Clinical application of a polymerase chain reaction assay for diagnosis of leptospirosis in dogs.
OBJECTIVE
To evaluate the use of a polymerase chain reaction (PCR) assay on urine samples for diagnosis of leptospirosis in dogs.


METHODS
Prospective case study.


METHODS
132 dogs with clinical signs suggestive of leptospirosis and 13 healthy dogs.


METHODS
PCR testing was performed on urine samples to detect leptospiral DNA; results were compared with results of conventional criteria for the diagnosis of leptospirosis.


RESULTS
Leptospirosis was diagnosed in 8 dogs via established criteria; all these dogs had positive results of PCR assay, including 1 dog with positive results before seroconversion developed. A positive PCR assay result was also obtained in 16 dogs that did not have a confirmed diagnosis of leptospirosis. In the 8 dogs that had a confirmed diagnosis of leptospirosis, serovars pomona (n = 3 dogs), grippotyphosa (2), canicola (2), and bratislava (1) were identified serologically. The remaining 121 dogs all had a diagnosis other than leptospirosis or were healthy. For PCR testing on urine, sensitivity was 100%, specificity was 88.3%, positive predictive value was 33%, and negative predictive value was 100%.


CONCLUSIONS
Positive PCR test results prior to seroconversion may have value in establishing an early diagnosis. Positive results in dogs that had signs consistent with leptospirosis despite failing to meet established criteria for leptospirosis raise questions regarding the sensitivity of serologic testing in diagnosis of leptospirosis. Serovars pomona, grippotyphosa, and canicola were most common.
Harkin
Kenneth R
KR
Department of Clinical Sciences, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506-5701, USA.
Roshto
Yvette M
YM
Sullivan
Jennifer T
JT
D000818:Animals; D001483:Base Sequence; D004269:DNA, Bacterial / Q000652:urine*; D003937:Diagnosis, Differential; D004283:Dog Diseases / Q000175:diagnosis* / Q000382:microbiology; D004285:Dogs; D007919:Leptospira / Q000235:genetics* / Q000472:pathogenicity; D007922:Leptospirosis / Q000175:diagnosis / Q000382:microbiology / Q000662:veterinary*; D008297:Male; D016133:Polymerase Chain Reaction / Q000379:methods / Q000662:veterinary*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D004269:DNA, Bacterial