PCR for Detecting Leptospira in Canine Urine and Its Clinical Applications

A comparative study was made for evaluating the detection sensitivity of first PCR and booster PCR for Lep-tospira in canine urine. Heat treatment was used to extract DNA samples from distilled water and canine urine, both containing Leptospira icterohaemorrhagiae. These samples were then submitted to first PCR. In addition, PCR products amplified by first PCR were used as DNA samples that were diluted (1: 100), centrifuged at 12, 000 rpm, and submitted to booster PCR. In first PCR, minimum numbers of Leptospira were 1.6×103/ml in distilled water and 1.6×104/ml in canine urine. In booster PCR, however, the figure was 1.6×10/ml for both distilled water and urine. This suggests that booster PCR is more sensitive than first PCR. In clinical cases, both PCR assays detected Leptospira in canine urine within one week after manifestation of signs sug-gestive of leptospirosis. This indicates that Leptospira appear in the urine earlier in the course of the disease than had previously been thought. PCR assays of Leptospira in canine urine were shown to be useful in the early diagnosis of leptospirosis.-Key words: antibody, dog, Lettos/ira, PCR, urine.