Introduction
Wildlife diseases play major roles in biodiversity conservation and the effects of most diseases in wildlife species remain unclear(Astorga et al., 2018; Sebastiano et al., 2019). A relatively recent event in China is the mass deaths of gorals (Naemorhedus goral ) and Chinese serows (Capricornis milneedwardsii ) , two rare and endangered animals listed in Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) appendix â… , belong to order Artiodactyla, family Bovidae, and subfamily Caprinae and are widely distributed in the Qinling Mountains, and these events have been recorded many times in local routine patrols since 2012. Unfortunately, those events have not attracted enough attentions from administrates and scholars because they thought that this was a normal ecological regulatory mechanism. Most of the carcasses had extensive white and thickened skin lesions characterized by lichenification and alopecia, and the causes of death were unclear until 2017. In 2017, a similar death event occurred in gorals in the Qinling Mountains again, and we confirmed initially that the sarcoptic mange, which was pathologically diagnosed, was an important factor in this event(Wu et al., 2019).
Sarcoptic mange, which is caused by the burrowing mite Sarcoptes scabiei (S. scabiei ), is globally endemic and is an emerging threat to wildlife(Escobar et al., 2022; Pence & Ueckermann, 2002). There have been reported disease outbreaks in many species, such as red fox (Vulpes vulpes ), wild boar (Sus scrofa ), Iberian ibex (Capra sibirica ) and alpine chamois (Rupicapra r. rupicapra ) in Europe; raccoon dogs (Nyctereutes procyonoides ) and blue sheep (Pseudois nayaur ) in Asia; cheetah (Acinonyx jubatus ) in Africa; and wombats (Vombatus ursinus ) in Australia, resulting in sharp declines in these wildlife populations in recent decades(Bianca et al., 2019; Dagleish et al., 2007; Gakuya et al., 2012; Haas et al., 2018; Iacopelli F et al., 2020; Old et al., 2018; Sugiura et al., 2018; Turchetto et al., 2014). According to these reports, herbivores seem to be more susceptible and have higher mortality rate than carnivores. Sarcoptic mange manifests as alopecia, hyperkeratosis, and bleeding crusts (mite-like lesions) on the skin of infected animals(Cardells et al., 2021). Recent sarcoptic mange outbreaks in wildlife appear to demonstrate ongoing geographic spread, increase in the diversity of hosts and increased virulence(Escobar et al., 2022). However, the impacts of the sarcoptic mange in wildlife populations, mechanisms involved in its eco-epidemiological dynamics, and risks to public and ecosystem health remain unclear(Astorga et al., 2018; Sosa et al., 2022).
Similarly, the situation in the Qinling Mountains is also urgent, as incoming impressionistic data suggests that sarcoptic mange may spread geographically and be transmitted among different species. The Qinling Mountains are the most important natural climatic, geographic and biological boundaries in China and have a high biodiversity(Huang et al., 2016). Many rare and endangered wild animals, such as the giant panda (Ailuropoda melanoleuca), takin (Budorcas taxicolor), golden monkey (Rhinopithecus), and crested ibis (Nipponia nippon), live within this ecosystem, and their populations have gradually recovered because of effective protection measures in of China in recent decades(Ma et al., 2018). Sarcoptic mange in the gorals and serows is very likely to bring risks to these sympatric rare animals.
To better understand sarcoptic mange and aid biodiversity conservation, we conducted this research to attempt to reveal the relationship between the disease and the mass death events in gorals and serows. Based on the previous case research, we expanded the temporal, spatial and species’ ranges in this study and collected data from interviews, pathological, parasitological and microbiological examinations of the skin samples and surveillance records from infrared cameras. This study is the first to illustrate the epidemic characteristics and threat of sarcoptic mange in wildlife populations in the Qinling Mountains.