Abstract: To determine the pathogen and related symptoms caused by renal failure,and to provide a reasonable diagnosis and treatment plan,a case of disease on Welsh Corgi dog was tested by the method of symptoms,blood routine examination,blood biochemical test,blood gas analysis and identification of pathogen.The results showed that these data of W-SCR,W-MID,MID and RDW-CV rose than normal reference index in blood routine examination before the hospitalization,respectively.Meanwhile,data of W-LCR,PCV,MCV,MCH and RDW-SD had reduced separately.These data of Ca²⁺,GLU,BUN,PHOS,AMYL and CRE were up than normal reference index in blood biochemical test,respectively.These data of GLU,BUN and K⁺ had risen respectively,nevertheless,these data of Na⁺,Cl^- and PCO₂ had lowered separately.The result was positive by the antigen testing with the Leptospira detector plate.After treatment with synthetical therapy,WBC and SCR had risen than normal references index,and data of RBC,HGB and PLT were down respectively.By the Hotelling T² analysis of the difference between before and after the therapy on blood routine index,it was significant difference in the multivariate test (F=1 905 045.32,P=0.001).These data of WBC,W-LCR,SCR,MID,HGB,PCV,MCV and RDW-SD were extremely significant differences in single variable analysis (P<0.01),and other data with significant differences were W-MID,RBC,MCH and PDW(P<0.05).But,in blood biochemical test,most of data were in normal reference values.The mental state of sick dog was recovering gradually normal than before.Multivariate test was no significant difference by the Hotelling T² analysis (F=85.21,P=0.081),but other data of GLU,BUN,PHOS,AMYL and CRE were extremely significantly different in single variable analysis (P<0.01).These data of GLU,BUN and K⁺ were up than after therapy in blood gas analysis,and data of Na⁺,Cl^- and PCO₂ reduced respectively.There were extremely significant differences in the multivariate test (F=7 978.48,P=0.008).These data with extremely significant differences were GLU and BUN in single variable analysis(P<0.01).The sick dog was recovering normal after treatment,and mental state went back to normal after 7 days therapy using the drugs of diuretics,antibiotics,rehydration electrolyte,energy medicine,vitamins and CoA.It should be noted that the part of high index of reexamination was a normal manifestation when the body was recovering to normal functioning.The method of synthetical fluid therapy was provided the correctness to treat the renal failure caused by canine Leptospira.

Key words: Leptospira; renal failure; Welsh Corgi dog