A Systematic Review of the Mortality from Untreated Leptospirosis

Human Case of Leptospirosis During a Canine Disease Outbreak - Wyoming, 2023

Leptospirosis is a zoonotic bacterial disease spread through the urine of infected animals; the typical incubation period is 5-14 days. In approximately 90% of human cases, illness is asymptomatic or mild, characterized by fever, chills, myalgia, nausea, vomiting, diarrhea, headache, calf pain, and conjunctival suffusion, but severe illness can progress to multiorgan dysfunction and death. Although Wyoming is considered a low-risk area for leptospirosis because of its cold and semiarid climate, the Wyoming Department of Health was notified of a probable human case in August 2023, the first reported in the state since 1983. The patient had occupational exposure to dogs but did not report other risk factors. The same week that the human patient's illness began, public health authorities received notification of an increase in canine leptospirosis cases. Public health authorities investigated to determine potential sources of infection, identify additional cases, and recommend control measures. After public health outreach activities were implemented, canine vaccination practices changed substantially in the affected city: a survey conducted after the outbreak revealed that all responding veterinary clinics in the affected city were recommending the vaccine more frequently to dog owners and reporting higher levels of owner compliance with vaccination recommendations. Increased vaccination coverage offers protection from leptospirosis for both dogs and persons exposed to them. Leptospirosis should be considered in the differential diagnosis of persons with occupational exposure to animals and clinically compatible signs and symptoms, including fever, chills, myalgia, nausea, vomiting, diarrhea, headache, calf pain, and conjunctival suffusion, irrespective of geographic location.

Relevance of Polymerase Chain Reaction in Early Diagnosis of Leptospirosis

Aim and background

Leptospirosis is common in India, especially in the southern states. Mortality is high among untreated cases. Diagnosis of leptospirosis remains a challenge in India as polymerase chain reaction (PCR), which is more sensitive than Immunoglobulin M (IgM) is not widely available. This study aimed to find out the difference in diagnostic yield with PCR and IgM in early leptospirosis.

Materials and methods

This retrospective, single-center study included 67 adults with laboratory-confirmed leptospirosis (IgM, PCR, or both) who presented within 7 days of symptom onset and were admitted to the intensive care unit (ICU). The difference in the diagnostic yield with PCR and IgM ELISA was studied.

Results

About 77.6% of the patients tested positive by PCR and 55.2% tested positive by IgM. There was a statistically significant difference in the detection of leptospirosis by PCR and IgM (p-value = 0.036). In the subgroup of patients who presented within 3 days of onset of symptoms, PCR positivity was 90.32% whereas IgM positivity was only 25.8%.

Conclusion

Our study showed that the sensitivity of leptospira PCR is significantly higher than IgM in the first week of illness. It also showed that among the subset of patients who died, a majority were detected only by PCR. Since PCR is not widely available, leptospirosis remains underdiagnosed and mortality from the same is underestimated. Polymerase chain reaction, if routinely done along with IgM for all suspected cases of leptospirosis that present within the first week of illness helps in prompt diagnosis and treatment.

How to cite this article

Sreevalsan TV, Chandra R. Relevance of Polymerase Chain Reaction in Early Diagnosis of Leptospirosis. Indian J Crit Care Med 2024;28(3):290-293.

Molecular Diagnosis as an Alternative for Public Health Surveillance of Leptospirosis in Colombia

Leptospirosis represents a public health problem in Colombia. However, the underreporting of the disease is an unfortunate reality, with a clear trend towards a decrease in cases since 2019, when the guidelines for its confirmatory diagnosis changed with the requirement of two paired samples. The purpose of this review is to highlight the importance of leptospirosis. While the access to rapid diagnosis is available at practically all levels of care for dengue and malaria, leptospirosis-a doubly neglected disease-deserves recognition as a serious public health problem in Colombia. In this manner, it is proposed that molecular tests are a viable diagnostic alternative that can improve the targeted treatment of the patient and the timeliness of data and case reporting to SIVIGILA, and reduce the underreporting of the disease. Taking advantage of the strengthened technological infrastructure derived from the SARS-CoV-2 pandemic for molecular diagnosis in Colombia, with a network of 227 laboratories distributed throughout the national territory, with an installed capacity for PCR testing, it is proposed that molecular diagnosis can be used as an alternative for early diagnosis. This would allow case confirmation through the public health network in Colombia, and, together with the microagglutination (MAT) technique, the epidemiological surveillance of this disease in this country would be strengthened.

A Fish Farmer's Encounter With Leptospirosis: A Case Report

Leptospirosis is a zoonotic infection primarily caused by bacteria of the genus Leptospira. This infectious disease mainly occurs through direct contact with infected animals or indirect contact via contaminated soil or water. While the incidence rate of leptospirosis in the developing world is as high as 100 cases per 100,000 population, the incidence rate in the United Kingdom is low (0.14 cases per 100,000 population). We present a 56-year-old male fish farmer who presented to the emergency department with a history of intense thigh pain and sudden inability to mobilise following a week-long period of a flu-like illness, characterised by worsening myalgia localised to the inner thighs, fever, and episodes of passing dark red urine. Initial investigations demonstrated acute renal impairment, hepatitis, thrombocytopenia, mild rhabdomyolysis and raised inflammatory markers. With a suspected diagnosis of leptospirosis after a detailed clinical history and preliminary blood tests, treatment was immediately commenced with intravenous antibiotics, intravenous rehydration and vigilant monitoring of urinary output. The patient's condition rapidly improved and the diagnosis was later confirmed by a positive Leptospira polymerase chain reaction (PCR) report and serology. We believe prompt treatment prevented deterioration in this case. The aim of this case report is to highlight the importance of a detailed clinical history, with a particular focus on occupational exposure, especially in the developed world. Additionally, a low clinical threshold for leptospirosis is imperative, as rapid clinical deterioration can happen if no immediate medical intervention is performed.

Fatal acute undifferentiated febrile illness among clinically suspected leptospirosis cases in Colombia, 2016-2019

BACKGROUND

Acute undifferentiated febrile illness is a common challenge for clinicians, especially in tropical and subtropical countries. Incorrect or delayed diagnosis of febrile patients may result in medical complications or preventable deaths. Common causes of acute undifferentiated febrile illness in Colombia include leptospirosis, rickettsioses, dengue fever, malaria, chikungunya, and Zika virus infection. In this study, we described the acute undifferentiated febrile illness in postmortem patients reported as suspected cases of leptospirosis through the national leptospirosis surveillance in Colombia, 2016-2019.

METHODOLOGY/PRINCIPAL FINDINGS

We retrospectively analyze human fresh and formalin-fixed tissue samples from fatal suspected leptospirosis cases reported by the Public Health Laboratories in Colombia. Leptospirosis confirmation was made by immunohistochemistry, real-time polymerase chain reaction (PCR) in the tissue samples. In some cases, the serum sample was used for confirmation by Microagglutination test (MAT). Simultaneously, tissue samples were tested by PCR for the most common viral (dengue, Zika, and chikungunya), bacterial (Brucella spp., and Rickettsia spp.), and parasitic (malaria). Fresh tissue samples from 92 fatal suspected leptospirosis cases were reported to the National Reference Laboratory from 22/32 departments in Colombia. We confirmed leptospirosis in 27% (25/92) of cases. Other pathogens identified by real-time PCR were Brucella spp. (10.9%), Rickettsia spp. (14.1%), and dengue (2.2%). Dengue (6.9%), hepatitis (3.5%), and Yellow Fever cases (2.2%) were detected by the pathology. All patients were negative for chikungunya and Plasmodium spp. Most cases were classified as undifferentiated febrile illnesses (45.7%; 42/92).

CONCLUSIONS/SIGNIFICANCE

This study underscores the importance of early and accurate recognition of leptospirosis to prevent mortalities. Moreover, it draws attention to the existence of other febrile syndromes in Colombia, including rickettsiosis and brucellosis, that currently lack sufficient human surveillance and regular reporting. Expanding laboratory surveillance to include viruses such as Hantavirus, Mayaro virus, Oropouche virus, and West Nile virus is crucial.

Demographic and clinical risk factors associated with severity of lab-confirmed human leptospirosis in Colombia, 2015-2020

BACKGROUND

Leptospirosis is a common zoonoses and is a major global public health threat. Most cases are mild, typically presenting as a non-specific acute febrile illness. However, leptospirosis can have life-threatening manifestations, including pulmonary hemorrhage syndrome, and acute kidney injury. In Colombia, notification and lab-confirmation of suspected human cases are mandatory. However, little is known about the demographic and clinical factors associated with severe leptospirosis, which could help to reduce clinical complications and mortality. Our aim was to identify risk factors associated with severe leptospirosis, intensive care unit (ICU) admission, and mortality in lab-confirmed cases in Colombia, 2015-2020.

METHODS AND FINDINGS

We analyzed 201 lab-confirmed human leptospirosis cases by microagglutination test. We used a logistic regression to identify the demographic and clinical risk factors associated with severe leptospirosis, admission to ICU, and death. Most leptospirosis confirmed cases occurred in men (85.6%); the mean age was 36.7 years. We classified severe cases (43.3%) by clinical manifestations as renal (29.9%) and liver (27.4%) failure, multiple-organ failure (24.4%), septic shock (24.4%), Weil syndrome (18.4%), pulmonary hemorrhage (18.4%), and meningitis (2.5%), admitted to the ICU (30.3%), and fatal (8.5%). Clinical conditions associated with severe leptospirosis were dyspnea (OR: 5.54; 95% CI: 1.46 to 20.98), tachycardia (OR:9.69; 95% CI: 15.96 to 58.8), and rash (OR: 10.25; 95% CI: 25.01 to 42.08).

CONCLUSIONS

We identified demographic characteristics and clinical symptoms associated with severe leptospirosis in Colombia. We hope these results can support clinicians in providing timely treatment to leptospirosis patients to avoid preventable medical complications or deaths.

Cellular Pathophysiology of Leptospirosis: Role of Na/K-ATPase

Inada and Ido identified Leptospira sp. as the pathogen responsible for Weil's Disease in 1915. Later, it was confirmed that Leptospira causes leptospirosis. The host microorganism's interaction at the cellular level remained misunderstood for many years. Although different bacterial components have been isolated and purified, the complexity of the molecular interactions between these components and the host and the molecular mechanisms responsible for the systemic dysfunctions still needs to be fully unveiled. Leptospirosis affects virtually all animal species. Its cellular pathophysiology must involve a ubiquitous cellular mechanism in all eukaryotes. Na/K-ATPase is the molecular target of the leptospiral endotoxin (glycolipoprotein-GLP). Na/K-ATPase dysfunctions on different types of cells give rise to the organ disorders manifested in leptospirosis. Concomitantly, the development of a peculiar metabolic disorder characterized by dyslipidemia, with increased levels of circulating free fatty acids and an imbalance in the fatty acid/albumin molar ratio, triggers events of cellular lipotoxicity. Synergistically, multiple molecular stimuli are prompted during the infection, activating inflammasomes and Na/K-ATPase signalosome, leading to pro-inflammatory and metabolic alterations during leptospirosis. Leptospirosis involves diverse molecular mechanisms and alteration in patient inflammatory and metabolic status. Nonetheless, Na/K-ATPase is critical in the disease, and it is targeted by GLP, its components, and other molecules, such as fatty acids, that inhibit or trigger intracellular signaling through this enzyme. Herein, we overview the role of Na/K-ATPase during leptospirosis infection as a potential therapeutic target or an indicator of disease severity.

Distribution, frequency and clinical presentation of leptospirosis and coinfections: a systematic review protocol

INTRODUCTION

Leptospirosis is a zoonotic disease with high prevalence in low-income and middle-income countries and tropical and subtropical regions. The clinical symptoms of the disease are similar to symptoms presented by other endemic infectious diseases that could be present simultaneously. Thus, leptospirosis could be masked by similar infections like dengue, malaria, hantavirus, melioidosis and borreliosis, among others. Therefore, leptospirosis could present itself as an under-reported infection or as a coinfection with another pathogen, as has been reported in the literature. However, there is a lack of documented evidence about the specific risk factors of leptospirosis infection, the symptoms, the coinfection's mortality and the frequency of coinfection. Additionally, leptospirosis coinfections have not been considered a neglected public health concern. Therefore, this systematic review aims to evaluate published articles that show the risk factors associated with leptospirosis infection and coinfection with other pathogens.

METHODS AND ANALYSIS

The search process to identify eligible studies will be conducted including the LILACS, ProQuest, PubMed and Scopus databases with no restriction in terms of publication date. Also, grey literature will be included in the research. Authors will independently screen the title and abstracts of the articles identified from the search using Rayyan free software. Eligibility criteria include peer-reviewed research articles written in English or Spanish, including observational studies, cohorts, case-control, cross-sectional, ecological studies and report cases. The systematic review will include studies that report descriptions of leptospirosis cases with coinfection or co-occurrence. The search will be accomplished by articles from 1950 to May 2022. The data will be extracted in a standard extraction form using an Excel format.

ETHICS AND DISSEMINATION

Results will be published in a peer-reviewed journal. Also, findings will be disseminated through scientific meetings. Ethical approval will not be required as this is a systematic review and primary data will be not collected or included.

PROSPERO REGISTRATION NUMBER

CRD42021234754.

Weil's Disease-Immunopathogenesis, Multiple Organ Failure, and Potential Role of Gut Microbiota

Leptospirosis is an important zoonotic disease, causing about 60,000 deaths annually. In this review, we have described in detail the immunopathogenesis of leptospirosis, the influence of cytokines, genetic susceptibility on the course of the disease, and the evasion of the immune response. These data are combined with information about immunological and pathomorphological changes in the kidneys, liver, and lungs, which are most affected by Weil's disease. The review also suggests a possible role of the gut microbiota in the clinical course of leptospirosis, the main mechanisms of the influence of gut dysbiosis on damage in the liver, kidneys, and lungs through several axes, i.e., gut-liver, gut-kidney, and gut-lungs. Modulation of gut microbiota by probiotics and/or fecal microbiota transplantation in leptospirosis may become an important area of scientific research.

Genetic diversity of Leptospira isolates in Lao PDR and genome analysis of an outbreak strain

Background

Although Southeast Asia is one of the most leptospirosis afflicted regions, little is known about the diversity and molecular epidemiology of the causative agents of this widespread and emerging zoonotic disease.

Methodology/Principal findings

We used whole genome sequencing to examine genetic variation in 75 Leptospira strains isolated from patients in the Lao PDR (Laos) between 2006 and 2017.

Eleven serogroups from 4 Leptospira species and 43 cgMLST-defined clonal groups (CGs) were identified. The most prevalent CG was CG272 (n = 18, 26.8%), composed of L. interrogans serogroup Autumnalis isolates. This genotype was recovered throughout the 12-year period and was associated with deaths, and with a large outbreak in neighbouring Thailand. Genome analysis reveals that the CG272 strains form a highly clonal group of strains that have, for yet unknown reasons, recently spread in Laos and Thailand. Additionally, accessory genes clearly discriminate CG272 strains from the other Leptospira strains.

Conclusions/Significance

The present study reveals a high diversity of Leptospira genotypes in Laos, thus extending our current knowledge of the pan- and core-genomes of these life-threatening pathogens. Our results demonstrate that the CG272 strains belong to a unique clonal group, which probably evolved through clonal expansion following niche adaptation. Additional epidemiological studies are required to better evaluate the spread of this genotype in Southeast Asia. To further investigate the key factors driving the virulence and spread of these pathogens, more intense genomic surveillance is needed, combining detailed clinical and epidemiological data.

Pathogenic Leptospira are the causative agents for leptospirosis, a neglected and emerging zoonosis occurring worldwide. In this study, we investigated the genetic diversity of Leptospira strains isolated from patients over a 12-year period in Lao PDR. Our genome analysis revealed a high diversity of Leptospira genotypes in this endemic country for leptospirosis, including a group of clonal strains which was responsible for a large outbreak in neighboring Thailand. Further progress in our understanding of the epidemiology of Leptospira circulating genotypes should contribute to the implementation of prevention and intervention measures to reduce the risk of leptospirosis transmission.

Clinical spectrum of endemic leptospirosis in relation to cytokine response

OBJECTIVES

To describe the clinical spectrum and the cytokine response of leptospirosis patients in an endemic setting of Sri Lanka.

METHODS

Patients presenting to the university teaching hospital, Anuradhapura, Sri Lanka with a leptospirosis-compatible illness were recruited over a period of 12 months starting from June 2012. Daily clinical and biochemical parameters of the patients were prospectively assessed with a follow-up of 14 days after discharge. A magnetic bead-based multiplex cytokine kit was used to detect 17 cytokines.

RESULTS

Of the 142 clinically suspected leptospirosis patients recruited, 47 were confirmed and, 29 cases were labeled as "probable." Thrombocytopenia and leukocytosis were observed at least once during the hospital stay among 76(54%) and 39(28%) patients, respectively. Acute kidney injury was observed in 31 patients (22%) and it was significantly higher among confirmed and probable cases. Hu TNF-α and IL-1β were detected only in patients without complications. Hu MIP-1b levels were significantly higher among patients with complications. During the convalescence period, all tested serum cytokine levels were lower compared to the acute sample, except for IL-8. The cytokine response during the acute phase clustered in four different groups. High serum creatinine was associated GM-CSF, high IL-5 and IL-6 level were correlates with lung involvement and saturation drop. The patients with high billirubin (direct)>7 mmol/l had high IL-13 levels.

CONCLUSIONS

Results of this study confirms that the knowledge on cytokine response in leptospirosis could be more complex than other similar tropical disease, and biosignatures that provide diagnostic and prognostic information for human leptospirosis remain to be discovered.

Identification and validation of circulating miRNAs as potential new biomarkers for severe liver disease in patients with leptospirosis

Background

Leptospirosis, a global zoonotic infectious disease, has various clinical manifestations ranging from mild self-limiting illness to life-threatening with multi-organ damage, including liver involvement. This study was aimed at identifying circulating microRNAs (miRNAs) as novel biomarkers for predicting severe liver involvement in patients with leptospirosis.

Methods

In a discovery set, 12 serum samples of patients with anicteric and icteric leptospirosis at initial clinical presentation were used for miRNA profiling by a NanoString nCounter miRNA assay. In a validated cohort, top candidate miRNAs were selected and further tested by qRT-PCR in serum samples of 81 and 16 individuals with anicteric and icteric leptospirosis, respectively.

Results

The discovery set identified 38 significantly differential expression miRNAs between the two groups. Among these, miR-601 and miR-630 were selected as the top two candidates significantly up-regulated expressed in the icteric group. The enriched KEGG pathway showed that these miRNAs were mainly involved in immune responses and inflammation. In the validated cohort, miR-601 and miR-630 levels were significantly higher in the icteric group compared with the anicteric group. Additionally, these two miRNAs displayed good predictors of subsequent acute liver failure with a high sensitivity of 100%. On regression analysis, elevated miR-601 and miR-630 expression were also predictive of multi-organ failures and poor overall survival.

Conclusion

Our data indicated that miRNA expression profiles were significantly differentiated between the icteric and anicteric groups. Serum miR-601 and miR-630 at presentation could potentially serve as promising biomarkers for predicting subsequent acute liver failure and overall survival in patients with leptospirosis.

Transcriptomic signatures of exacerbated progression in leptospirosis subclinical chronic kidney disease with secondary nephrotoxic injury

High-incidence regions of leptospirosis caused by Leptospira spp. coincide with chronic kidney disease. This study investigated whether asymptomatic leptospirosis is an emerging culprit that predisposes to progressive chronic kidney disease when superimposed on secondary nephrotoxic injury. Kidney histology/function and whole transcriptomic profiles were evaluated for Leptospira-infected C57/BL6 mice with adenine-induced kidney injury. The extent of tubulointerstitial kidney lesions and expression of inflammation/fibrosis genes in infected mice with low-dose (0.1%) adenine, particularly in high-dose (0.2%) adenine-fed superimposed on Leptospira-infected mice, were significantly increased compared with mice following infection or adenine diet alone, and the findings are consistent with renal transcriptome analysis. Pathway enrichment findings showed that integrin-β- and fibronectin-encoding genes had distinct expression within the integrin-linked kinase-signaling pathway, which were upregulated in 0.2% adenine-fed Leptospira-infected mice but not in 0.2% adenine-fed mice, indicating that background subclinical Leptospiral infection indeed enhanced subsequent secondary nephrotoxic kidney injury and potential pathogenic molecules associated with secondary nephrotoxic leptospirosis. Comparative analysis of gene expression patterns with unilateral ureteric obstruction-induced mouse renal fibrosis and patients with chronic kidney disease showed that differentially expressed orthologous genes such as hemoglobin-α₂, PDZ-binding kinase, and DNA topoisomerase II-α were identified in infected mice fed with low-dose and high-dose adenine, respectively, revealing differentially expressed signatures identical to those found in the datasets and may serve as markers of aggravated kidney progression. This study indicates that background subclinical leptospirosis, when subjected to various degrees of subsequent secondary nephrotoxic injury, may predispose to exacerbated fibrosis, mimicking the pathophysiological process of progressive chronic kidney disease.NEW & NOTEWORTHY Leptospira-infected mice followed by secondary nephrotoxic injury exacerbated immune/inflammatory responses and renal fibrosis. Comparison with the murine model revealed candidates involved in the progression of renal fibrosis in chronic kidney disease (CKD). Comparative transcriptome study suggests that secondary nephrotoxic injury in Leptospira-infected mice recapitulates the gene expression signatures found in CKD patients. This study indicates that secondary nephrotoxic injury may exacerbate CKD in chronic Leptospira infection implicating in the progression of CKD of unknown etiology.

Mortality associated with Blastomyces dermatitidis infection: A systematic review of the literature and meta-analysis

Published case fatality in blastomycosis patients ranges between 4% and 78%. This study aimed to assess mortality associated with blastomycosis and identify its associated risk factors. We conducted a systematic review of publications related to Blastomyces dermatitidis available in PubMed and Scopus databases. Studies that reported data on blastomycosis mortality and that were published from inception through February 2018 were assessed and included in the analysis. Using the R meta package, a random-effect model meta-analysis was used to calculate pooled and stratified estimates of case-fatality proportions and risk ratios. Of 1553 publications, we included 20 studies reporting on a total of 2820 cases of blastomycosis between 1970 and 2014 and three case series reports with 10, 21, and 36 patients. The mean or median ages ranged from 28 to 59 years. Mortality was defined as attributable mortality caused by blastomycosis in 13 studies. Among 14 studies with a standard error ≤0.05, the overall pooled mortality was 6.6% (95% confidence interval [CI], 4.9-8.2) with 57% heterogeneity. The mortality rate was 37% (95% CI, 23-51) in immunocompromised patients and 75% (95% CI, 53-96) in patients who developed an acute respiratory distress syndrome (ARDS) (n = 3 studies each). ARDS was the only identified risk factor in general patients (risk ratio = 10.2). The overall mortality was significantly higher in studies involving immunocompromised patients and ARDS patients. Our analysis showed considerable heterogeneity among studies. Inconsistent mortality definitions may have contributed to the observed heterogeneity. Further research is needed to assess potential risk factors for mortality.

Weil's Disease: A Rare Cause of Jaundice

Weil’s disease is a complication of untreated leptospirosis and can be fatal. Awareness of leptospirosis and its hepatic manifestations are limited. We report the case of a 50-year-old man with gastrointestinal symptoms and a cholestatic pattern of liver injury diagnosed with Weil’s disease. The patient showed remarkable improvement after treatment with appropriate antibiotics with normalization of liver function in one month. This case highlights the importance of recognizing leptospirosis and its myriad presentations. 

Correction pen based paper fluidic device for the detection of multiple gene targets of Leptospira using Loop Mediated Isothermal Amplification

Paper-based nucleic acid testing techniques are increasingly in demand. Hence, we have developed a simple and cheap paper fluidic device to detect multiple gene targets in Leptospira. Fluidic channels of the penta-clover device are drawn using a correction pen on Whatman filter paper 1. The fluid blocks the pores of the paper, avoiding leakage and ensuring the equal flow of sample to the reaction pads. The target genes are amplified by performing Loop-Mediated Isothermal Amplification (LAMP) with dry reaction components. Thecolor change of leuco crystal violetallows real-time monitoring of a positive amplification. The difference in color intensity is captured with a smartphone and analyzed using image processing software. The device amplifies the target within 15 min, detects the pathogen at a concentration as low as 50 attogram μL^-1, detects Leptospira in blood samples without prior treatment and differentiates the Leptospira species even after 21 days of storage at room temperature.

Leptospirosis as an unusual culprit of acute pancreatitis and portal vein thrombosis in a New Yorker

Leptospirosis often takes clinicians by surprise when presenting in urban locations with unusual manifestations. This delays diagnosis and treatment which increases mortality rate. Our case illustrates the importance of taking into account the socioeconomic backgrounds, environmental exposures, and clinical presentations of patients to create a good differential diagnosis.

Leptospirosis: a neglected tropical zoonotic infection of public health importance-an updated review

Leptospirosis is a zoonotic and waterborne disease worldwide. It is a neglected, reemerging disease of global public health importance with respect to morbidity and mortality both in humans and animals. Due to negligence, rapid, unplanned urbanization, and poor sanitation, leptospirosis emerges as a leading cause of acute febrile illness in many of the developing countries. Every individual has a risk of getting infected as domestic and wild animals carry leptospires; the at-risk population varies from the healthcare professionals, animal caretakers, farmers and agricultural workers, fishermen, rodent catchers, water sports people, National Disaster Response Force (NDRF) personnel, people who volunteer rescue operations in flood-affected areas, sanitary workers, sewage workers, etc. The clinical manifestations of leptospirosis range from flu-like illness to acute kidney failure (AKF), pneumonia, jaundice, pulmonary hemorrhages, etc. But many rare and uncommon clinical manifestations are being reported worldwide. This review will cover all possible updates in leptospirosis from occurrence, transmission, rare clinical manifestations, diagnosis, treatment, and prophylactic measures that are currently available, their advantages and the future perspectives, elaborately. There are less or very few reviews on leptospirosis in recent years. Thus, this work will serve as background knowledge for the current understanding of leptospirosis for researchers. This will provide a detailed analysis of leptospirosis and also help in finding research gaps and areas to focus on regarding future research perspectives.

Restructuring the Modified Faine's Criteria for the Diagnosis of Leptospirosis in Monsoon: A Study from South Gujarat

Context:

Clinical and epidemiological variables in the modified Faine's criteria offered low validity in our study setting.

Aims:

Restructuring and validating modified Faine's criteria for leptospirosis to better suit health scenario of south Gujarat.

Subjects and Methods:

Clinical, epidemiological, and laboratory features of derivation cohort (1216 suspected leptospirosis cases) admitted at a tertiary care hospital of south Gujarat (2007–2015) that significantly correlated with confirmed leptospirosis were used in binary logistic regression to derive scoring models and receiver operating characteristic to determine cutoff values. Validity and net reclassification improvement (NRI) were estimated in validation cohort (82 cases, 2016–2017) and algorithm for diagnosis was prepared.

Results:

Screening model consisted of the presence of conjunctival suffusion, calf tenderness, raised serum creatinine, headache with conjunctival suffusion and/or jaundice, and dyspnea/meningism. Area under curve (AUC) for screening model was 0.590 (standard error [SE] ±0.017) and cutoff score ≥9 gave sensitivity 79.16%, specificity 50%. The confirmatory model consisted of laboratory parameters, namely polymerase chain reaction, immunoglobulin M ELISA, and microscopic agglutination test and gave AUC 0.998 (SE ± 0.001), sensitivity 89.58%, specificity 85.29%, positive predictive value 89.58%, and negative predictive value 85.29% at cutoff score ≥100. Net sensitivity of algorithm was 98.27% at the point of screening (screening model and rapid test) and net specificity 87.89% at the point of confirmation (screening followed by confirmatory model) in validation cohort.

Conclusions:

Simultaneous use of screening model and rapid test gave NRI 81.25% and sequential use of confirmatory test gave NRI 47.18% compared to corresponding parts of the modified Faine's criteria.

Economic considerations support C-reactive protein testing alongside malaria rapid diagnostic tests to guide antimicrobial therapy for patients with febrile illness in settings with low malaria endemicity

Malaria is no longer a common cause of febrile illness in many regions of the tropics. In part, this success is a result of improved access to accurate diagnosis and effective anti-malarial treatment, including in many hard-to-reach rural areas. However, in these settings, management of other causes of febrile illness remains challenging. Health systems are often weak and other than malaria rapid tests no other diagnostics are available. With millions of deaths occurring annually due to treatable bacterial infections and the ever increasing spread of antimicrobial resistance, improvement in the management of febrile illness is a global public health priority. Whilst numerous promising point-of-care diagnostics are in the pipeline, substantial progress can be made in the interim with existing tools: C-reactive protein (CRP) is a highly sensitive and moderately specific biomarker of bacterial infection and has been in clinical use for these purposes for decades, with dozens of low-cost devices commercially available. This paper takes a health-economics approach to consider the possible advantages of CRP point-of-care tests alongside rapid diagnostic tests for malaria, potentially in a single multiplex device, to guide antimicrobial therapy for patients with febrile illness. Three rudimentary assessments of the costs and benefits of this approach all indicate that this is likely to be cost-effective when considering the incremental costs of the CRP tests as compared with either (i) the improved health outcomes for patients with bacterial illnesses; (ii) the costs of antimicrobial resistance averted; or (iii) the economic benefits of better management of remaining malaria cases and shorter malaria elimination campaigns in areas of low transmission. While CRP-guided antibiotic therapy alone cannot resolve all challenges associated with management of febrile illness in remote tropical settings, in the short-term a multiplexed CRP and malaria RDT could be highly cost-effective and utilize the well-established funding and distribution systems already in place for malaria RDTs. These findings should spark further interest amongst industry, academics and policy-makers in the development and deployment of such diagnostics, and discussion on their geographically appropriate use.

Study protocol: characterising the clinical, epidemiological and aetiological aspects of leptospirosis in Sri Lanka: a hospital based clinico-epidemiological study

INTRODUCTION

Sri Lanka has one of the highest incidences of leptospirosis worldwide. We hypothesised that different geographical locations and patient context will have a distinct molecular epidemiology of leptospirosis, based on microgeographical characteristics related to regiona-specific Leptospira predominance. Our objective is to characterise the clinical, epidemiological and molecular aspects of leptospirosis in Sri Lanka to understand disease progression, risk factors and obtain isolates of Leptospira.

METHODS AND ANALYSIS

We designed a multicentre prospective study in Sri Lanka to recruit undifferentiated febrile patients and conduct follow-ups during hospital stays. Patients will be recruited from outpatient departments and medical wards. This study will be conducted at two main sites (Anuradhapura and Peradeniya) and several additional sites (Awissawella, Ratnapura and Polonnaruwa). Blood and urine will be collected from patients on the day of admission to the ward or presentation to the outpatient department. Bedside inoculation of 2-4 drops of venous blood will be performed with Ellinghausen-McCullough-Johnson-Harris (EMJH) semisolid media supplemented with antibiotics. Regionally optimised microscopic agglutination test, culture and qPCR-evidence will be performed to confirm the presence of Leptospira in blood which in turn will confirm the presence of disease. Whole genome sequencing will be carried out for all isolates recovered from patients. Multilocus sequence typing (MLST) will be used for the genotyping of new isolates. Sri Lankan isolates will be identified using three published MLST schemes for Leptospira.

ETHICS AND DISSEMINATION

Ethical clearance for the study was obtained from Ethics Review Committees (ERC), Medicine and Allied Sciences (FMAS), Rajarata University of Sri Lanka (RUSL) and University of Peradeniya. All genomic data generated through this project will be available at GenBank. Anonymised data will be deposited at the ERC, FMAS, RUSL.

Risk of Dementia in Patients with Leptospirosis: A Nationwide Cohort Analysis

Background: Studies have linked some bacterial infections with an increased likelihood for development of dementia. However, there is a paucity of data on the relationship between dementia and leptospirosis. In view of this, we conducted a retrospective cohort study to determine whether leptospirosis is a risk factor for dementia. Methods: Data were collected from the Taiwan National Health Insurance Research Databases (2000–2010) to investigate the incidence of and risk factors for dementia in patients with leptospirosis. Patients with leptospirosis who did not have a history of dementia were enrolled in the study. For each leptospirosis patient, four controls were randomly selected after frequency matching of age, sex, and index date. Cox proportional hazard regression models were used for the analyses of dementia risk. Results: A greater risk of dementia was observed in the leptospirosis cohort than in the non-leptospirosis cohort both in patients without any comorbidity (adjusted HR (aHR) = 1.23, 95% CI = 1.06–1.43) and with a comorbidity (aHR = 2.06, 95% CI = 1.7–2.5). Compared with the non-leptospirosis cohort without these comorbidities, the leptospirosis cohort with ≥2 comorbidities exhibited a significantly increased risk of dementia (aHR = 6.11, 95% CI = 3.15–11.9), followed by those with any one comorbidity (adjusted HR = 3.62, 95% CI = 1.76–7.46). Conclusions: Patients with leptospirosis were at a 1.89-fold greater risk of subsequent dementia, but potential genetic susceptibility bias in the study group is a major confound.

Accounting for aetiology: can regional surveillance data alongside host biomarker-guided antibiotic therapy improve treatment of febrile illness in remote settings?

Background: Across Southeast Asia, declining malaria incidence poses a challenge for healthcare providers, in how best to manage the vast majority of patients with febrile illnesses who have a negative malaria test. In rural regions, where the majority of the population reside, empirical treatment guidelines derived from central urban hospitals are often of limited relevance. In these settings, health workers with limited training deliver care, often without any laboratory diagnostic support. In this paper, we model the impact of point-of-care C-reactive protein testing to inform the decision to prescribe antibiotics and regional surveillance data to inform antibiotic selection, and then simulate the subsequent impact on mortality from febrile illnesses, rooted in the real-world context of rural Savannakhet province, southern Laos. Methods: Our model simulates 100 scenarios with varying quarterly incidence of six key pathogens known to be prevalent in rural Laos. In the simulations, community health workers either prescribe antibiotics in-line with current practice as documented in health facilities in rural Laos, or with the aid of the two interventions. We provide cost-effectiveness estimates for each strategy alone and then for an integrated approach using both interventions. Results: We find that each strategy is predicted to be highly cost-effective, and that the combined approach is predicted to result in the biggest reduction in mortality (averting a predicted 510 deaths per year in rural Savannakhet, a 28% reduction compared to standard practice) and is highly cost-effective, with an incremental cost-effectiveness ratio of just $66 per disability-adjusted life year averted. Conclusions: Substantial seasonal variation in the predicted optimal empirical antibiotic treatment for febrile illness highlights the benefits of up-to-date information on regional causes of fever. In this modelling analysis, an integrated system incorporating point-of-care host biomarker testing and regional surveillance data appears highly cost-effective, and may warrant piloting in a real-life setting.

Leptospirosis in the elderly: the role of age as a predictor of poor outcomes in hospitalized patients

Background: The aim of this study was to investigate factors associated with poor outcomes among elderly hospitalized patients with leptospirosis. Methods: This is a retrospective cohort study with leptospirosis patients admitted to three tertiary hospitals in Fortaleza, Brazil, from January 1985 to July 2017. Patients were divided into two groups: elderly (age ≥60 years) and young (age <60 years). A comparison of demographical, clinical and laboratory data, treatment and outcomes was executed in order to investigate differences between groups. Results: A total of 507 hospitalized patients were included, with mean age 38 ± 15 years. Elderly group presented lower incidence of myalgia, vomiting, and dyspnea, as well as, higher medium systolic blood pressure. Elderly also manifested higher frequency of AKI (85.9 vs. 74.7%, p = 0.05), hemodialysis requirement (54.7 vs. 37.0%, p = 0.007) and death (32.8 vs. 12.2%, p < 0.001). In multivariate analysis, age ≥60 years was a predictor of hemodialysis requirement (p = 0.008, OR = 2.049, 95% CI = 1.207-3.477) and death (p < 0.001, OR = 3.520, 95% CI = 1.940-6.386). Conclusion: Leptospirosis in the elderly is associated with less hemodynamic impairment and higher frequency of AKI. Advanced age was also a predictor of poor outcomes, such as hemodialysis requirement and death, mostly due to kidney involvement.

Sequel and therapeutic modalities of leptospirosis associated severe pulmonary haemorrhagic syndrome (SPHS); a Sri Lankan experience

BACKGROUND

The emergence of leptospirosis-associated severe pulmonary hemorrhagic syndrome (SPHS) with high case fatality has been reported from many countries. Understanding of clinical disease and sequel of SPHS needs larger studies with adequate numbers. The purpose of this study was to describe the characteristics and sequel by different therapeutic approaches for SPHS in Leptospirosis in Sri Lanka.

METHODS

This study was conducted at Teaching Hospital-Karapitiya (THK), Galle, Sri Lanka from June 2015 to December 2017. THK is the main tertiary care center for the Southern Province. All confirmed-cases of leptospirosis who presented during this period and were admitted to five medical units of THK were included in this study. SPHS was defined as a patient presenting; haemoptysis, arterial hypoxemia (Acute Lung Injury Score < 2.5), haemoglobin drop (10% from the previous value), or diffused alveolar shadows in the chest radiograph, without alternative explanation other than leptospirosis.

RESULTS

Of the 128 MAT confirmed cases of leptospirosis, 111 (86.7%) had acute kidney injury (AKI) whilst SPHS was seen in 80 (62.5%). Patients typically developed SPHS within the first week of illness, mostly on days 4 and 5. The case fatality rate of this study sample was 28.1% (n = 36), while for patients with SPHS, it was 41.5%. Most of the deaths (n = 19) were within the first 3 days of admission (on the same day 8, and within next 48 h 11). Among SPHS patients, 59 received therapeutic plasma exchange (TPE). The survival rate was higher (n = 35, 74.5%) when the TPE was performed within the first 48 h of detecting SPHS compared to patients in whom the procedure was done after 48 h (n = 5, 54.5%). Of the 19 leptosprosis patients with SPHS who did not receive TPE, 17 died (89.5%). However, the group of patients who received TPE was primarily the patients survived beyond day 3.

CONCLUSIONS

We observed that during the study period, SPHS was common and the mortality rate was higher in the study area. The treatment modalities tested need further evaluation and confirmation.

Antimicrobial Susceptibility Testing of Leptospira spp. in the Lao People's Democratic Republic Using Disk Diffusion

Leptospirosis is a global zoonotic disease caused by pathogenic bacteria of the Leptospira genus, which are fastidious, slow-growing organisms. Antimicrobial susceptibility data are limited; traditionally, the organisms have not been culturable on solid media. The recent development of Leptospira Vanaporn Wuthiekanun (LVW) agar, which facilitates rapid growth of Leptospira spp., provides the opportunity for antimicrobial susceptibility testing. Eighty-three Leptospira spp. clinical isolates originating from patients in Laos between 2006 and 2016 were tested against six antimicrobials (azithromycin, ceftriaxone, ciprofloxacin, doxycycline, gentamicin, and penicillin G) using disk diffusion on LVW agar. Quality control was undertaken using American Type Culture Collection (ATCC) reference strains with known susceptibilities on both standard media and LVW agar. All Leptospira spp. isolates produced large zones of inhibition around each of the six antimicrobials. All zones were greater than 25 mm: gentamicin produced the smallest zones (median 35 mm; interquartile range 30 mm-37 mm) and azithromycin produced the largest zones (median 85 mm; interquartile range 85 mm-85 mm). Zones produced by non-leptospiral ATCC reference strains on LVW agar were within 2 mm of accepted strain-specific quality control range on standard media. Antimicrobial activity on LVW agar appears to be similar to that on standard media. As there are no published susceptibility guidelines for the Leptospira genus, zone interpretation was subjective. Leptospira Vanaporn Wuthiekanun agar enabled antimicrobial susceptibility testing of multiple Leptospira isolates on solid media; the large zone sizes observed suggest that resistance has not emerged to these six antimicrobials in Lao Leptospira spp.

Genus-wide Leptospira core genome multilocus sequence typing for strain taxonomy and global surveillance

Leptospira is a highly heterogeneous bacterial genus that can be divided into three evolutionary lineages and >300 serovars. The causative agents of leptospirosis are responsible of an emerging zoonotic disease worldwide. To advance our understanding of the biodiversity of Leptospira strains at the global level, we evaluated the performance of whole-genome sequencing (WGS) as a genus-wide strain classification and genotyping tool. Herein we propose a set of 545 highly conserved loci as a core genome MLST (cgMLST) genotyping scheme applicable to the entire Leptospira genus, including non-pathogenic species. Evaluation of cgMLST genotyping was undertaken with 509 genomes, including 327 newly sequenced genomes, from diverse species, sources and geographical locations. Phylogenetic analysis showed that cgMLST defines species, clades, subclades, clonal groups and cgMLST sequence types (cgST), with high precision and robustness to missing data. Novel Leptospira species, including a novel subclade named S2 (saprophytes 2), were identified. We defined clonal groups (CG) optimally using a single-linkage clustering threshold of 40 allelic mismatches. While some CGs such as L. interrogans CG6 (serogroup Icterohaemorrhagiae) are globally distributed, others are geographically restricted. cgMLST was congruent with classical MLST schemes, but had greatly improved resolution and broader applicability. Single nucleotide polymorphisms within single cgST groups was limited to <30 SNPs, underlining a potential role for cgMLST in epidemiological surveillance. Finally, cgMLST allowed identification of serogroups and closely related serovars. In conclusion, the proposed cgMLST strategy allows high-resolution genotyping of Leptospira isolates across the phylogenetic breadth of the genus. The unified genomic taxonomy of Leptospira strains, available publicly at http://bigsdb.pasteur.fr/leptospira, will facilitate global harmonization of Leptospira genotyping, strain emergence follow-up and novel collaborative studies of the epidemiology and evolution of this emerging pathogen.

Building prognostic models for adverse outcomes in a prospective cohort of hospitalised patients with acute leptospirosis infection in the Philippines

Leptospirosis is endemic to the Philippines. Ten per cent of cases will develop severe or fatal disease. Predicting progression to severity is difficult. Risk factors have been suggested, but few attempts have been made to create predictive models to guide clinical decisions. We present two models to predict the risk of mortality and progression to severe disease. Data was used from a prospective cohort study conducted between 2011 and 2013 in San Lazaro Hospital, Manila. Predictive factors were identified from a literature review. A strategy utilizing backwards stepwise-elimination and multivariate fractional polynomials identified key predictive factors. A total of 203 patients met the inclusion criteria. The overall mortality rate was 6.84%. Multivariable logistic regression revealed that neutrophil counts [OR 1.38, 95% CI 1.15-1.67] and platelet counts [OR 0.99, 95% CI 0.97-0.99] were predictive for risk of mortality. Multivariable logistic regression revealed that male sex (OR 3.29, 95% CI 1.22-12.57) and number of days between symptom onset and antibiotic use (OR 1.28, 95% CI 1.08-1.53) were predictive for risk of progression to severe disease. The multivariable prognostic models for the risks of mortality and progression to severe disease developed could be useful in guiding clinical management by the early identification of patients at risk of adverse outcomes.

Severe leptospirosis in a patient with positive serological test for spotted fever rickettsiosis

Here, we report a case of a 64-year-old man with severe leptospirosis infected in an area in Japan that is non-endemic to leptospirosis. Initially, findings of high-grade fever, mild generalised arthralgia, rashes on the trunk, mild thrombocytopenia, elevated liver enzymes and renal dysfunction led to the suspicion of rickettsiosis, which was an endemic infectious disease in the area. Subsequently, leptospirosis was also considered after carefully reviewing patient history, which revealed that he may have been exposed to mice urine. Finally, leptospirosis was diagnosed after the serum indicated a positive PCR for leptospirosis. Furthermore, due to serum antibody positivity for Rickettsia japonica, false-positivity or coinfection of spotted fever rickettsiosis was suspected. Despite the delayed diagnosis, the patient recovered with antibiotic treatment. Thus, to prevent diagnostic errors, leptospirosis should be potentially considered with high suspicion in patients with acute undifferentiated fever, even in non-endemic areas of leptospirosis.

Accounting for aetiology: can regional surveillance data alongside host biomarker-guided antibiotic therapy improve treatment of febrile illness in remote settings?

Background: Across Southeast Asia, declining malaria incidence poses a challenge for healthcare providers, in how best to manage the vast majority of patients with febrile illnesses who have a negative malaria test. In rural regions, where the majority of the population reside, empirical treatment guidelines derived from central urban hospitals are often of limited relevance. In these settings, relatively untrained health workers deliver care, often without any laboratory diagnostic support. In this paper, our aim was to model the impact on mortality from febrile illness of using point-of-care C-reactive protein testing to inform the decision to prescribe antibiotics and regional surveillance data to inform antibiotic selection, rooted in the real-world context of rural Savannakhet province, southern Laos. Methods: Our model simulates 100 scenarios with varying quarterly incidence of six key pathogens known to be prevalent in rural Laos. In the simulations, community health workers either prescribe antibiotics in-line with current practice as documented in health facilities in rural Laos, or with the aid of the two interventions. We provide cost-effectiveness estimates for each strategy alone and then for an integrated approach using both interventions. Results: We find that each strategy alone is predicted to be highly cost-effective, and that the combined approach is predicted to result in the biggest reduction in mortality (averting a predicted 510 deaths per year in rural Savannakhet, a 28% reduction compared to standard practice) and is highly cost-effective, with an incremental cost-effectiveness ratio of just $66 per disability-adjusted life year averted. Conclusions: Substantial seasonal variation in the predicted optimal empirical antibiotic treatment for febrile illness highlights the benefits of up-to-date information on regional causes of fever. In this modelling analysis, an integrated system incorporating point-of-care host biomarker testing and regional surveillance data appears highly cost-effective, and may warrant piloting in a real-life setting.

Molecular detection and clinical characteristics of Bartonella bacilliformis, Leptospira spp., and Rickettsia spp. in the Southeastern Peruvian Amazon basin

BACKGROUND

Acute febrile illness (AFI) represent a significant health challenge in the Peruvian Amazon basin population due to their diverse etiologies and the unavailability of specific on-site diagnostic methods, resulting in underreporting of cases. In Peru, one of the most endemic regions to dengue and leptospirosis is Madre de Dios, a region also endemic to emergent bacterial etiologic agents of AFI, such as bartonellosis and rickettsiosis, whose prevalence is usually underreported. We aimed to molecularly identify the presence of Leptospira spp., Bartonella bacilliformis, and Rickettsia spp. by Polymerase Chain Reaction in serum samples from patients with AFI from Puerto Maldonado-Madre de Dios in Peru.

METHODS

Serum samples from patients with acute febrile illness were analyzed by real-time PCR for detecting the presence of Bartonella bacilliformis, Leptospira spp. and Rickettsia spp.

RESULTS

Bartonella bacilliformis was the most prevalent bacteria identified in 21.6% (30/139) of the samples, followed by Leptospira spp. in 11.5% (16/139) and Rickettsia spp. in 6.5% (9/139) of the samples. No co-infections were observed between these bacteria. The most frequent symptoms associated with fever among all groups, were headaches, myalgias, and arthralgias. We found no statistically significant differences in the clinical presentation between patients infected with each bacterium.

CONCLUSIONS

In a previous study, we shown the presence of dengue, chikungunya, Zika and oropouche virus. We were able to identify these pathogens in 29.5% of all the samples, with chikungunya and OROV as the most frequently found in 9.4 and 8.6% of all the samples, respectively. In this study we show that B. bacilliformis (21.6%), Leptospira spp. (11.5%) and Rickettsia spp. (6.5%) accounted for the main etiologies of AFI in samples from Puerto Maldonado-Madre de Dios, Perú. Our analysis of their clinical presentation, further shows the importance of implementing more sensitive and specific on-site diagnostic tools in the national surveillance programs.This study confirms that the un-specificity of signs and symptoms is not only associated with arboviral infections, but also with the clinical presentation of endemic bacterial infections.

A 3-year retrospective analysis on the prevalence of antileptospiral antibodies among children in Chennai City, India

PURPOSE

Leptospirosis is a re-emerging infectious disease that has been reported from all over the world, including South India. Several studies have documented the prevalence of Leptospira in the general population. However, the data on leptospirosis in children were limited. We evaluated the prevalence of antileptospiral antibodies and the distribution of Leptospira serovars in children and adolescents.

METHODOLOGY

In this retrospective study, details for a total of 5407 children who presented with fever and whose test results for antileptospiral antibodies available were recorded. A microscopic agglutination test (MAT) was performed to detect the presence of anti-leptospiral antibodies and a titre of more than 1 : 80 was considered positive. The antigen panel included the following six serovars: Icterohaemorrhagiae, Canicola, Autumnalis, Australis, Grippotyphosa and Patoc. Demographics such as age and gender were recorded.

RESULTS

An overall seropositivity rate of 30.8 % (95 % CI: 21.54-25.81) was observed. More male children (59 %) were infected than female children (41 %). Leptospirosis occurs throughout the year among children. Cases peak in the summer time and during the months of November and December. The most prevalent serovar in this study was L. Canicola followed by L. Australis and L. Autumnalis.

CONCLUSION

This seroprevalence study suggested that leptospirosis occurs among children throughout the year in Chennai, India. This makes it almost mandatory to include it in the differential diagnosis for febrile illnesses in children. Early detection and treatment, together with control measures, may significantly reduce the spread of this endemic pathogen in this city.

Leptospirosis in Ukraine (Lviv Oblast): Clinical and Epidemiological Features

The article describes the results of a retrospective analysis of medical records of 395 patients with a clinical diagnosis of leptospirosis treated at the Lviv Oblast Infectious Disease Clinical Hospital (Ukraine) between 2002 and 2016. The main risk factors for leptospirosis were contact with rodents or their excrements (26.84%) and bathing in ponds, small lakes, and reservoirs (10.63%). Among 276 patients in whom the anti-leptospira antibodies were detected by the microscopic agglutination test (MAT), the most common serotypes were Leptospira icterohaemorrhagiae (33.33%) and Leptospira grippotyphosa (25.0%). The mortality rate was significantly higher in patients where leptospirosis diagnosis was established based on clinical symptoms without confirmation by MAT (15.13% vs. 5.43%, p < 0.01).

Detection of intraocular Leptospira spp. by real-time polymerase chain reaction in horses with recurrent uveitis in Belgium

BACKGROUND

Equine recurrent uveitis (ERU) has been associated with Leptospira spp. infection. No information exists concerning the prevalence of Leptospira-associated ERU in Belgium and about the sensitivity of detection of Leptospira in different ocular media.

OBJECTIVES

To establish the prevalence of intraocular Leptospira spp. in ERU-affected and healthy eyes of horses examined at the Equine Clinic of the University of Liège by real-time PCR and to compare the results of the aqueous and vitreous humour of the same eye.

STUDY DESIGN

Cross-sectional.

METHODS

Sixty-six eyes from 59 client-owned horses with a diagnosis of equine recurrent uveitis (ERU-group) were studied from May 2015 to December 2017. Fifty healthy eyes from 28 euthanised horses for unrelated reasons examined during the same period were included in the control group. Intraocular fluids (aqueous and/or vitreous humours) from ERU-affected eyes were sampled and analysed by real-time PCR for Leptospira spp. Aqueous and vitreous humours from the control group were processed in the same way.

RESULTS

Both groups were comparable regarding age, sex, eye sampled (OS/OD), humours sampled (aqueous/vitreous humour) but not regarding breeds, with an over-representation of Warmbloods and Appaloosas in the ERU-group. The prevalence of Leptospira spp. was 30.3% (20/66 eyes) in the ERU-group. Leptospira spp. DNA was identified in 11 aqueous and 17 vitreous humours with eight horses testing positive in both humours, nine horses testing positive for vitreous humour alone and third horses for aqueous humour alone. The phi-correlation between aqueous and vitreous humour Leptospira-PCR results is 0.47 suggesting a low association. All the control eyes were negative.

MAIN LIMITATIONS

The diagnostic method selected for this study (lipL32 qPCR) did not allow identification of the serovars.

CONCLUSIONS

Leptospirosis is a potential cause of ERU in Belgium. Testing both intraocular media is advised whenever possible. The Summary is available in Spanish - see Supporting Information.

The Spiraling Case of a Yellow Chef: Isolated Hyperbilirubinemia

Leptospirosis is a common bacterial disease in tropical regions of the world due to greater exposure to rodents and domestic animals; however, this condition can also occur in US urban areas, though it often goes unrecognized. Gastrointestinal symptoms are very commonly seen, and icteric leptospirosis is often confused for other conditions resulting in delayed diagnosis and worse outcomes. As mortality increases with more extensive hepatic involvement, gastroenterologists should be aware of the constellation of gastrointestinal symptoms related to leptospirosis, as it can occur in the absence of classic exposure history.

Assessment of animal hosts of pathogenic Leptospira in northern Tanzania

Leptospirosis is a zoonotic bacterial disease that affects more than one million people worldwide each year. Human infection is acquired through direct or indirect contact with the urine of an infected animal. A wide range of animals including rodents and livestock may shed Leptospira bacteria and act as a source of infection for people. In the Kilimanjaro Region of northern Tanzania, leptospirosis is an important cause of acute febrile illness, yet relatively little is known about animal hosts of Leptospira infection in this area. The roles of rodents and ruminant livestock in the epidemiology of leptospirosis were evaluated through two linked studies. A cross-sectional study of peri-domestic rodents performed in two districts with a high reported incidence of human leptospirosis found no evidence of Leptospira infection among rodent species trapped in and around randomly selected households. In contrast, pathogenic Leptospira infection was detected in 7.08% cattle (n = 452 [5.1-9.8%]), 1.20% goats (n = 167 [0.3-4.3%]) and 1.12% sheep (n = 89 [0.1-60.0%]) sampled in local slaughterhouses. Four Leptospira genotypes were detected in livestock. Two distinct clades of L. borgpetersenii were identified in cattle as well as a clade of novel secY sequences that showed only 95% identity to known Leptospira sequences. Identical L. kirschneri sequences were obtained from qPCR-positive kidney samples from cattle, sheep and goats. These results indicate that ruminant livestock are important hosts of Leptospira in northern Tanzania. Infected livestock may act as a source of Leptospira infection for people. Additional work is needed to understand the role of livestock in the maintenance and transmission of Leptospira infection in this region and to examine linkages between human and livestock infections.

Pet rodents as possible risk for leptospirosis, Belgium and France, 2009 to 2016

Leptospirosis is an under-reported and emerging zoonotic disease which is potentially fatal in humans. Rodents are the main reservoirs for pathogenic Leptospira spp., but diagnosis in these animals is difficult, and their infection, which does not induce symptoms, usually goes unoticed. Although the exposures of most human cases of leptospirosis are poorly documented, we were able to identify six human cases of leptospirosis which were associated with direct contact with pet rodents (mice or rats) in Belgium and France between 2009 and 2016. All cases had severe disease and for all, the presence of Leptospira spp. DNA in the kidneys of their pet animals was confirmed, strongly suggesting that excretion of leptospires in urine was the way of transmission. Half of the cases shared the serogroup Icterohaemorrhagiae, which is usually associated with severe disease, with the pet rats which they were in contact with. With the popularity of rats and mice as pets, this study should contribute to raising awareness on asymptomatic pet rodents as a source of Leptospira infections.

Danger in Paradise

A 31-year-old man presented to the Student Health Center for evaluation 3 days after departing Hong Kong. On the last day of his 3-week-long trip to Southeast Asia, he developed sudden onset of fever, arthralgia, and headache. He initially attributed his symptoms to exhaustion, but the symptoms persisted. He also had several loose, non-bloody stools, a problem that resolved without intervention.

Leptospirosis-associated catastrophic respiratory failure supported by extracorporeal membrane oxygenation

A previously healthy, 39-year-old obese farmer, arrived hypotensive and tachycardic, with fever, myalgia, headache, abdominal pain, diarrhea, and progressive dyspnea. Ten days before symptoms onset, he was in direct contact with mice and working in a contaminated drain. Patient laboratory showed acute kidney injury and thrombocytopenia. Chest X-ray exhibited bilateral diffuse interstitial infiltrates. First-line empirical antibiotics were started and influenza discarded. Patient evolved with severe respiratory failure, associated with hemoptysis, and rapidly severe hemodynamic compromise. Despite neuromuscular blockade and prone positioning, respiratory failure increased. Accordingly, veno-venous ECMO was initiated, with bilateral femoral extraction and jugular return. After ECMO connection, there was no significant improvement in oxygenation, and low pre-membrane saturations and low arterial PaO2 of the membrane showed that we were out of the limits of the rated flow. Thus, a second membrane oxygenator was installed in parallel. Afterward, oxygenation improved, with subsequent perfusion enhancement. Regarding etiology, due to high suspicion index, Leptospira serology was performed, coming back positive and meropenem was maintained. The patient ultimately recovered and experience excellent outcome. The clinical relevance of the case is the scared evidence of leptospirosis-associated severe respiratory failure treated with ECMO. This experience emphasizes the importance of an optimal support, which requires enough membrane surface and flow for an obese, highly hyperdynamic patient, during this reversible disease. A high index of suspicion is needed for an adequate diagnosis of leptospirosis to implement the correct treatment, particularly in the association of respiratory failure, pulmonary hemorrhage, and an epidemiological-related context.

Leptospirosis: Report from the task force on tropical diseases by the World Federation of Societies of Intensive and Critical Care Medicine

Leptospirosis is a zoonosis caused by a gram negative aerobic spirochete of the genus Leptospira. It is acquired by contact with urine or reproductive fluids from infected animals, or by inoculation from contaminated water or soil. The disease has a global distribution, mainly in tropical and subtropical regions that have a humid, rainy climate and is also common in travelers returning from these regions. Clinical suspicion is critical for the diagnosis and it should be included in the differential diagnosis of any patient with a febrile hepatorenal syndrome in, or returning from endemic regions. The leptospiremic phase occurs early and thereafter there is an immunologic phase in which the most severe form, Weil's disease, occurs. In the latter, multiple organ dysfunction predominates. The appropriate diagnostic test depends on the stage of the disease and consists of direct and indirect detection methods and cultures. Severely ill patients need to be monitored in an ICU with appropriate anti-bacterial agents and early, aggressive and effective organ support. Antibiotic therapy consists of penicillins, macrolides or third generation cephalosporins.

A comparison of two molecular methods for diagnosing leptospirosis from three different sample types in patients presenting with fever in Laos

OBJECTIVES

To compare two molecular assays (rrs quantitative PCR (qPCR) versus a combined 16SrRNA and LipL32 qPCR) on different sample types for diagnosing leptospirosis in febrile patients presenting to Mahosot Hospital, Vientiane, Laos.

METHODS

Serum, buffy coat and urine samples were collected on admission, and follow-up serum ∼10 days later. Leptospira spp. culture and microscopic agglutination tests (MAT) were performed as reference standards. Bayesian latent class modelling was performed to estimate sensitivity and specificity of each diagnostic test.

RESULTS

In all, 787 patients were included in the analysis: 4/787 (0.5%) were Leptospira culture positive, 30/787 (3.8%) were MAT positive, 76/787 (9.7%) were rrs qPCR positive and 20/787 (2.5%) were 16SrRNA/LipL32 qPCR positive for pathogenic Leptospira spp. in at least one sample. Estimated sensitivity and specificity (with 95% CI) of 16SrRNA/LipL32 qPCR on serum (53.9% (33.3%-81.8%); 99.6% (99.2%-100%)), buffy coat (58.8% (34.4%-90.9%); 99.9% (99.6%-100%)) and urine samples (45.0% (27.0%-66.7%); 99.6% (99.3%-100%)) were comparable with those of rrs qPCR, except specificity of 16SrRNA/LipL32 qPCR on urine samples was significantly higher (99.6% (99.3%-100%) vs. 92.5% (92.3%-92.8%), p <0.001). Sensitivities of MAT (16% (95% CI 6.3%-29.4%)) and culture (25% (95% CI 13.3%-44.4%)) were low. Mean positive Cq values showed that buffy coat samples were more frequently inhibitory to qPCR than either serum or urine (p <0.001).

CONCLUSIONS

Serum and urine are better samples for qPCR than buffy coat, and 16SrRNA/LipL32 qPCR performs better than rrs qPCR on urine. Quantitative PCR on admission is a reliable rapid diagnostic tool, performing better than MAT or culture, with significant implications for clinical and epidemiological investigations of this global neglected disease.

Molecular diagnostics for human leptospirosis

PURPOSE OF REVIEW

The definitive diagnosis of leptospirosis, which results from infection with spirochetes of the genus Leptospira, currently relies on the use of culture, serological testing (microscopic agglutination testing), and molecular detection. The purpose of this review is to describe new molecular diagnostics for Leptospira and discuss advancements in the use of available methods.

RECENT FINDINGS

Efforts have been focused on improving the clinical sensitivity of Leptospira detection using molecular methods. In this review, we describe a reoptimized pathogenic species-specific real-time PCR (targeting lipL32) that has demonstrated improved sensitivity, findings by two groups that real-time reverse-transcription PCR assays targeting the 16S rrs gene can improve detection, and two new loop-mediated amplification techniques. Quantitation of leptospiremia, detection in different specimen types, and the complementary roles played by molecular detection and microscopic agglutination testing will be discussed. Finally, a protocol for Leptospira strain subtyping using variable number tandem repeat targets and high-resolution melting will be described.

SUMMARY

Molecular diagnostics have an established role for the diagnosis of leptospirosis and provide an actionable diagnosis in the acute setting. The use of real-time reverse-transcription PCR for testing serum/plasma and cerebrospinal fluid, when available, may improve the detection of Leptospira without decreasing clinical specificity.

Pre-treatment with Lactobacillus plantarum prevents severe pathogenesis in mice infected with Leptospira interrogans and may be associated with recruitment of myeloid cells

Recent estimates on global morbidity and mortality caused by Leptospirosis point to one million cases and almost 60,000 deaths a year worldwide, especially in resource poor countries. We analyzed how a commensal probiotic immunomodulator, Lactobacillus plantarum, affects Leptospira interrogans pathogenesis in a murine model of sub-lethal leptospirosis. We found that repeated oral pre-treatment of mice with live L. plantarum restored body weight to normal levels in mice infected with L. interrogans. Pre-treatment did not prevent L. interrogans access to the kidney but it affected the inflammatory response and it reduced histopathological signs of disease. Analysis of the immune cell profiles in lymphoid tissues of mice pre-treated with L. plantarum showed increased numbers of B cells as well as naïve and memory CD4+ helper T cell populations in uninfected mice that shifted towards increased numbers of effector CD4⁺ helper T in infected mice. CD8⁺ cytotoxic T cell profiles in pre-treated uninfected and infected mice mirrored the switch observed for CD4+ except that CD8+ memory T cells were not affected. In addition, pre-treatment led to increased populations of monocytes in lymphoid tissues of uninfected mice and to increased populations of macrophages in the same tissues of infected mice. Immunohistochemistry of kidney sections of pre-treated infected mice showed an enrichment of neutrophils and macrophages and a reduction of total leucocytes and T cells. Our results suggest that complex myeloid and T cell responses orchestrate the deployment of monocytes and other cells from lymphoid tissue and the recruitment of neutrophils and macrophages to the kidney, and that, the presence of these cells in the target organ may be associated with reductions in pathogenesis observed in infected mice treated with L. plantarum.

Leptospirosis is an emerging neglected zoonotic disease with worldwide distribution that affects nearly all vertebrates and causes infection in ~1 million people on a yearly basis. Effective cross-protective vaccines are not available and antibiotic treatment is only effective if used early in the course of infection. In this study we describe how repeated oral treatment of mice with a commonly used probiotic, Lactobacillus plantarum, did not completely prevent colonization of the kidney by Leptospira interrogans but it did reduce signs and symptoms of leptospirosis. We also analyzed a number of immune cell types in spleen, lymph nodes and kidney after treatment and found that complex responses orchestrate the deployment of phagocytes to the kidney in infected mice. Our results suggest that pre-treatment with L. plantarum modulates systemic immune responses in a beneficial way in a mammalian host later exposed to L. interrogans infection.

Leptospira Immunoglobulin-Like Protein B Interacts with the 20th Exon of Human Tropoelastin Contributing to Leptospiral Adhesion to Human Lung Cells

Leptospira immunoglobulin-like protein B (LigB), a surface adhesin, is capable of mediating the attachment of pathogenic leptospira to the host through interaction with various components of the extracellular matrix (ECM). Human tropoelastin (HTE), the building block of elastin, confers resilience and elasticity to lung, and other tissues. Previously identified Ig-like domains of LigB, including LigB4 and LigB12, bind to HTE, which is likely to promote Leptospira adhesion to lung tissue. However, the molecular mechanism that mediates the LigB-HTE interaction is unclear. In this study, the LigB-binding site on HTE was further pinpointed to a N-terminal region of the 20th exon of HTE (HTE20N). Alanine mutants of basic and aromatic residues on HTE20N significantly reduced binding to the LigB. Additionally, HTE-binding site was narrowed down to the first β-sheet of LigB12. On this binding surface, residues F1054, D1061, A1065, and D1066 were critical for the association with HTE. Most importantly, the recombinant HTE truncates could diminish the binding of LigB to human lung fibroblasts (WI-38) by 68%, and could block the association of LigA-expressing L. biflexa to lung cells by 61%. These findings should expand our understanding of leptospiral pathogenesis, particularly in pulmonary manifestations of leptospirosis.

Acute kidney injury due to tropical infectious diseases and animal venoms: a tale of 2 continents

South and Southeast Asia and Latin American together comprise 46 countries and are home to approximately 40% of the world population. The sociopolitical and economic heterogeneity, tropical climate, and malady transitions characteristic of the region strongly influence disease behavior and health care delivery. Acute kidney injury epidemiology mirrors these inequalities. In addition to hospital-acquired acute kidney injury in tertiary care centers, these countries face a large preventable burden of community-acquired acute kidney injury secondary to tropical infectious diseases or animal venoms, affecting previously healthy young individuals. This article reviews the epidemiology, clinical picture, prevention, risk factors, and pathophysiology of acute kidney injury associated with tropical diseases (malaria, dengue, leptospirosis, scrub typhus, and yellow fever) and animal venom (snakes, bees, caterpillars, spiders, and scorpions) in tropical regions of Asia and Latin America, and discusses the potential future challenges due to emerging issues.

Association between Opisthorchis viverrini and Leptospira spp. infection in endemic Northeast Thailand

Opisthorchiasis caused by Opisthorchis viverrini is an important foodborne trematodiasis in Thailand, Laos and Cambodia. Interestingly, the opisthorchiasis endemic region overlaps with an area of leptospirosis emergence. Here we report an association between opisthorchiasis and leptospirosis in Thailand. Of 280 sera collected from villagers living around the Lawa wetland complex in Khon Kaen province, 199 (71%) were seropositive for leptospirosis by immunochromatography. Individuals with O. viverrini infection had a significantly higher rate of leptospirosis than those without (P=0.001). Significant higher leptospirosis prevalence was found in males than females (P=0.002). However, females but not males with O. viverrini infection showed a significantly higher seroprevalence of leptospirosis. Twenty-one of 35 environmental samples from the lake (water, mud and fish skin mucus) were positive for Leptospira spp. DNA sequencing, sequence alignment, and phylogenetic analysis of some positive nested PCR products revealed both pathogenic and intermediate pathogenic strains of Leptospira in the samples. Strikingly, O. viverrini metacercariae from the fish were positive for L. interrogans. These results suggest a close association between opisthorchiasis and leptospirosis. Contact with water, mud or eating raw fish harboring liver fluke metacercariae may be risk factors for Leptospira infection.