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BackgroundSerology (the detection of antibodies formed by the host against an infecting pathogen) is frequently used to assess current infections and past exposure to specific pathogens. However, the presence of cross-reactivity among host antibodies in serological data makes it challenging to interpret the patterns and draw reliable conclusions about the infecting pathogen or strain.Methodology/principal findingsIn our study, we use microscopic agglutination test (MAT) serological data from three host species [California sea lion (Zalophus californianus), island fox (Urocyon littoralis), and island spotted skunk (Spilogale gracilis)] with confirmed infections to assess differences in cross-reactivity by host species and diagnostic laboratory. All host species are known to be infected with the same serovar of Leptospira interrogans. We find that absolute and relative antibody titer magnitudes vary systematically across host species and diagnostic laboratories. Despite being infected by the same Leptospira serovar, three host species exhibit different cross-reactivity profiles to a 5-serovar diagnostic panel. We also observe that the cross-reactive antibody titer against a non-infecting serovar can remain detectable after the antibody titer against the infecting serovar declines below detectable levels.Conclusions/significanceCross-reactivity in serological data makes interpretation difficult and can lead to common pitfalls. Our results show that the highest antibody titer is not a reliable indicator of infecting serovar and highlight an intriguing role of host species in shaping reactivity patterns. On the other side, seronegativity against a given serovar does not rule out that serovar as the cause of infection. We show that titer magnitudes can be influenced by both host species and diagnostic laboratory, indicating that efforts to interpret absolute titers (e.g., as indicators of recent infection) must be calibrated to the system under study. Thus, we implore scientists and health officials using serological data for surveillance to interpret the data with caution.

BACKGROUND: Pathogenic Leptospira species are globally important zoonotic pathogens capable of infecting a wide range of host species. In marine mammals, reports of Leptospira have predominantly been in pinnipeds, with isolated reports of infections in cetaceans. CASE PRESENTATION: On 28 June 2021, a 150.5 cm long female, short-beaked common dolphin (Delphinus delphis delphis) stranded alive on the coast of southern California and subsequently died. Gross necropsy revealed multifocal cortical pallor within the reniculi of the kidney, and lymphoplasmacytic tubulointerstitial nephritis was observed histologically. Immunohistochemistry confirmed Leptospira infection, and PCR followed by lfb1 gene amplicon sequencing suggested that the infecting organism was L.kirschneri. Leptospira DNA capture and enrichment allowed for whole-genome sequencing to be conducted. Phylogenetic analyses confirmed the causative agent was a previously undescribed, divergent lineage of L.kirschneri. CONCLUSIONS: We report the first detection of pathogenic Leptospira in a short-beaked common dolphin, and the first detection in any cetacean in the northeastern Pacific Ocean. Renal lesions were consistent with leptospirosis in other host species, including marine mammals, and were the most significant lesions detected overall, suggesting leptospirosis as the likely cause of death. We identified the cause of the infection as L.kirschneri, a species detected only once before in a marine mammal - a northern elephant seal (Mirounga angustirostris) of the northeastern Pacific. These findings raise questions about the mechanism of transmission, given the obligate marine lifestyle of cetaceans (in contrast to pinnipeds, which spend time on land) and the commonly accepted view that Leptospira are quickly killed by salt water. They also raise important questions regarding the source of infection, and whether it arose from transmission among marine mammals or from terrestrial-to-marine spillover. Moving forward, surveillance and sampling must be expanded to better understand the extent to which Leptospira infections occur in the marine ecosystem and possible epidemiological linkages between and among marine and terrestrial host species. Generating Leptospira genomes from different host species will yield crucial information about possible transmission links, and our study highlights the power of new techniques such as DNA enrichment to illuminate the complex ecology of this important zoonotic pathogen.

Background: Leptospirosis is one of the most common zoonoses in the world which is associated with a severe febrile disease in humans causing a variety of syndromes including meningitis, interstitial nephritis, hepatitis, and sometimes death. Leptospirosis is caused by different pathogenic Leptospira species divided into almost 30 serogroups and more than 300 serovars which are carried by some animal asymptomatic chronic infections. Humans can become infected through direct contact with animal urine or indirectly by coming into contact with fresh water or mud contaminated with urine. Methodology/Principal findings: In this research, we looked for leptospiral DNA in urine samples from dogs living in a rural, low-income and highly endemic community in the coast of Ecuador. We used molecular biology and next-generation sequencing for the detection. Our results showed evidence of two Leptospira species, L interrogans and L. santarosai, genomes in three dogs. Conclusions/Significance: It has been widely known that animal carriers are typically infected with a single leptospiral strain. However, recent reports, including the present one, indicate that carrier animals may be coinfected with two or more leptospiral species. [ABSTRACT FROM AUTHOR]

Terrestrial and aquatic environments contaminated with animal urine may contribute to the transmission of Leptospira, a causative agent of leptospirosis in humans and wild/domesticated animals. Although enormous amounts of work have been done decoding the ecophysiology, the factors governing the cell growth and virulence in Leptospires derived from environmental samples still remain elusive. Here, we show oxidation of a wide array of organic acids including acetoacetate by a new strain of Leptospira interrogans designated as KeTo, isolated from a sewage sample originating from a wildlife enclosure located at Mangalore, India. We further demonstrate the susceptibility of KeTo to ethyl ester of acetoacetate (ethyl acetoacetate, EA). A 4.7 Mbp genome of KeTo shared the highest relatedness to pathogenic L. interrogans RGAT (99.3%), followed by L. kirschneri 3522CT (91.3%) and other related species of Leptospira (80.8‒74.3%), and harbored genes encoding acetoacetyl-CoA synthetase and acetoacetate decarboxylase respectively involved in the acetoacetate utilization and acetone formation. In line with this, strain KeTo oxidized acetoacetate when supplied as a sole carbon. Aqueous EA suppressed biofilm formation (p < 0.0001) of KeTo in basal Ellinghausen–McCullough–Johnson–Harris (EMJH) medium. Similarly, significant inhibition in the growth/biofilm of Leptospira was recorded in semisolid EMJH with/without blood supplementation when exposed to volatile EA. The extent of ketone body oxidation and susceptibility to EA was found to vary with strain as evident through the analysis of L. interrogans serogroup Australis sv. Australis strain Ballico and L. interrogans serogroup Icterohaemorrhagiae sv. Lai Like strain AF61. In conclusion, our study demonstrated the ketone body metabolic ability and susceptibility to an esterified derivative of a major ketone body in the tested strains of L. interrogans. Molecular aspects governing EA-driven growth inhibition warrant further investigations to develop optimal therapeutics for leptospirosis. [ABSTRACT FROM AUTHOR]

Leptospirosis is an emerging zoonotic disease with high health and economic damage. In this study, we developed a deterministic mathematical model that describes the dynamics of leptospirosis transmission within a cattle herd, incorporating asymptomatic infected and vaccinated compartments. The study examined the transmission role of asymptomatic cattle that contaminate herds without farmers' knowledge. We proved the well-posedness of the proposed model and found the basic reproduction number using the next-generation matrix. Analytically, we demonstrated that the disease-free equilibrium point is locally and globally asymptotically stable when R 0 is less than unity and is otherwise unstable. Graphically, we further established the local asymptotic stability of disease-free and endemic equilibria. Sensitivity analysis showed that the contact rate with asymptomatic infected cattle, β A , is the most sensitive parameter in the stated model, followed by the recovery rate of asymptomatic infected cattle, σ , and the vaccination rate of susceptible cattle, τ . Numerical simulations revealed that a reduction in contact rate with asymptomatic infected cattle significantly reduced pathogen Leptospira transmission in the herd. In addition, fostering the recovery rate of asymptomatic infected cattle can significantly reduce new infections in the herd. Furthermore, augmenting the vaccination rate among susceptible cattle resulted in a notable decrease in disease prevalence within the herd. Findings of this study underscore the remarkable importance of targeted interventions, such as reducing contact rates with asymptomatic infected cattle, increasing recovery rates using proper treatments, and enhancing vaccination efforts to manage leptospirosis transmission in cattle herds. [ABSTRACT FROM AUTHOR]

The present study investigates the public health impact of flooding on leptospirosis incidence after Storm Daniel in Thessaly, Greece, in September 2023. A notable increase in cases was observed, with seven cases of female patients and a mean age of 40.2 years, indicating a significant risk among working-age adults. From the end of September to the beginning of November 2023, a total of 35 patients from flood-prone areas presented to the Emergency Department of the Tertiary University Hospital of Larissa. Diagnosis of leptospirosis was established by meeting the criteria suggested by the national public health organisation (EODY)-compatible clinical course, epidemiological exposure, molecular and serologic confirmation by the detection of immunoglobulin M antibodies to leptospira spp. using a commercially available enzyme-linked immunosorbent assay and real-time quantitative PCR for the molecular detection of leptospira. The larger part (84.6%) of leptospirosis cases were associated with contact with floodwater. The majority of these patients (71.4%) were from the prefecture of Larissa, followed by 14.3% from the prefecture of Karditsa, 8.6% from the prefecture of Trikala, and 5.7% from the prefecture of Magnesia. Occupational exposure and urbanisation were key risk factors. The most prevalent clinical feature was rash (69.2%), followed by fever (61.5%) and myalgia (30.7%). The findings emphasise the need for robust public health strategies, improved sanitation, rodent control, and protective measures for sanitation workers. The data highlight the broader implications of climate change on public health and the necessity for ongoing surveillance and community education to mitigate future outbreaks. [ABSTRACT FROM AUTHOR]

Simple Summary: The platypus (Ornithorhynchus anatinus) is a monotreme, a rare kind of mammal that lays eggs and suckles its young. It is amphibious, lives in freshwater, and is found only in Australia, where it is closely protected. During prior conservation studies, several pathogens had been discovered in the platypus, including leptospires, which are a kind of bacterium that can cause severe disease in animals and people. We evaluated the available data concerning this infection in platypuses, tested blood samples in the Platypus Serum Bank, and combined the results with historical records. We found evidence of leptospirosis in 50% of platypuses from 14 river basins in southeastern Australia. Leptospiral infection did not stop females from breeding and juvenile platypuses were recruited to the population each year. The high seroprevalence, evidence of ongoing exposure to leptospires, lack of disease, mild kidney pathology, and visible leptospires in the kidney tubules suggest that the platypus may be a reservoir host for leptospires rather than an accidental host that suffers from the disease. Cattle on adjacent farms also had leptospirosis, but the evidence was not convincing that cattle caused the infection in platypuses. A landscape-wide study is recommended to determine the actual infection pathway. The platypus (Ornithorhynchus anatinus) is an amphibious, egg-laying mammal of high conservation value that is found only in Australia. The zoonotic bacterium Leptospira interrogans serovar Hardjo was discovered in platypuses in prior studies, but little is known about its epidemiology. Samples in the Platypus Serum Bank were tested in 2023 and the results were combined with historical records. Antibodies against L. interrogans serovar Hardjo were found in 50% of 464 serum samples from 411 platypuses collected from 14 river basins in southeastern Australia between 1981 and 2012; prevalence remained high over three decades in the Shoalhaven River population. Seroprevalence increased with age, suggesting environmental exposure. Individual platypuses had persistent titres, some for six years. Seropositive females lactated, juveniles were recruited into the population, and there were no reports of clinical leptospirosis. Three necropsied platypuses were seropositive and had mild nephritis with leptospires in the renal tubules. The high seroprevalence, persistent titres, lack of disease, mild renal lesions, and renal colonisation suggest the platypus may be a maintenance host. Sympatric cattle had L. interrogans serovar Hardjo titres, but the spatial association with seropositive platypuses was statistically weak. Other mammalian wildlife species and sheep also have L. interrogans serovar Hardjo titres; therefore, a complex ecological network must be considered. A landscape-wide study is recommended to properly assess transmission pathways and confirm who is infecting whom. [ABSTRACT FROM AUTHOR]

In an integrated swine farm with 135 sows in Nagasaki Prefecture, premature births and stillbirths were observed in six sows in June and July 2023, and their etiology was investigated. Leptospiral flaB gene was detected in the kidney of one stillborn fetus and the placenta of its sow by nested PCR. Multilocus sequence typing revealed that the infecting strain was Leptospira interrogans ST118. In addition, leptospiral antigens were detected in lesions of the above tissues by immunohistochemical staining. The examined sow and several other sows in the farm had antibodies against serogroup Hebdomadis. These results suggested that L. interrogans serogroup Hebdomadis ST118 was the causative agent of premature births and stillbirths that occurred in this farm. [ABSTRACT FROM AUTHOR]

Leptospirosis is a widespread zoonosis caused by spirochaetes belonging to the pathogenic species of Leptospira, which are classified into more than 25 serogroups and 250 serovars. Vaccination can prevent the disease in dogs but offers incomplete efficacy because of a lack of cross-protection between serogroups. The aim of this study was to validate a robust recruitment and sampling process, with the objectives of isolating and typing circulating Leptospira pathogenic strains and then selecting those of proven virulence and pathogenicity for vaccine development. Blood and urine samples from dogs with clinical syndromes compatible with acute leptospirosis were sterilely collected and transported to a reference laboratory for a micro-agglutination test (MAT), PCR, and bacterial isolation. Isolated strains underwent molecular typing using RNA16S, variable-number tandem repeat (VNTR), and pulsed-field gel electrophoresis (PFGE). Subtyping was performed using core genome multilocus sequence typing (CgMLST). Among 64 included dogs, 41 had MAT and/or PCR results compatible with Leptospira infection, and 14 Leptospira strains were isolated. Based on molecular typing, 11 isolates were classified as L. interrogans serogroup Australis, serovar Bratislava, and 3 as serogroup Icterohaemorrhagiae, serovar Icterohaemorrhagiae. CgMLST subtyping revealed a diversity of clonal groups (CGs) distributed in several regional clusters. Besides validating a robust recruitment and sampling process, this study outlines the value of combining PCR and serological testing when suspecting leptospirosis and the usefulness of implementing molecular typing methods to identify circulating field strains. It also confirms the epidemiological importance of the Australis serogroup and allows for the collection of different highly pathogenic strains for vaccine development. [ABSTRACT FROM AUTHOR]

Leptospirosis is a worldwide zoonotic disease caused by pathogenic Leptospira spp., often occurring in tropical and subtropical regions. Focusing on development of rapid diagnostic methods to facilitate early diagnosis and a universal vaccine are the main critical issues to overcome the burden of leptospirosis. Here, we have studied the immunogenic potential of prepared recombinant Loa22 protein (rLoa22) of local pathogenic Leptospira species in mice and its ability to induce humoral and cellular immunity, being further evaluated by analyzing the immunoglobulin G (IgG) subclasses and cytokines produced through immunization. Based on the results, mice immunized with rLoa22/adjuvant and a trivalent vaccine, induced high titers of total IgG. All immunized groups increased IgG1 almost on the same level; but, IgG2a level was significantly higher in the vaccine and rLoa22/adjuvant groups than rLoa22 alone group. Animals immunized with the vaccine produced more interleukin 4 than rLoa22/adjuvant group. The results of evaluating interferon gamma level showed that the rLoa22/adjuvant and vaccine groups had a significant increase compared to the rLoa22 alone group. The results also demonstrated that the rLoa22 protein, in indirect enzyme-linked immunosorbent assay, was able to detect the anti-Leptospira antibodies in mice serum that can be used as a marker in assessing the seroprevalence of leptospirosis and/or in combination with other leptospiral antigens in development of an effective vaccine against leptospirosis. [ABSTRACT FROM AUTHOR]

Background: Zoonotic infections, characterized with huge pathogen diversity, wide affecting area and great society harm, have become a major global public health problem. Early and accurate prediction of their outbreaks is crucial for disease control. The aim of this study was to develop zoonotic diseases risk predictive models based on time-series incidence data and three zoonotic diseases in mainland China were employed as cases. Methods: The incidence data for schistosomiasis, echinococcosis, and leptospirosis were downloaded from the Scientific Data Centre of the National Ministry of Health of China, and were processed by interpolation, dynamic curve reconstruction and time series decomposition. Data were decomposed into three distinct components: the trend component, the seasonal component, and the residual component. The trend component was used as input to construct the Long Short-Term Memory (LSTM) prediction model, while the seasonal component was used in the comparison of the periods and amplitudes. Finaly, the accuracy of the hybrid LSTM prediction model was comprehensive evaluated. Results: This study employed trend series of incidence numbers and incidence rates of three zoonotic diseases for modeling. The prediction results of the model showed that the predicted incidence number and incidence rate were very close to the real incidence data. Model evaluation revealed that the prediction error of the hybrid LSTM model was smaller than that of the single LSTM. Thus, these results demonstrate that using trending sequences as input sequences for the model leads to better-fitting predictive models. Conclusions: Our study successfully developed LSTM hybrid models for disease outbreak risk prediction using three zoonotic diseases as case studies. We demonstrate that the LSTM, when combined with time series decomposition, delivers more accurate results compared to conventional LSTM models using the raw data series. Disease outbreak trends can be predicted more accurately using hybrid models. [ABSTRACT FROM AUTHOR]

Leptospirosis, an acute bacterial zoonotic disease, is endemic in Puerto Rico. Infection in approximately 10%-15% of patients with clinical disease progresses to severe, potentially fatal illness. Increased incidence has been associated with flooding in endemic areas around the world. In 2022, Hurricane Fiona, a Category 1 hurricane, made landfall and inundated Puerto Rico with heavy rainfall and severe flooding, increasing the risk for a leptospirosis outbreak. In response, the Puerto Rico Department of Health (PRDH) changed guidelines to make leptospirosis cases reportable within 24 hours, centralized the case investigation management system, and provided training and messaging to health care providers. To evaluate changes in risk for leptospirosis after Hurricane Fiona to that before the storm, the increase in cases was quantified, and patient characteristics and geographic distribution were compared. During the 15 weeks after Hurricane Fiona, 156 patients experienced signs and symptoms of leptospirosis and had a specimen with a positive laboratory result reported to PRDH. The mean weekly number of cases during this period was 10.4, which is 3.6 as high as the weekly number of cases during the previous 37 weeks (2.9). After Hurricane Fiona, the proportion of cases indicating exposure to potentially contaminated water increased from 11% to 35%, and the number of persons receiving testing increased; these factors likely led to the resulting overall surge in reported cases. Robust surveillance combined with outreach to health care providers after flooding events can improve leptospirosis case identification, inform clinicians considering early initiation of treatment, and guide public messaging to avoid wading, swimming, or any contact with potentially contaminated floodwaters. [ABSTRACT FROM AUTHOR]

Background: Leptospirosis is a globally neglected zoonotic disease with significant morbidity and mortality in dogs, particularly in resource-limited settings. Aim: This study aimed to characterize prognostic factors and survival outcomes in dogs with suspected leptospirosis, emphasizing the potential underestimation of disease burden. Methods: This retrospective study was conducted using medical records of dogs diagnosed with urinary Leptospira polymerase chain reaction (PCR). Results: Urinary Leptospira PCR was positive in 22 dogs and negative in 62. Azotemia was present in approximately two-thirds of both groups, with no predictive value identified between PCR-positive and PCR-negative dogs. However, PCR-positive dogs exhibited significantly shorter survival times for both all-cause mortality (median 60 days, range: 8-601 days) and leptospirosis-related death (median 27 days, range: 8-67 days) compared to PCR-negative dogs (median 402 days, range: 7-812 days) (p < 0.01). The neutrophil-to-lymphocyte ratio (NLR) in-dependently predicted leptospirosis-related death (HR = 1.073, 95%CI: 1.02-1.13, p = 0.01), while the BUN-to-creatinine ratio predicted allcause mortality (HR = 1.02, 95% CI: 1.003-1.03, p = 0.02). Conclusion: Our findings underscore the severity of leptospirosis in older dogs, particularly those with azotemia or positive PCR results. NLR and BUN to creatinine ratios could be valuable tools for risk assessment and guiding treatment strategies in this vulnerable population. [ABSTRACT FROM AUTHOR]

This research aims to apply and compare two semi-analytical techniques, the Variational Iterative Method (VIM) and the New Iterative Method (NIM), for solving a pre-formulated mathematical model of Fractional-order Leptospirosis. Leptospirosis is a significant bacterial infection affecting humans and animals. By implementing the VIM and NIM algorithms, numerical experiments are conducted to solve the leptospirosis model. Comparing the obtained findings demonstrates that VIM and NIM are effective semi-analytical methods for solving systems of fractional differential equations. Notably, our study unveils a crucial dynamic in the disease's spread. The application of VIM and NIM offers a refined depiction of the biological dynamics, highlighting that the susceptible human population gradually decreases, the infectious human population declines, the recovered human population increases, and a significant rise in the infected vector population is observed over time. This nuanced portrayal of the disease's dynamics is crucial for understanding the intricate interplay of Leptospirosis among human and vector populations. The study's outcomes contribute valuable insights into the applicability and performance of the methods in solving the Fractional Leptospirosis model. Results indicate rapid convergence and comparable outcomes for both methods. [ABSTRACT FROM AUTHOR]

The emergence of infectious disease outbreaks and 'superbugs' related to pollution combined with climate change is a current problem, not just a future threat. In May 2024, an extreme flood hit the Rio Grando Sul State, southern Brazil, triggering an important leptospirosis outbreak in urban settings with deficient sanitation systems. This and other cases discussed in this article exemplify how extreme weather events exacerbate the consequences of environmental pollution by multiple classes of pathogens in the global scenario of increasing anthropogenic pressures on the environment. A combination of actions to combat climate change and improvements in sanitation systems is essential to mitigate this problem. [ABSTRACT FROM AUTHOR]

Pathogenic Leptospira spp. causes leptospirosis in animals and humans globally, leading to systemic infections that can impact vital organs in affected animals. The purpose of this study was to evaluate kidney injury and to perform a retrospective analysis of leptospirosis infection in follow-up dog samples. The retrospective study collected epidemiological information obtained through paraclinical exams, immunohistochemistry (IHC), and molecular biology (qPCR) of cases from the Faculty of Veterinary Medicine from Timisoara between September 2016 and May 2023. No correlations were found between Leptospira infection and breed (p = 0.714), gender or castration status (p = 0.890), and anatomic pathology exam results (p = 0.608). Significant associations were found in cases with high levels of azotemia (p = 0.000) and immunological status (vaccinated vs. unvaccinated, p = 0.000), with the leptospirosis risk in unvaccinated animals calculated at OR = 85.500 (95%CI, 6.82–1071.26, p = 0.000). Retrospectively, leptospirosis was diagnosed in 27/65 cases (42%) using the IHC method, while the qPCR assay detected 29/65 cases (45%). This study demonstrates that qPCR is a robust and specific method for postmortem diagnosis of Leptospira spp. infection in dogs, offering higher specificity and reliability compared to traditional IHC methods, which showed 94.74% specificity in our study. [ABSTRACT FROM AUTHOR]

Introduction Similar presenting manifestations in early phase and lack of awareness of aetiology of acute febrile illness (AFI) are major challenges in management of AFI. Material and Methods This was a retrospective observational cross-sectional study conducted in the Department of Microbiology, NRS Medical College, from 1 July 2022 to 30 June 2023 in serologically diagnosed febrile patients attending the outpatient department or admitted. Clinical and epidemiological data and laboratory parameters were recorded in a pretested structured questionnaire study tool, and collected data were analysed on MS-Excel sheets with various charts and tables. Results A total of 1711 serologically diagnosed febrile patients showed preponderance of dengue (38.3%), followed by leptospirosis (25%), scrub typhus (23.9%), malaria (12.6%), and enteric fever (1.92%). A majority of cases were male, less than 40 years of age, and from the rural population (73.2%), except in malaria (urban = 79.6%). The mean duration of fever was 9 days. Febrile cases were recorded maximum during the monsoon and postmonsoon periods (66.5%). The common manifestations are fever, headache (46.2%), pain abdomen (7.8%), nausea, and vomiting (9.4%). Thrombocytopenia with bleeding manifestation was higher in dengue (18%) cases. Mortality in dengue cases was recorded with multiorgan dysfunction syndrome (MODS). Scrub typhus cases showed seizure (8.3%) and altered sensorium (5%) due to fatal meningoencephalitis. Fatality in leptospirosis was mostly due to acute kidney injury (29.5%) and Weil’s disease (4.4%). Conclusion Misdiagnosis or incorrect diagnosis and delay in initiation of appropriate treatment results in increased morbidity and mortality in AFI. Determination of epidemiological features and clinical manifestations of AFI along with timely correct diagnosis will benefit clinicians in proper treatment initiation, thereby reducing morbidity and mortality.

Abstract Terrestrial and aquatic environments contaminated with animal urine may contribute to the transmission of Leptospira, a causative agent of leptospirosis in humans and wild/domesticated animals. Although enormous amounts of work have been done decoding the ecophysiology, the factors governing the cell growth and virulence in Leptospires derived from environmental samples still remain elusive. Here, we show oxidation of a wide array of organic acids including acetoacetate by a new strain of Leptospira interrogans designated as KeTo, isolated from a sewage sample originating from a wildlife enclosure located at Mangalore, India. We further demonstrate the susceptibility of KeTo to ethyl ester of acetoacetate (ethyl acetoacetate, EA). A 4.7 Mbp genome of KeTo shared the highest relatedness to pathogenic L. interrogans RGAT (99.3%), followed by L. kirschneri 3522CT (91.3%) and other related species of Leptospira (80.8‒74.3%), and harbored genes encoding acetoacetyl-CoA synthetase and acetoacetate decarboxylase respectively involved in the acetoacetate utilization and acetone formation. In line with this, strain KeTo oxidized acetoacetate when supplied as a sole carbon. Aqueous EA suppressed biofilm formation (p

The aim of the work was to analyze the epizootic and epidemiological situation on leptospirosis in the territory of the Russian Federation in 2023 and to forecast its development for 2024. In the period between 2000 and 2023, the long-term dynamics of morbidity in Russia tended to decrease. Leptospirosis incidence was mainly sporadic. In 2023, cases of this infection in humans were reported in all federal districts, with the exception of the North Caucasian one. The highest incidence rates were recorded in the Southern and Central Federal Districts. The results of testing material from small mammals using bacteriological, immunological and molecular-biological methods confirmed the circulation of pathogenic Leptospira in 50 constituent entities of the Russian Federation in all federal districts. Specific prevention measures were carried out: 20,114 people were vaccinated in 27 entities. The probability of human infection is higher in the territories of the Southern, Central, Northwestern, Volga and Ural Federal Districts. Imported cases of infection from regions with subequatorial and equatorial climates, which are actively visited by tourists, are not excluded.

The aim of the study was to determine the prevalence of leptospiroses and hemorrhagic fever with renal syndrome (HFRS) among residents of some administrative districts of the Leningrad Region. Materials and methods. 958 blood serum samples of conventionally healthy individuals living in the following territories of the Leningrad Region: Boksitogorsky, Volosovsky, Vyborgsky, Kingiseppsky, Lodeynopolsky, Luzhsky, Podporozhsky, Priozersky, Slantsevsky and Tikhvinsky districts – were analyzed by enzyme immunoassay. The retrospective epidemiological analysis of the incidence of leptospirosis and HFRS in the population of the Leningrad Region in 2011–2020 was carried out based on the data from the Rospotrebnadzor Administration and Forms No. 2 “Information on infectious and parasitic diseases”. Results and discussion. All in all, 54 cases of leptospirosis and 104 cases of HFRS were registered in the Leningrad Region in 2011–2020. The long-term average annual incidence rate (LTAAIR) for leptospirosis was 0.32. In Boksitogorsky, Vyborgsky, Lodeynopolsky, Podporozhsky and Slantsevsky districts, cases of leptospirosis were not recorded, but IgG-antibodies to Leptospira interrogans were detected in residents of those areas. The LTAAIR for HFRS was 0.63. There are no registered cases of HFRS in the Kingiseppsky, Podporozhsky, and Slantsevsky districts. IgG-antibodies to Orthohantavirus were detected in volunteers in all surveyed areas. The detection of specific antibodies in the blood sera of conventionally healthy people living in the Leningrad Region indicates contact of the population with pathogens of leptospirosis and HFRS. The lack of registered morbidity in some areas is probably due to their hypo-diagnosis, as evidenced by the detection of antibodies to the pathogens of these infections in people living in the corresponding territories.

The present study investigates the public health impact of flooding on leptospirosis incidence after Storm Daniel in Thessaly, Greece, in September 2023. A notable increase in cases was observed, with seven cases of female patients and a mean age of 40.2 years, indicating a significant risk among working-age adults. From the end of September to the beginning of November 2023, a total of 35 patients from flood-prone areas presented to the Emergency Department of the Tertiary University Hospital of Larissa. Diagnosis of leptospirosis was established by meeting the criteria suggested by the national public health organisation (EODY)-compatible clinical course, epidemiological exposure, molecular and serologic confirmation by the detection of immunoglobulin M antibodies to leptospira spp. using a commercially available enzyme-linked immunosorbent assay and real-time quantitative PCR for the molecular detection of leptospira. The larger part (84.6%) of leptospirosis cases were associated with contact with floodwater. The majority of these patients (71.4%) were from the prefecture of Larissa, followed by 14.3% from the prefecture of Karditsa, 8.6% from the prefecture of Trikala, and 5.7% from the prefecture of Magnesia. Occupational exposure and urbanisation were key risk factors. The most prevalent clinical feature was rash (69.2%), followed by fever (61.5%) and myalgia (30.7%). The findings emphasise the need for robust public health strategies, improved sanitation, rodent control, and protective measures for sanitation workers. The data highlight the broader implications of climate change on public health and the necessity for ongoing surveillance and community education to mitigate future outbreaks.

Relevance. Leptospirosis is a zoonotic ubiquitous natural focal infectious disease that has an adverse effect on human and pet health. The territory of the Republic of Belarus in terms of its natural-climatic and soil-geographical conditions is favorable for the existence of both natural and anthropurgical foci of leptospirosis. The purpose of the work is to study the long-term dynamics of the incidence of leptospirosis in the population of the Gomel region and the clinical and epidemiological features of leptospirosis. Materials and methods. The material for the study was the data of the state statistical reporting «Report on individual infectious, parasitic diseases and their carriers» for the period from 2002 to 2022. In this work, epidemiological diagnostic methods and statistical research methods were used. Descriptive retrospective continuous study of these case histories of patients diagnosed with Leptospirosis of the Gomel Regional Infectious Diseases Clinical Hospital institution was conducted to describe clinical data. Results. In the period from 2002 to 2022, 161 cases of leptospirosis were registered in the Gomel region with an average incidence rate of 0.52 per 100 thousand population. Over this period of time, the incidence of leptospirosis was characterized by an uneven distribution and was undulating. Periods with a low incidence of 0.14–0.42 cases per 100 thousand population lasting 5-6 years alternated with periods of rising incidence to 0.99 cases per 100 thousand population lasting 3 years. In 2022, a sharp rise in the incidence of leptospirosis in the Gomel region was registered, and therefore 15.8 times higher than the incidence in 2021, the incidence rate was 1.11 per 100 thousand of the population and exceeded the national average by 4.6 times. Adults predominated among the sick (93.3%). At the same time, 73.0% of the patients were urban residents. The source of infection in 81.2% of cases were rodents, in 7.52% of cases domestic animals. In 7.52% of cases, the disease appeared as a result of professional activity, only in 3.76% of cases the disease occurred after swimming in open water. Thus, the main route of transmission of leptospirosis at present is contact (88.72%), alimentary and water are less important, respectively 7.52% and 3.76%. Results of serological examination for leptospirosis by RMA showed that 5 serogroups of leptospir circulate among rodents: L. Pomona and L. Canicola, L. Grippotyphosa, L. Icterohaemorrhagiae, L. A. Ustralis. 36.4% of the samples showed a positive result at the same time to several serogroups. L. Grippotyphosa, L. Cterohaemorrhagiae and L. Pomona were detected more often, in total, these pathogens accounted for 46.5% of positive samples. The results of the survey of farm animals showed that 60.6% of the sera studied had positive results of RMA with leptospirs of several serogroups. L. Sejroe was also isolated – in 12.3% of samples, L. Hebdomad – in 1.3% of samples, L. Icterohaemorrhagiae – in 1.2%, L. Pomona – in 0.3%, others – 24.2%. In the period from 2002 to 2021, the following serogroups were isolated in patients with leptospirosis: L. Grippotyphosa – 36%, L. Pomona and L. Canicola – 16%, L. Australi – 13%, L. Wolffi – 9%, L. Icterohaemorrhagiae – 7% and L. Tarassovi – 3%. In 2022, there is a change in the polytypage of leptospir: L. Icterohaemorrhagiae (6.7%), L. Tarassovi (6.7%), L. Wolffi (6.7%), L. Pomona (13.3), L. Astralis (13.3), L. Canicola (6.7%), 6.7% – L. Sejroe, L. Grippotyphosa Moskva – 40%. For the period from 2005 to 2022, 49 people diagnosed with leptospirosis were treated at the Gomel Regional Infectious Diseases Hospital, of which men accounted for 69%, the average age of patients was 34.5 ± 3.8 years. Most patients are hospitalized on day 6 [4 – 8] of illness. All patients complained of fever, 86% of patients had muscle pain, headaches were recorded in 56.0%, yellowing of the skin and sclera – 34.0%, abdominal pain – 38%, 25% of patients reported nausea, vomiting, diarrhea syndrome. 28.6% of patients had an icteric form of leptospirosis, Weil's syndrome was diagnosed in 9.3% of patients, hemorrhagic syndrome was observed in 18.7% of patients. All patients had laboratory confirmation of the diagnosis. The duration of hospitalization was 15 [9 – 23] days. 1 case of the disease ended with a detailed outcome for the entire observation period. Conclusion. The incidence of leptospirosis in the Gomel region is undulating and is characterized by a change in periods of rising incidence lasting up to 3 years with periods of low incidence lasting up to 5 years. The results of the study suggest that the emergence and spread of the leptospira serotype in the territory led to a new increase in the incidence. Thus, continuous qualitative monitoring of leptospira serotypes among the population of sources of infection should be carried out.

Background: Leptospirosis is among transfusion transmissible infections but is not screened routinely among blood donors and is endemic in Southern India. The presence of carrier state and the donors being asymptomatic may lead to transfusion transmission in the absence of screening. We aimed to study the prevalence of leptospirosis among blood donors and to assess the need to implement screening strategies for its detection. Methods: A prospective observational study was conducted among blood donors using Purposive sampling to select donors for the study. The samples collected for routine transfusion transmissible infections screening were used to screen for Ig M antibodies to leptospira infection by Enzyme linked immunosorbent assay (ELISA) method. Samples that were reactive twice were true positive. These donors were contacted telephonically to enquire if they developed any symptoms of the infection. Results: A total of 3576 came for blood donation during the study period of which 124 participated in the study. Among the 124 donors screened, a total of seven samples (5.64%) samples were found to be reactive for IgM Leptospira antibodies. The mean age of the donors that were found to be reactive was 27.5 years (SD: 3.15, Range: 20-45 years) with a male to female ratio of 6:1. All these donors were asymptomatic before or after seven days and 2 weeks of blood donation. Conclusion: Approximately six out of 100 donors screened were positive for IgM antibodies of Leptospira without any symptoms. As there is a risk of transmission via blood transfusion, regular screening may be needed at least in areas of high prevalence.

Background: Leptospirosis and Scrub typhus are zoonotic illnesses that are found worldwide. Scrub typhus is a rickettsial infection caused by Orientia tsutsugamushi and spread through the biting of a mite’s chigger. Leptospirosis is an anthropozoonotic illness that can be found anywhere but is most common in tropical and subtropical areas. In this study, we report the seroprevalence of Scrub typhus and Leptospirosis with relation to demographic factors in clinically suspected patients attending a tertiary care hospital in Theni, Tamil Nadu. Methods: This is a retrospective study in which 9574 serum samples from clinically suspected cases were collected from January 2018 to December 2023 and tested for immunoglobulin M (IgM) antibodies for Scrub typhus using the enzyme-linked immunosorbent assay (ELISA) and rapid test. A blood sample was taken from each patient, and an IgM ELISA was performed to make the diagnosis. The ELISA cut-off was determined. Results: In this study, 9574 probable cases, 4306 were examined for Leptospira IgM ELISA and 5268 for Scrub typhus IgM ELISA. Out of 4306 suspected Leptospira cases, 167 (3.8%) were positive and 485 (9.2%) were positive in 5268 suspected Scrub typhus cases. The bulk of Leptospirosis and Scrub typhus cases were in the 21–40 years’ age range, followed by the 0–20 years’ age range. Males were found to have higher seroprevalence (57.1%) than females (42.9%). Conclusions: Scrub typhus and leptospirosis are developing infections, and prompt treatment can save many lives. It is strongly advised to take a programmatic approach to the prevention, control, and management of these developing diseases.

Objective: To examine the socio-environmental factors associated with the assemblage of small mammals and the prevalence of Leptospira pathogen in poor suburban communities of Terengganu, Malaysia. Methods: We trapped small mammals from 119 trapping points scattered around three suburban communities of Terengganu using sausage-baited live traps. On the average, we set up five traps for three nights at each sampling point during the trapping period. Kidneys of captured animals were harvested and processed for Leptospira investigation. Additionally, environmental survey was conducted at each trapping point to obtain information about possible variables supporting small mammal assemblage. We used a generalized linear model to evaluate the effect of different socio-environmental variables on small mammals’ assemblage. Results: A total of 89 small mammals, specifically, Rattus norvegicus (n=39), Rattus rattus (n=27), Rattus exulans (n=10), Suncus murinus (n=11), and Tupaia glis (n=2) were captured from 1 385 trap nights. Fourteen individuals (15.7%) of the captured animals tested positive for Leptospira bacteria using PCR detection. Results of our generalized linear model showed only residences bordering vacant lots as the variable positively associated with small mammal occurrence in the three study sites. Conclusions: Small mammal community, especially the often neglected species, could harbour and potentially contribute towards pathogenic Leptospira maintenance in the study sites. To adequately control small mammals’ population and subsequent human zoonoses transmission, it is critical to advocate and promote appropriate infrastructure and suburban services, together with good hygiene practices that can reduce the animals’ access to food and harborage.

The emergence of infectious disease outbreaks and ‘superbugs’ related to pollution combined with climate change is a current problem, not just a future threat. In May 2024, an extreme flood hit the Rio Grando Sul State, southern Brazil, triggering an important leptospirosis outbreak in urban settings with deficient sanitation systems. This and other cases discussed in this article exemplify how extreme weather events exacerbate the consequences of environmental pollution by multiple classes of pathogens in the global scenario of increasing anthropogenic pressures on the environment. A combination of actions to combat climate change and improvements in sanitation systems is essential to mitigate this problem.

Leptospirosis is a zoonotic disease that must be studied on the One Health point of view. It is possible that there are particularities in the epidemiology of leptospirosis in Caatinga biome, where the environment is often unfavorable and challenges the adaptability of Leptospira spp. Overall, 100 dogs (47 shelter and 53 stray dogs) selected based on sampling calculation were used to evaluate the Leptospira spp. seroprevalence and associated factors. The microscopic agglutination test (MAT) was applied to detect anti-Leptospira spp. antibodies (cut-off titer 50). Risk factors were identified using the robust Poisson regression analysis. Twenty-four animals (24%; 95% CI = 15.6% - 32.4%) were seroreactive, antibody titers ranged from 50 to 200, and the reacting serogroups were Ballum (17%), Autumnalis (6%) and Djasiman (1%). The factors/categories associated with seropositivity were the environment where the animal stay/soil (prevalence ratio [PR] = 6.03; 95% CI for PR: 1.86 - 7.69; P < 0.001) and access to polluted water/yes (PR = 3.79; 95% CI for PR: 1.85 - 24.22; P = 0.011). The results suggested leptospirosis as a concern in the One Health context in stray and shelter dogs from the Caatinga biome despite the adverse conditions of this biome for the survive of Leptospira spp. on the environment. Moreover, despite being social and government issues, factors such as environment where the animal stay (soil) and access to polluted water must be carefully deemed and corrected to avoid the transmission of leptospires to animals and humans. [ABSTRACT FROM AUTHOR]

The state of Rio Grande do Sul has a great diversity of reptile species distributed throughout its territory. Due to human actions, such as habitat fragmentation, these animals have been frequently observed in urban and peri-urban environments. This facilitates the spread of pathogens between animals and humans, posing a unique health risk, as many diseases are considered zoonoses. Leptospirosis is among the most common zoonoses in the world and is caused by pathogenic species of bacteria of the genus Leptospira. The role of reptiles in the cycle of this disease is yet unknown. However, serological studies have demonstrated positivity for antibodies against Leptospira spp. in tortoises and snakes, which may indicate that these animals act in maintaining the pathogen in the environment. This observed the presence of antiLeptospira antibodies in rescued reptiles taken to the Center for Rehabilitation of Wild Fauna and Screening Center for Wild Animals at the Universidade Federal de Pelotas (NURFS-CETAS/UFPEL). Samples were collected from 55 animals (39 Trachemys dorbigni; 3 Philodryas patagoniensis; 3 Caiman latirostris; 3 Salvator merianae; 2 Acanthochelys spixii; 2 Phrynops hilarii; 2 Hydromedusa tectifera; 1 Philodryas aestiva) from August 2022 to December 2023 and tested for 12 reference serovars. Two animals demonstrated positivity, one for the pathogenic serovar Pyrogenes and the other for the pathogenic serovar Canicola. This result reflected the importance of different species besides mammals as potential reservoirs and responsible for maintaining leptospirosis in the environment. [ABSTRACT FROM AUTHOR]

Background and purpose: Leptospirosis is an acute febrile illness that affects the whole range of symptoms, the symptoms can be a mild form of the flu-like illness to more severe symptoms such as jaundice, bleeding, kidney failure, and death. In this disease, the skin lesions are usually in the form of macular, maculopapular, urticaria, and petechiae. Due to the variety of symptoms of this disease, to add to our knowledge in this field, we designed a study to evaluate the skin symptoms of this disease in patients admitted with this diagnosis. Materials and methods: This cross-sectional study was conducted from the beginning of 2014 to the end of 2020. The studied population was all hospitalized patients with leptospirosis whose disease was proven through serological tests. Checklist information includes age, sex, occupation, clinical signs, the first sign of disease onset, skin symptoms including any skin lesion including papules, macules, petechiae, purpura, hemorrhagic rashes, etc. at the beginning of the disease is manifested, and also how it has changed in the course of treatment and also what lesions are valuable to us at the end of treatment. All patient information is recorded on a special form. Data analysis was performed by SPSS software version 20. Results: 800 people (652 (81.50%) men and 148 (18.50%) women) were examined in this study. The average age of the studied patients was 48.55 ± 16.23 years with a minimum age of 15 and a maximum age of 87 years. The chi-square test was used to check the relationship between skin symptoms and patients' gender and age. the result showed that 150 patients had jaundice (62.76%), which was significantly more frequent than other skin symptoms (P

Abstract The Omp85 family of outer membrane proteins are ubiquitously distributed among diderm bacteria and play essential roles in outer membrane (OM) biogenesis. The majority of Omp85 orthologs are bipartite and consist of a conserved OM-embedded 16-stranded beta-barrel and variable periplasmic functional domains. Here, we demonstrate that Leptospira interrogans encodes four distinct Omp85 proteins. The presumptive leptospiral BamA, LIC11623, contains a noncanonical POTRA4 periplasmic domain that is conserved across Leptospiraceae. The remaining three leptospiral Omp85 proteins, LIC12252, LIC12254 and LIC12258, contain conserved beta-barrels but lack periplasmic domains. Two of the three ‘noNterm’ Omp85-like proteins were upregulated by leptospires in urine from infected mice compared to in vitro and/or following cultivation within rat peritoneal cavities. Mice infected with a L. interrogans lic11254 transposon mutant shed tenfold fewer leptospires in their urine compared to mice infected with the wild-type parent. Analyses of pathogenic and saprophytic Leptospira spp. identified five groups of noNterm Omp85 paralogs, including one pathogen- and two saprophyte-specific groups. Expanding our analysis beyond Leptospira spp., we identified additional noNterm Omp85 orthologs in bacteria isolated from diverse environments, suggesting a potential role for these previously unrecognized noNterm Omp85 proteins in physiological adaptation to harsh conditions.

Abstract Background Both dengue and Leptospira infections are endemic to tropical and subtropical regions, with their prevalence increasing in recent decades. Coinfection with these pathogens presents significant diagnostic challenges for clinicians due to overlapping clinical manifestations and laboratory findings. This case report aims to elucidate two clinical scenarios where the coinfection of dengue and leptospirosis complicates the disease course, creating a diagnostic conundrum. Case presentation We present the clinical scenarios of two Bangladeshi males, aged 25 and 35 years, who were admitted to our hospital with acute febrile illness. The first patient exhibited hepatic and renal involvement, while the second presented with symptoms initially suggestive of meningoencephalitis. Both cases were initially managed under the presumption of dengue infection based on positive serology. However, further evaluation revealed coinfection with Leptospira, complicating the disease course. Both patients received appropriate treatment for dengue and antibacterial therapy for leptospirosis, ultimately resulting in their recovery. Conclusion These case scenarios underscore the critical importance for clinicians in regions where dengue and Leptospira are endemic to consider both diseases when evaluating patients presenting with acute febrile illness.

Leptospirosis is a common but underdiagnosed zoonosis. We conducted a 1-year prospective study in La Guaira State, Venezuela, analyzing 71 hospitalized patients who had possible leptospirosis and sampling local rodents and dairy cows. Leptospira rrs gene PCR test results were positive in blood or urine samples from 37/71 patients. Leptospira spp. were isolated from cultured blood or urine samples of 36/71 patients; 29 had L. interrogans, 3 L. noguchii, and 4 L. venezuelensis. Conjunctival suffusion was the most distinguishing clinical sign, many patients had liver involvement, and 8/30 patients with L. interrogans infections died. The Leptospira spp. found in humans were also isolated from local rodents; L. interrogans and L. venezuelensis were isolated from cows on a nearby, rodent-infested farm. Phylogenetic clustering of L. venezuelensis isolates suggested a recently expanded outbreak strain spread by rodents. Increased awareness of leptospirosis prevalence and rapid diagnostic tests are needed to improve patient outcomes.

Leptospirosis is considered to be the most widespread, yet neglected, re-emerging zoonotic disease caused by infection with a pathogenic species of the genus Leptospira. Although this disease is prevalent in Bangladesh, the recent epidemiological status has not yet been well documented. In this study, we aimed to determine the prevalence of leptospirosis among febrile patients using different diagnostic methods and to characterize the epidemiological features and species of Leptospira in Mymensingh, north–central Bangladesh. Among the blood samples of 186 patients with suspected leptospirosis who met the inclusion criteria, including having a fever for more than 5 days (November 2021–June 2022), 88 samples (47%) were Leptospira-positive according to IgM LAT, IgM ELISA, or nested PCR (positivity rates: 38%, 37%, and 42%, respectively). Nested PCR showed a significantly higher positivity rate (54%) in patients with a short fever (5–10 day) than the other methods did, with lower rates among those with a longer fever. Leptospirosis cases were more common in males (68%), those 16–45 years of age (70%), residents of rural areas (81%), and farmers (41%). In addition to a fever, myalgia and jaundice were found in more than 70% of the patients, while variable symptoms were observed. The 16S rRNA sequencing analysis revealed that the Leptospira species in all the 22 samples tested were L. wolffii, belonging to the pathogenic subclade P2. This study showed the recent epidemiological features of leptospirosis in Bangladesh, indicating the presumptive predominance of L. wolffii since 2019.

Background and purpose: Leptospirosis is a common disease between humans and animals, the source of which is rodents, canines, etc., the disease is transmitted by scratching the skin and getting it contaminated with water contaminated with animal urinary waste and is currently an endemic disease in neighboring northern provinces of Iran. The purpose of this study was to investigate the findings of chest X-ray and lung CT scans in leptospirosis with or without pulmonary symptoms. Materials and methods: The current descriptive and retrospective research examined the findings of chest X-ray and CT scan of the lungs in patients with leptospirosis with or without pulmonary manifestations in Razi Ghaemshahr Hospital. In this study, 49 hospitalized patients were randomly selected from the records of leptospirosis patients in Razi Ghaemshahr Hospital during the spring and summer of 2017 from an information form based on clinical epidemiological characteristics and risk factors for leptospirosis patients using the mentioned characteristics. The disease was prepared in the infectious reference books and articles published in Farsi and English about this disease, and help was taken from a radiologist colleague to interpret the findings of the chest X-ray and CT scan of the lungs. After recording in SPSS 16 software, the data were analyzed through a Q_Q graph and skewness index. The clinical and epidemiological findings of leptospirosis were considered as inclusion criteria in the study, and the absence of serological tests to confirm leptospirosis was considered as exclusion criteria. Results: Among 49 hospitalized patients with leptospirosis, 11 patients had abnormal radiological findings and 38 patients had normal X-rays. Among 11 patients with abnormal radiological findings, 6 patients had respiratory symptoms, which included 54.54% cough and 18.18% bloody sputum. Among 38 patients with normal radiography, 11 patients had pulmonary symptoms, which included 29.94% cough and 2.63% bloody sputum. The amount of cough was significantly higher. Abnormal findings in chest X-ray, alveolar infiltration, ground glass opacity, and consolidation were the most frequent in the CT scan of the lung. Conclusion: Considering the significant percentage of normal chest radiographs in patients suffering from rice field fever with pulmonary symptoms, it is essential to perform a CT scan of the chest and decide on more effective therapeutic interventions. Therefore, it is considerable that usually changes in the chest CT scan in the severe form of the disease that causes vasculitis and alveolar bleeding appear before the appearance of severe symptoms such as bloody sputum and make a decision to start more effective drugs in the patient's treatment plan. As a result, pulmonary involvement in patients with leptospirosis is of special importance and it should be given special attention due to the endemicity of leptospirosis in the province, considering the associated complications and high mortality and the possibility of its occurrence even in patients who do not have respiratory complaints at the time of presentation. It is suggested to conduct more extensive research based on the population in this field.

Leptospirosis is a bacterium with a worldwide distribution and belongs to the group of zoonoses that can affect both humans and animals. Most cases of leptospirosis present as a mild, anicteric infection. However, a small percentage of cases develop Weil’s disease, characterized by bleeding and elevated levels of bilirubin and liver enzymes. It can also cause inflammation of the gallbladder. Acute acalculous cholecystitis has been described as a manifestation of leptospirosis in a small percentage of cases; however, no association between leptospirosis and acute acalculous cholecystitis has been found in the literature.

Abstract This study evaluated the level of risk practices and awareness of leptospirosis among residents of Zaria, Nigeria. A pre-tested questionnaires were administered via face-to-face interview to 100 residents. The data was analyzed using chi-square and multivariate analysis to identify risk factors for leptospirosis. The demography showed that the majority of the respondents were male, aged 21–40 years, and majorly crop farmers. The risk factors identified showed that males were 4.14 times more likely to be affected by leptospirosis (OR 4.14, 95% CI [1.93–5.37], p = 0.02) and the source of animal’s water was 5.56 times more likely to be contaminated by Leptospira spp. (OR 4.14, 95% CI [2.88–8.03], p = 0.01) and these relationships were significant. The majority of respondents were not aware of the disease (OR 1.87, 95% CI [1.22–4.57], p = 0.01) with 78% of the respondents not sure of which of the animal species leptospirosis affected (OR 1.67, 95% CI [1.07–2.62], p = 0.02). This study has demonstrated the existence of risk behaviors, and paucity of knowledge about leptospirosis in the study area. It is therefore recommended to organize an enlightenment program and the need for protective clothing for individuals occupationally at risk of infection by Leptospira spp.

A stochastic model of leptospirosis with vector and environmental transmission is established in this paper. By mathematical analysis of the model, the threshold for eliminating the disease is obtained. The partial rank correlation coefficient was used to analyze the parameters that have a greater impact on disease elimination, and a sensitivity analysis was conducted on the parameters through numerical simulation. Further, combined with the data of leptospirosis case reports in China from 2003 to 2021, two parameter estimation methods, Least Squares method (LSM) and Markov Chain Monte Carlo-Metropolis Hastings method (MCMC-MH), are applied to estimate the important parameters of the model and the future trend of leptospirosis in China are predicted.

A stochastic model of leptospirosis with vector and environmental transmission is established in this paper. By mathematical analysis of the model, the threshold for eliminating the disease is obtained. The partial rank correlation coefficient was used to analyze the parameters that have a greater impact on disease elimination, and a sensitivity analysis was conducted on the parameters through numerical simulation. Further, combined with the data of leptospirosis case reports in China from 2003 to 2021, two parameter estimation methods, Least Squares method (LSM) and Markov Chain Monte Carlo-Metropolis Hastings method (MCMC-MH), are applied to estimate the important parameters of the model and the future trend of leptospirosis in China are predicted.

Leptospirosis, classified by the World Health Organization as an emerging and neglected disease, is caused by the zoonotic pathogen Leptospira interrogans. This review aims to outline the Mexican epidemic of L. interrogans in dogs, including diagnosis and prevention methods. This review article searched articles from the publishers Wiley, Springer, PubMed, Redalyc, SciElo, and Elsevier. Among the 200 Mexican articles concerning Leptospira epidemiology, diagnosis, treatment, and vaccination, those that failed to meet the set inclusion criteria were excluded. The worldwide study of L. interrogans has focused on this bacterium. In Mexico, up-to-date information on canine prevalence, diagnosis, and vaccine use is scarce. Flow cytometrically detected Salmonella serovars differ from those in current vaccines, emphasizing the importance of broadening vaccine serovar coverage.

Abstract Leptospirosis is a global disease that impacts people worldwide, particularly in humid and tropical regions, and is associated with significant socio-economic deficiencies. Its symptoms are often confused with other syndromes, which can compromise clinical diagnosis and the failure to carry out specific laboratory tests. In this respect, this paper presents a study of three algorithms (Decision Tree, Random Forest and Adaboost) for predicting the outcome (cure or death) of individuals with leptospirosis. Using the records contained in the government National System of Aggressions and Notification (SINAN, in portuguese) from 2007 to 2017, for the state of Pará, Brazil, where the temporal attributes of health care, symptoms (headache, vomiting, jaundice, calf pain) and clinical evolution (renal failure and respiratory changes) were used. In the performance evaluation of the selected models, it was observed that the Random Forest exhibited an accuracy of 90.81% for the training dataset, considering the attributes of experiment 8, and the Decision Tree presented an accuracy of 74.29 for the validation database. So, this result considers the best attributes pointed out by experiment 10: time first symptoms medical attention, time first symptoms ELISA sample collection, medical attention hospital admission time, headache, calf pain, vomiting, jaundice, renal insufficiency, and respiratory alterations. The contribution of this article is the confirmation that artificial intelligence, using the Decision Tree model algorithm, depicting the best choice as the final model to be used in future data for the prediction of human leptospirosis cases, helping in the diagnosis and course of the disease, aiming to avoid the evolution to death.

Abstract Leptospirosis is one of the most neglected zoonotic infections of public health concern worldwide and a remerging infection in tropical countries such as India. The infection least explored disease and the epidemiological and other critical data are scarce for the disease rate reported and to control the infection. Leptospirosis as sapronosis is as underrated as the infection itself, and this article aims to explore the significance of this aspect of the disease. The research review aimed at the epidemiological understanding of the infection to control the negative impact of the disease. A mixed review and analysis were carried out to understand the knowledge published on the critical and understudied areas like epidemiology, transmission, diagnosis, treatment, and control of infection. A systematic analysis was carried out to extract information about the reported circulating strains, and research lacunae in India with the published data available in PubMed. The article elaborately discusses crucial inference areas of infection transmission and addresses lacunae in critically unacclaimed areas of infection to control the spread of infection using one health approach (OHA), and strategies to control leptospiral infection are proposed. The article also reviewed how and why Leptospirosis can be best studied and controlled by “One health approach” in India. Graphical Abstract

Leptospirosis is a significant zoonosis worldwide, with disease severity ranging from a mild non-specific illness to multi-organ dysfunction and hemorrhage. The disease is caused by pathogenic bacteria of the genus Leptospira, which are classified into pathogenic and saprophytic clades. Bacterial binding to host molecules and cells, coordinated by adhesin proteins, is an important step in pathogenesis. While many leptospiral adhesins have been identified, the vast majority have not been characterized in vivo. Herein, we present an overview of the current methodologies and successes in identifying adhesins in Leptospira, including known biological roles in vivo. We will also identify and discuss potential areas for future research. [ABSTRACT FROM AUTHOR]