Abstract: [Objective] After the reintroduction to their ancestral home in Kalamaili Mountain Ungulate Nature Reserve, Xinjiang, the Przewalski's horses (Equus przewalskii) have been infected by Gasterophilus spp.. Previous study has shown that the high prevalence and intensity restricted the wild process seriously. In the purpose to located the main cross-infection area and master its feature of Gasterophilus among the host, we investigated and analyzed the spatial distribution of equine faeces, an indicator to pupation region in this study.[Method] Quadrat and belt transect method were adopted to explore the location and quantity of equine faeces in the surrounding areas of four main water resources (WP1, WP2, WP3, WP4) and the donkey roads had been highly utilized by Przewalski's horses. The length of the belt transect based on the donkey roads is 1.5 km outward the water resource. The quadrat is the circular area with a radius of 200 m around the WP1 water resource. The Mann-Whitney U method was taken to analyse the density of faeces in water resource. The LSD method was used to compare the distribution of equine faeces among different seasons. The clustering analysis was employed to analyze the distribution of faeces in four water resources.[Result] 1) In general, the number of equine faeces decreased outward from the water source and significantly within 300 meters of water source. The best model (x:distance from the water resource; y:number of equine faeces) for faeces distribution in donkey roads in the four water resources was the reciprocal type (WP1:y=3.873+59.000/x,R²=70%; WP2:y=3.940+16.342/x,R²=64%; WP3:y=5.248+12.841/x,R²=55%; WP4:y=-0.481+44.869/x,R²=69%). 2) There were no significant difference (P>0.05) in fecal distribution trend over three donkey roads in WP1 among months. But the number of faeces increased significantly (P<0.05) in August. The proportion of equidae faeces increased with to the coming dry season in the range of 200 meters of three donkey roads from water source of WP1 from May to August. 3) The number and distribution of equidae faeces in donkey roads varied in different types of water source. Equine faeces were more and concentrated in the distribution in permanent natural water resources and they were less but more evenly distributed in artificial modification of water resources.[Conclusion] The shortage of water resources in the arid desert steppe result ed in the concentrated pupal development platform Gasterophilus spp.. This platform as a key checkpoint of the water channel, created close contact conditions of Gasterophilus spp. among the equids objectively and became the main transmission areas for Gasterophilus spp. in Kalamaili. The result of this study revealed that the prevalence of Gasterophilus myiasis is related to local environmental conditions and the behavior of equine animals in arid desert steppe. It is important for further research on the biology, epidemiology and prevention and control of Gasterophilus spp. in Przewalski's horses.

Key words: equine faece, water resource, donkey road, Gasterophilus spp., arid desert steppe