Overview
Leptospirosis is a zoonotic disease with a worldwide distribution caused by infection with any of several pathogenic serovars of Leptospira. The disease affects virtually all mammals and has a broad range of clinical effects, from mild, subclinical infection to multiple-organ failure and death. Leptospira are aerobic, gram-negative spirochetes that are fastidious, slow growing, and have characteristic corkscrew-like motility. Essentially all mammals are susceptible to infection with pathogenic Leptospira, although some species are more resistant to disease. Among common companion animals and livestock, leptospirosis is most frequently recognized in cattle, swine, dogs, and horses. Cats have historically been considered to be resistant to disease but have been shown to seroconvert on exposure to leptospires.More than >250 serovars of pathogenic Leptospira are recognized.
- Maintenance hosts are often wildlife species and, sometimes, domestic animals and livestock. Each serovar behaves differently within its maintenance host species than it does in other, incidental host species. In maintenance hosts, leptospirosis is generally characterized by a high prevalence of infection, relatively mild acute clinical signs, and persistent infection in the kidneys and sometimes the genital tract.
Clinical findings
Despite the many serovars of Leptospira and host species, the key steps in pathogenesis of the disease are similar in all host/serovar combinations. Leptospires invade the body after penetrating exposed mucous membranes or damaged skin. After a variable incubation period (4–20 days), leptospires circulate in the blood and replicate in many tissues including the liver, kidneys, lungs, genital tract, and CNS for 7–10 days. During the period of bacteremia and tissue colonization, the clinical signs of acute leptospirosis, which vary by serovar and host, occur. Agglutinating antibodies can be detected in serum soon after leptospiremia occurs and coincide with clearance of the leptospires from blood and most organs. As the organisms are cleared, the clinical signs of acute leptospirosis begin to resolve, although damaged organs may take some time to return to normal function. In some cases, severely damaged organs may not recover, leading to chronic disease or death.
- The clinical signs of leptospirosis depend on the host species, the pathogenicity of the strain and serovar of Leptospira, and the age and physiologic state of the animal.there may be effects on other body systems resulting in clinical problems such as uveitis, pancreatitis, bleeding, hemolytic anemia, muscle pain, or respiratory disease.
Diagnosis and differentials
serological testing. The microscopic agglutination test (MAT) is most frequently used. ELISA.
Treatment and control
The cornerstone of leptospirosis prevention is vaccination with polyvalent inactivated vaccines.
- Public Health & Zoonotic Because leptospirosis is a zoonotic disease, all veterinary personnel should take appropriate precautions when handling known or suspected infected animals. Such dogs do not need to be placed in isolation but should be nursed with barrier precautions, paying particular attention to avoiding exposure of skin or mucous membranes to urine or blood. Infected dogs should be allowed to urinate in designated areas that can subsequently be cleaned and disinfected. The organisms are killed by all commonly used disinfectants.