Risk factors and predictors of severe leptospirosis in New Caledonia

ELISA for leptospiral 3-hydroxyacyl-CoA dehydrogenase in urine is a promising screening tool for acute leptospirosis

Introduction. Leptospirosis is a zoonotic disease that is prevalent worldwide. Leptospiral 3-hydroxyacyl-CoA dehydrogenase (3-HADH) is excreted in the urine of infected individuals. However, the potential use of 3-HADH as a biomarker for the diagnosis of leptospirosis using enzyme-linked immunosorbent assay (ELISA) has not been investigated. A technique that identifies Leptospira in a patient in urine sample will be valuable in regular diagnostics and epidemic scenarios, as opposed to existing serological approaches. This study aimed to develop and evaluate an ELISA that can detect 3-HADH in the urine of patients with confirmed acute leptospirosis and to assess its potential as a screening test for leptospirosis. Methods. Laboratory confirmation of acute leptospirosis was done by flaB-nested polymerase chain reaction (PCR) of plasma samples from suspected patients. ELISA-based determination of the presence of 3-HADH in the urine of PCR-positive patients versus PCR-negative patients matched for fever date was performed by coating ELISA plates with urine supernatants and using rabbit anti-3-HADH as the primary antibody. Receiver operating characteristic curve analysis was used to determine the cutoff values for the ELISA. The diagnostic measures between the PCR-positive and PCR-negative patients were compared using the Mann-Whitney U test. Results. In total, 158 febrile patients were assessed, of whom 121 (76.6 %) were male. Of the 15 flaB-nested PCR-positive patients, 12 were in the acute phase of the febrile illness. The best cutoff was an average optical density (ODav) value of 0.2200 for febrile patients. Sensitivity and specificity were 83.33% [95 % confidence interval (CI), 51.59-97.91 %) and 83.33 % (95 % CI, 76.05-89.13 %), respectively. The ODav values for PCR-positive patients in the acute phase of the disease (≤7 days of fever) were significantly higher than those for PCR-negative patients (P<0.001, U=114.0, z=-4.946). Conclusion. Detection of 3-HADH in urine by ELISA appears to be promising for the screening of acute leptospirosis in suspected patients.

A 16-year-old man with leptospirosis and atypical disseminated intravascular coagulation: a case report

BACKGROUND

Leptospirosis is known for its pulmonary form characterized by intra-alveolar hemorrhage, exhibiting a high mortality rate. Management by venous-venous extracorporeal membrane oxygenation has been reported in a small number of cases.

CASE PRESENTATION

We report herein the case of a 16-year-old Caucasian male who was admitted with rapidly deteriorating respiratory and digestive complaints. He developed severe acute respiratory distress syndrome secondary to disseminated intravascular coagulation and intra-alveolar hemorrhage, requiring initiation of venous-venous extracorporeal membrane oxygenation. Initial infectious and immunological assessments were inconclusive, but repeat serology on the tenth day of admission confirmed a diagnosis of leptospirosis. The patient received multiple transfusions, and upon favorable response to treatment with corticosteroids and antibiotics, he was successfully weaned off venous-venous extracorporeal membrane oxygenation, which was discontinued after 12 days.

CONCLUSION

Leptospirosis is a rare cause of severe acute respiratory failure following pulmonary hemorrhage. It is typically diagnosed by serology, with detectable IgM antibodies 5-7 days after the onset of symptoms. We report that early support with respiratory extracorporeal membrane oxygenation favors timely clearance of endobronchial clotting, parenchymal recovery, and prevention of ventilator-induced lung injury. Major hypofibrinogenemia, which did not seem to worsen during extracorporeal membrane oxygenation application, was managed by repeated transfusions. Further studies investigating the pathogenesis of this coagulopathy are required to further optimize the management of this rare and severe complication.

An investigation of geographical clusters of leptospirosis during the outbreak in Pangandaran, West Java, Indonesia

Leptospirosis is neglected in many tropical developing countries, including Indonesia. Our research on this zoonotic disease aimed to investigate epidemiological features and spatial clustering of recent leptospirosis outbreaks in Pangandaran, West Java. The study analysed data on leptospirosis notifications between September 2022 and May 2023. Global Moran I and local indicator for spatial association (LISA) were applied. Comparative analysis was performed to characterise the identified hotspots of leptospirosis relative to its neighbourhoods. A total of 172 reported leptospirosis in 40 villages from 9 sub-districts in Pangandaran District were analysed. Of these, 132 cases (76.7%) were male. The median age was 49 years (interquartile range [IQR]: 34-59 years). Severe outcomes including renal failure, lung failure, and hepatic necrosis were reported in up to 5% of the cases. A total of 30 patients died, resulting in the case fatality rate (CFR) of 17.4%. Moran's I analysis showed significant spatial autocorrelation (I=0.293; p=0.002) and LISA results identified 7 High-High clusters (hotspots) in the Southwest, with the total population at risk at 26,184 people. The hotspots had more cases among older individuals (median age: 51, IQR: 36-61 years; p<0.001), more farmers (79%, p=0.001) and more evidence of the presence of rats (p=0.02). A comprehensive One Health intervention should be targeted towards these high-risk areas to control the transmission of leptospirosis. More empirical evidence is needed to understand the role of climate, animals and sociodemographic characteristics on the transmission of leptospirosis in the area studied.

Identifying risk factors and disease severity in leptospirosis: A meta-analysis of clinical predictors

Leptospirosis is a bacterial zoonosis with a wide spectrum of clinical presentations. In order to identify potential risk factors and predictors of disease severity, a meta-analysis of the clinical features of severe and non-severe leptospirosis patients was conducted. PubMed was searched to collect studies on the difference in clinical characteristics of severe and nonsevere patients, and data were analyzed using Comprehensive Meta-Analysis V3 software. Results showed that patients with severe outcomes were more likely to have dyspnoea, oliguria, and hemorrhagic symptoms than nonsevere patients. Determining these predictors in the early stages of the disease could thus significantly reduce the development of severe cases and related mortality.

Epidemiological Characteristics and Trends in the Incidence of Leptospirosis in Japan: A Nationwide, Observational Study from 2006 to 2021

During this age of climate change, the incidence of tropical diseases may change. This study compared the epidemiological characteristics and trends of leptospirosis in Japan between the endemic region, Okinawa, and the rest of the country. Infectious Diseases Weekly Reports were used to determine the numbers and crude incidence rates of leptospirosis. Data were stratified by sex, age, the estimated location of the infection, the notified regions, and the reporting month. A joinpoint regression analysis was performed to estimate the annual percentage change (APC). During the 16-year study period (2006-2021), 543 leptospirosis cases were reported, with male dominance (86.2%). Approximately half of these cases were reported from Okinawa (47.1%). The patients were relatively younger in Okinawa (20-29 years, 23.4%; 30-39 years, 20.7%) than outside Okinawa. The frequency of imported cases was significantly higher outside Okinawa (0.4% versus 14.3%). The incidences of leptospirosis in and outside Okinawa were apparently higher during the summer and typhoon seasons. The annual crude incidence ratios were 20-200 times higher in Okinawa than in the rest of the country. The average APCs for the entire study period in Okinawa and the rest of Japan were 1.6% (95% CI: -5.9 to 9.6) and -1.8% (95% CI: -7.8 to 4.6), respectively, without any particular trends. Collectively, the patient profile of leptospirosis differed between Okinawa (younger men) and outside Okinawa (middle- or older-aged men with a history of traveling abroad). The disease remains a neglected tropical disease; continuous surveillance with close monitoring is required.

Leptospirosis and characterization of Leptospira isolates from patients in Koprivnica-Križevci County, Croatia from 2000-2004

Introduction

Leptospirosis, caused by spirochetes of the genus Leptospira , is present in the Koprivnica-Križevci County area, Croatia. Clinical manifestation can range from asymptomatic, short-term mild, non-specific febrile disease, to severe forms with high mortality rates.

Aim

The aim of the study was to valuate culture in front of microscopic agglutination test (MAT) for diagnosis of infection, and to evaluate clinical and laboratory features of the disease. Moreover, we want to characterize Leptospira strains involved in infection in Koprivnica-Križevci County, Croatia.

Methods

We included 68 patients with clinical presentation consistent with leptospirosis collected in a 5-year period (2000-2004). Clinical samples (blood, urine and cerebrospinal fluid, CSF) were inoculated in Kolthoff's medium; species of isolated Leptospira strains was determined with Tm of real-time PCR, serogroup/serovar with MAT and NotI-RFLP analysis. Demonstration of specific antibodies in patients' sera was done using microscopic agglutination test.

Results

Leptospira was isolated from the blood of 14/51(27.5 %) patients and the most often identified serogroup/serovar was Icterohaemorrhagiae (8/10, 80%) followed by Grippotyphosa (10%). Regarding to species level, 8/10 isolated belonged to L. interrogans sensu stricto and one to L. kirschneri species. MAT was carried out on 51 patients with suspected leptospirosis, and was positive in 11/51(21.5 %) patients. Most of our patients presented with moderate severe symptoms, were hospitalized from August to October, and were infected mainly during the work or recreation in our county. The frequency of particular clinical features and pathological laboratory findings correlated with the severity of the clinical condition.

Conclusions

Leptospirosis can be confirmed microbiologically, culture and MAT contributed almost equally to the diagnosis of infection. Serovar Icterohaemorrhagiae was found as the dominant one, and L. interrogans sensu stricto as dominant species in our county. Epidemiological data shown that leptospirosis occurs seasonally, affects the rural population, and most commonly is presented with moderate severe clinical course.

Core genome sequencing and genotyping of Leptospira interrogans in clinical samples by target capture sequencing

BACKGROUND

The life-threatening pathogen Leptospira interrogans is the most common agent of leptospirosis, an emerging zoonotic disease. However, little is known about the strains that are currently circulating worldwide due to the fastidious nature of the bacteria and the difficulty to isolate cultures. In addition, the paucity of bacteria in blood and other clinical samples has proven to be a considerable challenge for directly genotyping the agent of leptospirosis directly from patient material. Our understanding of the genetic diversity of strains during human infection is therefore limited.

METHODS

Here, we carried out hybridization capture followed by Illumina sequencing of the core genome directly from 20 clinical samples that were PCR positive for pathogenic Leptospira to elucidate the genetic diversity of currently circulating Leptospira strains in mainland France.

RESULTS

Capture with RNA probes covering the L. interrogans core genome resulted in a 72 to 13,000-fold increase in pathogen reads relative to standard sequencing without capture. Variant analysis of the genomes sequenced from the biological samples using 273 Leptospira reference genomes was then carried out to determine the genotype of the infecting strain. For samples with sufficient coverage (19/20 samples with coverage > 8×), we could unambiguously identify L. interrogans serovars Icterohaemorrhagiae and Copenhageni (14 samples), L. kirschneri serovar Grippotyphosa (4 samples), and L. interrogans serovar Pyrogenes (1 sample) as the infecting strains.

CONCLUSIONS

We obtained high-quality genomic data with suitable coverage for confident core genome genotyping of the agent of leptospirosis for most of our clinical samples. The recovery of the genome of the serovars Icterohaemorrhagiae and Copenhageni directly from multiple clinical samples revealed low adaptive diversification of the core genes during human infection. The ability to generate culture-free genomic data opens new opportunities for better understanding of the epidemiology of this fastidious pathogen and pathogenesis of this neglected disease.

Prognostic Factors for Leptospirosis Infection Severity

BACKGROUND

Leptospirosis is an important health problem in Thailand. People infected with leptospirosis may not have any mild symptoms, whereas some people have acute and severe illnesses. It is crucial to strengthen critical patients' diagnosis and treatment to prevent severe complications and reduce mortality. This study was performed to explore a set of parameters for the prediction of severe leptospirosis illness under routine clinical practice.

METHODS

A case-control study was conducted in eight general hospitals in Thailand. Retrospective collection data were used, and key information was retrieved from inpatient medical files. Patients were grouped into two severity categories, severe and non-severe infection. Backward elimination was used to reach the final multivariate model.

RESULTS

The six significant predictors identified in the study were hemoptysis (OR = 25.80, 95% CI 5.69, 116.92), hypotension (blood pressure < 90/60 mmHg) (OR = 17.33, 95% CI 6.89, 43.58), platelet count < 100,000/µL (OR = 8.37, 95% CI 4.65, 15.09), white blood cell count (WBC) > 14,000/µL (OR = 5.12, 95% CI 2.75, 9.51), hematocrit ≤ 30% (OR = 3.49, 95% CI 1.61, 7.57), and jaundice (OR = 3.11, 95% CI 1.71, 5.65). These predictors could correctly predict the severity of leptospirosis infection in 91.31% of the area under the receiver operation curve (AuROC).

CONCLUSIONS

The results of this study showed that severe leptospirosis infections have identifiable predictors. The predictors may be used to develop a scoring system for predicting the level of severity.

C-reactive protein: An easy marker for early differentiation between leptospirosis and dengue fever in endemic area

In tropical regions, leptospirosis and dengue fever (DF) are infectious diseases of epidemiological importance and have overlapping symptomatic features. The objective of this study was to identify the factors associated to diagnosing leptospirosis that differentiate it to DF at the initial hospital evaluation. A multicenter retrospective study was conducted comparing confirmed leptospirosis to DF cases. Clinical/laboratory findings were compiled at hospital admission on Reunion Island between 2018 and 2019. Multivariable logistic regression was used to identify the predictors of leptospirosis. In total, 98 leptospirosis and 673 DF patients were included with a mean age of 47.8 (±17.1) and 48.9 (±23.3) years, respectively. In the multivariate analyses, the main parameters associated with leptospirosis were: i) increased neutrophil counts, ii) C-reactive protein values, iii) the absence of prolonged partial thromboplastin time, and iv) a decrease of platelets. The most discriminating parameter was C-reactive protein (CRP). With a threshold of 50mg/L, CRP taken alone had a sensitivity of 94% and a specificity of 93.5%. The positive and negative likelihood ratios were 14.5 and 0.06, respectively. In the setting of an early presumptive diagnosis, we found that an increased CRP value (>50 mg/L) could help diagnose leptospirosis and aid the decision process for hospital surveillance and/or a potential antibiotic treatment regimen.

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.

Clinical characteristics and prognosis of patient with leptospirosis: A multicenter retrospective analysis in south of China

Purpose

Leptospirosis is a zoonotic disease caused by pathogenic spirochetes of the genus Leptospira. However, there is currently no consensual definition or diagnostic criteria for severe and different forms of leptospirosis. Therefore, more insight on clinical manifestations, risk factors, and outcomes of leptospirosis is warranted. The identification of leptospirosis with distinct clinical manifestations and prognosis in our population.

Methods

Multiple correspondence analysis and hierarchical classification on principal components were presented to identify different clinical types of leptospirosis. The outcomes were clinical phenotypes, laboratory and imaging findings, and prognosis.

Results

The 95 enrolled patients had median values of 54.0 years (39.0-65.0) for age, 9.0 (7.0-14.0) for total hospital stay lengths, of whom 86.3% was male and 40.0% was transferred to ICU. Three clinical types were distinguished: mild leptospirosis (n=43, 45.3%) with less organ dysfunction and shorter hospital stays; respiratory leptospirosis (n=28, 29.5%) with hemoptysis, and respiratory and circulatory failure; and hepato-renal leptospirosis (n=24, 25.3%) with worst liver and kidney dysfunction. Total hospital mortality was 15.8% and was associated with dyspnea and high levels of neutrophil counts.

Conclusions

The identification of leptospirosis with distinct clinical manifestations and prognosis in our population may assist clinicians to distinguish leptospirosis-like disease. Moreover, dyspnea and neutrophil count were found to be independent risk factors for severe leptospirosis progression.

Determinants of prolonged hospitalization and mortality among leptospirosis patients attending tertiary care hospitals in northeastern state in peninsular Malaysia: A cross sectional retrospective analysis

Background

Leptospirosis is the most common anthropozoonosis worldwide and imposes a major public health problem in many tropical countries. It is a leading cause of disease burden in form of mortality, morbidity and hospital admission. Identifying patients at high risk for mortality or for prolonged hospitalization may save lives and preserve economy. The aim of the current study is to identify significant factors associated with disease mortality and prolonged hospitalization.

Design

Cress-sectional retrospective study.

Settings

Tertiary care teaching hospitals in Kelantan, Peninsular Malaysia.

Participants

Adult patients proven to have leptospirosis depending on IgM ELISA were classified into two classes depending on prolonged hospitalization (&gt;7 days or ≤ 7 days) and mortality (fatal cases or non-fatal cases). Patients' clinico-laboratory data were compared according to these two outcomes using the appropriate statistical test.

Results

Of the 525 patients enrolled, 136 (25.9%) had prolonged hospitalization. The mean length of stay was 6.77 ± 5.68 days. Logistic regression analysis identified acute kidney injury (AKI) (OR 2.3), Jaundice (OR 2.7), elevated alanine aminotransferase (ALT) (OR 2), and prolonged prothrombin time (PT) (OR 1.9) independently associated with prolonged hospitalization. Case fatality rate was 6.48% and around one third of fatal cases had prolonged hospitalization of more than seven days. Factors associated with leptospirosis mortality included age &gt;40 years (p &lt; 0.001), patients presented with tachypnea (p = 0.002), pulmonary infiltrate (p &lt; 0.001), T-wave changes (p &lt; 0.001), atrial fibrillation (p = 0.013), conducting abnormality (p &lt; 0.001), chronic kidney diseases (p &lt; 0.001), multiple organ dysfunctions (p &lt; 0.0010), respiratory failure (p &lt; 0.001), pneumonia (p &lt; 0.001), sepsis (p = 0.004), low venous PH (p = 0.042), AKI (P &lt; 0.001), elevated AST (p &lt; 0.001) or ALT (p = 0.004), hypoalbuminemia (p &lt; 0.001), rhabdomyolysis (p &lt; 0.001), severe thrombocytopenia (p = 0.042), prolonged PT (p &lt; 0.001) or prolonged aPTT (p &lt; 0.017).

Conclusions

Significant proportion of leptospirosis patients (25.9%) had prolonged hospital stay and less proportion died (6.48%). Early identifying patients with factors associated with prolonged hospitalization and death will positively impact practitioners' decisions regarding the proper and fast course of management including ICU admission.

Predictors of lethality in severe leptospirosis in Transcarpathian region of Ukraine

Leptospirosis is one of the most widespread zoonoses in the Transcarpathian region, with an average lethality of 12.5%. To determine the predictors of lethality, a retrospective study of 97 medical records of patients with leptospirosis in the period from 2009 to 2018 was conducted. Quantitative variables in the presence of normal distribution were compared using a paired Student's t-test, and in the case of an abnormal distribution, the Mann-Whitney U test was used. The criterion χ² was used for qualitative variables. Multivariate analysis was used for the calculation of the Odds ratio. The following factors that are associated with death from leptospirosis have been identified: total bilirubin greater than 300 mcmol/L (OR, 4.25; 95% confidence interval [CI], 1.57-11.53), platelets less than 50 × (10⁹/L) (OR, 3.95; 95% confidence interval [CI], 1.45-10.73), creatinine above 200 mcmol/L (OR, 1.95; 95% confidence interval [CI], 1.47-2.60) and jaundice (OR, 1.39; 95% confidence interval [CI], 1.21-1.60). Detection of these predictors will help to quickly identify a patient at risk of severe course of the disease and death, which will allow deciding on the use of early intensive care.

The epidemiology and outcomes of central nervous system infections in Far North Queensland, tropical Australia; 2000-2019

Background

The epidemiology of central nervous system (CNS) infections in tropical Australia is incompletely defined.

Methods

A retrospective study of all individuals in Far North Queensland, tropical Australia, who were diagnosed with a CNS infection between January 1, 2000, and December 31, 2019. The microbiological aetiology of the infection was correlated with patients’ demographic characteristics and their clinical course.

Results

There were 725 cases of CNS infection during the study period, meningitis (77.4%) was the most common, followed by brain abscess (11.6%), encephalitis (9.9%) and spinal infection (1.1%). Infants (24.3%, p<0.0001) and Aboriginal and Torres Strait Islander Australians (175/666 local residents, 26.3%, p<0.0001) were over-represented in the cohort.

A pathogen was identified in 513 cases (70.8%); this was viral in 299 (41.2%), bacterial in 175 (24.1%) and fungal in 35 (4.8%). Cryptococcal meningitis (24 cases) was diagnosed as frequently as pneumococcal meningitis (24 cases). There were only 2 CNS infections with a S. pneumoniae serotype in the 13-valent pneumococcal vaccine after its addition to the National Immunisation schedule in 2011. Tropical pathogens–including Cryptococcus species (9/84, 11%), Mycobacterium tuberculosis (7/84, 8%) and Burkholderia pseudomallei (5/84, 6%)–were among the most common causes of brain abscess. However, arboviral CNS infections were rare, with only one locally acquired case—a dengue infection in 2009—diagnosed in the entire study period. Intensive Care Unit admission was necessary in 14.3%; the overall case fatality rate was 4.4%.

Conclusion

Tropical pathogens cause CNS infections as commonly as traditional bacterial pathogens in this region of tropical Australia. However, despite being highlighted in the national consensus guidelines, arboviruses were identified very rarely. Prompt access to sophisticated diagnostic and supportive care in Australia’s well-resourced public health system is likely to have contributed to the cohort’s low case-fatality rate.

Rapid and sensitive point-of-care detection of Leptospira by RPA-CRISPR/Cas12a targeting lipL32

Background

One of the key barriers preventing rapid diagnosis of leptospirosis is the lack of available sensitive point-of-care testing. This study aimed to develop and validate a clustered regularly-interspaced short palindromic repeat (CRISPR)/CRISPR-associated protein 12a (CRISPR/Cas12a) platform combined with isothermal amplification to detect leptospires from extracted patient DNA samples.

Methodology/Principal findings

A Recombinase Polymerase Amplification (RPA)-CRISPR/Cas12a-fluorescence assay was designed to detect the lipL32 gene of pathogenic Leptospira spp. The assays demonstrated a limit of detection (LOD) of 100 cells/mL, with no cross-reactivity against several other acute febrile illnesses. The clinical performance of the assay was validated with DNA extracted from 110 clinical specimens and then compared to results from qPCR detection of Leptospira spp. The RPA-CRISPR/Cas12a assay showed 85.2% sensitivity, 100% specificity, and 92.7% accuracy. The sensitivity increased on days 4–6 after the fever onset and decreased after day 7. The specificity was consistent for several days after the onset of fever. The overall performance of the RPA-CRISPR/Cas12a platform was better than the commercial rapid diagnostic test (RDT). We also developed a lateral flow detection assay (LFDA) combined with RPA-CRISPR/Cas12a to make the test more accessible and easier to interpret. The combined LFDA showed a similar LOD of 100 cells/mL and could correctly distinguish between known positive and negative clinical samples in a pilot study.

Conclusions/Significance

The RPA-CRISPR/Cas12 targeting the lipL32 gene demonstrated acceptable sensitivity and excellent specificity for detection of leptospires. This assay might be an appropriate test for acute leptospirosis screening in limited-resource settings.

Clinical signs and symptoms of leptospirosis are similar to those of other infectious diseases such as dengue, sepsis, and malaria, making it difficult to diagnose. In this study, we developed an RPA-CRISPR/Cas12a -based detection platform to identify the lipL32 gene of pathogenic Leptospira spp. The results showed that the limit of detection (LOD) was approximately 10² cells/mL without cross-reactivity against other infectious diseases. The platform was validated using 110 patients from 15 hospitals in Sisaket province, Thailand. The sensitivity, specificity, and accuracy was found to be 85.2%, 100% and 92.7%, respectively, for the diagnosis of leptospirosis. Assay sensitivity increased at 4–6 d post-onset of fever, with a consistent specificity every day after the onset of fever. We also developed a lateral flow detection assay combined with RPA-CRISPR/Cas12a, which also had a LOD of 10² cells/mL and could correctly distinguish known positive and negative clinical samples in a pilot study. Findings from this study demonstrate the potential effectiveness of the RPA-CRISPR/Cas12a platform in improving speed and accuracy of leptospirosis diagnosis especially in limited-resource settings.

The Applicability of Commonly Used Severity of Illness Scores to Tropical Infections in Australia

Many patients with leptospirosis, melioidosis, and rickettsial infection require intensive care unit (ICU) admission in tropical Australia every year. The multi-organ dysfunction associated with these infections results in significantly elevated severity of illness (SOI) scores. However, the accuracy of these SOI scores in predicting death from these tropical infections is incompletely defined. This retrospective study was performed at Cairns Hospital, a tertiary-referral hospital in tropical Australia. All patients admitted to ICU with laboratory-confirmed leptospirosis, melioidosis, and rickettsial disease between January 1, 1999 and June 30, 2020, were eligible for the study. The ability of Acute Physiology and Chronic Health Evaluation (APACHE) II, APACHE III, Simplified Acute Physiology Scores (SAPS) II, and Sequential Organ Failure Assessment (SOFA) scores to predict death before ICU discharge was evaluated. Overall, 18 (12.1%) of the 149 included patients died: 15/74 (20.3%) with melioidosis, 2/54 (3.7%) with leptospirosis and 1/21 (4.8%) with rickettsial disease. However, the APACHE II, APACHE III, SAPS II, and SOFA scores significantly overestimated the case-fatality rate of all the infections; the disparity between the predicted and observed mortality was most marked in the cases of leptospirosis and rickettsial disease. Commonly used SOI scores significantly overestimate the case-fatality rate of melioidosis, leptospirosis, and rickettsial infections in Australian ICU patients. This may be at least partly explained by the unique pathophysiology of these infections, particularly leptospirosis and rickettsial disease. However, SOI scores may still be useful in facilitating the comparison of disease severity in clinical trials that examine patients with these pathogens.

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.

Laboratory diagnostic, epidemiological, and clinical characteristics of human leptospirosis in Okinawa Prefecture, Japan, 2003-2020

BACKGROUND

Leptospirosis is considered an endemic disease among agricultural workers in Okinawa Prefecture, which is the southernmost part of Japan and has a subtropical climate, but data on the current status and trend of this disease are scarce.

METHODOLOGY/PRINCIPAL FINDINGS

We conducted a retrospective study of clinically suspected leptospirosis patients whose sample and information were sent to the Okinawa Prefectural Institute of Health and Environment from November 2003 to December 2020. Laboratory diagnosis was established using culture, nested polymerase chain reaction (PCR), and/or microscopic agglutination test (MAT) with blood, cerebrospinal fluid, and/or urine samples. Statistical analyses were performed to compare the epidemiological information, clinical features, and sensitivities of diagnostic methods among laboratory-confirmed cases. Serogroups and the species of Leptospira isolates were determined by MAT using 13 antisera and flaB sequencing. A total of 531 clinically suspected patients were recruited, among whom 246 (46.3%) were laboratory confirmed to have leptospirosis. Among the confirmed cases, patients aged 20-29 years (22.4%) and male patients (85.7%) were the most common. The most common estimated sources of infection were recreation (44.5%) and labor (27.8%) in rivers. Approximately half of the isolates were of the L. interrogans serogroup Hebdomadis. The main clinical symptoms were fever (97.1%), myalgia (56.3%), and conjunctival hyperemia (52.2%). Headache occurred significantly more often in patients with Hebdomadis serogroup infections than those with other serogroup infections. The sensitivities of culture and PCR exceeded 65% during the first 6 days, while the sensitivity of MAT surpassed that of culture and PCR in the second week after onset. PCR using blood samples was a preferable method for the early diagnosis of leptospirosis.

CONCLUSIONS/SIGNIFICANCE

The results of this study will support clinicians in the diagnosis and treatment of undifferentiated febrile patients in Okinawa Prefecture as well as patients returning from Okinawa Prefecture.

Risk Factors for Hospitalisation amongst Leptospirosis Patients in New Zealand

Leptospirosis is a neglected zoonotic disease that is widespread in tropical and subtropical regions such as Oceania, which includes New Zealand. The incidence rate of leptospirosis in New Zealand remains high in comparison to other high-income countries, with over half of the notified patients hospitalised, and the factors associated with hospitalisation are poorly understood. This study aimed to estimate the risk factors for hospitalisation amongst leptospirosis patients using passive surveillance data: notifications from 1 January 1999 to 31 December 2017 extracted from New Zealand’s notifiable disease database. There were 771 hospitalised and 673 non-hospitalised patients. Multivariable logistic regression was used to identify risk factors. The year of notification was significantly and positively associated with hospitalisation, with adjusted (adj.) OR 1.03 (95% CI:1.01–1.05). Occupation was significantly associated with hospitalisation, with the adjusted odds of hospitalisation amongst dairy farmers notified with leptospirosis at adj. OR 1.44 (95% CI: 1.02–2.02) times the adjusted odds of hospitalisation amongst farmers that worked with other livestock. Seropositivity for Leptospira interrogans Copenhageni (adj. OR 5.96, 95% CI: 1.68–21.17) and Pomona (adj. OR 1.14, 95% CI: 0.74–1.74)) was more likely to result in hospitalisation when compared to Leptospira borgpetersenii Ballum (baseline). Seropositivity for Leptospira borgpetersenii Hardjo (adj. OR 0.71, 95% CI: 0.49–1.01) and Tarassovi (adj. OR 0.39, 95% CI: 0.23–0.66) was less likely to result in hospitalisation when compared to Ballum (baseline). All the estimates were additionally adjusted for the effect of sex, age, ethnicity, reported occupational exposure, geographical location, reported season, and deprivation status Although passive surveillance data has limitations we have been able to identify that the New Zealand dairy farming population may benefit from a targeted awareness campaign.

The role of leptospiremia and specific immune response in severe leptospirosis

Leptospirosis can cause a high mortality rate, especially in severe cases. This multicenter cross-sectional study aimed to examine both host and pathogen factors that might contribute to the disease severity. A total of 217 leptospirosis patients were recruited and divided into two groups of non-severe and severe. Severe leptospirosis was defined by a modified sequential organ failure assessment (mSOFA) score of more than two or needed for mechanical ventilation support or had pulmonary hemorrhage or death. We found that leptospiremia, plasma neutrophil gelatinase-associated lipocalin (pNGAL), and interleukin 6 (IL-6) at the first day of enrollment (day 1) and microscopic agglutination test (MAT) titer at 7 days after enrollment (days 7) were significantly higher in the severe group than in the non-severe group. After adjustment for age, gender, and the days of fever, there were statistically significant associations of baseline leptospiremia level (OR 1.70, 95% CI 1.23–2.34, p = 0.001), pNGAL (OR 9.46, 95% CI 4.20–21.33, p < 0.001), and IL-6 (OR 2.82, 95% CI 1.96–4.07, p < 0.001) with the severity. In conclusion, a high leptospiremia, pNGAL, and IL-6 level at baseline were associated with severe leptospirosis.

Clinical Features and Severity of Leptospirosis Cases Reported in the Hawke's Bay Region of New Zealand

AIMS

To record demographics, symptoms, signs, and laboratory features of confirmed leptospirosis cases in the Hawke's Bay area of New Zealand to aid clinicians in diagnosis and recognition of severity.

METHODS

Review of suspected leptospirosis cases referred to the reference laboratory from hospitals in the Hawke's Bay region between March 2003 and March 2012. Inclusion criteria were IgM positivity and diagnosis confirmed with either polymerase chain reaction (PCR) or microscopic agglutination test (MAT). A retrospective systematic review of case notes was completed for demographic and laboratory data.

RESULTS

Forty-three cases were included. Most common presenting symptoms were pyrexia (93%), myalgia, and headache (both 86%). 93% of patients worked in the farming or meat industries. The most common biochemical abnormalities were elevated CRP (100%) and abnormal urinalysis (93%). There was no difference in disease severity between icteric and anicteric patients. Compared to other studies, patients in New Zealand have less severe disease.

CONCLUSION

Contrary to popular understanding, this study has not found icteric leptospirosis to be related to more severe disease. Anicteric leptospirosis should be a differential diagnosis in patients presenting with pyrexia, myalgia, and headache who have elevated CRP and abnormal urinalysis.

Ending the Neglect of Treatable Bacterial Zoonoses Responsible for Non-Malaria Fevers

Bacterial zoonotic diseases such as leptospirosis, Q fever, melioidosis, spotted fever group rickettsioses, and brucellosis are increasingly recognized causes of non-malaria acute fevers. However, though readily treatable with antibiotics, these diseases are commonly misdiagnosed resulting in poor outcomes in patients. There is a considerable deficit in the understanding of basic aspects of the epidemiology of these neglected diseases and diagnostic tests for these zoonotic bacterial pathogens are not always available in resource-poor settings. Raising awareness about these emerging bacterial zoonoses is directly beneficial to the patients by allowing a test-and-treat approach and is essential to control these life-threatening diseases.

Vinetz J. 12 Novel clonal groups of Leptospira infecting humans in multiple contrasting epidemiological contexts in Sri Lanka

Leptospirosis is a ubiquitous zoonotic disease and a major clinical challenge owing to the multitude of clinical presentations and manifestations that are possibly attributable to the diversity of Leptospira, the understanding of which is key to study the epidemiology of this emerging global disease threat. Sri Lanka is a hotspot for leptospirosis with high levels of endemicity as well as annual epidemics. We carried out a prospective study of Leptospira diversity in Sri Lanka, covering the full range of climatic zones, geography, and clinical severity. Samples were collected for leptospiral culture from 1,192 patients from 15 of 25 districts in Sri Lanka over two and half years. Twenty-five isolates belonging to four pathogenic Leptospira species were identified: L. interrogans, L. borgpetersenii, L. weilii, and L. kirschneri. At least six serogroups were identified among the isolates: Autumnalis (6), Pyrogenes (4), Icterohaemorrhagiae (2), Celledoni (1), Grippotyphosa (2) and Bataviae (1). Seven isolates did not agglutinate using available antisera panels, suggesting new serogroups. Isolates were sequenced using an Illumina platform. These data add 25 new core genome sequence types and were clustered in 15 clonal groups, including 12 new clonal groups. L. borgpetersenii was found only in the dry zone and L. weilii only in the wet zone. Acute kidney injury and cardiovascular involvement were seen only with L. interrogans infections. Thrombocytopenia and liver impairment were seen in both L. interrogans and L. borgpetersenii infections. The inadequate sensitivity of culture isolation to identify infecting Leptospira species underscores the need for culture-independent typing methods for Leptospira.

There is a huge diversity in pathogenic Leptospira species worldwide, and our knowledge of the currently circulating species is deficient owing to limited isolation and identification of Leptospira species from endemic countries. This prospective study reveals the wide pathogen diversity that causes human leptospirosis in Sri Lanka, representing four species, more than six serogroups, and fifteen clonal groups. Further, the different geographic and climatic zone distributions and clinical manifestations observed underscores the need for prospective studies to expand the molecular epidemiological approaches to combat leptospirosis.

Application of PCR for Specific Diagnosis of Leptospirosis in Humans in Ukraine

Leptospirosis remains one of the most widespread zoonotic diseases in the world and Ukraine, in particular. Ukrainian clinicians have been faced with early detection of the disease due to the availability of only a serological method for routine diagnostics in Ukraine, namely the microscopic agglutination test (MAT). This paper demonstrates the first results of the complex application of MAT and polymerase chain reaction (PCR) for routine verification of leptospirosis, which were first applied simultaneously in Lviv Oblast of Ukraine in 2016. We examined the sera of 150 patients clinically suspected of leptospirosis, 31 of whom were treated at the Lviv Oblast Clinical Hospital for Infectious Diseases (LOCHID). The application of PCR during the first seven days of the disease allowed increasing the share of confirmed leptospirosis cases by 16,1% in patients that were treated in LOCHID during 2016-2017.

Age-specific epidemiology of human leptospirosis in New Caledonia, 2006-2016

With over one million cases worldwide annually and a high fatality in symptomatic forms, human leptospirosis is a growing public health concern for the most vulnerable populations, especially in the context of global warming and unplanned urbanization. Although the Asia-Pacific region is particularly affected, accurate epidemiological data are often lacking. We conducted an eleven-year retrospective laboratory-based epidemiological survey of human leptospirosis in New Caledonia. From 2006 to 2016, 904 cases were laboratory-confirmed, including 29 fatalities, corresponding to an average annual incidence of 30.6/100,000 and a case fatality rate of 3.2%. Over the period, there was a major shift from indirect serological diagnosis by MAT to direct diagnosis by real-time PCR, a more specific and sensitive test when performed early in the course of the disease. The systematic implementation of genotyping informed on the variety of the infective strains involved, with a predominance of serogroups Icterohaemorrhagiae and Pyrogenes. The epidemiological pattern showed a marked seasonality with an annual peak in March-April. Interestingly, the seasonal peak in children of school age was significantly earlier and corresponded to school holidays, suggesting that attending school from February on could protect children from environment-borne leptospirosis.

An Observational Study of Human Leptospirosis in Seychelles

A 1-year population-based prospective study was launched in Seychelles, a country with one of the highest human incidence of leptospirosis worldwide, to describe the characteristic features of the epidemiology of the disease and highlight the most prominent risk factors. Diagnosis was based on the IgM enzyme-linked immunosorbent assay, microscopic agglutination test, and real-time PCR. A standardized questionnaire was administered to 219 patients aged ≥ 13 years consulting for acute febrile illness. The high incidence of leptospirosis in Seychelles was confirmed. The disease was particularly severe, as the case fatality rate was 11.8%. Leptospirosis was positively associated in univariate analysis with socio-professional and clinical variables including gardening/farming, oliguria, jaundice, conjunctivitis, history of hepatitis C virus infection, anemia, thrombocytopenia, and/or biological renal failure. Epidemiological analyses of the questionnaires highlighted a link of the disease with living in houses (versus apartment), the presence of animals around and in houses, gardening, and misuse of personal protective equipment. Multivariate analyses indicated that being a farmer/landscaper and having cattle and cats around the home are the most significant drivers of leptospirosis. Biological features most associated with leptospirosis were thrombocytopenia, leukocytosis, high values for renal function tests, and elevated total bilirubin. We report changes in behavior and exposure compared with data collected on leptospirosis 25 years ago, with indication that healthcare development has lowered case fatality. Continuous health education campaigns are recommended as well as further studies to clarify the epidemiology of human leptospirosis, especially the role of domestic animals.

Detection of Leptospira kmetyi at recreational areas in Peninsular Malaysia

Humans can be infected by pathogenic Leptospira through contact with infected animals or contaminated environments. Recreational exposure has been associated with human leptospirosis; however, there is a lack of information on the distribution of Leptospira spp. in recreational areas. Thus, we conducted this study to detect and describe the distributions of Leptospira spp. and to determine the prevalence of pathogenic leptospires at recreational areas in Peninsular Malaysia. Soil and water samples were randomly collected from 33 recreational areas in Peninsular Malaysia from December 2018 to April 2019. Each culture was examined under dark-field microscopy prior to genus confirmation by polymerase chain reaction using primers for the 16S rRNA gene. A total of 390 water and soil samples were collected, and 131 cultures were positive for Leptospira under dark-field microscope examination. Leptospira was identified in most of the recreational areas sampled, and at least one pathogenic Leptospira species was isolated from 17 recreational areas. The prevalence of saprophytic, intermediate, and pathogenic Leptospira spp. was 19.7%, 5.6%, and 8.2%, respectively. The dominant pathogenic species found in the samples was Leptospira kmetyi. This study provides important data on the distribution and prevalence of Leptospira spp. from soil and water, as well as the dominant pathogenic species, at recreational areas in Peninsular Malaysia. Therefore, preventive measures should be taken to ensure the safety of visitors.

Circulating genotypes of Leptospira in French Polynesia : An 9-year molecular epidemiology surveillance follow-up study

Background

Leptospirosis is a widespread zoonosis with global impact, particularly among vulnerable populations in resource-poor settings in tropical countries. Rodents have been considered to be the main reservoir of the disease; however, a wide variety of mammals can act as hosts as well. Here we examine the genetic diversity of Leptospira strains from biological samples of patients and animals in French Polynesia (FP) from 2011 to 2019.

Methodology/Principal findings

From 2011 to 2019, we have collected 444 blood samples from patients diagnosed as having leptospirosis. The limited volume of clinical material and low amount of leptospiral DNA in blood samples led us to develop a nested PCR targeting the secY locus that enabled us to amplify and sequence 244 samples (55%). In addition, 20 Leptospira strains recovered from the blood of patients from 2002 to 2011 were sequenced and fully characterized at the serogroup level and used as reference strains for the association of different phylogenetic branches with respective serogroups. The secY sequences were compared with publicly available sequences from patients and animal reservoirs in FP (n = 79). We identified rats as the main source of infection for L. borgpetersenii serogroup Ballum and L. interrogans serogroup Icterohaemorrhagiae, dogs as the main source of infection for L. interrogans serogroup Australis, and farm pigs as the main source of infection for L. interrogans serogroups Pomona or Canicola. L. interrogans was associated with the most severe infections with 10 and 5 fatal cases due to serogroups Icterohaemorrhagiae and Australis, respectively. Mortality was significantly associated with older age (p-value < 0.001).

Conclusions/Significance

We described the population dynamics of leptospires circulating among patients in FP, including two patients who were reinfected with unrelated Leptospira genotypes, and clarified the local role of the animal reservoirs in the transmission route of leptospirosis to humans. Routine Leptospira genotyping directly on biological samples should allow the epidemiological follow-up of circulating strains and assess the impact of control interventions on disease transmission.

Pathogenic Leptospira are the causative agents for leptospirosis, a neglected zoonosis occurring worldwide with the highest incidence of the disease found in the Pacific region, including French Polynesia (FP). In this study, a nested PCR of blood specimens allowed a high isolation frequency of Leptospira DNA among patients with febrile illness in FP. Infecting Leptospira isolates were characterized by sequencing of the secY gene from 244 clinical samples from 2011 to 2019. The genotypes have been assigned to Leptospira species and serogroups by comparing the secY sequences with the genomes of strains isolated prior to 2011 in FP. This study therefore enables to follow the distribution of genotypes/serogroups over a 18-year time period. Leptospiral sequences from patients were also compared with secY sequences from different animal reservoirs from a previous study in FP showing that not only rats but also dogs and pigs might play an important role in the circulation of pathogenic Leptospira strains in FP. 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 in FP.

The Predictive Factors for Severe Leptospirosis Cases in Kedah

Over the past decade, increased awareness about leptospirosis disease in developing and industrialized countries has resulted in increased numbers of leptospirosis cases being reported worldwide. About 5% to 15% of leptospirosis patients end up with severe forms of the disease. Complication due to leptospirosis requires monitoring, specific treatments, and intensive care admission, thus increasing the cost of treating severe leptospirosis cases. Currently, we have data on incident and mortality rates, but we do not have data on the number of patients with severe form of leptospirosis or how many patients have complications, and whether or not these complications were resolved. Therefore, we carried out this study to determine the predictive factors for severe leptospirosis cases in Kedah. We conducted a cross-sectional study. The data of patients diagnosed with leptospirosis were obtained from the surveillance unit, Kedah Health Department, through the e-notification system. These data were then sorted according to the hospitals where the patients were admitted. The patients’ medical records were collected, and their information was obtained using a checklist. A total of 456 confirmed leptospirosis cases were included in the study, with 199 patients classified as severe cases and 257 patients as mild cases, based on the Malaysian leptospirosis guidelines. Most patients were male (71.5%) with a mean SD age of 36.62 ± 20.75 years. The predictive factors for severe leptospirosis include abnormal lung sounds (OR: 3.07 [CI 1.58–6.00]), hepatomegaly (OR: 7.14 [1.10–45.98]), hypotension (OR: 2.16 [1.08–4.34]), leukocytosis (OR: 2.12 [1.37–3.29]), low hematocrit (OR: 2.33 [1.43–3.81]), and increased alanine aminotransferase (SGPT ALT) (OR: 2.12 [1.36–3.30]). In conclusion, knowing these predictive factors will help clinicians identify severe leptospirosis cases earlier and develop their treatment plans accordingly, to reduce the complications and death from severe leptospirosis.

Pulmonary haemorrhage in Weil's disease

Leptospirosisis a zoonosis caused by spirochaetes from the species Leptospira. The more severe form of leptospirosis, known as Weil’s disease, is characterised by the triad of jaundice, renal impairment and haemorrhages. Pulmonary involvement occurs in 20%–70% of the patients, with severity ranging from non-productive cough to respiratory failure mainly due to pulmonary haemorrhage. Recognition of Weil’s disease in patients presenting with pulmonary symptoms can be difficult. This case illustrates a classic case of pulmonary haemorrhagic involvement in Weil’s disease.

Leptospirosis: Increasing importance in developing countries

Leptospirosis is a zoonotic disease caused by the pathogenic helical spirochetes, Leptospira. Symptoms include sudden-onset fever, severe headaches, muscle pain, nausea and chills. Leptospirosis is endemic in developing countries such as Malaysia, India, Sri Lanka, and Brazil where thousands of cases are reported annually. The disease risk factors include the high population of reservoirs, environmental factors, recreational factors, and occupational factors. To end the endemicity of leptospirosis, these factors need to be tackled. The management of leptospirosis needs to be refined. Early diagnosis remains a challenge due to a lack of clinical suspicion among physicians, its non-specific symptoms and a limited availability of rapid point-of-care diagnostic tests. The purpose of this review is to provide insight into the status of leptospirosis in developing countries focusing on the risk factors and to propose methods for the improved management of the disease.

Seroprevalence and associated risk factors of leptospirosis in slaughter pigs; a neglected public health risk, western Kenya

BACKGROUND

Leptospirosis is a neglected zoonosis of public health importance transmitted through contact with contaminated soil, water or urine of infected animals. In pigs the disease is characterized by abortion, still births and weak piglets. A cross-sectional study was conducted in May to July 2018 to estimate the sero-prevalence of leptospirosis and factors associated with seropositivity in slaughter pigs. A questionnaire was used to collect information on animal demographics. Serum was tested for anti-leptospiral antibodies using microscopic agglutination test (MAT) with a panel of 8 serovars. Sera were considered positive for sero-reactivity at a MAT titre ≥1:40 against at least one serovar. Chi-square tests were used to measure the strength of association between the MAT test result and exploratory variables.

RESULTS

A total of 252 pig serum samples from seven slaughterhouses were tested for Leptospira antibodies by MAT. Of the 252 pigs sampled, 88.8% (244/252) were indigenous breeds; 55.6% (140/252) were female and 88.7% (220/252) were reared in extensive production systems. Eighty-three (32.9%; 83/252) sera samples tested positive on MAT against at least one serovar. Of the 8 serovars, the highest prevalence was recorded for serovar Lora 21.4% followed by Kenya 5.2%, Sokoine 3.6% and Grippotyphosa at 3.2%. Risk factors for leptospirosis seropositivity in pigs were: originating from farms with other types of livestock (OR 2.3; 95% CI 1.0-4.5) and mature pigs (OR 1.9; 95% CI 1.1-3.3).

CONCLUSION

This study demonstrates that there is a high prevalence of leptospirosis positive pigs at slaughter in a small-holder livestock keeping region of the Lake Victoria basin. The potential for cross species transmission of pathogenic serovars is highlighted as well as the potential for occupational exposure to slaughterhouse personnel. Improvements in husbandry practices (confinement and rodent control) and public health education among slaughterhouse workers and other high-risk groups is recommended.

Identifying factors associated with treatment delay in leptospirosis: A retrospective study of patients admitted to hospital in Reunion (Indian Ocean) between 2014 and 2015

BACKGROUND

Leptospirosis is a life-threatening zoonotic disease for which delayed treatment onset has been associated to poor prognosis. The purpose of the study was to identify the determinants of therapeutic delay in hospitalized leptospirosis cases.

PATIENTS AND METHODS

We carried out a retrospective multicenter study in the 4 public hospitals of Reunion Island, South Western Indian Ocean. Medical records of confirmed leptospirosis cases occurring in 2014-2015 were reviewed for socio-economic, demographic, geographic and medical data. The primary outcome measure was the therapeutic delay, defined as the time elapsed between the onset of symptoms and initiation of antibiotics.

RESULTS

Of the 117 patients included, 107 were men, with an average age of 44.9±15years. The median therapeutic delay was 4 days (interquartile: 2-5 days) and this delay was not found to be associated with severity. The following were found to be at increased risk of having a longer therapeutic delay: cases occurring outside the epidemic period, or rainy season (OR 2.8 [1.08-7.3], P=0.04) and cases with first medical evaluation in primary health care (OR 4.63 [1.43-14.93]; P=0.01) instead of emergency unit. No socio-economic or geographic characteristics were found to be linked to a longer therapeutic delay.

CONCLUSION

Although delayed treatment was not associated to disease severity, our results indicate that leptospirosis awareness is needed all year in the subtropical area of Reunion Island and particularly in primary care.

Usefulness of C-Reactive Protein in Differentiating Acute Leptospirosis and Dengue Fever in French Guiana

Objective

Leptospirosis and dengue fever (DF) are hard-to-differentiate diseases in cocirculating areas, especially during DF epidemics. Misdiagnosis and ensuing lack of antibiotic therapy can be detrimental in leptospirosis. The objective of this study was to identify factors that help differentiate acute leptospirosis from dengue fever on admission.

Method

Patients with leptospirosis (positive serology or polymerase chain reaction) were compared with patients with DF (positive nonstructural 1 [NS1] antigen) in a case-control study with age matching. Data on admission were compared using bivariate analysis and multivariate analysis.

Results

Seventy-two patients with leptospirosis were compared to 216 patients with DF. In bivariate analysis, the factors associated with leptospirosis were male gender, cough, anemia, and elevated blood levels of C-reactive protein (CRP), leukocytes, creatinine, bilirubin, and creatine phosphokinase. Exanthema, purpura, myalgia, headache, and neutropenia were associated with DF. In multivariate analysis, elevated blood levels of leukocytes, bilirubin, and CRP were associated with leptospirosis. The CRP threshold of 50 mg/L taken alone had elevated sensitivity and specificity.

Conclusions

The CRP level, an easy-to-obtain biomarker, was a powerful tool to differentiate on admission leptospirosis and DF. Facing a dengue-like syndrome in cocirculating areas and awaiting new specific rapid diagnostic tests, CRP dosing could help the clinician to promptly consider the diagnosis of leptospirosis and initiate antibiotic therapy early.

Infections tropicales graves dans les départements français d’Amérique, Antilles françaises et Guyane

Les Antilles-Guyane (AG) sont les départements français du continent américain, situés en zone intertropicale. La diversité des écosystèmes ainsi que le climat tropical à très forte pluviosité exposent à un vaste panel de pathologies infectieuses. Ces territoires sont de plus l’objet de mouvements importants de populations, voyageurs ou migrants, ce qui joue un rôle significatif dans le développement d’épidémies et/ou de pathologies émergentes. Ces pathologies infectieuses dites « tropicales » peuvent nécessiter une prise en charge en réanimation. Nous rapportons ici les principales données récentes concernant ces pathologies (hors infection liée au VIH) ainsi que les stratégies diagnostiques et thérapeutiques, à l’usage des réanimateurs amenés à exercer en zone tropicale AG ou recevant en métropole des patients issus de cette région.

Weil's disease with haemoptysis and acute respiratory distress syndrome

A 35-year-old male patient reached the emergency department after an episode of massive haemoptysis a few hours ago. Fever and dyspnea were mentioned to be present the last 5 days. His medical history included only malaria, successfully treated 2 years ago. Clinical examination revealed high fever, jaundice, cyanosis, tachypnea and bilateral rales on pulmonary auscultation. Laboratory investigation showed high erythrocyte sedimentation rate and C reactive protein, leucocytosis, anaemia, mild thrombocytopaenia, renal impairment, hyperbilirubinaemia and abnormal liver function tests; arterial blood gas analysis showed respiratory alkalosis with severe hypoxia. Thoracic X-ray revealed bilateral pulmonary infiltrates, whereas abdominal and heart ultrasound detected hepatomegaly and small pericardial infusion, respectively. The diagnosis of leptospirosis along with acute respiratory distress syndrome was confirmed by positive IgM Leptospira antibodies. Empirical treatment with triple antibiotic therapy and corticosteroids was applied. The patient was discharged after 1 week, without any symptoms and with almost normal laboratory tests.

Environmental and Behavioral Risk Factors for Severe Leptospirosis in Thailand

A nationwide prevention and control campaign for leptospirosis in Thailand has led to a decreased incidence rate, but the mortality and case fatality rates have remained stable. Regarding the limited knowledge of risk factors, a case-control study of the association between environmental and behavioral exposure with severe leptospirosis was implemented to identify the risk factors among adults in Thailand. The study was conducted in 12 hospital-based sites. Hospitalized patients with suspected clinical symptoms of leptospirosis were tested for leptospirosis by culture, loop mediated isothermal amplification (LAMP), real-time PCR, and the microscopic agglutination test (MAT). All participants answered a standardized questionnaire about potential risk factors. Risk factors were identified by univariable and multivariable logistic regression. Of the 44 confirmed cases, 33 (75.0%) presented with severe illness, as determined by clinical criteria, and were categorized as severe cases. Non-severe cases were defined as patients with non-severe symptoms of leptospirosis. Living nearby a rubber tree plantation (adjusted OR 11.65, 95% CI 1.08–125.53) and bathing in natural bodies of water (adjusted OR 10.45, 95% CI 1.17–93.35) were both significantly associated with an increased risk of severe leptospirosis. We recommend designating rubber plantations in Thailand as high-risk zones and closely monitoring hospitalized patients in those areas.

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.

A simple score to predict severe leptospirosis

Background

The case-fatality rate of severe leptospirosis can exceed 50%. While prompt supportive care can improve survival, predicting those at risk of developing severe disease is challenging, particularly in settings with limited diagnostic support.

Methodology/Principal findings

We retrospectively identified all adults with laboratory-confirmed leptospirosis in Far North Queensland, Australia, between January 1998 and May 2016. Clinical, laboratory and radiological findings at presentation were correlated with the patients’ subsequent clinical course. Medical records were available in 402 patients; 50 (12%) had severe disease. The presence of oliguria (urine output ≤500 mL/24 hours, odds ratio (OR): 16.4, 95% confidence interval (CI): 6.9–38.8, p<0.001), abnormal auscultatory findings on respiratory examination (OR 11.2 (95% CI: 4.7–26.5, p<0.001) and hypotension (systolic blood pressure ≤100 mmHg, OR 4.3 (95% CI 1.7–10.7, p = 0.002) at presentation independently predicted severe disease. A three-point score (the SPiRO score) was devised using these three clinical variables, with one point awarded for each. A score could be calculated in 392 (98%) patients; the likelihood of severe disease rose incrementally: 8/287 (3%), 14/70 (20%), 18/26 (69%) and 9/9 (100%) for a score of 0, 1, 2 and 3 respectively (p = 0.0001). A SPiRO score <1 had a negative predictive value for severe disease of 97% (95% CI: 95–99%).

Conclusions/Significance

A simple, three-point clinical score can help clinicians rapidly identify patients at risk of developing severe leptospirosis, prompting early transfer to referral centres for advanced supportive care. This inexpensive, bedside assessment requires minimal training and may have significant utility in the resource-limited settings which bear the greatest burden of disease.

Leptospirosis, a neglected tropical disease with a global distribution, is estimated to kill 60,000 people every year. Predicting those at risk of developing severe disease is challenging, and a simple scoring system to quantify the risk of severe disease has proven elusive. Identifying the high-risk patient is important, as it might expedite the initiation of life-saving supportive care. This review of 402 adult patients with leptospirosis in tropical Australia determined that three clinical variables identified at presentation independently predicted severe disease (a subsequent requirement for Intensive Care Unit admission, intubation, vasopressor support, renal replacement therapy or the development of pulmonary haemorrhage). These three variables (abnormal auscultatory findings on respiratory examination, hypotension and oliguria) were used to generate a simple, three-point clinical score which can be determined rapidly and reliably at the bedside by health care workers with minimal training. This simple score may help the clinical management of patients with leptospirosis, particularly in lower and middle-income countries that bear the greatest burden of disease.

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.

[Update on leptospirosis]

Leptospirosis is a worldwide spirochetal zoonosis whose global incidence is increasing and is probably underestimated. Leptospirosis has long been associated with occupational contact with animals (rats and cattle) and has become in developed countries a pathology more related to recreational activities with exposure to fresh water (canoeing, swimming, canyoning) and to an environment contaminated by urine from leptospires excretory rodents. Leptospirosis should be one of the differential diagnoses to be considered when returning from travel to tropical areas, particularly Southeast Asia, and particularly during the rainy season. The clinical symptoms, particularly in the initial phase, are not specific and can limit to a flu-like syndrome or "dengue-like" making diagnosis often difficult. It is then necessary to look carefully for clinical (muscle pain, cough, conjunctival involvement, jaundice) and biological arguments (thrombocytopenia, cholestasis, rhabdomyolysis, frank elevation of CRP) that will help to diagnose leptospirosis and lead to quick antibiotic therapy before the progression to a severe icterohaemorrhagic (Weil's disease) or respiratory form associated with significant mortality. Treatment is based on injectable beta-lactams in severe forms (mainly cephalosporins) and amoxicillin, doxycycline or azithromycin in non-severe forms. Some atypical or delayed forms of leptospirosis occurring in the late immune phase of the disease are to know. Rapid diagnostic tools are currently being studied to improve diagnosis in remote areas and facilitate access to early treatment.

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.

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).

Epidemiology of Human Leptospirosis in French Guiana (2007-2014): A Retrospective Study

Leptospirosis is a worldwide zoonotic bacterial infection with a rising incidence. French Guiana is mostly covered by Amazonian rain forest. Despite a potentially favorable environment, leptospirosis has been barely studied in French Guiana. The objective of this study was to describe the current trends of leptospirosis epidemiology in French Guiana. A cross-sectional study was performed in the two main hospitals of French Guiana. Cases of leptospirosis from 2007 to 2014 were retrospectively identified with a systematic screening of serological and polymerase chain reaction results to classify them as confirmed, probable, or excluded cases. Medical files were reviewed to collect epidemiological data. Among the 72 included patients, 55 (76.4%) cases were confirmed and 17 (23.6%) were probable. The median age was 39 years (range: 16-82 years) and the M/F sex ratio 6.2. Sixty-two (86.1%) patients required hospitalization, including 12 (16.7%) in the intensive care unit. Three (4.2%) patients died. The monthly distribution of cases was correlated with rainfall (P = 0.004) and moisture (P = 0.038). Professional exposure was frequently identified (especially gold mining and construction). Among 16 different serogroups identified by microagglutination test, Icterohaemorrhagiae was the most frequent (38.0%). This study revealed an epidemiology close to that observed in Brazilian regions, and professional and climatic risk factors. The high diversity of serogroups may reveal a complex environmental reservoir requiring further investigations. Only 20% of leptospirosis patients were suspected as such on hospital admission, thus emphasizing the need to inform local physicians.

A systematic review of human and animal leptospirosis in the Pacific Islands reveals pathogen and reservoir diversity

Background

The Pacific Islands have environmental conditions highly favourable for transmission of leptospirosis, a neglected zoonosis with highest incidence in the tropics, and Oceania in particular. Recent reports confirm the emergence and outbreaks of leptospirosis in the Pacific Islands, but the epidemiology and drivers of transmission of human and animal leptospirosis are poorly documented, especially in the more isolated and less developed islands.

Methodology/Principal findings

We conducted a systematic review of human and animal leptospirosis within 25 Pacific Islands (PIs) in Polynesia, Melanesia, Micronesia, as well as Easter Island and Hawaii. We performed a literature search using four international databases for articles published between January 1947 and June 2017. We further included grey literature available on the internet. We identified 148 studies describing leptospirosis epidemiology, but the number of studies varied significantly between PIs. No data were available from four PIs. Human leptospirosis has been reported from 13 PIs, with 63% of all studies conducted in Hawaii, French Polynesia and New Caledonia. Animal leptospirosis has been investigated in 19 PIs and from 14 host species, mainly pigs (18% of studies), cattle (16%) and dogs (11%). Only 13 studies provided information on both human and animal leptospirosis from the same location. Serology results were highly diverse in the region, both in humans and animals.

Conclusions/Significance

Our study suggests that, as in other tropical regions, leptospirosis is widespread in the PIs while showing some epidemiological heterogeneity. Data are scarce or absent from many PIs. Rodents, cattle, pigs and dogs are all likely to be important carriers, but the relative importance of each animal species in human infection needs to be clarified. Epidemiological surveys with appropriate sampling design, pathogen typing and data analysis are needed to improve our understanding of transmission patterns and to develop effective intervention strategies.

Leptospirosis is an important bacterial zoonosis that affects people and animals worldwide. It is common in tropical areas, especially in island ecosystems. Because islands are relatively small, isolated, and have limited health and diagnostic facilities, the disease burden is often underestimated. In this systematic review, we aimed to describe the extent of leptospirosis in the Pacific Islands, including the diversity of pathogens and animal reservoirs. We identified 148 studies from 21 Pacific islands that described Leptospira infection in humans or animals. In hospitalized febrile patients, leptospirosis was a common cause of the acute febrile illness, but accurate diagnosis was challenging and often delayed because symptoms overlapped with many other infectious diseases, and access to laboratory diagnosis was limited. A wide variety of animal hosts of Leptospira were identified, with rodents, cattle, pigs and dogs reported as important hosts; however, their relative importance in human infection remains unclear. Our review demonstrates that the epidemiology of leptospirosis varies across the Pacific Islands, but information about risk factors and transmission routes is currently limited. We recommend more integrated studies, using an eco-epidemiological approach that includes human, veterinary and environmental factors, and interactions between factors at different ecological scales.

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.