Leptospirosis

Leptospirosis is an infectious disease caused by pathogenic spirochetes of the genus Leptospira. Contracted by exposure to contaminated urine of infected animals it is considered the most common zoonosis in the world. The mild form of leptospirosis (accounting for ~90% of all cases) is rarely fatal, but if not treated at an early stage may lead to severe complications such as renal dysfunction, meningitis, uveitis and vascular bleeding, with a mortality rate averaging 10%. Most deaths result from renal failure, massive hemorrhage, or acute respiratory distress syndrome (ARDS).

Weil syndrome, the severe form of leptospirosis, primarily manifests as profound jaundice, renal dysfunction, hepatic necrosis, pulmonary dysfunction, and hemorrhagic diathesis. Pulmonary manifestations include coughing, dyspnea, chest pain, blood-stained sputum, hemoptysis, and respiratory failure.

In dogs acute leptospirosis (Weil's disease, or acute icteric leptospirosis) is a life-threatening condition with zoonotic potential. Suspicion of Weil's disease on dogs which requires rapid laboratory confirmation for accurate diagnosis, because prompt intervention is essential for the survival of the animal. The causative pathogenic leptospires can be isolated from a wide range of -healthy- animal species, many of which function as maintenance hosts (reservoirs). Rodents and other small animals are the primary reservoirs for the Leptospira that is pathogenic to humans and domestic animals. Dogs can host Leptospira belonging to a range of serogroups, but particularly the members of the serogroups Icterohaemorrhagiae and Canicola may cause severe acute icteric disease. Canine leptospirosis is considered a public health issue because of the high risk of transmission to dog owners and caretakers.

The protean manifestations make this disease a true diagnostic challenge.The most commonly applied serological test, the microscopic agglutination test (MAT), requires specific laboratory facilities and expertise to detect agglutinating antibodies. Paired serum samples with an interval of at least 10 days are needed for an accurate diagnosis of leptospirosis by MAT. ELISA testing for Leptospira-specific IgM antibodies presents a reliable test for detection of acute leptospirosis in a single sample as specific IgM antibodies rise rapidly in the early stage of disease onset, but also needs to be performed in the laboratory and takes hours to produce a result. PCR can be used for the detection of the Leptospira bacteria, but also required a specifically equipped laboratory and expertise. Furthermore, especially in animals subclinical infections occur on a wide scale, limiting the diagnostic value of agent detection.

The MondialDx Lepto Human IgM LFA provides a simple, rapid and accurate alternative to these complex and laborious tests, and can be used directly beside the patient at the point-of-care. The human and canine LFAs detect specific IgM antibodies against all pathogenic serovars, yielding reliable results in 10-15 minutes.

Literature

• Smits et al. Lateral-flow assay for rapid serodiagnosis of human leptospirosis. Clin Diagn Lab Immunol 8: 166-169 (2001)
• Abdoel et al. Rapid test for the serodiagnosis of acute canine leptospirosis. Vet Microbiol 150: 211-213 (2011)Goris et al. Prospective validation of three rapid diagnostic tests for the diagnosis of human leptospirosis. Plos NTD 7: e2290 (2013)