The diagnostic workup for canine leptospirosis combines acute-phase point-of-care (POC) screening with confirmatory microscopic agglutination test (MAT) paired titers and polymerase chain reaction (PCR), and definitive treatment is doxycycline 5 mg/kg PO q12h [10 mg/kg/day total] for 14 days.
Diagnostic Workup
Begin with rapid POC antibody testing (IgM and IgG) at initial presentation. Positive POC results in dogs with compatible clinical signs strongly indicate acute leptospirosis, while negative results require additional testing to exclude infection.The Veterinary… POC tests have the greatest value early in the course of illness, before MAT and PCR results are available.Veterinary Clin…
Submit paired MAT titers as the reference serologic test. Acute and convalescent samples collected 10–14 days apart are required; a fourfold rise in titer confirms recent infection.Journal of Vete…+1 In the presence of clinical signs, a single titer ≥800 can suggest infection but cannot confirm a diagnosis.WSAVA Global Gu… The MAT does not reliably predict the infecting serogroup, and there is considerable interlaboratory variation in results.Journal of Vete…+1
Submit PCR on both blood and urine concurrently with the acute MAT. PCR on blood and/or urine is a valuable early diagnostic tool and can detect infection before antibody titers rise.Veterinary Clin…+1 Culture of blood or urine is possible but takes 8–12 weeks and is infrequently used in clinical practice.Journal of Vete…
Common clinicopathological findings at presentation include azotemia (68%), elevated alanine transaminase activity (66%), hyperbilirubinemia (55%), hypoalbuminemia (49%), thrombocytopenia (43%), anemia (42%), and glucosuria (32%).Veterinary Reco… Acute kidney injury is the most common presentation in recent years.MSD Vet Manuals Disease manifestations include renal involvement alone (16%), hepatic involvement alone (37%), and combined hepatic and renal involvement (47%).Veterinary Reco…
Treatment Protocol
Doxycycline at 5 mg/kg PO q12h for 14 days is the recommended treatment for optimal clearance of organisms from the renal tubules and elimination of zoonotic shedding risk.Journal of Vete…+1 With prompt recognition and treatment, 90% of infected dogs have a positive outcome.Journal of Vete…
Early in the disease course, amoxicillin or ampicillin may be used prior to transitioning to doxycycline, which is the agent relied upon to eliminate organisms from the renal tubules.Journal of Vete…
Supportive care is administered alongside antimicrobial therapy.MSD Vet Manuals Dogs with renal involvement have reduced survival to discharge compared to those with hepatic-only disease — non-survivors present with higher creatinine at admission.Veterinary Reco…
Follow-up urine PCR is recommended after completing treatment to confirm clearance of leptospires. A subset of dogs fails to achieve a negative urine PCR despite standard doxycycline therapy, and persistent leptospiruria is associated with development of chronic kidney disease and ongoing zoonotic risk.Journal of Vete… Persistent leptospiruria despite treatment should prompt consideration of antibiotic resistance and a change in antimicrobial therapy.Journal of Vete… Long-term persistent azotemia occurs in fewer than 6% to up to 18% of surviving dogs.Journal of Vete…
| Test | Protocol | Performance | Key Caveat |
|---|---|---|---|
| Rapid POC (IgM/IgG) | At presentation | Positive result with compatible signs strongly indicates leptospirosis; negative requires further testing | Cannot replace confirmatory testingThe Veterinary… |
| MAT (paired) | Acute + convalescent 10–14 days apart | Fourfold rise confirms recent infection; single titer ≥800 suggests but does not confirm | Does not reliably predict infecting serogroup; interlaboratory variationJournal of Vete…+1 |
| PCR (blood and/or urine) | At presentation; repeat post-treatment | Valuable early before titers rise; follow-up confirms clearance | Persistent positive post-treatment suggests resistance or treatment failureVeterinary Clin…+1 |
| Doxycycline | 5 mg/kg PO q12h × 14 days | 90% positive outcome with prompt treatment | Follow-up urine PCR needed; persistent shedding documented despite standard therapyJournal of Vete…+2 |
Would you like to discuss vaccination protocols and which serovars are covered by currently available canine leptospirosis vaccines?