Abstract: To understand the parasite infection situation and influencing factors of Elaphurus davidianus in Beijing Nanhaizi Milu park,53 faeces,9 soil samples,9 lake water and sludge samples were collected in April and October 2018.The parasite eggs in deer faeces and the soil were tested by the saturated salt water float method,precipitation accumulation,the improved anti-acid staining,the saturated magnesium sulfate floating,the test tube filter paper culture and the filter membrane culture.At the same time,the shellfish,which came from the water and sludge of the park,were classified and identified.The results showed that the parasite infection rate of Elaphurus davidianus was 100%.And the infected parasites were mainly nematodes,trematodes,tapeworm and protozoa,of which nematodes and trematodes were predominant,mostly mixed infections.In the deep soil of the park,90-95 cm,the detection rate of parasite eggs was 100%,which was higher than that in the middle soil (30-35 cm)and shallow surface layer (2-7 cm) 33%,but no hookworm and ascaris eggs were detected.In the water and silt,three kinds of medical mollusc were detected,of which the main was Bellamya jousseaume,which could be the intermediate host of Angiostrongylus cantonensis,Clonorchis sinensis and Echinotrematodes.This study indicated that there was widespread parasite infection among Elaphurus davidianus in Beijing Milu park,which was closely related to the living environment.The main factors that affected the prevalence of parasite were insufficient deinsectization and rotational grazing,no harmless treatment of faeces and ponds,and the eggs discharged with faeces became an important factor of circulating infection.So effective comprehensive control measures should be taken to ensure the healthy development of the Elaphurus davidianus population.

Key words: Elaphurus davidianus; parasite; epidemic; infection