Introduction

Classification

Taxonomy

• Order: Spirochaetales.
• Family: Leptospiraceae.
• Genus: Leptospira.
• Species: interrogans.
• Serovar: icterohemorrhagiae.

Etymology

• Gk: lepto - thin, narrow; spira - a coil.
• Gk: ikteros - jaundice; haima - blood; rhegnunai - to break, burst.

Active Forms

Clinical Effects

Epidemiology

Habitat

• Inhabits the tubules of mammalian kidneys.
• Main reservoir hosts are rats.
• Also found in dogs, cattle, pigs and wildlife.

Lifecycle

• Long generation time (12 hours).

Transmission

• Transmitted via contact of mucous membranes or skin with urine-contaminated water, fomites, or feed.
• Milk from acutely infected cows, and genital excretions from cattle and pigs are also sources of infection.

Pathological effects

• Antibodies important for clearance.

• Rats are the chief reservoir of this serovar; dogs, cattle and pigs are alternatives.
• In cattle, may cause hemoglobinuria, jaundice and fever; less commonly in young adults.
• In pigs, causes infertility, abortions and stillbirths.
• In dogs, causes acute hemorrhagic disease with high fever, vomiting and often early death.
• May also cause less intense icteric disease in dogs.

Control

Control via animal

• Antibiotics are used to treat infection and to eliminate the carrier state.
• Vaccination is generally effective against disease, but not against infection or carriage.

Control via chemotherapies

• Susceptible to penicillin Benzylpenicillin , tetracycline Tetracycline , chloramphenicol, streptomycin and erythromycin Erythromycin.
• Treatment must be instituted early in the course of infection.
• Antibiotics are effective in reducing shedding, treating carriers, and can be used prophylactically after known exposure.

Control via environment

• Avoid contact with contaminated water, especially near rodent habitats.

Vaccination

• Serovar-specific vaccination is available against L. icterohemorrhagiae.
• Annual boosters are required.
• Vaccination provides protection against disease, but not against infection or shedding.

Diagnosis

Further Reading

Publications

Refereed papers

• Recent references from PubMed and VetMedResource.
• Rentko V T, Clark N, Ross L A et al (1992) Canine leptospirosis. A retrospective study of 17 cases. J Vet Intern Med 6 (4), 235-244 PubMed.
• Venkataraman K S & Nedunchelliyan S (1992) Epidemiology of an outbreak of leptospirosis in man and dog. Comp Immunol Microbiol Infect Disease 15 (4), 243-247 PubMed.