Leptospira Infection Research Articles

Analysis of Complement Factor H gene polymorphisms and their association with clinical manifestations ofleptospirosis.

Leptospirosis is caused by pathogenic leptospires, posing a significant public health problem. Host susceptibility to Leptospira infection is a multifactorial trait, and the host's genetic background can influence both the establishment of infection and the severity of the disease. Complement Factor H (FH) plays a crucial role in the interaction between pathogenic bacteria and the host. Genetic variants in the FH gene CFH have previously been associated with non-infectious diseases. Here, we aimed to analyze the effect of CFH variants on individual susceptibility to leptospirosis and disease severity. To accomplish this, we sequenced CFH exons 7, 9, 21, 22, and 23 in a case/control cohort (184/162) from two endemic leptospirosis areas in Brazil and Argentina. We identified twenty-one single nucleotide variants (SNVs). In the Brazilian cohort, the intronic variant rs34815383 exhibited a higher frequency in patients than in controls, resulting in a significant association with leptospirosis (p = 0.032; OR: 0.32; 95% CI 0.1-1) and also renal disorder (p = 0.001; OR: 5.3; 95%CI 1.8-15.57). This SNV is reported to be a splicing variant, negatively impacting CFH expression, and has previously been associated with Complement-driven renal disease. A second synonymous variant, rs61822181, was significantly less frequent in patients than in controls (p = 0.002; OR: 7.33; 95% CI 1.59-33.7), representing a protective factor against the development of leptospirosis. Our study represents the first documentation of the frequency of CFH SNVs in South America and identifies the variant rs34815383 T > C as a risk factor for leptospirosis and leptospirosis-related renal complications.

Leptospiral infection in domestic mares in North Queensland.

Leptospira species are found worldwide, favouring tropical regions, and infect a wide range of animal species. Although renal persistence in infected individuals and excretion in urine is thought to be the primary mechanism of disease transmission, recent reports have suggested that persistence in the reproductive tract may be a feature in certain species, including the horse. The aim of this study was to investigate leptospiral infection, particularly within the reproductive tract, in healthy, non-breeding mares. Serum and endometrial swab samples were collected from 50 mares from the James Cook University Teaching Animal Herd, as well as, where possible, free-catch urine (n = 19). Sera were screened for antibodies to 24 Leptospira serovars, using the microscopic agglutination test (MAT). Endometrial and urine samples underwent real-time PCR testing, targeting the leptospiral rrs gene. Overall, the seroprevalence of leptospirosis was 48% (95% CI: 34%-62%), with serovars Arborea, Bratislava and Australis detected most frequently. PCR positive results were obtained from 1 of 50 (2%) endometrial swabs and 2 of 19 (11%) urine samples. This is the first report of serovar Bratislava in horses in Australia.

Isolation and Molecular Characterization of Pathogenic Leptospira spp. from Brown Rats (Rattus norvegicus) in Zaria and Environs, Kaduna, Nigeria, 2022.

Leptospirosis caused by the pathogenic serovars of Leptospira spp. is a zoonotic disease of global importance. Brown rats (Rattus norvegicus), due to their worldwide distribution and reservoir host status, are considered the most important reservoir for environmental leptospiral persistence and infections in animals. We aimed to isolate, identify, and characterize Leptospira spp. circulating among brown rat populations in Zaria, Kaduna state, Nigeria. Kidney samples from 305 brown rats from different locations in Zaria were collected April-June 2022 and cultured using bacteriologic methods. We also extracted DNA from 24 kidney tissue samples for molecular detection of pathogenic Leptospira spp. and for phylogenetic analysis. Leptospira spp. was detected in 57.7% of the samples by using culture methods and in 91.7% of the samples by using PCR. The phylogenetic tree revealed two distinct clusters among the reference sequences, aligning with the known P1 and P2 subclades. The sequences from this study all clustered together on the phylogenetic tree and were most similar to Leptospira interrogans serovar Pomona strain RZ 11. The high prevalence of Leptospira spp. detected in Zaria suggests that further surveillance and assessment of the public risk are warranted.

Mixed Leptospira infections in domestic animals from a rural community with high leptospirosis endemicity.

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. 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. 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.

Leptospira spp. Antibody Seroprevalence in Stray Dogs and Cats: A Study in Milan, Northern Italy

Leptospirosis is a widespread zoonosis recognised as a re-emerging infectious disease in both humans and dogs, yet the actual seroprevalence of Leptospira in pets in Italy is relatively unknown. The aim of this study was to evaluate Leptospira antibody prevalence in dogs and cats from a shelter by the microscopic agglutination test (MAT), the gold standard test in leptospiral serology, and to assess risk factors for Leptospira infection. This seroepidemiological study investigated the prevalence of leptospiral antibodies in a cohort of 106 dogs and 51 cats housed in a municipal shelter in Milan. Blood samples were collected from the animals during two sampling periods: spring/summer 2014 and autumn/winter 2016/2017. Eight serogroups were evaluated: L. Australis, L. Ballum, L. Canicola, L. Grippotyphosa, L. Icterohaemorrhagiae, L. Pomona, L. Sejroe, and L. Tarassovi. Antibody titres ranged from 1:100 to 1:6400. The results indicated that 21.7% of dogs had antibodies against serogroups L. Icterohaemorrhagiae and L. Australis, making them the most often found. Conversely, none of the cats showed any presence of antibodies. Seropositivity was higher in the spring/summer period (32.7%) than in autumn/winter (11.1%), and no statistically significant results were found regarding sex or age. These findings underscore the importance of ongoing serological surveillance and biosecurity measures in shelter environments to mitigate the zoonotic risk posed by leptospirosis.

Isolation of Virulent Leptospira Serogroup Australis Field Strains from Symptomatic Dogs for Canine Leptospiral Vaccine Development.

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.

Enhancement of clinical signs in C3H/HeJ mice vaccinated with a highly immunogenic Leptospira methyl-accepting chemotaxis protein following challenge.

Leptospirosis is the most widespread zoonosis and a life-threatening disease in humans and animals. Licensed killed whole-cell vaccines are available for animals; however, they do not offer heterologous protection, do not induce long-term protection, or prevent renal colonization. In this study, we characterized an immunogenic Leptospira methyl-accepting chemotaxis protein (MCP) identified through a reverse vaccinology approach, predicted its structure, and tested the protective efficacy of a recombinant MCP fragment in the C3H/HeJ mice model. The predicted structure of the full-length MCP revealed an architecture typical for topology class I MCPs. A single dose of MCP vaccine elicited a significant IgG antibody response in immunized mice compared to controls (P < 0.0001), especially the IgG1 and IgG2a subclasses. The vaccination with MCP, despite eliciting a robust immune response, did not protect mice from disease and renal colonization. However, survival curves significantly differed between groups, and the MCP-vaccinated group developed clinical signs faster than the control group. There were differences in gross and histopathological changes between the MCP-vaccinated and control groups. The factors leading to enhanced disease process in vaccinated animals need further investigation. We speculate that anti-MCP antibodies may block the MCP signaling cascade and may limit chemotaxis, preventing Leptospira from reaching its destination, but facilitating its maintenance and replication in the blood stream. Such a phenomenon may exist in endemic areas where humans are highly exposed to Leptospira antigens, and the presence of antibodies might lead to disease enhancement. The role of this protein in Leptospira pathogenesis should be further evaluated to comprehend the lack of protection and potential exacerbation of the disease process. The absence of immune correlates of protection from Leptospira infection is still a major limitation of this field and efforts to gather this knowledge are needed.

The Leptospira interrogans proteome's response to zinc highlights the potential involvement of this metal in translational-machinery and virulence.

Leptospires, as motile Gram-negative bacteria, employ sophisticated strategies for efficient invasion and dissemination within their hosts. In response, hosts counteract pathogens through nutritional immunity, a concept involving the deprivation of essential metals such as zinc. Zinc, pivotal in modulating pathogen-host interactions, influences proteins structural, catalytic, and regulatory functions. A comprehensive understanding of how leptospires regulate intracellular zinc availability is crucial for deciphering their survival mechanisms. This study explores the proteomic profile of Leptospira interrogans sv. Copenhageni str. 10A cultivated in Ellinghausen-McCullough-Johnson-Harris medium supplemented with the zinc chelator TPA or ZnCl2. Among the 2161 proteins identified, 488 were subjected to scrutiny, revealing 102 less abundant and 81 more abundant in response to TPA. Of these 488 proteins, 164 were exclusive to the presence of TPA and 141 were exclusive to the zinc-enriched conditions. Differentially expressed proteins were classified into clusters of orthologous groups (COGs) with a distribution in metabolic functions (37.8%), information storage/processing (21.08%), cellular processes/signaling (28.04%), and poorly characterized proteins (10.65%). Differentially expressed proteins are putatively involved in processes like 1-carbon compound metabolism, folate biosynthesis, and amino acid/nucleotide synthesis. Zinc availability significantly impacted key processes putatively related to leptospires' interactions with their host, such as motility, biofilm formation, and immune escape. Under conditions of higher zinc concentration, ribosomal proteins, chaperones and components of transport systems were observed, highlighting interactions between regulatory networks responsive to zinc and iron in L. interrogans. This study not only revealed hypothetical proteins potentially related to zinc homeostasis, but also identified possible virulence mechanisms and pathogen-host adaptation strategies influenced by the availability of this metal. There is an urgent need, based on these data, for further in-depth studies aimed at detailing the role of zinc in these pathways and mechanisms, which may ultimately determine more effective therapeutic approaches to combat Leptospira infections.

Disentangling the influence of reservoir abundance and pathogen shedding on zoonotic spillover of the Leptospira agent in urban informal settlements.

Rats are major reservoirs for pathogenic Leptospira, the bacteria causing leptospirosis, particularly in urban informal settlements. However, the impact of variation in rat abundance and pathogen shedding rates on spillover transmission to humans remains unclear. This study aimed to investigate how spatial variation in reservoir abundance and pathogen pressure affect Leptospira spillover transmission to humans in a Brazilian urban informal settlement. A longitudinal eco-epidemiological study was conducted from 2013 to 2014 to characterize the spatial distribution of rat abundance and Leptospira shedding rates in rats and determine the association with human infection risk in a cohort of 2,206 community residents. Tracking plates and live-trapping were used to measure rat abundance and quantify rat shedding status and load. In parallel, four sequential biannual serosurveys were used to identify human Leptospira infections. To evaluate the role of shedding on human risk, we built three statistical models for: (1) the relative abundance of rats, (2) the shedding rate by individual rats, and (3) human Leptospira infection, in which "total shedding", obtained by multiplying the predictions from those two models, was used as a risk factor. We found that Leptospira shedding was associated with older and sexually mature rats and varied spatially and temporally-higher at valley bottoms and with seasonal rainfall (December to March). The point estimate for "total shedding" by rat populations was positive, i.e., Leptospira infection risk increased with total shedding, but the association was not significant [odds ratio (OR) = 1.1; 95% confidence interval (CI): 0.9, 1.4]. This positive trend was mainly driven by rat abundance, rather than individual rat shedding (OR = 1.8; 95% CI: 0.6, 5.4 vs. OR = 1.0; 95% CI: 0.7, 1.4]. Infection risk was higher in areas with more vegetative land cover (OR = 2.4; 95% CI: 1.2, 4.8), and when floodwater entered the house (OR = 2.4; 95% CI: 1.6, 3.4). Our findings indicate that environmental and hydrological factors play a more significant role in Leptospira spillover than rat associated factors. Furthermore, we developed a novel approach combining several models to elucidate complex links between animal reservoir abundance, pathogen shedding and environmental factors on zoonotic spillover in humans that can be extended to other environmentally transmitted diseases.

A systematic survey of environmental DNA in Palau's lakes and waterfalls reveals an increase in Leptospira levels after flooding

ObjectiveLeptospirosis is an important bacterial zoonosis which is widespread in tropical and subtropical islands and influences human and animal health which has secondary economic effects. Although leptospirosis is endemic in Palau, an Oceanian Pacific Island country, few systematic surveys of potential risk factors for Leptospira infection, such as weather and host animals, have been conducted in the natural environment. We used environmental DNA metabarcoding to assess the distribution, species diversity, and abundance of pathogenic Leptospira in this endemic region to investigate the potential environmental risks. MethodsForty-two paired water samples, representing fine and rainy weather conditions, were collected from four representative waterfalls and lakes on Babeldaob Island, the largest island in Palau. High-throughput sequencing analysis was conducted for polymerase chain reaction products of leptospiral 16S rRNA and vertebrate animal mitochondrial 12S rRNA genes. ResultsWe revealed greater Leptospira diversity and abundance in samples collected after continuous rain, particularly in the presence of flooding, compared with samples collected under typhoon, monsoon, or fine weather conditions. From same samples, six mammalian species including cats (Felis catus), mice (Mus musculus), Yap flying fox (Pteropus yapensis), rats (Rattus spp.), and pigs (Sus scrofa) were repeatedly detected. These may be candidates of host animals of Leptospira in Palau; however, their detection was not clearly correlated with that of Leptospira. ConclusionWe repeatedly detected several species of pathogenic Leptospira from water samples of a wide region of Babeldaob Island. We confirmed that Leptospira contamination in freshwater environments increased under rainy conditions, particularly in the presence of flooding. This information could be used to improve public health control measures in this region.

Diagnostic Pathways of Leptospira spp. in Dogs with Kidney Injury.

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.

Extracorporeal life support for severe leptospirosis: Case series and narrative review

Introduction: Leptospirosis can be associated with multi-system organ failure (MSOF) and significant morbidity and mortality. Extracorporeal life support (ECLS) has been used as salvage therapy for severe leptospirosis complicated by acute respiratory distress syndrome (ARDS). Current knowledge in this field is limited, with no standardized treatment approaches. We aim to describe the literature to date on the use of ECLS in patients with leptospirosis, highlighting associations, outcomes, and complications. Methods: We report on the successful use of ECLS in two cases of severe leptospirosis and conduct a narrative review of the literature. Using a search strategy developed in consultation with a medical librarian and validated across pre-selected articles, several databases were searched. We included case reports, case series, cohort studies, and prospective studies of adult patients with confirmed leptospirosis undergoing ECLS. Editorials, surveys, or opinion articles without primary patient data were excluded. Overall mortality was our primary outcome. Results: Two cases of previously healthy males presenting with ARDS due to leptospiral infection are described. Literature review identified 25 articles containing 43 reported cases of patients treated with ECLS for severe leptospirosis. Patients were mostly young and male. Overall mortality was 16%. The most common complication recognized was acute renal failure requiring renal replacement therapy. Additional complications included diffuse intravascular coagulation, necrotizing pancreatitis, and limb ischemia. Conclusion: Leptospirosis should be considered in patients with epidemiologic exposure(s) presenting with critical illness, including ARDS and MSOF. ECLS is a viable rescue strategy in severe leptospirosis, even with established MSOF.

Leptospira infection of rodents captured at the slaughterhouses and their risk to public health in Unguja island, Tanzania

Background: Leptospira infection is an invasion of animal or human body with the pathogenic spirochete bacteria of the genus Leptospira resulting to a disease called leptospirosis. This study aimed to investigate Leptospira infection and the carrier status of rodents caught near slaughterhouses at Unguja Island, Tanzania. Methods: This cross-sectional study was conducted from January to April 2022 at Unguja Island to determine the seroprevalence of Leptospira infection in rodents captured in and around the slaughterhouse’s compounds. A total of 302 sera samples from four slaughterhouses were tested for anti-leptospiral antibodies using microscopic agglutination test (MAT) with a panel of 5 Leptospira serovars: Pomona, Lora, Hebdomadis, Grippotyphosa and Sokoine; and were considered positive at MAT titer ≥1:20. Chi-square test and the Fisher exact test were used to assess the statistical association between variables at a p value of &lt; 0.05. Results: The overall seroprevalence of Leptospira infection in rodents was 10.6% (32/302). Individual rodent species had seroprevalence of 8.5% for Mus musculus, 0.0% for Mastomys natalensis, 20.8% for Rattus norvegicus, 9.3% for Rattus rattus and Cricetomys gambianus at 12.5%. However, the apparent seroprevalence in the individual slaughter facilities was 15.0% (15/100) Kinyasini, 10.4% (5/48) Mfenesini, 9.3% (5/54) Kisakasaka, and 7.0% (7/100) Muwanda. Conclusion: With over ten percent of rodents testing positive for Leptospira infection, it is crucial to implement rodent control measures to prevent the spread of the disease to those working in or around the slaughterhouses in Unguja Island.

In silico analysis and functional characterization of a leucine-rich repeat protein of Leptospira interrogans

Pathogenic spirochetes of the genus Leptospira are the causative agent of leptospirosis, a widely disseminated zoonosis that affects humans and animals. The ability of leptospires to quickly cross host barriers causing infection is not yet fully understood. Thus, understanding the mechanisms of pathogenicity is important to combat leptospiral infection. Outer membrane proteins are interesting targets to study as they are able to interact with host molecules. Proteins containing leucine-rich repeat (LRR) domains are characterized by the presence of multiple regions containing leucine residues and they have putative functions related to host-pathogen interactions. Hence, the present study aimed to clone and express the recombinant protein encoded by the LIC11098 gene, an LRR protein of L. interrogans serovar Copenhageni. In silico analyses predicted that the target protein is conserved among pathogenic strains of Leptospira, having a signal peptide and multiple LRR domains. The DNA sequence encoding the LRR protein was cloned in frame into the pAE vector, expressed without mutations in Escherichia coli and purified by His-tag chromatography. Circular dichroism (CD) spectrum showed that the recombinant protein was predominantly composed of β-sheets. A dose-dependent interaction was observed with cellular and plasma fibronectins, laminin and the complement system component C9, suggesting a possible role of the protein encoded by LIC11098 gene at the initial stages of infection.

Monitoring of pathogenic Leptospira infection in wolves (Canis lupus) from Spain and Italy

Leptospirosis is a bacterial disease of worldwide distribution with relevant implications for animal and human health. Different large wild carnivore species can act as reservoirs of this zoonotic pathogen. This study aimed to evaluate the circulation of Leptospira spp. in free-ranging wolves (Canis lupus) from southern Europe. A total of 281 kidney samples of wolves from Spain and Italy were collected between 2017 and 2023. The presence of Leptospira DNA was analysed by real-time PCR and phylogenetic analyses were carried out using a Bayesian approach. The overall prevalence was 3.2 % (9/281; 95 %CI: 1.1–5.3). Leptospira DNA was detected in nine of the 180 wolves from Spain (5.0 %; 95 %CI: 1.8–8.2), but not in the Italian wolf population (0 %; 0/101). Molecular analyses revealed high homology between the sequences obtained in the present study and isolates of Leptospira interrogans and Leptospira borgpetersenii from different rodent and domestic ungulate species. Our results provide evidence of a low and spatially heterogeneous circulation of this pathogen in wolf populations of southern Europe. The detection of zoonotic Leptospira species in this survey supports the need to consider wolf populations in monitoring programs for leptospirosis with a One Health approach.

Dengue and leptospirosis coinfection: a case series

BackgroundBoth 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 presentationWe 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.ConclusionThese 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.

Frequency of Leptospira in the Blood of Patients with Fever of Unknown Origin in Sinaloa, Mexico.

Background: Leptospira is a genus of bacteria that causes the zoonotic disease known as leptospirosis, which mainly affects countries with tropical and subtropical climates. Its prevalence may be underestimated because the initial stage of the infection is characterized by presenting a febrile condition that is easily confused with other diseases, such as dengue. This work reports the frequency of leptospirosis in the blood of patients with febrile symptoms of unknown origin. Materials and Methods: A total of 218 peripheral blood samples were analyzed from volunteer participants from Culiacan Sinaloa in June 2019, one half corresponded to patients with undiagnosed febrile symptoms and the other half to asymptomatic volunteers. Data collected included the age and sex of the participants. Leptospira was detected by qPCR using a fragment of the lipL32 gene from the bacteria's genome as a target. Fisher's exact test was used as a statistical method to estimate the relationship between the infection and the data collected. Results: The study group comprised 134 female and 84 male patients ranging from ages 1 to 92 years, averaging 41 years. In this study, Leptospira infection was identified in the blood of 22/218 participating volunteers (10.09%), of which 20/109 (18.34%) presented febrile symptoms, whereas 2/109 (1.83%) were asymptomatic. The most affected participants were women with ages between 27 and 59 years. However, the analysis of the relationship between infection and the variables studied did not show statistical significance. Conclusions: Leptospirosis was detected in blood samples from patients with undiagnosed febrile illness and asymptomatic symptoms in Sinaloa. The lipL32 gene is useful as a target in identifying Leptospira in human blood in the acute phase of the disease.

Prevalence and transmission of the most relevant zoonotic and vector-borne pathogens in the Yucatan peninsula: A review.

Habitat modification and land use changes impact ecological interactions and alter the relationships between humans and nature. Mexico has experienced significant landscape modifications at the local and regional scales, with negative effects on forest cover and biological biodiversity, especially in the Yucatan peninsula in southeastern Mexico. Given the close relationship between landscape modification and the transmission of zoonotic and vector-borne diseases, it is essential to develop criteria for identifying priority zoonoses in the south of the country. We reviewed 165 published studies on zoonotic and vector-borne diseases in the region (2015-2024). We identified the most frequent vectors, reservoirs, and hosts, the most prevalent infections, and the factors associated with transmission risk and the anthropogenic landscape modification in urban, rural, ecotone, and sylvatic habitats. The most relevant pathogens of zoonotic risk included Trypanosoma cruzi, arboviruses, Leishmania, Rickettsia, Leptospira, and Toxoplasma gondii. Trypanosoma cruzi was the vector-borne agent with the largest number of infected vertebrate species across habitats, while Leishmania and arboviruses were the ones that affected the greatest number of people. Dogs, cats, backyard animals, and their hematophagous ectoparasites are the most likely species maintaining the transmission cycles in human settlements, while rodents, opossums, bats, and other synanthropic animals facilitate connection and transmission cycles between forested habitats with human-modified landscapes. Pathogens displayed different prevalences between the landscapes, T. cruzi, arbovirus, and Leptospira infections were the most prevalent in urban and rural settlements, whereas Leishmania and Rickettsia had similar prevalence across habitats, likely due to the diversity and abundance of the infected vectors involved. The prevalence of T. gondii and Leptospira spp. may reflect poor hygiene conditions. Additionally, results suggest that prevalence of zoonotic and vector-borne diseases is higher in deforested areas and agricultural aggregates, and in sites with precarious health and infrastructure services. Some hosts, vectors, and transmission trends of zoonotic and vector-borne diseases in the YP are well known but others remain poorly recognized. It is imperative to reinforce practices aimed at increasing the knowledge, monitoring, prevention, and control of these diseases at the regional level. We also emphasize the need to perform studies on a larger spatio-temporal scale under the socio-ecosystem perspective, to better elucidate the interactions between pathogens, hosts, vectors, environment, and sociocultural and economic aspects in this and many other tropical regions.

Unveiling Leptospira Antibody Seroprevalence among Voluntary Blood Donors: Insights from a Single-center Observational Study

Abstract 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.

Leptospira infection in bats in Vietnam

Bats from three provinces in Vietnam (Lai Chau, Son La, and Dong Thap) were examined for the presence of pathogenic Leptospira or specific antibodies using polymerase chain reaction (PCR), enzyme-linked immunosorbent assay (ELISA), and microscopic agglutination test (MAT). Tissue specimens from 298 bats belonging to 11 species were analyzed using a real-time PCR assay specific for leptospires of pathogenic species. Leptospiral DNA was identified in 40 bats from following species: Rousettus amplexicaudatus (5/9; 55.5 %), Rousettus leschenaultii (17/42; 40.4 %), Myotis hasseltii (8/25; 32 %), Taphozous longimanus (3/12; 25 %), and Eonycteris spelaea (7/32; 21.9 %). Based on secY phylogeny, sequences from M. hasseltii bore a strong resemblance to L. borgpetersenii. Sequences from other species revealed unique lineages: one of them resembled Leptospira sp., previously identified in Rousettus madagascariensis (Madagascar) and Rousettus aegyptiacus (South Africa); the second lineage showed close relation to L. kirshneri; and the third held an intermediary position between L. noguchii and L. interrogans. Through ELISA, anti-Leptospira antibodies were found in 83 of 306 bats, with the highest seroprevalence observed in R. leschenaultii (44/48; 91.6 %), R. amplexicaudatus (6/8; 75 %), and E. spelaea (19/25; 76 %). 66 of these ELISA-positive samples were tested using MAT; 41 of them were confirmed in MAT as positive. The predominant serogroups in our study were Tarassovi and Mini.