Leptospira IgG
The Leptospira IgG ELISA test is an enzyme immunoassay for the detection of antibodies to Leptospira biflexa (serovar patoc 1) for the serological confirmation of infections in serum and plasma.
The clinical manifestations of leptospirosis range from a mild catarrh-like illness to icteric disease with severe liver and kidney involvement. Natural reservoirs for leptospirosis include rodents as well as a large variety of domesticated mammals. The organisms occupy the lumen of nephritic tubules in their natural host and are shed into the urine. Human infection derives from direct exposure to infected animals (veterinarians, abattoir workers, or dairy workers for example) or by exposure to environments contaminated by animal carriers (e.g. agricultural workers). Bathing or swimming in water sources about which livestock have been pastured has been demonstrated to be a potential infection hazard. The organisms enter the host through skin abrasions, mucosal surfaces or the eye. The incubation period can range from 3 to 30 days but is usually found to be 10 to 12 days. Antibodies can become detectable by the 6th to 10th day of disease and generally reach peak levels within 3 to 4 weeks. Antibody levels then gradually recede but may remain detectable for years. Epidemiologic factors, clinical findings, exposure in endemic regions and other laboratory results should be considered in diagnosing acute disease. Acute disease diagnosis will also include a positive laboratory confirmation in many cases. This test is designed to measure acute infections with leptospira. Confirmation of a positive sample by additional methods should be followed.
The microwells are coated with purified Leptospira Patoc 1 antigen. During the first incubation with the diluted patient sera, any antibodies which are reactive with the antigen will bind to the coated wells. After washing to remove the rest of the sample, the Enzyme Conjugate is added. If antibodies have been bound to the wells, the Enzyme Conjugate will then bind to these antibodies. After another series of washes, a chromogen (tetramethylbenzidine, or TMB) is added. If the Enzyme Conjugate is present, the peroxidase will catalyze a reaction that consumes the peroxide and turns the chromogen from clear to blue. Addition of the Stop Solution ends the reaction and turns the blue color to a bright yellow color.
- Kelly PW. Leptospirosis. In, Infectious disease in medicine and surgery. Gorbach S, Bartlett J, Balcklow N, (eds): Philadelphia, Saunders, 1991, pp.1295-1302.
- Ribeiro MA, Assis CSN, Romero EC. Serodiagnosis of human leptospirosis employing immunodominant antigen. Serodiagn. Immunother. Infect. Disease 1994; 6:140-144.
- Turner LH. Leptospirosis II. Trans. Royal Soc. Trop. Med. & Hygiene 1968; 62:880-889.
- Pappas MG, Ballou WR, Gray MR, et. al. Rapid serodiagnosis of leptospirosis using the IgM-specific dot- ELISA: Comparison with the microscopic agglutination test. Am J Trop Med Hyg 1985; 34(2):346-354.
- Alder B, Murphy AM, Locarnini SA, et.al. Detection of specific anti-leptospiral immunoglobulin M and immunoglobulin G in human serum by solid phase enzyme-linked immunosorbent assay. J. Clin. Micro 1980; 11:452-457.
- Cinco M, Balanzini D, Banfi E. Evaluation of an immunoenzymatic test (ELISA) for the diagnosis of leptospirosis in Italy. Eur. J. Epidemiology 1992; 8:677-682.
- Ribeiro MA, Sousa CC, Almeida SHP. Dot-ELISA for human leptospirosis employing immunodominant antigen. J. Trop.Med. Hyg. 1995; 98:452-456.
- Gussenhoven GC, van der Hoorn M, Goris M, et. al. LEPTO dipstick, a dipstick assay for detection of leptospira-specific immunoglobulin M antibodies in human sera. J. Clin. Micro. 1997; 35(1):92-97.
- Watt G, Alquiza LM, Padre LP, et. al. The rapid diagnosis of leptospirosis: A prospective comparison of the dot enzyme-linked immunosorbent assay and the genus-specific microscopic agglutination test at different stages of illness. J. Infect. Dis. 1988; 157(4)840-842.
- Levett PN, Branch SL, Paxton H. Prospective Evaluation of Dot-ELISA Method for Detection of Acute Leptospirosis. Abstract of the 37th ICAAC (ASM) 1997; D-4: 83.