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Pathogenic Leptospira can cause leptospirosis: a widespread, potentially fatal bacterial zoonosis whose risk is mediated by the soil and water features, animal host distributions, meaning the local ecosystem. When human cases of leptospirosis occur, it is challenging to track down their source because ecosystem-level epidemiological knowledge on Leptospira is needed. Between 2016 and 2019 in a focal riparian ecosystem, the human population experienced an outbreak and successive cases of leptospirosis attributable to L. kirschneri and L. interrogans. The epidemiological investigation was carried out using the One Health approach, as described in international health guidelines. As a first step in this process, we investigated leptospiral carriage in the main animal hosts found in the region. We sampled 143 nutrias, 17 muskrats, and 10 Norway rats using convenient trapping. DNA was extracted from their kidneys, lungs, and urine and subjected to real-time PCR (RT-PCR) targeting the Leptospira 16S rDNA and lfb1 genes. In the farms along the river's stretch of interest, we sampled serum from 439 cattle and used a microscopic agglutination test to detect the presence of antibodies against Leptospira. Urine samples were concomitantly obtained from 145 cattle and were used in two analyses: RT-PCR targeting the Leptospira 16S rDNA gene and Leptospira culturing. We found th, wt rodents were the most likely source of the L. interrogans behind the human cases. The cattle tested negative for Leptospira DNA but positive for antibodies against the serogroups implicated in the human cases. We failed to identify the potential source of the L. kirschneri responsible for several human cases of leptospirosis. Our results call for further clarification of the Leptospira maintenance community, which may comprise known maintenance hosts, such as rodents, as well as taxa not commonly considered to be maintenance hosts but that can still spread Leptospira. The resulting research network will collaboratively conduct future eco-epidemiological surveys to illuminate the leptospirosis risks faced by humans and animals within ecosystems.

Abstract Leptospirosis is a globally distributed zoonotic disease. The standard serological test, known as Microscopic Agglutination Test (MAT), requires the use of live Leptospira strains. To enhance its sensitivity and specificity, the usage of locally circulating strains is recommended. However, to date, no local strain is available from Austria. This study aimed to isolate circulating Leptospira strains from cattle in Austria to enhance the performances of the routine serological test for both humans and animals. We used a statistical approach combined with a comprehensive literature search to profile cattle with greater risk of leptospirosis infection and implemented a targeted sampling between November 2021 and October 2022. Urine and/or kidney tissue were sampled from 410 cattle considered at higher risk of infection. Samples were inoculated into EMJH-STAFF culture media within 2–6 h and a real-time PCR targeting the lipL32 gene was used to confirm the presence/absence of pathogenic Leptospira in each sample. Isolates were further characterised by core genome multilocus sequence typing (cgMLST). Nine out of 429 samples tested positive by PCR, from which three isolates were successfully cultured and identified as Leptospira borgpetersenii serogroup Sejroe serovar Hardjobovis, cgMLST cluster 40. This is the first report on the isolation and genotyping of local zoonotic Leptospira in Austria, which holds the potential for a significant improvement in diagnostic performance in the country. Although the local strain was identified as a cattle-adapted serovar, it possesses significant zoonotic implications. Furthermore, this study contributes to a better understanding of the epidemiology of leptospirosis in Europe.

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 Anosmia was identified as a hallmark of COVID-19 early in the pandemic, however, with the emergence of variants of concern, the clinical profile induced by SARS-CoV-2 infection has changed, with anosmia being less frequent. Here, we assessed the clinical, olfactory and neuroinflammatory conditions of golden hamsters infected with the original Wuhan SARS-CoV-2 strain, its isogenic ORF7-deletion mutant and three variants: Gamma, Delta, and Omicron/BA.1. We show that infected animals develop a variant-dependent clinical disease including anosmia, and that the ORF7 of SARS-CoV-2 contributes to the induction of olfactory dysfunction. Conversely, all SARS-CoV-2 variants are neuroinvasive, regardless of the clinical presentation they induce. Taken together, this confirms that neuroinvasion and anosmia are independent phenomena upon SARS-CoV-2 infection. Using newly generated nanoluciferase-expressing SARS-CoV-2, we validate the olfactory pathway as a major entry point into the brain in vivo and demonstrate in vitro that SARS-CoV-2 travels retrogradely and anterogradely along axons in microfluidic neuron-epithelial networks.

Abstract Despite the rapid growth in viral genome sequencing, statistical methods face challenges in handling historical viral endemic diseases with large amounts of underutilized partial sequence data. We propose a phylogenetic pipeline that harnesses both full and partial viral genome sequences to investigate historical pathogen spread between countries. Its application to rabies virus (RABV) yields precise dating and confident estimates of its geographic dispersal. By using full genomes and partial sequences, we reduce both geographic and genetic biases that often hinder studies that focus on specific genes. Our pipeline reveals an emergence of the present canine-mediated RABV between years 1301 and 1403 and reveals regional introductions over a 700-year period. This geographic reconstruction enables us to locate episodes of human-mediated introductions of RABV and examine the role that European colonization played in its spread. Our approach enables phylogeographic analysis of large and genetically diverse data sets for many viral pathogens.

Rodents are recognized as the main reservoirs of Leptospira spp. Rats, in particular, serve as hosts for the widely predominant Leptospira interrogans serovar Icterohaemorrhagiae, found worldwide. Several studies have shown the importance of other reservoirs, such as mice or hedgehogs, which harbor other leptospires' serovars. Nevertheless, our knowledge of circulating Leptospira spp. in reservoirs other than rats remains limited. In this context, we proposed an eco-health approach to assess the health hazard associated with leptospires in urban green spaces, where contacts between human/small mammals and domestic animals are likely. We studied the prevalence, the diversity of circulating strains, and epidemiology of pathogenic Leptospira species in small terrestrial mammal communities (rodents and shrews), between 2020-2022, in two parks in Lyon metropolis, France. Our study showed a significant carriage of Leptospira spp. in small terrestrial mammals in these parks and unveiled a global prevalence rate of 11.4%. Significant variations of prevalence were observed among the small mammal species (from 0 to 26.1%), with Rattus norvegicus exhibiting the highest infection levels (26.1%). We also observed strong spatio-temporal variations in Leptospira spp. circulation in its reservoirs. Prevalence seems to be higher in the peri-urban park and in autumn in 2021 and 2022. This is potentially due to differences in landscape, abiotic conditions and small mammal communities' composition. Our study suggests an important public health relevance of rats and in a lesser extent of other rodents (Apodemus spp., Clethrionomys glareolus and Mus musculus) as reservoirs of L. interrogans, with rodent species carrying specific serogroups/serovars. We also emphasize the potential hazard associated between the shrew Crocidura russula and L. kirschneri. Altogether, these results improve our knowledge about the prevalence of leptospirosis in an urban environment, which is an essential prerequisite for the implementation of prevention of associated risks.

Abstract Background Coevolution between pathogens and their hosts decreases host morbidity and mortality. Bats host and can tolerate viruses which can be lethal to other vertebrate orders, including humans. Bat adaptations to infection include localized immune response, early pathogen sensing, high interferon expression without pathogen stimulation, and regulated inflammatory response. The immune reaction is costly, and bats suppress high-cost metabolism during torpor. In the temperate zone, bats hibernate in winter, utilizing a specific behavioural adaptation to survive detrimental environmental conditions and lack of energy resources. Hibernation torpor involves major physiological changes that pose an additional challenge to bat-pathogen coexistence. Here, we compared bat cellular reaction to viral challenge under conditions simulating hibernation, evaluating the changes between torpor and euthermia. Results We infected the olfactory nerve-derived cell culture of Myotis myotis with an endemic bat pathogen, European bat lyssavirus 1 (EBLV-1). After infection, the bat cells were cultivated at two different temperatures, 37 °C and 5 °C, to examine the cell response during conditions simulating euthermia and torpor, respectively. The mRNA isolated from the cells was sequenced and analysed for differential gene expression attributable to the temperature and/or infection treatment. In conditions simulating euthermia, infected bat cells produce an excess signalling by multitude of pathways involved in apoptosis and immune regulation influencing proliferation of regulatory cell types which can, in synergy with other produced cytokines, contribute to viral tolerance. We found no up- or down-regulated genes expressed in infected cells cultivated at conditions simulating torpor compared to non-infected cells cultivated under the same conditions. When studying the reaction of uninfected cells to the temperature treatment, bat cells show an increased production of heat shock proteins (HSPs) with chaperone activity, improving the bat’s ability to repair molecular structures damaged due to the stress related to the temperature change. Conclusions The lack of bat cell reaction to infection in conditions simulating hibernation may contribute to the virus tolerance or persistence in bats. Together with the cell damage repair mechanisms induced in response to hibernation, the immune regulation may promote bats’ ability to act as reservoirs of zoonotic viruses such as lyssaviruses.

Leptospirosis is a bacterial zoonotic disease. Humans and dogs are susceptible hosts, with similar clinical manifestations ranging from a febrile phase to multiple organ dysfunction. The incidence of leptospirosis in mainland France is relatively high, at about 1 case per 100,000 inhabitants, but our knowledge of the strains circulating in humans and dogs remains limited. We studied the polymorphism of the lfb1 gene sequences in an exhaustive database, to facilitate the identification of Leptospira strains. We identified 46 species-groups (SG) encompassing the eight pathogenic species of Leptospira. We sequenced the lfb1 gene amplification products from 170 biological samples collected from 2019 to 2021: 110 from humans and 60 from dogs. Epidemiological data, including vaccination status in dogs, were also collected. Three Leptospira species displaying considerable diversity were identified: L. interrogans, with eight lfb1 species-groups (including five new lfb1 species-groups) in humans and dogs; L. kirschneri, with two lfb1 species-groups in humans and dogs; and L. borgpetersenii, with one lfb1 species-group in humans only. The lfb1 species-group L. interrogans SG1, corresponding to serovar Icterohaemorrhagiae or Copenhageni, was frequently retrieved from both humans and dogs (n=67/110; 60.9% and n=59/60; 98.3% respectively). A high proportion of the affected dogs developed the disease despite vaccination (n=30/60; 50%). Genotyping with the polymorphic lfb1 gene is both robust and simple. This approach provided the first global picture of the Leptospira strains responsible for acute infections in mainland France, based on biological samples but without the need for culture. Identification of the Leptospira strains circulating and their changes over time will facilitate more precise epidemiological monitoring of susceptible and reservoir species. It should also facilitate the monitoring of environmental contamination, making it possible to implement preventive measures and to reduce the burden of this disease.

Rabies is an acute and lethal encephalomyelitis caused by lyssaviruses, among which rabies virus (RABV) is the most prevalent and important for public health. Although preventable through the post-exposure administration of rabies vaccine and immunoglobulins (RIGs), the disease is almost invariably fatal since the onset of clinical signs. Two human neutralizing monoclonal antibodies (mAbs), RVC20 and RVC58, have been shown to be effective in treating symptomatic rabies. To better understand how these mAbs work, we conducted structural modeling and in vitro assays to analyze their mechanisms of action, including their ability to mediate Fc-dependent effector functions. Our results indicate that both RVC20 and RVC58 recognize and lock the RABV-G protein in its pre-fusion conformation. RVC58 was shown to neutralize more potently the extra-cellular virus, while RVC20 mainly acts by reducing viral spreading from infected cells. Importantly, RVC20 was more effective in promoting effector functions compared to RVC58 and 17C7-RAB1 mAbs, the latter of which is approved for human rabies post-exposure treatment. These results provide valuable insights into the multiple mechanisms of action of RVC20 and RVC58 mAbs, offering relevant information for the development of these mAbs as treatment for human rabies.

Abstract Bioluminescence resonance energy transfer (BRET) saturation is a method of studying protein–protein interaction (PPI) upon quantification of the dependence of the BRET signal on the acceptor/donor (A:D) expression ratio. In this study, using the very bright Nluc/YFP BRET pair acquired respectively with microplate reader and automated confocal microscopy, we significantly improved BRET saturation assay by extending A:D expression detection range and normalizing A:D expression with a new BRET-free probe. We next found that upon using variable instead of fixed amount of donor molecules co-expressed with increasing acceptor concentrations, BRET saturation assay robustness can be further improved when studying cytosolic protein, although the relative amounts of dimers (BRETmax) and the relative dimer affinity (BRET50) remain similar. Altogether, we show that our method can be applied to many PPI networks, involving the NF-κB pathway, high-affinity nanobody, rabies virus-host interactions, mTOR complex and JAK/STAT signaling. Altogether our approach paves the way for robust PPI validation and characterization in living cells.

[This corrects the article DOI: 10.1371/journal.pntd.0009449.].

Here the authors generate a measles virus-based vaccine expressing SARSCoV-2 spike protein and show immunogenicity and protection in mice and hamsters, including neutralization of circulating variants of concerns in vitro.

BackgroundMost emerging pathogens are zoonoses and have a wildlife origin. Anthropization and disruption of ecosystems favor the crossing of inter-species barriers. We hypothesize that the marginalized population of undocumented goldminers in the Amazon is at risk of acquiring zoonoses.MethodA multicentric cross-sectional study included consenting gold-mining adult workers in 2019. A clinical examination recorded dermatological signs of leishmaniosis and past history of yellow fever vaccination. Biological tests were performed for yellow fever, Q fever and leptospirosis serologies. Additional blood samples from a previous study in 2015 were also tested for leptospirosis.ResultsIn 2019, 380 individuals were included in the study, along with 407 samples from the 2015 biological collection. The seroprevalence of leptospirosis was 31.0% [95%CI = 26.4-35.5] in 2015 and 28.1% [23.5-32.7] in 2019. The seroprevalence of Q fever was 2.9% [1.2-4.6]. The majority of participants reported being vaccinated against yellow fever (93.6%) and 97.9% had seroneutralizing antibodies. The prevalence of suspected active mucocutaneous leishmaniasis was 2.4% [0.8-3.9].DiscussionThese unique data shed new light on the transmission cycles of zoonoses still poorly understood in the region. They support the existence of a wild cycle of leptospirosis but not of Q fever. Leishmaniasis prevalence was high because of life conditions and tree felling. High yellow fever vaccine coverage was reassuring in this endemic area. In the era of global health, special attention must be paid to these vulnerable populations in direct contact with the tropical ecosystem and away from the health care system.

Summary: Biobanking infrastructures, which are crucial for responding early to new viral outbreaks, share pathogen genetic resources in an affordable, safe, and impartial manner and can provide expertise to address access and benefit-sharing issues. The European Virus Archive has had a crucial role in the global response to the COVID-19 pandemic by distributing EU-subsidised (free of charge) viral resources to users worldwide, providing non-monetary benefit sharing, implementing access and benefit-sharing compliance, and raising access and benefit-sharing awareness among members and users. All currently available SARS-CoV-2 material in the European Virus Archive catalogue, including variants of concern, are not access and benefit-sharing cases per se, but multilateral benefit-sharing has nevertheless occurred. We propose and discuss how a multilateral system enabling access and benefit-sharing from pathogen genetic resources, based on the European Virus Archive operational model, could help bridge the discrepancies between the current bilateral legal framework for pathogen genetic resources and actual pandemic response practices.

Despite recent therapeutic advances, ischemic stroke is still a leading cause of death and disability. There is renewed attention on peripheral inflammatory signaling as a way of modulating the post-ischemic neuro-inflammatory process. The immune-brain crosstalk has long been the focus for understanding the mechanisms of sickness behavior, which is an adaptive autonomic, neuroendocrine, and behavioral response to a peripheral inflammation. It is mediated by humoral and neural pathways that mainly involve the circumventricular organs and vagal nerve, respectively. In this review we address the question of how sepsis and stroke can dysregulate this adaptive response, notably by impairing the central integration of peripheral signaling, but also by efferent control of the immune response. We highlight the potential role of gut–brain and brain–spleen signaling in stroke.

Rabies is a zoonotic disease caused by rabies virus (RABV). As rabies advances, patients develop a variety of severe neurological symptoms that inevitably lead to coma and death. Unlike other neurotropic viruses that can induce symptoms of a similar range, RABV-infected post-mortem brains do not show significant signs of inflammation nor the structural damages on neurons. This suggests that the observed neurological symptoms possibly originate from dysfunctions of neurons. However, many aspects of neuronal dysfunctions in the context of RABV infection are only partially understood, and therefore require further investigation. In this study, we used differentiated neurons to characterize the RABV-induced transcriptomic changes at the early time-points of infection. We found that the genes modulated in response to the infection are particularly involved in cell cycle, gene expression, immune response, and neuronal function-associated processes. Comparing a wild-type RABV to a mutant virus harboring altered matrix proteins, we found that the RABV matrix protein plays an important role in the early down-regulation of host genes, of which a significant number is involved in neuronal functions. The kinetics of differentially expressed genes (DEGs) are also different between the wild type and mutant virus datasets. The number of modulated genes remained constant upon wild-type RABV infection up to 24 h post-infection, but dramatically increased in the mutant condition. This result suggests that the intact viral matrix protein is important to control the size of host gene modulation. We then examined the signaling pathways previously studied in relation to the innate immune responses against RABV, and found that these pathways contribute to the changes in neuronal function-associated processes. We further examined a set of regulated genes that could impact neuronal functions collectively, and demonstrated in calcium imaging that indeed the spontaneous activity of neurons is influenced by RABV infection. Overall, our findings suggest that neuronal function-associated genes are modulated by RABV early on, potentially through the viral matrix protein-interacting signaling molecules and their downstream pathways.

Rabies is caused by neurotropic rabies virus (RABV), contributing to 60,000 human deaths annually. Even though rabies leads to major public health concerns worldwide, we still do not fully understand factors determining RABV tropism and why glial cells are unable to clear RABV from the infected brain. Here, we compare susceptibilities and immune responses of CNS cell types to infection with two RABV strains, Tha and its attenuated variant Th2P-4M, mutated on phospho- (P-protein) and matrix protein (M-protein). We demonstrate that RABV replicates in human stem cell-derived neurons and astrocytes but fails to infect human iPSC-derived microglia. Additionally, we observed major differences in transcription profiles and quantification of intracellular protein levels between antiviral immune responses mediated by neurons, astrocytes (IFNB1, CCL5, CXCL10, IL1B, IL6, and LIF), and microglia (CCL5, CXCL10, ISG15, MX1, and IL6) upon Tha infection. We also show that P- and M-proteins of Tha mediate evasion of NF-κB- and JAK-STAT-controlled antiviral host responses in neuronal cell types in contrast to glial cells, potentially explaining the strong neuron-specific tropism of RABV. Further, Tha-infected astrocytes and microglia protect neurons from Tha infection via a filtrable and transferable agent. Overall, our study provides novel insights into RABV tropism, showing the interest in studying the interplay of CNS cell types during RABV infection.

Rabies virus (RABV), the causative agent for rabies disease is still presenting a major public health concern causing approximately 60,000 deaths annually. This neurotropic virus (genus Lyssavirus, family Rhabdoviridae) induces an acute and almost always fatal form of encephalomyelitis in humans. Despite the lethal consequences associated with clinical symptoms of rabies, RABV limits neuro-inflammation without causing major histopathological lesions in humans. Nevertheless, information about the mechanisms of infection and cellular response in the central nervous system (CNS) remain scarce. Here, we investigated the expression of inflammatory genes involved in immune response to RABV (dog-adapted strain Tha) in mice, the most common animal model used to study rabies. To better elucidate the pathophysiological mechanisms during natural RABV infection, we compared the inflammatory transcriptome profile observed at the late stage of infection in the mouse brain (cortex and brain stem/cerebellum) with the ortholog gene expression in post-mortem brain biopsies of rabid patients. Our data indicate that the inflammatory response associated with rabies is more pronounced in the murine brain compared to the human brain. In contrast to murine transcription profiles, we identified CXC motif chemokine ligand 16 (CXCL16) as the only significant differentially expressed gene in post-mortem brains of rabid patients. This result was confirmed in vitro, in which Tha suppressed interferon alpha (IFN-α)-induced CXCL16 expression in human CNS cell lines but induced CXCL16 expression in IFN-α-stimulated murine astrocytes. We hypothesize that RABV-induced modulation of the CXCL16 pathway in the brain possibly affects neurotransmission, natural killer (NK) and T cell recruitment and activation. Overall, we show species-specific differences in the inflammatory response of the brain, highlighted the importance of understanding the potential limitations of extrapolating data from animal models to humans.

The environment of the central nervous system (CNS) represents a double-edged sword in the context of viral infections. On the one hand, the infectious route for viral pathogens is restricted via neuroprotective barriers; on the other hand, viruses benefit from the immunologically quiescent neural environment after CNS entry. Both the herpes simplex virus (HSV) and the rabies virus (RABV) bypass the neuroprotective blood–brain barrier (BBB) and successfully enter the CNS parenchyma via nerve endings. Despite the differences in the molecular nature of both viruses, each virus uses retrograde transport along peripheral nerves to reach the human CNS. Once inside the CNS parenchyma, HSV infection results in severe acute inflammation, necrosis, and hemorrhaging, while RABV preserves the intact neuronal network by inhibiting apoptosis and limiting inflammation. During RABV neuroinvasion, surveilling glial cells fail to generate a sufficient type I interferon (IFN) response, enabling RABV to replicate undetected, ultimately leading to its fatal outcome. To date, we do not fully understand the molecular mechanisms underlying the activation or suppression of the host inflammatory responses of surveilling glial cells, which present important pathways shaping viral pathogenesis and clinical outcome in viral encephalitis. Here, we compare the innate immune responses of glial cells in RABV- and HSV-infected CNS, highlighting different viral strategies of neuroprotection or Neuroinflamm. in the context of viral encephalitis.

• mAbs are suitable to replace rabies immunoglobulins in rabies prophylaxis. • mAb cocktails are recommended to limit the risk of failure due limited coverage and viral escape. • Two mAbs-based products are already licensed in India to be used in PEP. • One approach with a mAb cocktail described the cure of symptomatic rabies in mice. Rabies is a severe viral infection that causes an acute encephalomyelitis, which presents a case fatality of nearly 100% after the manifestation of neurological clinical signs. Rabies can be efficiently prevented with post-exposure prophylaxis (PEP), composed of vaccines and anti-rabies immunoglobulins (RIGs); however, no treatment exists for symptomatic rabies. The PEP protocol faces access and implementation obstacles in resource-limited settings, which could be partially overcome by substituting RIGs for monoclonal antibodies (mAbs). mAbs offer lower production costs, consistent supply availability, long-term storage/stability, and an improved safety profile. Here we summarize the key features of the different available mAbs against rabies, focusing on their application in PEP and highlighting their potential in a novel therapeutic approach. [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.

Rodents are recognized as the main reservoirs of Leptospira spp. Rats, in particular, serve as hosts for the widely predominant Leptospira interrogans serovar Icterohaemorrhagiae, found worldwide. Several studies have shown the importance of other reservoirs, such as mice or hedgehogs, which harbor other leptospires' serovars. Nevertheless, our knowledge of circulating Leptospira spp. in reservoirs other than rats remains limited. In this context, we proposed an eco-health approach to assess the health hazard associated with leptospires in urban green spaces, where contacts between human/small mammals and domestic animals are likely. We studied the prevalence, the diversity of circulating strains, and epidemiology of pathogenic Leptospira species in small terrestrial mammal communities (rodents and shrews), between 2020-2022, in two parks in Lyon metropolis, France. Our study showed a significant carriage of Leptospira spp. in small terrestrial mammals in these parks and unveiled a global prevalence rate of 11.4%. Significant variations of prevalence were observed among the small mammal species (from 0 to 26.1%), with Rattus norvegicus exhibiting the highest infection levels (26.1%). We also observed strong spatio-temporal variations in Leptospira spp. circulation in its reservoirs. Prevalence seems to be higher in the peri-urban park and in autumn in 2021 and 2022. This is potentially due to differences in landscape, abiotic conditions and small mammal communities' composition. Our study suggests an important public health relevance of rats and in a lesser extent of other rodents (Apodemus spp., Clethrionomys glareolus and Mus musculus) as reservoirs of L. interrogans, with rodent species carrying specific serogroups/serovars. We also emphasize the potential hazard associated between the shrew Crocidura russula and L. kirschneri. Altogether, these results improve our knowledge about the prevalence of leptospirosis in an urban environment, which is an essential prerequisite for the implementation of prevention of associated risks., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Garcia-Lopez et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Pathogenic Leptospira can cause leptospirosis: a widespread, potentially fatal bacterial zoonosis whose risk is mediated by the soil and water features, animal host distributions, meaning the local ecosystem. When human cases of leptospirosis occur, it is challenging to track down their source because ecosystem-level epidemiological knowledge on Leptospira is needed. Between 2016 and 2019 in a focal riparian ecosystem, the human population experienced an outbreak and successive cases of leptospirosis attributable to L. kirschneri and L. interrogans . The epidemiological investigation was carried out using the One Health approach, as described in international health guidelines. As a first step in this process, we investigated leptospiral carriage in the main animal hosts found in the region. We sampled 143 nutrias, 17 muskrats, and 10 Norway rats using convenient trapping. DNA was extracted from their kidneys, lungs, and urine and subjected to real-time PCR (RT-PCR) targeting the Leptospira 16S rDNA and lfb1 genes. In the farms along the river's stretch of interest, we sampled serum from 439 cattle and used a microscopic agglutination test to detect the presence of antibodies against Leptospira . Urine samples were concomitantly obtained from 145 cattle and were used in two analyses: RT-PCR targeting the Leptospira 16S rDNA gene and Leptospira culturing. We found th, wt rodents were the most likely source of the L. interrogans behind the human cases. The cattle tested negative for Leptospira DNA but positive for antibodies against the serogroups implicated in the human cases. We failed to identify the potential source of the L. kirschneri responsible for several human cases of leptospirosis. Our results call for further clarification of the Leptospira maintenance community, which may comprise known maintenance hosts, such as rodents, as well as taxa not commonly considered to be maintenance hosts but that can still spread Leptospira . The resulting research network will collaboratively conduct future eco-epidemiological surveys to illuminate the leptospirosis risks faced by humans and animals within ecosystems., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors. Published by Elsevier B.V.)

Leptospirosis is a globally distributed zoonotic disease. The standard serological test, known as Microscopic Agglutination Test (MAT), requires the use of live Leptospira strains. To enhance its sensitivity and specificity, the usage of locally circulating strains is recommended. However, to date, no local strain is available from Austria. This study aimed to isolate circulating Leptospira strains from cattle in Austria to enhance the performances of the routine serological test for both humans and animals. We used a statistical approach combined with a comprehensive literature search to profile cattle with greater risk of leptospirosis infection and implemented a targeted sampling between November 2021 and October 2022. Urine and/or kidney tissue were sampled from 410 cattle considered at higher risk of infection. Samples were inoculated into EMJH-STAFF culture media within 2-6 h and a real-time PCR targeting the lipL32 gene was used to confirm the presence/absence of pathogenic Leptospira in each sample. Isolates were further characterised by core genome multilocus sequence typing (cgMLST). Nine out of 429 samples tested positive by PCR, from which three isolates were successfully cultured and identified as Leptospira borgpetersenii serogroup Sejroe serovar Hardjobovis, cgMLST cluster 40. This is the first report on the isolation and genotyping of local zoonotic Leptospira in Austria, which holds the potential for a significant improvement in diagnostic performance in the country. Although the local strain was identified as a cattle-adapted serovar, it possesses significant zoonotic implications. Furthermore, this study contributes to a better understanding of the epidemiology of leptospirosis in Europe., (© 2024. The Author(s).)

Leptospira santarosai serovar Guaricura is adapted to bovines and is associated with a chronic disease that causes reproductive disorders, leading to important economic losses. Here, we present the draft genomes of three L. santarosai strains isolated from vaginal fluid and one from the urine of cows with reproductive disorders from Brazil., Competing Interests: The authors declare no conflict of interest.

Leptospirosis is a bacterial zoonotic disease. Humans and dogs are susceptible hosts, with similar clinical manifestations ranging from a febrile phase to multiple organ dysfunction. The incidence of leptospirosis in mainland France is relatively high, at about 1 case per 100,000 inhabitants, but our knowledge of the strains circulating in humans and dogs remains limited. We studied the polymorphism of the lfb1 gene sequences in an exhaustive database, to facilitate the identification of Leptospira strains. We identified 46 species-groups (SG) encompassing the eight pathogenic species of Leptospira . We sequenced the lfb1 gene amplification products from 170 biological samples collected from 2019 to 2021: 110 from humans and 60 from dogs. Epidemiological data, including vaccination status in dogs, were also collected. Three Leptospira species displaying considerable diversity were identified: L. interrogans , with eight lfb1 species-groups (including five new lfb1 species-groups) in humans and dogs; L. kirschneri , with two lfb1 species-groups in humans and dogs; and L. borgpetersenii , with one lfb1 species-group in humans only. The lfb1 species-group L. interrogans SG1, corresponding to serovar Icterohaemorrhagiae or Copenhageni, was frequently retrieved from both humans and dogs ( n= 67/110; 60.9% and n= 59/60; 98.3% respectively). A high proportion of the affected dogs developed the disease despite vaccination ( n= 30/60; 50%). Genotyping with the polymorphic lfb1 gene is both robust and simple. This approach provided the first global picture of the Leptospira strains responsible for acute infections in mainland France, based on biological samples but without the need for culture. Identification of the Leptospira strains circulating and their changes over time will facilitate more precise epidemiological monitoring of susceptible and reservoir species. It should also facilitate the monitoring of environmental contamination, making it possible to implement preventive measures and to reduce the burden of this disease., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could appear to influence the work reported in this paper., (Copyright © 2023 Garcia-Lopez, Lorioux, Soares, Trombert-Paolantoni, Harran, Ayral, Picardeau, Djelouadji and Bourhy.)

Background: Most emerging pathogens are zoonoses and have a wildlife origin. Anthropization and disruption of ecosystems favor the crossing of inter-species barriers. We hypothesize that the marginalized population of undocumented goldminers in the Amazon is at risk of acquiring zoonoses., Method: A multicentric cross-sectional study included consenting gold-mining adult workers in 2019. A clinical examination recorded dermatological signs of leishmaniosis and past history of yellow fever vaccination. Biological tests were performed for yellow fever, Q fever and leptospirosis serologies. Additional blood samples from a previous study in 2015 were also tested for leptospirosis., Results: In 2019, 380 individuals were included in the study, along with 407 samples from the 2015 biological collection. The seroprevalence of leptospirosis was 31.0% [95%CI = 26.4-35.5] in 2015 and 28.1% [23.5-32.7] in 2019. The seroprevalence of Q fever was 2.9% [1.2-4.6]. The majority of participants reported being vaccinated against yellow fever (93.6%) and 97.9% had seroneutralizing antibodies. The prevalence of suspected active mucocutaneous leishmaniasis was 2.4% [0.8-3.9]., Discussion: These unique data shed new light on the transmission cycles of zoonoses still poorly understood in the region. They support the existence of a wild cycle of leptospirosis but not of Q fever. Leishmaniasis prevalence was high because of life conditions and tree felling. High yellow fever vaccine coverage was reassuring in this endemic area. In the era of global health, special attention must be paid to these vulnerable populations in direct contact with the tropical ecosystem and away from the health care system., Competing Interests: The authors have declared that no competing interests exist.