Is CK-MB isoenzyme useful for diagnosis of cardiac involvement in icteric leptospirosis?

In the absence of heart failure or cardiogenic shock, cardiac involvement diagnosis in icteric leptospirosis is possible on the basis of abnormal electrocardiograms. As metabolic and electrolytic disorders are frequently seen during acute leptospirosis infection, they may be responsible for some electrocardiograms changes. We conducted a study to assess if creatine phosphokinase isoenzyme determinations are useful in selecting patients with a high cardiac involvement suspicion. Sixty-nine patients were studied prospectively. Ten patients out of 16 with cardiac involvement and 25 without had high CK-MB levels (p>0.05), although mean values of abnormal CK-MB levels were higher in the group with cardiac involvement (p<0.05). Our analysis indicates that serum CK-MB determination does not provide a specific indicator of myocardial involvement in the course of icteric leptospirosis.

Clinical-epidemiological study of leptospirosis in humans and reservoirs in Yucatán, México

A leptospirosis clinical-epidemiological study was made in humans and reservoirs in the state of Yucatán, México. Interviews and serological analyses were made on 400 persons from an open population, 439 probable cases of leptospirosis and 1060 animal reservoirs (cows, pigs, dogs, rats and opossums). IgM Leptospira DipstickTM and Microscopic Agglutination Test (MAT) was used to detect human antibodies to leptospiras and serovar respectively. Leptospirosis incidence in humans was 2.2/100,000 inhab. in 1998, 0.7/100,000 in 1999 and 0.9/100,000 in 2000. Overall seroprevalence was 14.2%, relatively unchanged from seroprevalences observed 20 years ago. Highest seropositivity was found in people over 56 years of age, predominating males over females. Predominant serovars in the open population were tarassovi, hardjo, pomona and panama. Leptospirosis cases were most frequent in rural areas, and the anicteric course predominated over the icteric. The panama, icterohaemorrhagiae and pomona serovars predominated in both anicteric and icteric courses. Dogs, pigs and rodents had the highest seropositivity among the reservoirs. Contact with rodents and natural water sources were significant factors (p £ 0.05). Human cases (74%) occurred during the rainy season. It is concluded that leptospirosis is still a serious illness with important clinical and epidemiological implications in the state of Yucatán, Mexico.

Comparative study of the in-hospital case-fatality rate of leptospirosis between pediatric and adult patients of different age groups

The main objective was to compare the in-hospital case-fatality rate of leptospirosis between pediatric (< 19 years) and adult (>19 years) patients, taking into account gender, renal function, duration of symptoms and jaundice. Medical records of 1016 patients were reviewed. Comparative analysis was restricted to 840 patients (100 pediatric, 740 adults) with recorded information on the variables included in the analysis. Among these patients 81.7% were male and 91.5% were icteric. The case-fatality rate of leptospirosis was 14.4%. The odds of death adjusted for gender, jaundice, duration of symptoms, serum urea and serum creatinine were almost four times higher for the adult than for the pediatric group (odds ratio (OR) = 3.94; 95% confidence interval = 1.19-13.03, p = 0.029). Among adults, increased age was also significantly and independently associated with increased risk of death (p < 0.01). Older patients were also more often treated by dialysis. In conclusion, the data suggest that the in-hospital case fatality rate of leptospirosis is higher for adults than for children and adolescents, even after taking into account the effects of several potential risk factors of death. Among adults, older age was also strongly and independently associated with higher risk of death.

Leptospiral glycolipoprotein as a candidate antigen for serodiagnosis of human leptospirosis

Aims: Development of a simple, specific, rapid and inexpensive Dot-ELISA test for early diagnosis of human leptospirosis. Methods and Results: Serum samples from 90 patients diagnosed with leptospirosis were analysed by Dot-ELISA test incorporating Glycolipoprotein (GLP) antigen from serovars Copenhageni and Patoc. Results were compared with those obtained with microscopic agglutination test, currently, the gold standard reference serological method. Serum samples from healthy blood bank donors and patients diagnosed with diseases other than leptospirosis were used as negative controls. The specificities of both GLP-based assays were 97 center dot 1% and 100% with serum samples from patients with other diseases and with serum samples from healthy control group, respectively. With serum samples from patients with acute leptospirosis, sensitivity was 76 center dot 6% with Dot-ELISA Copenhageni and 90 center dot 0% with Dot-ELISA Patoc. With serum samples from patients in convalescence, sensitivity was 100% with both GLP-based assays. Conclusions: This Dot-ELISA provides a candidate antigen for serodiagnosis of leptospirosis during all phases of illness and could be a good alternative method for the early diagnosis of leptospirosis. Significance and Impact of the Study: The Dot-ELISA test is simple, specific, rapid and inexpensive. It is suitable for identifying a large number of samples and, hence, reducing the death rate of patients with leptospirosis.

Predictors of Lethality in Severe Leptospirosis in Urban Brazil

To ascertain prognostic factors associated with fatal outcomes in severe leptospirosis, a retrospective case-control study was done using population-based surveillance data. Centralized death certificate reporting of leptospirosis mortality was combined with details of patients` hospitalizations, which were obtained from hospitals representing all sectors of Sao Paulo city. Among identified leptospirosis cases, 89 lethal cases and 281 survivor cases were analyzed. Predictors of death included age > 40 years, development of oliguria, platelet count < 70,000/mu L, creatinine > 3 mg/dL. and pulmonary involvement. The latter was the strongest risk Factor with all estimated odds ratio of 6.0 (95% confidence interval: 3.0-12.0). Serologic findings with highest titer against Leptospira interrogans serovar Copenhageni did not show significant differences between survivors and non-survivors. Lung involvement was an important predictor of death in leptospirosis in Sao Paulo, of relevance in leptospirosis-endemic regions where this complication is common.

Case Report: Severe, Symptomatic Hypomagnesemia in Acute Leptospirosis

We report a case severe hypomagnesemia in non-oliguric acute renal failure caused by leptospirosis that required large doses of magnesium replacement during the acute phase of disease. Biochemical studies confirmed kidney-related magnesium wasting and the mechanisms of this defect are discussed. Magnesium imbalance with its attendant clinical complications occurs in leptospirosis and should be monitored and treated aggressively in cases of leptospirosis-induced non-oliguric acute kidney injury.

Leptospirosis pulmonary haemorrhage syndrome is associated with linear deposition of immunoglobulin and complement on the alveolar surface

Leptospirosis is a zoonotic infection associated with severe diseases such as leptospirosis pulmonary haemorrhage syndrome (LPHS). The cause of pulmonary haemorrhage is unclear. Understanding which mechanisms and processes are involved in LPHS will be important in treatment regimens under development for this life-threatening syndrome. In the present study, we evaluated 30 lung specimens from LPHS patients and seven controls using histology and immunohistochemistry (detection of IgM, IgG, IgA and C3) in order to describe the pathological features associated with this syndrome. Immunoglobulin deposits were detected on the alveolar surface in 18/30 LPHS patients. Three staining patterns were observed for the immunoglobulins and C3 in the lung tissues of LPHS patients: AS, delicate linear staining adjacent to the alveolar surface, which was indicative of a membrane covering the luminal surface of type I and II pneumocyte cells; S, heterogeneous staining which was sporadically distributed along the alveolar septum; and IA, weak, focal intra-alveolar granular staining. Human LPHS is associated with individual and unique histological patterns that differ from those of other causes of pulmonary haemorrhage. In the present study, it was found that the linear deposition of immunoglobulins (IgA, IgG and IgM) and complement on the alveolar surface may play a role in the pathogenesis of pulmonary haemorrhage in human leptospirosis.

Early identification of leptospirosis-associated pulmonary hemorrhage syndrome by use of a validated prediction model

Objective: To identify prediction factors for the development of leptospirosis-associated pulmonary hemorrhage syndrome (LPHS). Methods: We conducted a prospective cohort study. The study comprised of 203 patients, aged >= 14 years, admitted with complications of the severe form of leptospirosis at the Emilio Ribas Institute of Infectology (Sao Paulo, Brazil) between 1998 and 2004. Laboratory and demographic data were obtained and the severity of illness score and involvement of the lungs and others organs were determined. Logistic regression was performed to identify independent predictors of LPHS. A prospective validation cohort of 97 subjects with severe form of leptospirosis admitted at the same hospital between 2004 and 2006 was used to independently evaluate the predictive value of the model. Results: The overall mortality rate was 7.9%. Multivariate logistic regression revealed that five factors were independently associated with the development of LPHS: serum potassium (mmol/L) (OR = 2.6; 95% CI = 1.1-5.9); serum creatinine (mmol/L) (OR = 1.2; 95% CI = 1.1-1.4); respiratory rate (breaths/min) (OR = 1.1; 95% CI = 1.1-1.2); presenting shock (OR = 69.9; 95% CI = 20.1-236.4), and Glasgow Coma Scale Score (GCS) < 15 (OR = 7.7; 95% CI = 1.3-23.0). We used these findings to calculate the risk of LPHS by the use of a spreadsheet. In the validation cohort, the equation classified correctly 92% of patients (Kappa statistic = 0.80). Conclusions: We developed and validated a multivariate model for predicting LPHS. This tool should prove useful in identifying LPHS patients, allowing earlier management and thereby reducing mortality. (C) 2009 The British Infection Society. Published by Elsevier Ltd. All rights reserved.

Different Patterns in a Cohort of Patients with Severe Leptospirosis (Weil Syndrome): Effects of an Educational Program in an Endemic Area

The aim of this study is to investigate the changes in clinical pattern and therapeutic measures in leptospirosis-associated acute kidney injury; a retrospective study with 318 patients in Brazil. Patients were divided according to the time of admission: 1985-1996 (group I) and 1997-2010 (group II). Patients were younger in group I (36 +/- 13 versus 41 +/- 16 years, P = 0.005) and the numbers of oliguria increased (21% versus 41% in group II, P = 0.014). Higher frequency of lung manifestations was observed in group II (P<0.0001). Although increased severity, there was a significant reduction in mortality (20% in group I versus 12% in group II, P = 0.03). Mortality was associated with advanced age, low diastolic blood pressure, oliguria, arrhythmia, and peritoneal dialysis, besides a trend to better mortality with penicillin administration. Leptospirosis is occurring in an older population, with a higher number of oliguria and lung manifestations. However, mortality is decreasing and can be the result of changes in treatment.

Targeted Mutagenesis in Pathogenic Leptospira Species: Disruption of the LigB Gene Does Not Affect Virulence in Animal Models of Leptospirosis

The pathogenic mechanisms of Leptospira interrogans, the causal agent of leptospirosis, remain largely unknown. This is mainly due to the lack of tools for genetically manipulating pathogenic Leptospira species. Thus, homologous recombination between introduced DNA and the corresponding chromosomal locus has never been demonstrated for this pathogen. Leptospiral immunoglobulin-like repeat (Lig) proteins were previously identified as putative Leptospira virulence factors. In this study, a ligB mutant was constructed by allelic exchange in L. interrogans; in this mutant a spectinomycin resistance (Spc(r)) gene replaced a portion of the ligB coding sequence. Gene disruption was confirmed by PCR, immunoblot analysis, and immunofluorescence studies. The ligB mutant did not show decrease virulence compared to the wild-type strain in the hamster model of leptospirosis. In addition, inoculation of rats with the ligB mutant induced persistent colonization of the kidneys. Finally, LigB was not required to mediate bacterial adherence to cultured cells. Taken together, our data provide the first evidence of site-directed homologous recombination in pathogenic Leptospira species. Furthermore, our data suggest that LigB does not play a major role in dissemination of the pathogen in the host and in the development of acute disease manifestations or persistent renal colonization.

Evaluation of Leptospiral Recombinant Antigens MPL17 and MPL21 for Serological Diagnosis of Leptospirosis by Enzyme-Linked Immunosorbent Assays

Leptospirosis is a zoonosis of multisystem involvement caused by pathogenic strains of the genus Leptospira. In the last few years, intensive studies aimed at the development of a vaccine have provided important knowledge about the nature of the immunological mechanisms of the host. The purpose of this study was to analyze the immune responses to two recombinant proteins, MPL17 and MPL21 (encoded by the genes LIC10765 and LIC13131, respectively) of Leptospira interrogans serovar Copenhageni in individuals during infection. The recombinant proteins were expressed in Escherichia coli as six-His tag fusion proteins and were purified from the soluble bacterial fraction by affinity chromatography with Ni2+ -charged resin. The recombinant proteins were used to evaluate their ability to bind to immunoglobulin G (IgG) (and IgG subclass) or IgM antibodies in serum samples from patients in the early and convalescent phases of leptospirosis (n = 52) by enzyme-linked immunosorbent assays. The prevalences of total IgG antibodies against MPL17 and MPL21 were 38.5% and 21.2%, respectively. The titers achieved with MPL17 were statistically significantly higher than those obtained by the reference microscopic agglutination test. The specificity of the assay was estimated to be 95.5% for MPL17 and 80.6% for MPL21 when serum samples from individuals with unrelated febrile diseases and control healthy donors were tested. The proteins are conserved among Leptospira strains that cause human and animal diseases. MPL17 and MPL21 are most likely new surface proteins of leptospires, as revealed by liquid-phase immunofluorescence assays with living organisms. Our results demonstrate that these recombinant proteins are highly immunogenic and, when they are used together, might be useful as a means of diagnosing leptospirosis.

Risk factors associated with leptospirosis in dairy goats under tropical conditions in Brazil

Serum samples from 248 adult dairy goats from 13 flocks with lowered fertility farmed in the Rio de Janeiro region of Brazil were examined for Leptospira antibodies by MAT with 24 serovars, cut off 100. A questionnaire was completed for each herd. Antibodies were detected in 20.8% of these goats, mainly to serovar Hardjo. Risk factors associated with seroprevalence to leptospirosis were the frequency of professional veterinary supervision (OR = 2.35), climate (OR = 2.63) and grazing for more than 2 h a day. Flock factors as size, type of milking and offering of food supplementation, as well as the location and topography, the type of animal housing or the presence of silos did not significantly affect seroprevalence. We suggest that a successful control program for goat leptospirosis should include a complete investigation of herd management practices, which could influence in the occurrence of the infection. (C) 2007 Elsevier Ltd. All rights reserved.

Use of saprophytic leptospira strains in the serodiagnosis of experimental leptospirosis in guinea-pigs (Cavia sp)

The efficiency of four Leptospira biflexa strains (Buenos Aires, Patoc 1, Rufino and São Paulo) as single antigen in the serodiagnosis in guinea-pigs experimentally infected with seven Leptospira interrogans serovars (canicola, grippotyphosa, hardjo, icterohaemorrhagiae, pomona, tarassovi and wolffi) was evaluated by the microscopic agglutination test. The four saprophytic strains were not able to reveal antibody titres in sera of guinea-pigs experimentally infected with Leptospira interrogans. Serological cross-reactions were observed between strains Patoc 1 and São Paulo and between serovars wolffi and hardjo.

Thrombocytopenia and leptospirosis

The present study has intended to contribute to the elucidation of the pathogenic mechanisms, involved in the thrombocytopenia and in the bleeding diathesis seen in the course of Leptospirosis. The group of cases included in the present prospective study consisted of 30 patients with Leptospirosis, admitted to the Infectious and Parasitic Diseases Ward, Hospital das Clínicas, Faculty of Medicine, University of São Paulo. The following possible mechanisms of thrombocytopenia have been considered and therefore investigated: platelet consumption, due to disseminated intravascular coagulation; immune-mediated platelet destruction, due to platelet-associated antibodies and an inhibited platelet production in the bone marrow. Thrombocytopenia occurred in 86.6% of 30 patients and did not seem to be immune-mediated by platelet-associated antibodies. Furthermore it did not seem to be due to a disseminated intravascular coagulation consumption. Although there was a statistically-significant correlation between bone marrow platelet production and platelet counts we think that the static microscopic examination of a bone marrow aspirate cannot accurately depict the dynamic mechanisms of platelet production when these cells are being consumed in peripheral blood. Vasculitis should be considered as the most important factor for the pathogenesis of the bleeding disturbances in Leptospirosis. However, we believe that thrombocytopenia, uremia and coagulation disorders, individually or as a group, should be included among the contributing factors that lead to and worsen bleeding episodes, which represent the leading cause of death in this disease.