Abstract: 【Objective】 A clinical case of Bufo gargarizans infection with parasite in multiple organs was clinically diagnosed, and its species classification was studied through molecular biological identification.【Method】 An emaciated female Bufo gargarizans raised in the laboratory died after food refusal was dissected and observed, and the histopathology was studied.The morphology of the isolated parasite was observed and studied by helminth autopsy and nodule pressing method, and the molecular biology was identified.【Result】 Autopsy study showed that the toad' heart, liver, other organs and multi-mesangium were infected by Acanthocephala, and no other common worms such as nematodes and trematodes were found in the toad.HE staining results showed that the infection of Acanthocephala caused mechanical damage and inflammatory reactions to toad' lung, liver and other organs, in which the mucosa of the intestinal wall was seriously damaged and detached.Cytochrome c oxidase subunit Ⅰ (COⅠ) gene was amplified by PCR, five COⅠ gene segments of the species of interest were obtained from different parts, and the Acanthocephala was identified by comparison with the same species in GenBank, the GC contents ranged from 40.14% to 40.83%, and the similarity of JS-01 strain was the closest to Sphaerirostris lanceoides (accession No.:MG931943.1), which was 99.5%.By means of molecular biological analysis and morphological observation, it was determined to be Sphaerirostris lanceoides.【Conclusion】 A large number of infection and parasitism of Sphaerirostris lanceoides caused the death of toads.The results of this experiment could provide reference for the prevention and control of echinocephalosis in medicinal toads in terms of clinical symptoms, pathology and molecular biology, and had reference value for the diagnosis and research of Sphaerirostris lanceoides in amphibians.

Key words: toads; Sphaerirostris lanceoides; histopathology