mange in the Iberian ibex will continue to decrease over the next 2 years. Despite the inherent challenges involved, diagnosing and monitoring of wildlife diseases are integral to obtaining reliable epidemiological data and designing appropriate management strategies.

Co-infection patterns in the ectoparasitic community affecting the Iberian ibex Capra pyrenaica

“…The prevalence values obtained for the different host locations (provinces) must be interpreted with caution since most samples were not obtained randomly and mangy animals were more likely to be selectively removed in different areas for humanitarian reasons and/or to manage ibex density and mange spread. In fact, a decreasing trend in mange prevalence has recently been reported in the ibex population from Sierra Nevada [ 22 ] despite the fact that more than 58% of samples from this location were positive for S. scabiei .…”

“…Briefly, a catabolic process leads ibex to lose weight [ 5 , 10 ] and causes lesions on the skin and in inner organs (which are reversible), which are compounded by secondary infections [ 13 ] and a loss of reproductive fitness [ 9 , 11 ]. After reaching its chronic phase, mange may kill hosts, although some ibex develop a degree of resistance [ 21 , 22 ].…”

Home range in genus Capra: from polygons to Brownian bridges of scabietic and healthy Iberian ibexes (Capra pyrenaica)

“…On the other hand, the low effect of sarcoptic mange in Iberian Ibex home ranges, coupled with the reported survival of mange-affected ibexes ( Alasaad et al 2013 ), indicate that Iberian Ibex spatial behavior is not severely affected by sarcoptic mange to the point of compromising individual survival of the host. This suggests the occurrence of individual and population resistance to S. scabiei in areas where sarcoptic mange is endemic ( Pérez et al 2022 ). It is possible that over time Iberian Ibex populations in these areas have developed some level of immunity or tolerance to the disease, allowing them to persist and survive despite being infected.…”

“…Currently, sarcoptic mange, caused by the bBurrowing Mite Sarcoptes scabiei , is probably the biggest threat for Iberian Ibex conservation ( Pérez et al 2002 ). Sarcoptic mange led to a reduction of over 90% in the Iberian Ibex population from Sierras de Cazorla, Segura y las Villas Natural Park (hereafter, SCSV; Fandos 1991 ), but had a minor demographic effect on the population in the Sierra Nevada Natural Space (hereafter, SN), suggesting the development of resistance against this disease ( Pérez et al 2022 ). Nonetheless, sarcoptic mange has now become endemic in both populations ( Espinosa et al 2020 ; Moroni et al 2021 ; Pérez et al 2022 ).…”

Sarcoptic mange in wild ungulates in the European Alps – A systematic review

“…Occurrence of sarcoptic mange within a susceptible naïve population frequently results in high mortality, thereafter, there is a periodic resurgence every 10–30 years. The non-permanent observation of mange outbreaks has been attributed to a permanent persistence of mite infestations within the population and a subsequent development of immunity that prevents the development of clinical disease ( Rossi et al, 1995 ; Greßmann et al, 2018 ; Pérez et al, 2022 ). Immunity has been linked to the major histocompatibility complex (MHC), with a positive correlation of MHC heterozygosity or certain alleles and resistance to infectious disease ( Buítkamp et al, 1996 ; Brambilla et al, 2018 ).…”