ABSTRACT
A leptospirose é a zoonose de maior distribuição geográfica, com estimativa de cerca de 60.000 mortes por ano. A doença é causada por bactérias do gênero Leptospira, que possui mais de 300 diferentes sorovares e 64 espécies já identificadas, sendo o ambiente a principal fonte de contaminação. A doença em humanos apresenta manifestações clínicas variadas e caráter bifásico, devendo ser confirmada por meio do diagnóstico laboratorial. O objetivo deste trabalho foi reunir conceitos atualizados sobre a leptospirose humana e as principais técnicas de diagnóstico laboratorial empregadas. A MAT é considerada o padrão-ouro para o diagnóstico da leptospirose, mas devido à baixa sensibilidade na fase inicial da doença é necessário o emprego de técnicas mais sensíveis neste período. Baseado em diversos estudos, as metodologias de PCR, ELISA-IgM e teste rápido apresentaram sensibilidade satisfatória nos primeiros dias após o início dos sintomas. Na segunda semana, a MAT apresentou 100% de sensibilidade, mantendo sua alta especificidade em ambas as fases. No geral, os testes sorológicos de ELISA-IgM e teste rápido apresentaram resultados satisfatórios como métodos de diagnóstico precoce, principalmente tratando-se de locais com pouca infraestrutura, diferente dos laboratórios de referência onde é possível empregar as técnicas de PCR e MAT.
Leptospirosis is the most widespread zoonosis, which has a balance of almost 60,000 deaths per year. Bacteria of Leptospira genus, which has more than 300 different serovars and 64 species already identified, cause the disease, being the environment the main source of contamination. The human disease presents a large set of clinical manifestations, showing biphasic presentation, the reason why leptospirosis must be confirmed by laboratory diagnosis. This study aimed to group recent concepts concerning human leptospirosis and the main diagnosis techniques employed at the laboratory. MAT is considered the gold standard for leptospirosis diagnosis, but has low sensitivity on the onset of disease, leading to the use of techniques with higher sensitivity on this period. Based on several studies, PCR, ELISA-IgM and rapid test presented satisfactory sensitivity on the onset of symptoms. In the second week, MAT showed 100% of sensitivity, maintaining its high specificity in both phases. In general, the ELISA-IgM and rapid serological tests showed satisfactory results as methods for early diagnosis, especially in the case of places with poor infrastructure, different from the reference laboratories where it is possible to use the PCR and MAT techniques.
Subject(s)
Weil Disease , Leptospirosis/diagnosis , Leptospirosis/etiology , Spirochaetales , Polymerase Chain Reaction , Clinical Laboratory Techniques , LeptospiraABSTRACT
Laboratory diagnosis of human leptospirosis usually relies on indirect methods exploring specific immune response. Isolation and identification of the involved strains are cumbersome, but can provide biological resources for pathogenic studies and relevant information for guiding prevention and control measures. The aim of the research we are hereby reporting was the characterization of Leptospira isolates obtained from humans and the environment in Uruguay. Blood cultures were performed from early samples of 302 Uruguayan patients, mainly rural workers, and from 36 water samples taken from their living or working environments. Eight human isolates and seven environmental isolates were obtained and analyzed by end point Polymerase Chain Reaction (PCR), Multilocus Variable Number of Tandem Repeat Analysis (MLVA) and other molecular methods. Human isolates corresponded to several serogroups and serovars of Leptospira interrogans and Leptospira kirschneri species, probably reflecting the infection with similar involved Leptospira species and serovars of an extended animal reservoir in rural settings of the country, mostly dedicated to meat and dairy production. Culture-positive patients were older than usually affected workers, and presented signs and symptoms of severe illness. A high organic and circulating bacterial burden may explain an easier positive result from these workers' samples. Environmental isolates were mainly identified as Leptospira biflexa strains, with a single L. meyeri isolate of uncertain significance.
Subject(s)
Leptospira/isolation & purification , Leptospirosis/blood , Leptospirosis/microbiology , Water Microbiology , Adult , Blood/microbiology , Blood Culture/methods , DNA, Bacterial , Electrophoresis, Gel, Pulsed-Field , Humans , Leptospira/genetics , Middle Aged , Minisatellite Repeats , Multilocus Sequence Typing , Polymerase Chain Reaction , Reference Values , Rural Population , Serogroup , UruguayABSTRACT
INTRODUCTION:: Leptospirosis is an important health concern in Brazil. Currently, information on the epidemiology of the disease in the rural areas of the country is lacking. METHODS:: Serological and molecular techniques were used to characterize a clinical isolate of Leptospira. RESULTS:: The strain CLEP 00060, isolated from a 59-year-old man in a rural area of Rio Grande do Sul state, Brazil, was identified as belonging to L. kirschneri serogroup Pomona serovar Mozdok. CONCLUSIONS:: This study contributes to the local epidemiological knowledge of leptospirosis, prevention of the disease by vaccines, and improvements in its diagnosis.
Subject(s)
Leptospira/classification , Leptospirosis/microbiology , Agglutination Tests , Brazil , Electrophoresis, Gel, Pulsed-Field , Humans , Leptospira/genetics , Leptospira/immunology , Leptospirosis/diagnosis , Male , Middle Aged , Multilocus Sequence Typing , Phylogeny , Rural Population , Serogroup , SerotypingABSTRACT
Abstract INTRODUCTION: Leptospirosis is an important health concern in Brazil. Currently, information on the epidemiology of the disease in the rural areas of the country is lacking. METHODS: Serological and molecular techniques were used to characterize a clinical isolate of Leptospira. RESULTS: The strain CLEP 00060, isolated from a 59-year-old man in a rural area of Rio Grande do Sul state, Brazil, was identified as belonging to L. kirschneri serogroup Pomona serovar Mozdok. CONCLUSIONS: This study contributes to the local epidemiological knowledge of leptospirosis, prevention of the disease by vaccines, and improvements in its diagnosis.
Subject(s)
Humans , Male , Leptospira/classification , Leptospirosis/microbiology , Phylogeny , Rural Population , Brazil , Agglutination Tests , Serotyping , Electrophoresis, Gel, Pulsed-Field , Multilocus Sequence Typing , Serogroup , Leptospira/genetics , Leptospira/immunology , Leptospirosis/diagnosis , Middle AgedABSTRACT
The presence of Leptospira spp. and Brucella spp. antibodies was investigated in serum samples from 28 collared anteaters (Tamandua tetradactyla) kept in seven Brazilian zoos. Sera were tested against 19 Leptospira serovars using microscopic agglutination. Samples reacted to the following serovars: two (7.14%) to Patoc, three (10.71%) to Tarrasovi, three (10.71%) to both Patoc and Tarrasovi, two (7.14%) to Wolffi, and one (3.57%) to Australis. Two (7.14%) samples reacted to the buffered Brucella antigen test, but no confirmatory reaction occurred using the 2-mercaptoethanol slow slide agglutination test. No sample was reactive in the agar gel immunodiffusion test for rugose species of Brucella. The presence of anti-leptospira agglutinins in captive T. tetradactyla serum indicates that this species may be susceptible to infection by these bacteria.
Subject(s)
Antibodies, Bacterial/blood , Brucella/immunology , Brucellosis/veterinary , Leptospira/immunology , Leptospirosis/veterinary , Xenarthra , Animals , Animals, Zoo , Brazil/epidemiology , Brucellosis/epidemiology , Brucellosis/immunology , Female , Leptospirosis/epidemiology , Leptospirosis/immunology , Male , Xenarthra/bloodABSTRACT
A leptospirose humana e animal representam um problema de saúde pública de importância no Brasil e no Mundo. O homem pode se contaminar pela exposição ao animal infectado ou ao seu meio ambiente. Diversos estudos têm focalizado o desenvolvimento de uma nova geração de vacinas baseadas na identificação de proteínas da membrana externa (OMPs), as quais podem ser relevantes na interação parasito-hospedeiro e estimular imunidade heteróloga. Contudo, há limitações no estabelecimento de modelos experimentais para o estudo de vacinas, sendo o principal objetivo deste trabalho avaliar a susceptibilidade e a resposta imune protetora em camundongos C3H/HeJ à infecção por Leptospira. Assim, foi utilizado um isolado clínico de Leptospira sorovar Copenhagen (25179) para os testes de susceptibilidade. Dezenove de 27 camundongos (4-5 semanas de idade) foram infectados com Leptospira nas doses equivalentes a 1,8 x 105, 2,5 x 105 e 2,3 x 106, nos três experimentos subseqüentes. Deste total, 9 camundongos foram susceptíveis à dose letal, sendo que o evento fatal ocorreu 7 a 10 dias após a infecção experimental.
No 21º dia, os 10 camundongos que sobreviveram foram sacrificados para a coleta de sangue, assim como a retirada dos rins e do fígado. Todos apresentaram títulos elevados de anticorpos aglutinantes (1:1600 a 1:6400) detectáveis pelo teste de aglutinação microscópica (MAT). Após extração de antígenos (LPS e OMPs) da cepa 25179, um soro imune de camundongo revelou uma banda de 39,35kDa do extrato de OMPs pela técnica de Western blotting (anticorpo secundário anti-IgG de camundongo). Porém, não houve revelação da banda característica do LPS de Leptospira utilizando o mesmo anticorpo secundário. As leptospiras foram isoladas em cultura dos rins de 8 e do fígado de 2, dentre 10 animais sobreviventes. PCR detectou DNA de Leptospira nos rins de 9 dos camundongos infectados. Os dados obtidos confirmam a susceptibilidade e a potencial utilização do modelo para estudos ligados à patogênese da leptospirose. Entretanto, tais resultados obtidos não são conclusivos devido à ausência de resposta imune de anticorpos dirigidos ao LPS, e de uma fraca resposta de anticorpos às proteínas da membrana externa. Investigações adicionais são necessárias na tentativa de entender o mecanismo imune e a patogênese da leptospirose humana.
