Paulo Hideki Yasuda

Human leptospirosis: a twenty-nine-year serological study in São Paulo, Brazil.

A retrospective study of 9,335 cases of human leptospirosis in the state of São Paulo, Brazil, diagnosed between 1969 and 1997 showed that the disease is endemic throughout the state. Middle-aged adults, with a range of 20-39 years, were most frequently infected (32.40%). The mean annual incidence was 0.53 per 100,000 population and the disease was more frequent in males (87.0%). Cases occurred mainly in January to April each year. A peak was observed in 1991 and 1996 which rainfall average was 159.9 and 160.3, respectively. These data emphasize the potential public health importance of leptospirosis in the state of São Paulo, Brazil.

Cardiovascular involvement in human and experimental leptospirosis: pathologic findings and immunohistochemical detection of leptospiral antigen

Twenty hearts from patients dying of leptospirosis were studied. Interstitial myocarditis was found in 50% of the cases, and a significant statistical correlation was observed between myocarditis and the inflammatory involvement of the conduction tissue. Acute coronary arteritis, affecting the main branches of the coronary arteries, was observed in 70% of the cases, and this finding also correlates significantly with interstitial myocarditis. Aortitis was found in 57.8% of the cases. When serum against L. interrogans serovar icterohaemorrhagiae was used, focal IP antigen deposits were observed in the coronary arteries and in the aorta. Experimental data from 12 guinea-pigs inoculated with L. interrogans serovar icterohaemorrhagiae showed a focal myocarditis involving mainly the subendocardial and pericoronary heart tissue, with IP antigen deposits in the same sites. Leptospirosis might be visualized as a generalized illness resembling other infectious vasculitides. The heart and main vessels are involved during the septicaemic phase of the disease, and bacterial migration, toxin(s), enzymes and/or antigenic products liberated by bacterial lysis might account for the increased endothelial permeability with antigen deposits and inflammation.

Sorovares de Leptospira interrogans isolados de casos de leptospirose humana em São Paulo, Brasil

Eighteen strains of L. interrogans isolated from human cases were serotyped by the Agglutinin-absorption test at Instituto Adolfo Lutz in Sao Paulo, Brazil. Fourteen were identified as serovar copenhageni (Icterohaemorrhagiae serogroup), 2 as canicola (Canicola serogroup), 1 as castellonis (Ballum serogroup) and 1 as Pomona serogroup (serovar not yet defined). The frequency of serovar copenhageni in 100% of the isolates in Icterohaemorrhagiae serogroup is emphasized and more studies to verify the real serovars prevalence as subsidy to the epidemiology of this infection are suggested by the authors

Molecular characterization of Leptospira sp. strains isolated from human subjects in São Paulo, Brazil using a polymerase chain reaction-based assay: a public health tool

A polymerase chain reaction (PCR)-based assay which amplifies repetitive DNA elements present within bacterial genomes was used to characterize and differentiate Leptospira sp. Thirty-five strains from a reference culture collection and 18 clinical isolates which had been previously analyzed by cross agglutinin absorption test (CAAT) were evaluated by this technique. PCR results from analysis of the reference culture collection showed no bands corresponding to serogroups Australis, Autumnalis, Bataviae, Celledoni, Cynopteri, Djasiman, Panama, Pomona, Pyrogenes, and Tarassovi. However, the PCR method was able to clearly discriminate the serogroups Andamana, Ballum, Canicola, Grippotyphosa, Hebdomadis, Icterohaemorrhagiae, Javanica, Sejroe, Semaranga, and Shermani. Clinical isolates previously characterized by CAAT as serovar Copenhageni, serovar Castellonis, and as serovar Canicola were in agreement with PCR results. The clinical isolate previously characterized as serovar Pomona was not differentiated by PCR. Forty additional clinical isolates from patients with leptospirosis obtained in São Paulo, Brazil were also evaluated by this PCR method. Thirty-nine of these were determined to belong to serogroup Icterohaemorrhagiae (97.5%) and one to serogroup Sejroe (2.5%). These results demonstrate that the PCR method described in this study has utility for rapid typing of Leptospira sp. at the serogroup level and can be used in epidemiological survey.

Experimental leptospirosis (L. interrogans serovar icterohaemorrhagiae) of the guinea pig: leptospiral antigen, gamma globulin and complement C3 detection in the kidney

Morphofunctional and immunofluorescent studies were done in guinea pigs experimentally infected with Leptospira interrogans serovar icterohaemorrhagiae to determine the role of leptospiral antigen, gamma-globulin, and complement C3 deposits in the pathogenesis of the renal lesions. A sharp increase in leptospiral antigen deposits was observed in the late phase of the experimental infection. Immunoglobulin and complement C3 were small compared with the heavy leptospiral antigen deposits. Moreover, leptospiral antigen was observed mainly in the interstitium whereas immunoglobulin and complement C3 deposits were seen in glomeruli and small blood vessel walls. In our experimental model bacterial migration and local liberation of factors causing virulence seems more likely to determine the renal damage.

Aseptic meningitis caused by Leptospira spp diagnosed by polymerase chain reaction

Leptospirosis is a zoonotic disease caused by the pathogenic Leptospira spp. The clinical presentations are diverse, ranging from undifferentiated fever to fulminant disease including meningeal forms. The neurological leptospirosis forms are usually neglected. The aim of this study was to investigate leptospirosis as the cause of aseptic meningitis using different diagnostic techniques including the polymerase chain reaction (PCR). Thirty-nine cerebrospinal fluid (CSF) samples from patients presenting with meningeal abnormalities, predominance of lymphocytes and negative results by traditional microbiological tests were processed by leptospiral culture, anti-leptospiral antibody response and PCR. Leptospira spp DNA was detected in 23 (58.97%) of the CSF samples. Anti-leptospiral antibodies were found in 13 (33.33%) CSF samples. Twelve CSF samples were positive by PCR assay and negative by microscopic agglutination test (MAT) assay. Two CSF samples were positive by MAT and negative by PCR. The positive and negative agreement between both tests was 11 and 14, respectively. CSF samples from six cases of unknown diagnosis were positive by PCR assay. Eight cases showed positive results using PCR and MAT. Leptospirosis could be detected by PCR assay from the 3rd-26th day after illness onset. The sensitivity of the PCR was assessed with confirmed cases of leptospirosis (by MAT) and found to be 89.5%. All CSFs were negative by culture. PCR was found to be a powerful tool for diagnosing meningitis cases of leptospirosis. We recommend that it may be used as a supplementary diagnostic tool, especially in the early stages of the disease, when other diagnostic techniques such as serology are not sensitive.

Surto de leptospirose humana por atividade recreacional no município de José dos Campos, São Paulo: estudo soroepidemiológico

An outbreak of human leptospirosis due to recreational activities ocurred at Sao Jose dos Campos, Sao Paulo, Brazil in November 1987. It involved a group of persons who had participated in a gathering in a suburb club which had a swimming pool fed with natural water. Epidemiological investigation was carried out and laboratorial tests from the patients were done. It was observed that a high prevalence of the pomona serotype (91%) was found in the serological analyses, while the presence of the agent of the infection could not be found in the water club swimming pool.An outbreak of human leptospirosis due to recreational activities occurred at São José dos Campos, São Paulo, Brazil in November 1987. It involved a group of persons who had participated in a gathering in a suburb club which had a swimming pool fed with natural water. Epidemiological investigation was carried out and laboratory tests from the patients were done. It was observed that a high prevalence of the pomona serotype (91%) was found in the serological analyses, while the presence of the agent of the infection could not be found in the water club swimming pool.

Glicolipoproteína de Leptospira interrogans sorogrupo icterohaemorrhagiae: distribuição em fígado e rim de cobaias experimentalmente infectadas

Tissue damage in leptospirosis has been ascribed to direct effect of the microorganisms and/or their virulence, including products synthetised by leptospires or released during their lysis. This study aimed at chemical extraction of the glycolipoprotein (GLP) from virulent leptospires, production of a rabbit anti-GLP and analysis of its distribution in liver and kidney of inoculated guinea-pigs, sacrificed sequentially from the 1st to 6th day of infection, covering the whole, spectrum of acute leptospirosis. The comparison of GLP expression to local injuries aimed at new pathogenetic data. GLP was detected in liver and kidney in 2 out of 6 guinea-pigs on the 5th day and in all 6 animais on the 6th day of infection. Granular forms were seen in the cytoplasm of macrophages, free in interstitium or adhered to endothelial and parenchimal cell membranes, especially in the most damaged sites. These findings lead us to the hypothesis of GLP as a toxic factor resulting from leptospiral lysis by macrophages. Although it was not proved as a promoter of initial lesions, it seems to be related to the enhancement of tissue damage late in the course of the disease.

An immunohistochemic assay to localize leptospires in tissue specimens

Os autores apresentam uma tecnica de imunoperoxidase para a identificacao de leptospiras em cortes de rim fixados em formol e emblocados em parafina. A variante metodologica inclui a utilizacao do complexo peroxidase-antiperoxidase, conferindo alta sensibilidade a reacao. Sao, ainda, discutidas algumas possiveis aplicacoes do metodo ao estudo do acometimento renal na leptospirose.

Variação sazonal na prevalência de leptospirose em cães de rua da cidade de São Paulo, Brasil

Utilizando a tecnica da soroaglutinacao microscopica para o diagnostico de leptospirose, 308 (21,6%) de 1428 soros de caes errantes da cidade de Sao Paulo (Brasil) mostraram-se reagentes. Na populacao canina estudada, a infeccao leptospirotica sofreu influencia sazonal. Verao (24,2%) e outono (24,9%) foram as estacoes do ano com maior numero de soros reatores, em oposicao a primavera (18,3%) e inverno (18,3%). Estas diferencas foram significantes, estatisticamente. O sorotipo canicola e o principal causador da leptospirose na populacao estudada (50,7%), seguido do icterohaemorrhagiae (25,5%); grippotyphosa (7,8%); pomona (6,7%) e ballum (4,4%).One thousand, four hundred and twenty-eight sera from stray dogs from the city of S. Paulo were examined using agglutination microscopic testing. Of the total of 1428 sera, 308 (21.6%) showed positive. Seasonal influence was observed in the leptospiral infection of the canine population studied in that the largest number of the reagent sera was verified in the summer (24.2%) and autumn (24.9%). In contrast, spring (18.3%) and winter (18.3%) prevalence levels were lower. These differences were considered significant from the statistical point of view. The canicola serotype was found to be the main cause of leptospirosis in the population examined (50.7%), followed by icterohaemorrhagiae (25.5%), grippetyphosa (7.8%), pomona (67%), and ballum (4.4%).