In order to explore the pathogenic characters,diagnosis and treatment of canine leptospirosis,a retrospective analysis of the pathogenetic factor,diagnosis and treatment of three dogs were reported which diagnosed as canine leptospirosis in China Agricultural University Teaching Animal Hospital from August to November,2015.The infected dogs showed symptoms of depressed,jaundice,anorexia and vomiting.Two of them had fever history and contacted the water resource outside before getting ill.All three dogs were confirmed anemia,liver and kidney damage by laboratory examination.They were diagnosed with canine leptospirosis according to the positive results of the Leptospira PCR examination base on urine.During the diagnosis and treatment process,one of them was dead,the rest two recovered after antibiotic and symptomatic therapy.In conclusion,dogs which infected with leptospirosis may have a contact with the infected water before.The Leptospira PCR examination base on urine can be used for the diagnosis method of the disease.As to treatment,the use of penicillin and tetracycline drugs such as doxycycline is recommended.

OBJECTIVE：To screen the effective compo nent in antioxi dant active fraction of Pueraria lobata . METHODS ：The antioxidant active fraction sample （S1-S20） of 20 batches of P. lobata were prepared. HPLC method was adopted. The determination was performed on SepaxBio-C 18 column with mobile phase consisted of methanol-water （gradient elution ）at the flow rate of 0.6 mL/min. The column temperature was set at 25 ℃，and detection wavelength was set at 250 nm. HPLC fingerprints of 20 batches of P. lobata were established by the Similarity Evaluation System of TCM Chromatographic Fingerprints （2012 edition），and common peaks were identified. Cluster analysis ，principal component analysis （PCA）and orthogonal partial least squares discriminant analysis （OPLS-DA）were used to screen the effective components in antioxidant active fraction of P. lobata . RESULTS：There were 18 common peaks in HPLC fingerprints of 20 batches of antioxidant active fraction in P. lobata ，and the similarity was more than 0.99. Eight common peaks were identified ，which were 3′-hydroxypuerarin（peak 2），puerarin（peak 3）， 3′-methoxypuerarin（peak 4），daidzein（peak 5），genistein（peak 7），formononetin（peak 11），daidzein（peak 13）and genistein （peak 16）. The results of cluster analysis and PCA analysis showed that samples S 1，S3，S4，S6，S8，S18 and S 19 were clustered into one category ，and samples S 2，S5，S7，S9-S17 and S 20 were clustered into one category ；peak 2，peak 3，peak 10，peak 11 and peak 13 had great influence on principal component 1；peak 8 and peak 9 had great influence on principal component 2. OPLS-DA analysis showed that peak 4，peak 3，peak 2，peak 16，peak 13 and peak 11 had great influence on the quality of antioxidant active fraction of P. lobata . CONCLUSIONS ： HPLC fingerprint for active fraction of P. lobata is established in the study and 8 components are identified ；among them ， com puerarin，3′-hydroxypuerarin，daidzein and formononetin maybe the material basis of antioxidant fraction of P. lobata .