Study Notes on the ACVIM Consensus Statement on Leptospirosis in Dogs

CONSENSUS STATEMENT

  • Consensus Statements of the American College of Veterinary Internal Medicine (ACVIM)

    • Purpose: Provide veterinary community with up-to-date information on pathophysiology, diagnosis, and treatment of clinically important animal diseases.

    • Oversight: Managed by the ACVIM Board of Regents including topic selection and panel member identification.

    • Framework: Evidence-based medicine as foundation, panel comments on cases of inadequate or contradictory evidence.

    • Draft Process: Panel prepares draft→ ACVIM membership input→ Submission to the Journal of Veterinary Internal Medicine (JVIM)→ Edited for publication.

    • Disclaimer: Findings and conclusions of authors do not represent the official position of CDC, IRIS, or ISCAID.

ABSTRACT

  • Key developments since last consensus statement on leptospirosis in dogs:

    • Revision of leptospiral taxonomy.

    • New diagnostic tests and vaccines adopted widely.

    • Improved understanding of disease epidemiology and pathophysiology.

  • Disease prevalence acknowledged in diverse populations of dogs, including small breeds and unvaccinated individuals.

  • Revised ACVIM consensus focus on leptospirosis approved in 2021.

  • A multidisciplinary expert panel employed the Delphi method for recommendations.

  • Draft shared at 2023 ACVIM Forum for member feedback before publication.

ABBREVIATIONS

  • ACVIM: American College of Veterinary Internal Medicine

  • AKI: Acute Kidney Injury

  • ALP: Alkaline Phosphatase

  • ALT: Alanine Aminotransferase

  • aPTT: Activated Partial Thromboplastin Time

  • ARDS: Acute Respiratory Distress Syndrome

  • CBC: Complete Blood Count

  • CDC: Centers for Disease Control and Prevention

  • CK: Creatine Kinase

  • CKDu: Chronic Kidney Disease of Uncertain Etiology

  • COVID-19: Coronavirus Disease of 2019

  • CT: Computed Tomography

  • DGGR: 1,2-o-dilauryl-rac-glycero-3-glutaric acid-(60-methylresorufin) ester

  • DNA: Deoxyribonucleic Acid

  • ECG: Electrocardiogram

  • EDTA: Ethylenediaminetetraacetic Acid

  • EKST: Extracorporeal Kidney Support Therapy

  • IRIS: International Renal Interest Society

  • ISCAID: International Society for Companion Animal Infectious Diseases

  • LOA: Level of Evidence

  • LPHS: Leptospiral Pulmonary Hemorrhage Syndrome

  • LPS: Lipopolysaccharide

  • MAT: Microscopic Agglutination Test

  • NAAT: Nucleic Acid Amplification Test

  • OR: Odds Ratio

  • PCR: Polymerase Chain Reaction

  • PT: Prothrombin Time

  • SARS-CoV-2: Severe Acute Respiratory Syndrome Coronavirus 2

  • SDMA: Symmetric Dimethyl Arginine

  • SDS-PAGE: Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis

  • ST: Sequence Type

  • SWGA: Selective Whole Genome Amplification

  • UPC: Urine Protein-to-Creatinine Ratio

INTRODUCTION AND EPIDEMIOLOGY

  • Pathogen & Transmission: Leptospirosis

    • Caused by spirochete Leptospira (zoonotic bacterial pathogen affecting mammals and poikilothermic animals).

    • Over 300 serovars based on outer lipopolysaccharide antigens, organized into antigenically related serogroups.

    • Confusion surrounding serogroup classification due to shared serovars across species.

    • New classification based on DNA sequence into pathogen subclades P1 (high virulence) and P2 (intermediately pathogenic) and saprophytic subclades S1 and S2.

    • P1 species: Leptospira interrogans, Leptospira borgpetersenii, Leptospira kirschneri primarily responsible for dog infections.

    • Infections occur via mucous membranes or abraded skin from exposure to shed strains from reservoir hosts, mainly rodents (like Rattus norvegicus) with a prevalence of infection reaching over 80% in certain areas.

  • Environmental Survival

    • Leptospires live in soil/water for weeks/months (optimal conditions aid viability).

    • Biofilms aid persistence in environment and renal tubules.

    • Seasonal incidence varies by geographic rainfall and temperature conditions, although direct contact with infected hosts can lead to disease outside optimal conditions.

CLINICAL MANIFESTATIONS

  • Manifestations: Multisystemic Effects

    • Most common: Acute tubulointerstitial nephritis, liver dysfunction.

    • Direct cytotoxicity on platelets and associations with various organ involvements, leading to complex clinical signs including:

    • Acute Kidney Injury: Signs include vomiting, diarrhea, dehydration.

    • Cholestatic Hepatopathy: Increased liver enzymes, jaundice symptoms.

    • LPHS: Tachypnea, hemoptysis, respiratory distress.

    • Hematologic alterations: Coagulopathy expressed through petechiae, hematomas.

  • Diagnostic Investigation of Organ Involvements

    • Diagnostic changes reflect renal, hepatic, and possibly cardiac involvement.

    • Clinicopathological changes vary with timing of presentation and severity of disease progression.

DIAGNOSIS OF LEPTOSPIROSIS

  • Consider leptospirosis in any dog presenting with AKI or liver dysfunction, regardless of vaccination history.

  • Confirm diagnosis via a combination of clinical suspicion, serology, and organism detection tests (MAT being the reference standard).

  • New point-of-care tests emerging, but MAT remains crucial for accurate diagnostics with recommendations on using a combination of tests.

  • Specific Testing Parameters: MAT titers ≥800, presence of IgM antibodies, NAAT for pathogen detection.

  • Precaution: A single positive MAT result does not confirm infection; titers should be measured over acute and convalescent phases.

    • Interpretation challenges present due to variable susceptibility and serogroup cross-reactivity.

TREATMENT AND PROGNOSIS

  • Treatment incorporates antimicrobial therapy tailored to organ dysfunction recovery through various supportive care strategies and specialized procedures such as EKST.

  • Antimicrobial Therapy: Initial treatment with IV penicillin variants; subsequent protocols often include oral doxycycline to avoid renal persistence. Dosing and timing protocols vary based on presenting symptoms and patient response.

  • Monitoring and Supportive Care: Emphasis on organ function management, nutrition, and fluid therapy to ensure recovery, while being vigilant against potential complications of overhydration.

  • Prognosis Factors: Negative indicators include hyperbilirubinemia, oliguria, severe coagulopathy, which are linked to mortality outcomes during acute veterinary care.

  • Preventive Measures: Vaccination protocols recommended due to zoonotic disease considerations, addressing both humane impacts and potential future outbreaks due to environmental and social factors.

PUBLIC HEALTH IMPLICATIONS

  • Zoonotic nature of leptospirosis requires precaution, especially in veterinary settings and among those with exposure to reservoirs. The CDC outlines handling precautions as imperative to prevent transmission.

  • Handling Protocols for Veterinary Staff: Implementing hygiene practices to mitigate risks of leptospirosis transmission, especially in acute cases needing urgent interventions.

  • Home Environment Precautions: Recommendations to owners include minimizing direct contact with the dog’s urine until post 48 hours post-antibiotics treatment.