Macroscopic Agglutination Test for Rapid Diagnosis of Human Leptospirosis

ABSTRACT A commercially available slide agglutination test (SAT) for the diagnosis of human leptospirosis was evaluated by comparing it to an immunoglobulin M (IgM) enzyme-linked immunosorbent assay (ELISA) and to the microscopic agglutination test (MAT). For all 108 patients, leptospirosis was diagnosed on the basis of a fourfold or greater increase in titer by MAT (seroconversion), and all but 1 of 245 controls were MAT negative (titers, &lt;1:100). Both SAT and the IgM ELISA failed to detect one case of infection (sensitivity, 99%). Only 3 of 145 blood donors and none of the 100 patients with other illnesses were SAT positive (specificity, 99%). The overall results were similar for the three tests; however, SAT and ELISA were statistically more sensitive as initial screening tests. For 22% of the patients, the diagnosis of leptospirosis was made earlier by SAT than by MAT. SAT detected 27 (44%) of 62 MAT-negative patients with the first serum sample. ELISA and SAT had very similar results. Follow-up of patients for 1 year after the onset of symptoms showed a decreasing rate of positivity by SAT from the third month on. The rate of positivity by ELISA decreased more slowly, to about 67% by the end of the study. By MAT all patients were persistently reactive. SAT and ELISA seem to be convenient methods for the rapid and early screening for leptospirosis and could replace the less sensitive MAT. ELISA gives less subjective results than SAT and provides information on IgM kinetics, but it can be performed only by the more sophisticated laboratories. SAT is inexpensive, can be performed more quickly and more easily than ELISA, and could be used by the less well equipped laboratories.</jats:p

Leptospirosis severity may be associated with the intensity of humoral immune response

A gravidade da leptospirose parece estar aumentando principalmente quanto ao envolvimento pulmonar. Essa maior gravidade poderia ser decorrente de uma resposta imunológica mais intensa, já que tanto a insuficiência renal, quanto a plaquetopenia e as lesões pulmonares são encontradas na fase imune da doença. Para investigar esta hipótese foram detectados por ELISA anticorpos IgM, IgG e IgA específicos em amostras de sangue de 35 pacientes internados com síndrome de Weil colhidas a partir de cerca de 15 dias do início dos sintomas até 1 ano após a alta. Os pacientes foram divididos em 2 grupos conforme o seu título de IgG na primeira amostra, colhida com até 2 semanas de sintomas: grupo 1 (n = 13) com título >;1:400 (positivo) e grupo 2 (n = 22) com títuloLeptospirosis severity may be increasing, with pulmonary involvement becoming more frequent. Does this increase result from an intense immune response to leptospire? Notice that renal failure, thrombocytopenia and pulmonary complications are found during the immune phase. Thirty-five hospitalized patients with Weil\u27s disease had 5 blood samples drawn, from the 15th day to the 12th month of symptoms, for ELISA-IgM, -IgG and -IgA specific antibody detection. According their 1st IgG titer, the patients were divided into: group 1 (n = 13) titer >; 1:400 (positive) and group 2 (n = 22) tite

A gravidade da leptospirose pode estar associada à intensidade da resposta imune humoral

Leptospirosis severity may be increasing, with pulmonary involvement becoming more frequent. Does this increase result from an intense immune response to leptospire? Notice that renal failure, thrombocytopenia and pulmonary complications are found during the immune phase. Thirty-five hospitalized patients with Weil's disease had 5 blood samples drawn, from the 15th day to the 12th month of symptoms, for ELISA-IgM, -IgG and -IgA specific antibody detection. According their 1st IgG titer, the patients were divided into: group 1 (n = 13) titer > 1:400 (positive) and group 2 (n = 22) titer <=1:400 (negative). Early IgG antibodies in group 1 showed high avidity which may indicate reinfection. Group 1 was older, had worse pulmonary and renal function, and fever for a longer period than group 2. Throughout the study, IgG and IgA titers remained higher in group 1. In conclusion, the severity of Weil's disease may be associated with the intensity of the humoral immune response to leptospire.A gravidade da leptospirose parece estar aumentando principalmente quanto ao envolvimento pulmonar. Essa maior gravidade poderia ser decorrente de uma resposta imunológica mais intensa, já que tanto a insuficiência renal, quanto a plaquetopenia e as lesões pulmonares são encontradas na fase imune da doença. Para investigar esta hipótese foram detectados por ELISA anticorpos IgM, IgG e IgA específicos em amostras de sangue de 35 pacientes internados com síndrome de Weil colhidas a partir de cerca de 15 dias do início dos sintomas até 1 ano após a alta. Os pacientes foram divididos em 2 grupos conforme o seu título de IgG na primeira amostra, colhida com até 2 semanas de sintomas: grupo 1 (n = 13) com título >1:400 (positivo) e grupo 2 (n = 22) com título <= 1:400 (negativo). Os anticorpos IgG no grupo 1 na primeira amostra mostraram alta avidez pelo antígeno o que sugere reinfecção. Mesmo em amostras mais tardias os títulos de IgG e IgA no grupo 1 foram mais elevados que no grupo 2. Os pacientes do grupo 1 eram mais idosos, permaneceram com febre por mais tempo e tiveram maior comprometimento renal e pulmonar. Estes resultados sugerem que a gravidade da leptospirose pode estar associada à intensidade da resposta humoral

Application of anti-leptospira ELISA-lgM for the etiologic elucidation of meningitis

A Leptospirose é uma das causas de meningite, embora sua importância seja pouco conhecida. O presente estudo contribui para este conhecimento ao demonstrar anticorpos específicos da classe IgM anti-Leptospira pelo método imunoenzimático (ELISA), em 14,6% das amostras de líqüido cefalorraquianos (LCR) de 171 pacientes com meningite considerada de etiología indeterminada. As freqüências de positividade foram parecidas nos casos com predomínio no LCR de leucócitos polimorfonucleares ou linfomononucleares. A distribuição por idade mostrou predomínio na faixa etária entre 5 e 15 anos (72%) e por sexo o predomínio do masculino (68%). Os autores discutem a contribuição desse método na elucidação etiológica das meningites.Leptospirosis is one of the causes of meningitis, although its importance is not well known. In the present study we contributed to this knowledge by demonstrating specific IgM class anti-leptospira antibodies by the immunoenzymatic method ELISA in 14.6% of cerebrospinal fluid (CSF) samples from 171 patients with meningitis considered to be of indeterminate etiology. The frequencies of positivity were similar in cases with predominance of polymorphonuclear or lymphomononuclear leucocytes in the CSF. Age distribution showed a predominance of the 5 to 15 year age range (72%), and sex distribution showed a predominance of males (68%). The authors discuss the contribution of this method to the etiologic elucidation of meningitis

Detection of <i>Leptospira</i> DNA in Patients with Aseptic Meningitis by PCR

ABSTRACT Samples of cerebrospinal fluid from 103 patients with aseptic meningitis were tested by PCR for detection of leptospires, and the results were compared with those of the microscopic agglutination test (MAT) and an enzyme-linked immunosorbent assay for detection of immunoglobulin M (ELISA-IgM). Of these samples, 39.80% were positive by PCR and 8.74 and 3.88% were positive by MAT and ELISA-IgM, respectively.</jats:p