Felis ISSN 2398-2950

Leptospira spp

Synonym(s): L. interrogans serovars

Contributor(s): Michele Bergmann, Katrin Hartmann, Melissa Kennedy

Introduction

Classification

Taxonomy

  • Classically, the genus Leptospira was divided into 2 species based on genetic analysis: L. interrogans sensu latu (pathogenic strains) and L. biflexa sensu latu (saprophytic strains).
  • L. interrogans is divided into more than 250 serovars on the basis of antigenic composition and further classified into antigenically related serogroups.
  • Serovar spectrum and frequency differs according to countries and regions (depending on distribution of rodent hosts, import of dogs from abroad, use of vaccination).
  • The main infecting serovars in dogs were Icterohaemorrhagiae and Canicola in Europe and America prior to 1960. Since the use of the bivalent vaccine against Canicola and Icterohaemorrhagiae, a shift to other serovars occurred.
  • Besides L. Icterohaemorrhagiae and L. Canicola, Serovars of importance in dogs include: GrippotyphosaBratislavaSaxkoebingSejroeCopenhagiAustralisBataviae, and PomonaAutumnalis, and Hardjo.
  • Icterohaemorrhagiae and Canicola infections in unvaccinated dogs still occur, indicating that these serovars are not fully eradicated.
  • Leptospires are motile, obligate aerobe, gram-negative bacteria, which are not visible in routinely fixed smears.
  • Dark field microscopy or phase contrast microscopy is necessary for visibility of unstained leptospires.

Etymology

  • Greek: lepto - thin, narrow; spira - a coil; leptospira - a fine coil.

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Clinical Effects

Epidemiology

Habitat

  • Leptospira spp are commonly sequestered in the renal tubules of mammalian kidneys.
  • Leptospires have been isolated from birds, reptiles, amphibians and invertebrates.
  • Rodents are the most frequent carriers; wild carnivores second.
  • Reservoir hosts show few or no signs of disease.
  • Different serovars typically have different reservoir hosts.

Lifecycle

  • Long generation time in culture media or host.

Transmission

  • Direct or indirect transmissions are possible.
  • Indirect transmission through contaminated water or soil is more common.

Pathological effects

  • Infection occurs through ingestion of infected rodents or penetration of mucosae or traumatized skin. Leptospiremia occurs within 1 week. Leptospires spread to other organ systems (kidneys, liver, spleen, endothelial cells, lungs, uvea/retina, skeletal and heart muscles, pancreas, and genital tract) and cause tissue damage, visceral and vascular inflammation.
  • Leptospiral pulmonary hemorrhage syndrome (LPHS) Lung: pulmonary hemorrhage can occur as severe manifestation of acute leptospirosis.
  • Leptospires can persist in immune privileged site (eg, renal tubes, eye).
  • In the presence of adequate antibody titers, leptospires are eliminated from most organs. In the presence of low antibody titers mild leptospiremia can continue with a subclinical course of disease.

Other Host Effects

  • Individual host may show little or no clinical signs but may be source of infection in the same animal species.
  • An animal that has recovered may become a long-term shedder of the organism.
  • Mainly dogs show disease; rodents often the reservoir.
  • In cats, disease is uncommon but asymptomatic infection and shedding in urine occurs.

Control

Control via chemotherapies

Antimicrobial therapy

  • Dogs with gastrointestinal signs should initially be treated with intravenous penicillin derivates (eg, ampicillin or amoxicillin  20-30 mg/kg q6-8h). These should be continued until gastrointestinal signs are under control and liver enzymes are normalized. A directly following antimicrobial therapy with 3 weeks of oral doxycycline (5 mg/kg q12h) is necessary for prevention of carrier states.
  • Dogs without gastrointestinal signs should immediately be treated with doxycycline.
  • Antibody testing of dogs living in the same household as infected dogs is recommended. Oral doxycycline 5 mg/kg q12h for 3 weeks) should be administered, if these dogs have antibodies.

Symptomatic treatment

  • Treatment of dogs with gastrointestinal sings includes antiemetics, gastroprotectants, and nutritional support.
  • Use of opioids in dogs with pain can be necessary.
  • Treatment of dogs with acute kidney injury includes correction of loss of fluid, electrolytes, acid-base imbalances and hypertension, and if necessary hemodialysis for patients with persistent oligoanuria, life-threatening hyperkalemia , or severe volume overload.
  • Oxygen therapy or mechanical ventilation can be necessary in dogs with LPHS.
  • Plasma transfusions can be necessary for patients with DIC .
  • Whole blood transfusion  can be helpful, if bleeding occurs.
  • Hemodialysis is necessary with acute renal failure.
  • Ventilation can be necessary in dogs with severe pulmonary hemorrhage due to LPHS.
    Human hazard group 2 pathogen. Zoonotic potential via contact with infected animals or contaminated water. Hospitalized animals should be handled with gloves and all tissues, etc treated with precaution. Owners should be informed of human health hazard, and potential for urinary shedding or organisms.

Vaccination

  • Used on dogs, cattle, pigs and occasionally humans.
  • Protection is serotype specific and temporary; at least annual boosters are required.

Diagnosis

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Further Reading

Publications

Refereed papers

  • Recent references from VetMedResource and PubMed.
  • Hartmann K et al (2013) Leptospira Species Infection in Cats: ABCD guidelines on prevention and management.  J Feline Med Surg 15, 576-581 PubMed.
  • Fraune C K, Schweighauser A & Francey T (2013) Evaluation of the diagnostic value of serologic microagglutination testing and a polymerase chain reaction assay for diagnosis of acute leptospirosis in dogs in a referral center. J Am Vet Med Assoc 242, 1373-1380 PubMed.
  • Abdoel T H, Houwers D J, van Dongen A M, Adesiyun A A, Jimenez-Coelloe M, Cardoso L, Suepaul S M, Ortega-Pacheco A & Smits H L (2011) Rapid test for the serodiagnosis of acute canine leptospirosis. Vet Microbiol 150, 211-213 PubMed.
  • Sykes J E, Hartmann K, Lunn K F, Moore G E, Stoddard R A & Goldstein R E (2011) 2010 ACVIM small animal consensus statement on leptospirosis: diagnosis, epidemiology, treatment, and prevention. J Vet Intern Med 25, 1-13 PubMed.
  • Brown C A, Roberts A W, Miller M A et al (1996) Leptospira interrogans serovar grippotyphosa infection in dogs. JAVMA 209(7), 265-7.
  • Harkin K R & Gartrell C L (1996) Canine leptospirosis in New Jersey and Michigan - 17 cases (1990-1995). JAAHA 32(6), 495-501.
  • Anderson J F, Miller D A, Post J E et al (1993) Isolation of Leptospira interrogans serovar grippotyphosa from the skin of a dog. JAVMA 203(11), 1550-1.

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