Hantavirus infections in Europe and their impact on public health

Evaluating climate-dependent distribution of orthohantaviruses with monitoring wild rodents: One Health Perspective†

Orthohantaviruses, cause hemorrhagic fever with renal syndrome, nephropathia epidemica, and hantavirus pulmonary syndrome, are major public health problems all over the world. Wild rodent surveillance for orthohantaviruses is of great importance for the preparedness against these human infections and the prediction of possible outbreak regions. Thus, we aimed to screen orthohantaviruses in wild rodents in Southern Anatolia, where the area has some of the glacial period refugia in the Mediterranean Basin, and interpret their current epidemiology with climatic biovariables in comparison with previously positive regions.We trapped muroid rodents between 2015 and 2017, and screened for orthohantaviruses. Then, we evaluated the relationship between orthohantavirus infections and bioclimatic variables. In spite of the long-term and seasonal sampling, we found no evidence for Orthohantavirus infections. The probable absence of orthohantaviruses in the sampling area was further evaluated from the climatic perspective, and results led us suggest that Orthohantavirus epidemiology might be relatively dependent on precipitation levels in driest and warmest quarters, and temperature fluctuations.These initial data might provide necessary perspective on wild rodent surveillance for orthohantaviruses in other regions, and help to collect lacking data for a such habitat suitability study in a bigger scale in the future.

Ingrained: Rice farming and the risk of zoonotic spillover, examples from Cambodia

Rice cultivation in Southeast Asia is a One Health interface intersecting human, animal, and environmental health. This complexity creates a potential for zoonotic transmission between diverse reservoirs. Bats harbor viruses like Nipah; mosquitoes transmit arboviruses; rodents spread hantaviruses. Domestic animals- including pigs with influenza and dogs with rabies and aquatic animals can also transmit pathogens. Climate change and urbanization may further disrupt rice agro-ecologies. This paper explores animal viral reservoirs, vectors, and historical practices associated with risk in rice farming. Climate and land use changes could enhance spillover. Solutions are proposed, including surveillance of animals, vectors, water, and air to detect threats before major outbreaks, such as improved biosecurity, hygiene, and livestock vaccinations. Ecological viral surveillance and agricultural interventions together can reduce zoonotic transmission from rice farming.

A Comprehensive Analysis of Renal and Endothelium Dysfunction Markers Fourteen Years after Hemorrhagic Fever with Renal Syndrome Contraction

While the pathology of acute hemorrhagic fever with renal syndrome (HFRS) has been widely researched, details on the chronic HFRS sequelae remain mainly unexplored. In this study, we analyzed the clinical and laboratory characteristics of 30 convalescent HFRS patients 14 years after the disease contraction, mainly emphasizing several endothelial dysfunction parameters. Convalescent HFRS patients exhibited significantly higher serum levels of erythrocyte sedimentation rate, von Willebrand factor, uric acid, C-reactive protein and immunoglobulin A when compared to healthy individuals. Furthermore, 24 h urine analyses revealed significantly lower sodium and potassium urine levels, as well as significantly higher proteinuria, microalbumin levels and β2-microglobulin levels when compared to healthy individuals. First morning urine analysis revealed significantly higher levels of hematuria in convalescent HFRS patients. None of the additional analyzed endothelium dysfunction markers were significantly different in post-HFRS patients and healthy individuals, including serum and urine P-selectin, E-selectin, soluble intercellular adhesion molecule 1, vascular intercellular adhesion molecule 1 (sVCAM-1) and vascular endothelial growth factor (VEGF). However, binary logistic regression revealed a weak association of serum sVCAM-1 and urine VEGF levels with HFRS contraction. Generally, our findings suggest mild chronic inflammation and renal dysfunction levels in convalescent HFRS patients 14 years after the disease contraction.

Epidemiological and clinical characteristics of death from hemorrhagic fever with renal syndrome: a meta-analysis

Introduction

Hemorrhagic fever with renal syndrome (HFRS) is an acute infectious disease comprising five stages: fever, hypotension, oliguria, diuresis (polyuria), and convalescence. Increased vascular permeability, coagulopathy, and renal injury are typical clinical features of HFRS, which has a case fatality rate of 1-15%. Despite this, a comprehensive meta-analyses of the clinical characteristics of patients who died from HFRS is lacking.

Methods

Eleven Chinese- and English-language research databases were searched, including the China National Knowledge Infrastructure Database, Wanfang Database, SinoMed, VIP Database, PubMed, Embase, Scopus, Cochrane Library, Web of Science, Proquest, and Ovid, up to October 5, 2023. The search focused on clinical features of patients who died from HFRS. The extracted data were analyzed using STATA 14.0.

Results

A total of 37 articles on 140,295 patients with laboratory-confirmed HFRS were included. Categorizing patients into those who died and those who survived, it was found that patients who died were older and more likely to smoke, have hypertension, and have diabetes. Significant differences were also observed in the clinical manifestations of multiple organ dysfunction syndrome, shock, occurrence of overlapping disease courses, cerebral edema, cerebral hemorrhage, toxic encephalopathy, convulsions, arrhythmias, heart failure, dyspnea, acute respiratory distress syndrome, pulmonary infection, liver damage, gastrointestinal bleeding, acute kidney injury, and urine protein levels. Compared to patients who survived, those who died were more likely to demonstrate elevated leukocyte count; decreased platelet count; increased lactate dehydrogenase, alanine aminotransferase, and aspartate aminotransferase levels; prolonged activated partial thromboplastin time and prothrombin time; and low albumin and chloride levels and were more likely to use continuous renal therapy. Interestingly, patients who died received less dialysis and had shorter average length of hospital stay than those who survived.

Conclusion

Older patients and those with histories of smoking, hypertension, diabetes, central nervous system damage, heart damage, liver damage, kidney damage, or multiorgan dysfunction were at a high risk of death. The results can be used to assess patients' clinical presentations and assist with prognostication.Systematic review registration:https://www.crd.york.ac.uk/prospero/, (CRD42023454553).

Nephropathia Epidemica Caused by Puumala Virus in Bank Voles, Scania, Southern Sweden

In 2018, a local case of nephropathia epidemica was reported in Scania, southern Sweden, more than 500 km south of the previously known presence of human hantavirus infections in Sweden. Another case emerged in the same area in 2020. To investigate the zoonotic origin of those cases, we trapped rodents in Ballingslöv, Norra Sandby, and Sörby in southern Sweden during 2020‒2021. We found Puumala virus (PUUV) in lung tissues from 9 of 74 Myodes glareolus bank voles by screening tissues using a hantavirus pan-large segment reverse transcription PCR. Genetic analysis revealed that the PUUV strains were distinct from those found in northern Sweden and Denmark and belonged to the Finnish PUUV lineage. Our findings suggest an introduction of PUUV from Finland or Karelia, causing the human PUUV infections in Scania. This discovery emphasizes the need to understand the evolution, cross-species transmission, and disease outcomes of this newly found PUUV variant.

Structural characterization of the oligomerization of full-length Hantaan virus polymerase into symmetric dimers and hexamers

Hantaan virus is a dangerous human pathogen whose segmented negative-stranded RNA genome is replicated and transcribed by a virally-encoded multi-functional polymerase. Here we describe the complete cryo-electron microscopy structure of Hantaan virus polymerase in several oligomeric forms. Apo polymerase protomers can adopt two drastically different conformations, which assemble into two distinct symmetric homodimers, that can themselves gather to form hexamers. Polymerase dimerization induces the stabilization of most polymerase domains, including the C-terminal domain that contributes the most to dimer's interface, along with a lariat region that participates to the polymerase steadying. Binding to viral RNA induces significant conformational changes resulting in symmetric oligomer disruption and polymerase activation, suggesting the possible involvement of apo multimers as protecting systems that would stabilize the otherwise flexible C-terminal domains. Overall, these results provide insights into the multimerization capability of Hantavirus polymerase and may help to define antiviral compounds to counteract these life-threatening viruses.

Epidemiological characteristics and prediction model construction of hemorrhagic fever with renal syndrome in Quzhou City, China, 2005-2022

Background

Hemorrhagic fever with renal syndrome (HFRS) is one of the 10 major infectious diseases that jeopardize human health and is distributed in more than 30 countries around the world. China is the country with the highest number of reported HFRS cases worldwide, accounting for 90% of global cases. The incidence level of HFRS in Quzhou is at the forefront of Zhejiang Province, and there is no specific treatment for it yet. Therefore, it is crucial to grasp the epidemiological characteristics of HFRS in Quzhou and establish a prediction model for HFRS to lay the foundation for early warning of HFRS.

Methods

Descriptive epidemiological methods were used to analyze the epidemic characteristics of HFRS, the incidence map was drawn by ArcGIS software, the Seasonal AutoRegressive Integrated Moving Average (SARIMA) and Prophet model were established by R software. Then, root mean square error (RMSE) and mean absolute error (MAE) were used to evaluate the fitting and prediction performances of the model.

Results

A total of 843 HFRS cases were reported in Quzhou City from 2005 to 2022, with the highest annual incidence rate in 2007 (3.93/100,000) and the lowest in 2022 (1.05/100,000) (P trend<0.001). The incidence is distributed in a seasonal double-peak distribution, with the first peak from October to January and the second peak from May to July. The incidence rate in males (2.87/100,000) was significantly higher than in females (1.32/100,000). Farmers had the highest number of cases, accounting for 79.95% of the total number of cases. The incidence is high in the northwest of Quzhou City, with cases concentrated on cultivated land and artificial land. The RMSE and MAE values of the Prophet model are smaller than those of the SARIMA (1,0,1) (2,1,0)12 model.

Conclusion

From 2005 to 2022, the incidence of HFRS in Quzhou City showed an overall downward trend, but the epidemic in high-incidence areas was still serious. In the future, the dynamics of HFRS outbreaks and host animal surveillance should be continuously strengthened in combination with the Prophet model. During the peak season, HFRS vaccination and health education are promoted with farmers as the key groups.

High-resolution phylogeographical surveillance of Hantaan orthohantavirus using rapid amplicon-based Flongle sequencing, Republic of Korea

Orthohantaviruses, etiological agents of hemorrhagic fever with renal syndrome (HFRS) and hantavirus cardiopulmonary syndrome, pose a critical public health threat worldwide. Hantaan orthohantavirus (HTNV) outbreaks are particularly endemic in Gyeonggi Province in northern area of the Republic of Korea (ROK). Small mammals were collected from three regions in the Gyeonggi Province during 2017 and 2018. Serological and molecular prevalence of HTNV was 25/201 (12.4%) and 10/25 (40%), respectively. A novel nanopore-based diagnostic assay using a cost-efficient Flongle chip was developed to rapidly and sensitively detect HTNV infection in rodent specimens within 3 h. A rapid phylogeographical surveillance of HTNV at high-resolution phylogeny was established using the amplicon-based Flongle sequencing. In total, seven whole-genome sequences of HTNV were newly obtained from wild rodents collected in Paju-si (Gaekhyeon-ri) and Yeoncheon-gun (Hyeonga-ri and Wangnim-ri), Gyeonggi Province. Phylogenetic analyses revealed well-supported evolutionary divergence and genetic diversity, enhancing the resolution of the phylogeographic map of orthohantaviruses in the ROK. Incongruences in phylogenetic patterns were identified among HTNV tripartite genomes, suggesting differential evolution for each segment. These findings provide crucial insights into on-site diagnostics, genome-based surveillance, and the evolutionary dynamics of orthohantaviruses to mitigate hantaviral outbreaks in HFRS-endemic areas in the ROK.

RNA virus diversity in rodents

Many zoonotic disease emergencies are associated with RNA viruses in rodents that substantially impact public health. With the widespread application of meta-genomics and meta-transcriptomics for virus discovery over the last decade, viral sequences deposited in public databases have expanded rapidly, and the number of novel viruses discovered in rodents has increased. As important reservoirs of zoonotic viruses, rodents have attracted increasing attention for the risk of potential spillover of rodent-borne viruses. However, knowledge of rodent viral diversity and the major factors contributing to the risk of zoonotic epidemic outbreaks remains limited. Therefore, this study analyzes the diversity and composition of rodent RNA viruses using virus records from the Database of Rodent-associated Viruses (DRodVir/ZOVER), which covers the published literatures and records in GenBank database, reviews the main rodent RNA virus-induced human infectious diseases, and discusses potential challenges in this field.

HantaNet: A New MicrobeTrace Application for Hantavirus Classification, Genomic Surveillance, Epidemiology and Outbreak Investigations

Hantaviruses zoonotically infect humans worldwide with pathogenic consequences and are mainly spread by rodents that shed aerosolized virus particles in urine and feces. Bioinformatics methods for hantavirus diagnostics, genomic surveillance and epidemiology are currently lacking a comprehensive approach for data sharing, integration, visualization, analytics and reporting. With the possibility of hantavirus cases going undetected and spreading over international borders, a significant reporting delay can miss linked transmission events and impedes timely, targeted public health interventions. To overcome these challenges, we built HantaNet, a standalone visualization engine for hantavirus genomes that facilitates viral surveillance and classification for early outbreak detection and response. HantaNet is powered by MicrobeTrace, a browser-based multitool originally developed at the Centers for Disease Control and Prevention (CDC) to visualize HIV clusters and transmission networks. HantaNet integrates coding gene sequences and standardized metadata from hantavirus reference genomes into three separate gene modules for dashboard visualization of phylogenetic trees, viral strain clusters for classification, epidemiological networks and spatiotemporal analysis. We used 85 hantavirus reference datasets from GenBank to validate HantaNet as a classification and enhanced visualization tool, and as a public repository to download standardized sequence data and metadata for building analytic datasets. HantaNet is a model on how to deploy MicrobeTrace-specific tools to advance pathogen surveillance, epidemiology and public health globally.

Hantavirus: an overview and advancements in therapeutic approaches for infection

Hantaviruses are a significant and emerging global public health threat, impacting more than 200,000 individuals worldwide each year. The single-stranded RNA viruses belong to the Hantaviridae family and are responsible for causing two acute febrile diseases in humans: Hantavirus pulmonary syndrome (HPS) and hemorrhagic fever with renal syndrome (HFRS). Currently, there are no licensed treatments or vaccines available globally for HTNV infection. Various candidate drugs have shown efficacy in increasing survival rates during the early stages of HTNV infection. Some of these drugs include lactoferrin, ribavirin, ETAR, favipiravir and vandetanib. Immunotherapy utilizing neutralizing antibodies (NAbs) generated from Hantavirus convalescent patients show efficacy against HTNV. Monoclonal antibodies such as MIB22 and JL16 have demonstrated effectiveness in protecting against HTNV infection. The development of vaccines and antivirals, used independently and/or in combination, is critical for elucidating hantaviral infections and the impact on public health. RNA interference (RNAi) arised as an emerging antiviral therapy, is a highly specific degrades RNA, with post-transcriptional mechanism using eukaryotic cells platform. That has demonstrated efficacy against a wide range of viruses, both in vitro and in vivo. Recent antiviral methods involve using small interfering RNA (siRNA) and other, immune-based therapies to target specific gene segments (S, M, or L) of the Hantavirus. This therapeutic approach enhances viral RNA clearance through the RNA interference process in Vero E6 cells or human lung microvascular endothelial cells. However, the use of siRNAs faces challenges due to their low biological stability and limited in vivo targeting ability. Despite their successful inhibition of Hantavirus replication in host cells, their antiviral efficacy may be hindered. In the current review, we focus on advances in therapeutic strategies, as antiviral medications, immune-based therapies and vaccine candidates aimed at enhancing the body's ability to control the progression of Hantavirus infections, with the potential to reduce the risk of severe disease.

Potential clinical biomarkers in monitoring the severity of Hantaan virus infection

Hantavirus, which causes hemorrhagic fever with renal syndrome (HFRS) is almost prevalent worldwide. While Hantaan virus (HTNV) causes the most severe form of HFRS with typical clinical manifestations of thrombocytopenia, increased vascular permeability, and acute kidney injury. Although the knowledge of the pathogenesis of HFRS is still limited, immune dysfunction and pathological damage caused by disorders of immune regulation are proposed to play a vital role in the development of the disorder, and the endothelium is considered to be the primary target of hantaviruses. Here, we reviewed the production and function of multiple molecules, mainly focusing on their role in immune response, endothelium, vascular permeability regulation, and platelet and coagulation activation which are closely related to the pathogenesis of HTNV infection. meanwhile, the relationship between these molecules and characteristics of HTNV infection including the hospital duration, immune dysfunction, thrombocytopenia, leukocytosis, and acute kidney injury are also presented, to provide a novel insight into the potential role of these molecules as monitoring markers for HTNV infection.

Predictive value of CD4+CD8+ double positive T cells for the severity of hemorrhagic fever with renal syndrome

PURPOSES

We aimed to investigate the levels of CD4+CD8+ double positive (DP) T cells in patients with various severities of hemorrhagic fever with renal syndrome (HFRS), and the predictive capacity of DP T cells for the severity of this disorder.

METHODS

The levels of DP T cells in 213 patients and 48 healthy donors were measured by flow cytometry, as were the levels of CD4+ T cells, CD8+ T cells, B lymphocytes, and natural killer (NK) cells. In each type of HFRS patient, we tested the basic clinical reference values for leukocytes, platelets, creatinine (Cr), uric acid (UA), and urea, and the values for activated partial thromboplastin time, prothrombin time, and fibrinogen, using conventional methods. The colloidal gold method was used to measure HFRS antibody levels in the patients.

RESULTS

The frequency of DP T cells increased with disease severity and peaked in patients with critical disease. Furthermore, the level of DP T cells proportionally correlated with the levels of Cr, UA, and urea in the serum. In contrast, there was an inverse correlation between DP T cells and platelets. Interestingly, the pattern of change in DP T cell frequency was similar to those of CD8+ T cells, B cells, and NK cells, but an inverse tendency was observed for CD4+ T cells. DP T cells demonstrated significant predictive value for the severity of HFRS.

CONCLUSIONS

The level of DP T cells is associated with HFRS severity, suggesting that it may be a potent indicator for the course of this disorder.

Hantavirus infections in the South‑Eastern European countries: A study of two cases and literature review

Hantavirus infection is a rare zoonosis in South-Eastern Europe. Depending on the serotype involved, the virus can cause hemorrhagic fever with renal syndrome which is also known as endemic nephropathy, and cardiopulmonary syndrome. Prompt diagnosis of the disease is essential for reducing the risk of severe manifestations and complications like chronic kidney disease, secondary hypertension or even death because there is no specific treatment or vaccine approved. The present study reported two cases of hemorrhagic fever with renal syndrome diagnosed in the Department of Nephrology of The Fundeni Clinical Institute (Romania). In both patients, kidney needle biopsy played a major role in establishing the diagnosis. The difficulties encountered in diagnosing this disease were also emphasized, taking into consideration the rarity of this infection in South-Eastern Europe. The key literature data on the epidemiology, pathogenesis and management of this infection were further reviewed.

A Development of Rapid Whole-Genome Sequencing of Seoul orthohantavirus Using a Portable One-Step Amplicon-Based High Accuracy Nanopore System

Whole-genome sequencing provides a robust platform for investigating the epidemiology and transmission of emerging viruses. Oxford Nanopore Technologies allows for real-time viral sequencing on a local laptop system for point-of-care testing. Seoul orthohantavirus (Seoul virus, SEOV), harbored by Rattus norvegicus and R. rattus, causes mild hemorrhagic fever with renal syndrome and poses an important threat to public health worldwide. We evaluated the deployable MinION system to obtain high-fidelity entire-length sequences of SEOV for the genome identification of accurate infectious sources and their genetic diversity. One-step amplicon-based nanopore sequencing was performed from SEOV 80-39 specimens with different viral copy numbers and SEOV-positive wild rats. The KU-ONT-SEOV-consensus module was developed to analyze SEOV genomic sequences generated from the nanopore system. Using amplicon-based nanopore sequencing and the KU-ONT-consensus pipeline, we demonstrated novel molecular diagnostics for acquiring full-length SEOV genome sequences, with sufficient read depth in less than 6 h. The consensus sequence accuracy of the SEOV small, medium, and large genomes showed 99.75-100% (for SEOV 80-39 isolate) and 99.62-99.89% (for SEOV-positive rats) identities. This study provides useful insights into on-site diagnostics based on nanopore technology and the genome epidemiology of orthohantaviruses for a quicker response to hantaviral outbreaks.

Structures of active Hantaan virus polymerase uncover the mechanisms of Hantaviridae genome replication

Hantaviruses are causing life-threatening zoonotic infections in humans. Their tripartite negative-stranded RNA genome is replicated by the multi-functional viral RNA-dependent RNA-polymerase. Here we describe the structure of the Hantaan virus polymerase core and establish conditions for in vitro replication activity. The apo structure adopts an inactive conformation that involves substantial folding rearrangement of polymerase motifs. Binding of the 5' viral RNA promoter triggers Hantaan virus polymerase reorganization and activation. It induces the recruitment of the 3' viral RNA towards the polymerase active site for prime-and-realign initiation. The elongation structure reveals the formation of a template/product duplex in the active site cavity concomitant with polymerase core widening and the opening of a 3' viral RNA secondary binding site. Altogether, these elements reveal the molecular specificities of Hantaviridae polymerase structure and uncover the mechanisms underlying replication. They provide a solid framework for future development of antivirals against this group of emerging pathogens.

Correlation analysis of CD8+ cell overexpression and prognosis of hemorrhagic fever with renal syndrome-a case-control study

Background

Hemorrhagic fever with Renal Syndrome (HFRS) is an infectious disease caused by Hantavirus with fever, hemorrhage and acute kidney injury (AKI) as clinical characteristics. The research on the etiology and pathogenesis of diseases has become a focus of attention. However, there are few related medical studies in children with HFRS. The prognosis of the children with HFRS remains to be explored.

Objectives

We explored risk factors in children with HFRS and summarize sensitive indicators that are conducive to the prognosis of the disease.

Methods

We designed a case-control study and recruited 182 HFRS pediatric patients (2014.01-2022.08). They were divided into two groups according to the severity of disease, including the control group(158 cases with mild and moderate subgroup)and the observation group (24 cases with severe and critical subgroup). Risk factors influencing prognosis were analyzed by binary logistic regression. The cutoff value, sensitivity and specificity of the risk factors prediction were calculated by receiver operating characteristic (ROC) and Yoden index.

Results

Lymphocyte subsets characteristics analysis showed that in observation group the indexes were decreased in lymphocyte, T lymphocytes (CD3)⁺, helper/inducible T lymphocytes (CD4⁺)/inhibition/cytotoxic T cells (CD8⁺), B lymphocytes (CD19⁺); and the elevated index was CD8⁺, the difference were all significant between two groups. (P < 0.05). With death as the primary outcome, it was found that the serum CD8⁺ (odds ratio [OR] 2.91, 95% confidence interval [CI] 1.65, 4.00; P < 0.01) was risk factor and significantly associated with mortality. The cutoff value of the serum CD8⁺ was 845 × 10⁶/L, the sensitivity and specificity were 78.5%, 85.4%. With complications as the secondary outcomes, the serum CD8⁺ (OR 2.69, 95% CI 1.15, 4.88; P < 0.01) was found to be risk factors. The cutoff of the serum CD8⁺ was 690 × 10⁶/L, the sensitivity and specificity were 69.3%, 75.1% respectively.

Conclusion

CD8⁺ may be significantly correlated with the severity and prognosis of HFRS in children.

The impact of wildlife and environmental factors on hantavirus infection in the host and its translation into human risk

Identifying factors that drive infection dynamics in reservoir host populations is essential in understanding human risk from wildlife-originated zoonoses. We studied zoonotic Puumala orthohantavirus (PUUV) in the host, the bank vole (Myodes glareolus), populations in relation to the host population, rodent and predator community and environment-related factors and whether these processes are translated into human infection incidence. We used 5-year rodent trapping and bank vole PUUV serology data collected from 30 sites located in 24 municipalities in Finland. We found that PUUV seroprevalence in the host was negatively associated with the abundance of red foxes, but this process did not translate into human disease incidence, which showed no association with PUUV seroprevalence. The abundance of weasels, the proportion of juvenile bank voles in the host populations and rodent species diversity were negatively associated with the abundance index of PUUV positive bank voles, which, in turn, showed a positive association with human disease incidence. Our results suggest certain predators, a high proportion of young bank vole individuals, and a diverse rodent community, may reduce PUUV risk for humans through their negative impacts on the abundance of infected bank voles.

Puumala Hantavirus Infections Show Extensive Variation in Clinical Outcome

The clinical outcome of Puumala hantavirus (PUUV) infection shows extensive variation, ranging from inapparent subclinical infection (70-80%) to severe hemorrhagic fever with renal syndrome (HFRS), with about 0.1% of cases being fatal. Most hospitalized patients experience acute kidney injury (AKI), histologically known as acute hemorrhagic tubulointerstitial nephritis. Why this variation? There is no evidence that there would be more virulent and less virulent variants infecting humans, although this has not been extensively studied. Individuals with the human leukocyte antigen (HLA) alleles B*08 and DRB1*0301 are likely to have a severe form of the PUUV infection, and those with B*27 are likely to have a benign clinical course. Other genetic factors, related to the tumor necrosis factor (TNF) gene and the C4A component of the complement system, may be involved. Various autoimmune phenomena and Epstein-Barr virus infection are associated with PUUV infection, but hantavirus-neutralizing antibodies are not associated with lower disease severity in PUUV HFRS. Wide individual differences occur in ocular and central nervous system (CNS) manifestations and in the long-term consequences of nephropathia epidemica (NE). Numerous biomarkers have been detected, and some are clinically used to assess and predict the severity of PUUV infection. A new addition is the plasma glucose concentration associated with the severity of both capillary leakage, thrombocytopenia, inflammation, and AKI in PUUV infection. Our question, "Why this variation?" remains largely unanswered.

Hemorrhagic Fever with Renal Syndrome in Asia: History, Pathogenesis, Diagnosis, Treatment, and Prevention

Hemorrhagic Fever with Renal Syndrome (HFRS) is the most frequently diagnosed zoonosis in Asia. This zoonotic infection is the result of exposure to the virus-contaminated aerosols. Orthohantavirus infection may cause Hemorrhagic Fever with Renal Syndrome (HRFS), a disease that is characterized by acute kidney injury and increased vascular permeability. Several species of orthohantaviruses were identified as causing infection, where Hantaan, Puumala, and Seoul viruses are most common. Orthohantaviruses are endemic to several Asian countries, such as China, South Korea, and Japan. Along with those countries, HFRS tops the list of zoonotic infections in the Far Eastern Federal District of Russia. Recently, orthohantavirus circulation was demonstrated in small mammals in Thailand and India, where orthohantavirus was not believed to be endemic. In this review, we summarized the current data on orthohantaviruses in Asia. We gave the synopsis of the history and diversity of orthohantaviruses in Asia. We also described the clinical presentation and current understanding of the pathogenesis of orthohantavirus infection. Additionally, conventional and novel approaches for preventing and treating orthohantavirus infection are discussed.

Orthohantaviruses in Reservoir and Atypical Hosts in the Czech Republic: Spillover Infection and Indication of Virus-Specific Tissue Tropism

Orthohantaviruses (genus Orthohantavirus) are a diverse group of viruses that are closely associated with their natural hosts (rodents, shrews, and moles). Several orthohantaviruses cause severe disease in humans. Central and western Europe are areas with emerging orthohantavirus occurrences. In our study, several orthohantaviruses, including the pathogenic Kurkino virus (KURV), were detected in their natural hosts trapped at several study sites in the Czech Republic. KURV was detected mainly in its typical host, the striped field mouse (Apodemus agrarius). Nevertheless, spillover infections were also detected in wood mice (Apodemus sylvaticus) and common voles (Microtus arvalis). Similarly, Tula virus (TULV) was found primarily in common voles, and events of spillover to rodents of other host species, including Apodemus spp., were recorded. In addition, unlike most previous studies, different tissues were sampled and compared to assess their suitability for orthohantavirus screening and possible tissue tropism. Our data suggest possible virus-specific tissue tropism in rodent hosts. TULV was most commonly detected in the lung tissue, whereas KURV was more common in the liver, spleen, and brain. Moreover, Seewis and Asikkala viruses were detected in randomly found common shrews (Sorex araneus). In conclusion, we have demonstrated the presence of human-pathogenic KURV and the potentially pathogenic TULV in their typical hosts as well as their spillover to atypical host species belonging to another family. Furthermore, we suggest the possibility of virus-specific tissue tropism of orthohantaviruses in their natural hosts. IMPORTANCE Orthohantaviruses (genus Orthohantavirus, family Hantaviridae) are a diverse group of globally distributed viruses that are closely associated with their natural hosts. Some orthohantaviruses are capable of infecting humans and causing severe disease. Orthohantaviruses are considered emerging pathogens due to their ever-increasing diversity and increasing numbers of disease cases. We report the detection of four different orthohantaviruses in rodents and shrews in the Czech Republic. Most viruses were found in their typical hosts, Kurkino virus (KURV) in striped field mice (Apodemus agrarius), Tula virus (TULV) in common voles (Microtus arvalis), and Seewis virus in common shrews (Sorex araneus). Nevertheless, spillover infections of atypical host species were also recorded for KURV, TULV, and another shrew-borne orthohantavirus, Asikkala virus. In addition, indications of virus-specific patterns of tissue tropism were observed. Our results highlight the circulation of several orthohantaviruses, including KURV, which is pathogenic to humans, among rodents and shrews in the Czech Republic.

Trends and focuses of hantavirus researches: a global bibliometric analysis and visualization from 1980 to 2020

Background

There have been worldwide changes in the researches on hantaviruses in the past several decades. Nevertheless, there are few bibliometric analysis studies this field. We aim to evaluate and visualize the research focuses and trends of this field using a bibliometric analysis way to help understand the developmet and future hotspots of this field.

Material and methods

Publications related to hantavirus studies were culled from the Web of Science Core Collection to generate trend analysis. The articles and reviews were re-extracted and Countries, institutions, authors, references and keywords in this field were visually analyzed by using VOSviewer and CiteSpace.

Results

A total of 4408 studies were included and the number of publications regarding hantaviruses significantly increased yearly. Three thousand seven hundred sixteen research articles and reviews were retrieved to generate bibliometric analysis. These studies mainly come from 125 countries led by USA and China and 3312 institutions led by the University of Helsinki. Twelve thousand five hundred twenty nine authors were identified and Vaheri A were the most influential author. Journal of Virology was the journal with the most studies and citations. After analysis, Hemorrhagic fever with renal syndrome, Hantavirus cardiopulmonary syndrome, nephropathia epidemica and related genotypes, clinical symptoms and rodents were the most common keywords and developing areas.

Conclusion

Research on hantavirus is flourishing. Cooperation among different countries and institutions in this field must be strengthened in the future. The ecology and clinical symptoms of new genotypes, the vaccine development and factors that affect host population distribution and density are current and developing areas of study.

A Portable Diagnostic Assay, Genetic Diversity, and Isolation of Seoul Virus from Rattus norvegicus Collected in Gangwon Province, Republic of Korea

Seoul virus (SEOV), an etiological agent for hemorrhagic fever with renal syndrome, poses a significant public health threat worldwide. This study evaluated the feasibility of a mobile Biomeme platform for facilitating rapid decision making of SEOV infection. A total of 27 Rattus norvegicus were collected from Seoul Metropolitan City and Gangwon Province in Republic of Korea (ROK), during 2016-2020. The serological and molecular prevalence of SEOV was 5/27 (18.5%) and 2/27 (7.4%), respectively. SEOV RNA was detected in multiple tissues of rodents using the Biomeme device, with differences in Ct values ranging from 0.6 to 2.1 cycles compared to a laboratory benchtop system. Using amplicon-based next-generation sequencing, whole-genome sequences of SEOV were acquired from lung tissues of Rn18-1 and Rn19-5 collected in Gangwon Province. Phylogenetic analysis showed a phylogeographical diversity of rat-borne orthohantavirus collected in Gangwon Province. We report a novel isolate of SEOV Rn19-5 from Gangwon Province. Our findings demonstrated that the Biomeme system can be applied for the molecular diagnosis of SEOV comparably to the laboratory-based platform. Whole-genome sequencing of SEOV revealed the phylogeographical diversity of orthohantavirus in the ROK. This study provides important insights into the field-deployable diagnostic assays and genetic diversity of orthohantaviruses for the rapid response to hantaviral outbreaks in the ROK.

Adenosine Deaminase is a Potential Molecular Marker for Diagnosis and Prognosis of Haemorrhagic Fever with Renal Syndrome

Objective

Haemorrhagic fever with renal syndrome (HFRS) is a serious zoonotic disease which seriously endangers physical health and mainly occurs in China. To date, there is still a lack of early and novel biomarkers to detect the severity of disease and prognosis of HFRS. This study was aimed to examine the value of the serum Adenosine deaminase (ADA) concentrations in the patients with HFRS.

Methods

The clinical and laboratory data of 124 adult patients with HFRS and 131 patients with similar clinical symptoms to HFRS were analyzed. A receiver operating characteristic (ROC) curve was used to analyze the diagnostic value of ADA in HFRS.

Results

The ADA levels in the serum of HFRS patients were significantly higher than those in control patients (P < 0.001), and ADA has a strong positive correlation with HFRS (r = 0.785, P < 0.001). The optimal cut-off value of ADA for diagnosis of HFRS was 18 U/L and the area under the curve (AUC) was 0.953 (95% CI: 0.925, 0.981). The sensitivity was 84.8%, the specificity was 93.1%, the positive predictive value was 92.2%, the negative predictive value was 86.5% and the Youden index was 77.9%. Serum ADA levels in patients with HFRS tended to decrease at discharge compared with those at admission.

Conclusion

ADA could be a potential molecular marker for diagnosis and prognosis of HFRS patients.

Infectious Diseases Associated with Hydrometeorological Hazards in Europe: Disaster Risk Reduction in the Context of the Climate Crisis and the Ongoing COVID-19 Pandemic

Hydrometeorological hazards comprise a wide range of events, mainly floods, storms, droughts, and temperature extremes. Floods account for the majority of the related disasters in both developed and developing countries. Flooding alters the natural balance of the environment and frequently establish a favorable habitat for pathogens and vectors to thrive. Diseases caused by pathogens that require vehicle transmission from host to host (waterborne) or a host/vector as part of their life cycle (vector-borne) are those most likely to be affected by flooding. Considering the most notable recent destructive floods events of July 2021 that affected several Central Europe countries, we conducted a systematic literature review in order to identify documented sporadic cases and outbreaks of infectious diseases in humans in Europe, where hydrometeorological hazards, mainly floods, were thought to have been involved. The occurrence of water-, rodent-, and vector-borne diseases in several European countries is highlighted, as flooding and the harsh post-flood conditions favor their emergence and transmission. In this context, strategies for prevention and management of infectious disease outbreaks in flood-prone and flood-affected areas are also proposed and comprise pre- and post-flood prevention measures, pre- and post-outbreak prevention measures, as well as mitigation actions when an infectious disease outbreak finally occurs. Emphasis is also placed on the collision of floods, flood-related infectious disease outbreaks, and the evolving COVID-19 pandemic, which may result in unprecedented multi-hazard conditions and requires a multi-hazard approach for the effective disaster management and risk reduction.

Cluster of human Puumala orthohantavirus infections due to indoor exposure?-An interdisciplinary outbreak investigation

Puumala orthohantavirus (PUUV) is the most important hantavirus species in Europe, causing the majority of human hantavirus disease cases. In central and western Europe, the occurrence of human infections is mainly driven by bank vole population dynamics influenced by beech mast. In Germany, hantavirus epidemic years are observed in 2- to 5-year intervals. Many of the human infections are recorded in summer and early autumn, coinciding with peaks in bank vole populations. Here, we describe a molecular epidemiological investigation in a small company with eight employees of whom five contracted hantavirus infections in late 2017. Standardized interviews with employees were conducted to assess the circumstances under which the disease cluster occurred, how the employees were exposed and which counteractive measures were taken. Initially, two employees were admitted to hospital and serologically diagnosed with hantavirus infection. Subsequently, further investigations were conducted. By means of a self-administered questionnaire, three additional symptomatic cases could be identified. The hospital patients' sera were investigated and revealed in one patient a partial PUUV L segment sequence, which was identical to PUUV sequences from several bank voles collected in close proximity to company buildings. This investigation highlights the importance of a One Health approach that combines efforts from human and veterinary medicine, ecology and public health to reveal the origin of hantavirus disease clusters.

Molecular Characterisation and Phylogeny of Tula Virus in Kazakhstan

Orthohantaviruses are zoonotic pathogens that play a significant role in public health. These viruses can cause haemorrhagic fever with renal syndrome in Eurasia. In the Republic of Kazakhstan, the first human cases were registered in the year 2000 in the West Kazakhstan region. Small mammals can be reservoirs of orthohantaviruses. Previous studies showed orthohantavirus antigens in wild-living small mammals in four districts of West Kazakhstan. Clinical studies suggested that there might be further regions with human orthohantavirus infections in Kazakhstan, but genetic data of orthohantaviruses in natural foci are limited. The aim of this study was to investigate small mammals for the presence of orthohantaviruses by molecular biological methods and to provide a phylogenetic characterization of the circulating strains in Kazakhstan. Small mammals were trapped at 19 sites in West Kazakhstan, four in Almaty region and at seven sites around Almaty city during all seasons of 2018 and 2019. Lung tissues of small mammals were homogenized and RNA was extracted. Orthohantavirus RT-PCR assays were applied for detection of partial S and L segment sequences. Results were compared to published fragments. In total, 621 small mammals from 11 species were analysed. Among the collected small mammals, 2.4% tested positive for orthohantavirus RNA, one sample from West Kazakhstan and 14 samples from Almaty region. None of the rodents caught in Almaty city were infected. Sequencing parts of the small (S) and large (L) segments specified Tula virus (TULV) in these two regions. Our data show that geographical distribution of TULV is more extended as previously thought. The detected sequences were found to be split in two distinct genetic clusters of TULV in West Kazakhstan and Almaty region. TULV was detected in the common vole (Microtus arvalis) and for the first time in two individuals of the forest dormouse (Dryomys nitedula), interpreted as a spill-over infection in Kazakhstan.

Abdominal CT findings in Puumala hantavirus-infected patients

BACKGROUND

Previous clinical studies have reported abdominal findings on ultrasonography or MRI in Puumala hantavirus-infected patients.

PURPOSE

To determine if abdominal computed tomography (CT) can lead to a diagnosis of Puumala virus infection in the presence of a suggestive clinical picture.

MATERIAL AND METHODS

CT findings were studied retrospectively in 30 patients who presented to the emergency department of two (Belgian) hospitals with serologically confirmed Puumala hantavirus infection.

RESULTS

The most frequent finding was perirenal fascial thickening (90%), followed by perirenal fat stranding (87%). Retroperitoneal fat stranding was found in 19 patients (64%) in the perivesical spaces along the fascia of the external iliac vessels with or without involvement of the presacral fat. Half of the patients had pelvic ascites, and pleural fluid was found in 7 of them. The right and left mean pole-to-pole kidney's lengths were respectively 125.7 mm and 127.8 mm in 28 patients.

CONCLUSION

Retroperitoneal fat stranding, perirenal fascial thickening and/or perirenal fat stranding were found in most patients with acute Puumala virus infection who have undergone CT. Although nonspecific, these findings may help to suggest Puumala hantavirus infection in the right clinical settings.

Long-Term Consequences of Puumala Hantavirus Infection

Several viral infections are associated with acute and long-term complications. During the past two years, there have been many reports on post-infectious symptoms of the patients suffering from COVID-19 disease. Serious complications occasionally occur during the acute phase of Puumala orthohantavirus caused nephropathia epidemica. Severe long-term consequences are rare. Fatigue for several weeks is quite common. Hormonal insufficiencies should be excluded if the patient does not recover normally.

Hemorrhagic Fever with Renal Syndrome: Literature Review, Epidemiology, Clinical Picture and Pathogenesis

Hantaviruses can cause two types of infections in humans: hemorrhagic fever with renal syndrome (HFRS) and hantavirus pulmonary syndrome. The old world hantaviruses, primarily Hantaan virus (HTNV), responsible for causing HFRS occurs endemically in Asia and Europe. Apodernus agraricus, a striped field mouse, is being considered as main host reservoir for HTNV. Infection in humans is typically accidental and occurs when virus-containing rodent excretions such as urine, feces, or saliva are aerosolized. The major clinical manifestations includes increased vascular permeability causing vascular leakage, acute kidney injury and coagulation abnormalities. The case fatality rate of HFRS varies around 5.0 - 10.0% depending on the causative viral agent. The direct effects of viral infection on endothelial cells, as well as the immunological response to the viral infection, have been suggested to play a key role in the pathogenesis of HFRS. This article summarizes the current knowledge of HFRS epidemiology in Korea and around the globe, etiology, host transmission, clinical presentation, pathogenesis, diagnostic techniques, treatment, and prevention.

Climate change accelerates winter transmission of a zoonotic pathogen

Many zoonotic diseases are weather sensitive, raising concern how their distribution and outbreaks will be affected by climate change. At northern high latitudes, the effect of global warming on especially winter conditions is strong. By using long term monitoring data (1980-1986 and 2003-2013) from Northern Europe on temperature, precipitation, an endemic zoonotic pathogen (Puumala orthohantavirus, PUUV) and its reservoir host (the bank vole, Myodes glareolus), we show that early winters have become increasingly wet, with a knock-on effect on pathogen transmission in its reservoir host population. Further, our study is the first to show a climate change effect on an endemic northern zoonosis, that is not induced by increased host abundance or distribution, demonstrating that climate change can also alter transmission intensity within host populations. Our results suggest that rainy early winters accelerate PUUV transmission in bank voles in winter, likely increasing the human zoonotic risk in the North.

Hantavirus Induced Kidney Disease

Hantavirus induced hemorrhagic fever with renal syndrome (HFRS) is an emerging viral zoonosis affecting up to 200,000 humans annually worldwide. This review article is focused on recent advances in the mechanism, epidemiology, diagnosis, and treatment of hantavirus induced HFRS. The importance of interactions between viral and host factors in the design of therapeutic strategies is discussed. Hantavirus induced HFRS is characterized by thrombocytopenia and proteinuria of varying severities. The mechanism of kidney injury appears immunopathological with characteristic deterioration of endothelial cell function and compromised barrier functions of the vasculature. Although multidisciplinary research efforts have provided insights about the loss of cellular contact in the endothelium leading to increased permeability, the details of the molecular mechanisms remain poorly understood. The epidemiology of hantavirus induced renal failure is associated with viral species and the geographical location of the natural host of the virus. The development of vaccine and antiviral therapeutics is necessary to avoid potentially severe outbreaks of this zoonotic illness in the future. The recent groundbreaking approach to the SARS-CoV-2 mRNA vaccine has revolutionized the general field of vaccinology and has provided new directions for the use of this promising platform for widespread vaccine development, including the development of hantavirus mRNA vaccine. The combinational therapies specifically targeted to inhibit hantavirus replication and vascular permeability in infected patients will likely improve the disease outcome.

Epidemiological study on the incidence of haemorrhagic fever with renal syndrome in five Western Balkan countries for a 10-year period: 2006-2015

BACKGROUND

Large-scale epidemics of haemorrhagic fever with renal syndrome (HFRS) have been reported mostly in Asia and Europe, with around 100,000 people affected each year. In the Southeast Europe, Balkan region, HFRS is endemic disease with approximately 100 cases per year. Our aim was to describe epidemiological characteristics of HFRS in five Western Balkan (WB) countries and to describe correlation between HFRS incidence and major meteorological event that hit the area in May 2014.

METHODS

National surveillance data of HFRS from Bosnia and Herzegovina, Croatia, Montenegro, North Macedonia and Serbia obtained from 1 January 2006 to 31 December 2015 were collected and analysed.

RESULTS

In a 10-year period, a total of 1,065 HFRS patients were reported in five WB countries. Cumulative incidence rate ranged from 0.05 to 15.80 per 100.000 inhabitants (in North Macedonia and Montenegro respectively). Increasing number of HFRS cases was reported with a peak incidence in three specific years (2008, 2012, and 2014). Average incidence for the entire area was higher in males than females (5.63 and 1.90 per 100.000 inhabitants respectively). Summer was the season with the highest number of cases and an average incidence rate of 1.74/100.000 inhabitants across 10-year period. Haemorrhagic fever with renal syndrome incidence was significantly increased (7.91/100.000 inhabitants) in 2014, when a few months earlier, severe floods affected several WB countries. A strong significant negative correlation (r = -.84, p < .01) between the monthly incidence of HFRS and the number of months after May's floods was demonstrated for the total area of WB.

CONCLUSION

Our findings demonstrate that the HFRS incidence had similar distribution (general, age, sex and seasonality) across majority of the included countries. Summer was the season with the highest recorded incidence. Common epidemic years were detected in all observed countries as well as a negative correlation between the monthly incidence of HFRS and the number of months after May's cyclone.

Severity Biomarkers in Puumala Hantavirus Infection

Annually, over 10,000 cases of hemorrhagic fever with renal syndrome (HFRS) are diagnosed in Europe. Puumala hantavirus (PUUV) causes most of the European HFRS cases. PUUV causes usually a relatively mild disease, which is rarely fatal. However, the severity of the infection varies greatly, and factors affecting the severity are mostly unrevealed. Host genes are known to have an effect. The typical clinical features in PUUV infection include acute kidney injury, thrombocytopenia, and increased vascular permeability. The primary target of hantavirus is the endothelium of the vessels of different organs. Although PUUV does not cause direct cytopathology of the endothelial cells, remarkable changes in both the barrier function of the endothelium and the function of the infected endothelial cells occur. Host immune or inflammatory mechanisms are probably important in the development of the capillary leakage. Several immunoinflammatory biomarkers have been studied in the context of assessing the severity of HFRS caused by PUUV. Most of them are not used in clinical practice, but the increasing knowledge about the biomarkers has elucidated the pathogenesis of PUUV infection.

Coumarin Derivative N6 as a Novel anti-hantavirus Infection Agent Targeting AKT

Hantaviruses are globally emerging zoonotic viruses that can cause hemorrhagic fever with renal syndrome (HFRS) in Asia and Europe, which is primarily caused by Hantaan virus (HTNV) infection, results in profound morbidity and mortality. However, no specific treatment is available for this disease. Coumarin derivatives have been reported as antiviral molecules, while studies about the bioactivity of coumarin derivatives against HTNV infection are limited. To study the potential antiviral activity of coumarin derivatives, 126 coumarin derivatives are synthesized, and their inhibitory activity against HTNV is analyzed in vitro. Among these compounds, N6 inhibits HTNV with relatively high selectivity index at 10.9, and the viral titer of HTNV is reduced significantly after 5, 10, and 20 μM N6 treatments. Furthermore, the administration of N6 at the early stage of HTNV infection can inhibit the replication and production of infectious HTNV in host cell, this therapeutic efficacy is confirmed in HTNV-infected newborn mice at the early stage of infection. The molecular docking results show that N6 forms interactions with the key amino acid residues at its active site, and reveals several molecular interactions responsible for the observed affinity, and the treatment of N6 can inhibit the expression of p (Ser473)Akt and HTNV nucleocapsid protein significantly. As such, these observations demonstrate that coumarin derivative N6 might be used as a potential agent against HTNV infection.

Dissection of the NKG2C NK cell response against Puumala Orthohantavirus

BACKGROUND

Infections with the Puumala orthohantavirus (PUUV) in humans may cause hemorrhagic fever with renal syndrome (HFRS), known as nephropathia epidemica (NE), which is associated with acute renal failure in severe cases. In response to PUUV-infections, a subset of potent antiviral NKG2C+ NK cells expand, whose role in virus defence and pathogenesis of NE is unclear. NKG2C+ NK cell proliferation is mediated by binding of NKG2C/CD94 to HLA-E on infected cells. The proliferation and activation of NKG2C+ NK cells via the NKG2C/HLA-E axis is affected by different NKG2C (NKG2Cwt/del) and HLA-E (HLA-E*0101/0103) alleles, which naturally occur in the human host. Homozygous (NKG2Cdel/del) and heterozygous (NKG2Cwt/del) deletions of the NKG2C receptor results in an impaired NKG2C/CD94 mediated proliferation and activation of NKG2C+ cells. We therefore analyzed the PUUV-mediated NKG2C+ NK cell responses and the impact of different NKG2C and HLA-E alleles in NE patients.

METHODOLOGY/PRINCIPAL FINDINGS

NKG2C+ NK cell expansion and effector functions in PUUV-infected cells were investigated using flow cytometry and it was shown that PUUV-infected endothelial cells led to a NKG2C/CD94 mediated NKG2C+ NK cell activation and expansion, dependent on the HLA-G-mediated upregulation of HLA-E. Furthermore, the NKG2Cdel and HLA-E*0101/0103 alleles were determined in 130 NE patients and 130 matched controls, and it was shown that in NE patients the NKG2Cwt/del allele was significantly overrepresented, compared to the NKG2Cwt/wt variant (p = 0.01). In addition, in vitro analysis revealed that NKG2Cwt/del NK cells exhibited on overall a lower proliferation (p = 0.002) and lower IFNγ expression (p = 0.004) than NKG2Cwt/wt NK cells.

CONCLUSIONS/SIGNIFICANCE

Our results corroborate the substantial impact of the NKG2C/HLA-E axis on PUUV-specific NK cell responses. A weak NKG2C+ NK cell response, as reflected by NKG2Cwt/del variant, may be associated with a higher risk for a severe hantavirus infections.

Occupational Hantavirus Infections in Agricultural and Forestry Workers: A Systematic Review and Metanalysis

Hantaviruses are zoonotic pathogens that can cause serious human disorders, including hemorrhagic fever with renal syndrome and hantavirus cardiopulmonary syndrome. As the main risk factor for human infections is the interaction with rodents, occupational groups such as farmers and forestry workers are reportedly at high risk, but no summary evidence has been collected to date. Therefore, we searched two different databases (PubMed and EMBASE), focusing on studies reporting the prevalence of hantaviruses in farmers and forestry workers. Data were extracted using a standardized assessment form, and results of such analyses were systematically reported, summarized and compared. We identified a total of 42 articles, including a total of 28 estimates on farmers, and 22 on forestry workers, with a total workforce of 15,043 cases (821 positive cases, 5.5%). A pooled seroprevalence of 3.7% (95% confidence interval [95% CI] 2.2–6.2) was identified in farmers, compared to 3.8% (95% CI 2.6–5.7) in forestry workers. Compared to the reference population, an increased occurrence was reported for both occupational groups (odds ratio [OR] 1.875, 95% CI 1.438–2.445 and OR 2.892, 95% CI 2.079–4.023 for farmers and forestry workers, respectively). In summary, our analyses stress the actual occurrence of hantaviruses in selected occupational groups. Improved understanding of appropriate preventive measures, as well as further studies on hantavirus infection rates in reservoir host species (rodents, shrews, and bats) and virus transmission to humans, is needed to prevent future outbreaks.

Association between haemorrhagic fever with renal syndrome and cancers

OBJECTIVES

To investigate the risk of haematologic and solid organ malignancies in patients with haemorrhagic fever with renal syndrome (HFRS) compared with the general population.

METHODS

This propensity-score-matched cohort study was conducted using data collected from the Korean national health insurance service (NHIS) between January 2003 and December 2017. The HFRS cohort included 5888 newly diagnosed cases of HFRS, and 412,804 general participants from the NHIS database were included as the control cohort. The incidence rate of malignancies was assessed and compared between the HFRS and control cohorts.

RESULTS

There were 64 cases of haematologic malignancy in 236,286 person-years of observation, and 1245 cases of solid organ cancer in 209,333 person-years. The risks of haematologic malignancy and solid organ cancer were significantly higher in the HFRS cohort [adjusted hazards ratio (aHR) 4.10, 95% confidence interval (CI) 2.36-7.14] than the control cohort [aHR 2.97, 95% CI 2.60-3.38). In subgroup analysis, the HFRS cohort was associated with high hazard ratios for leukaemia and non-Hodgkin lymphoma. The HFRS cohort also had increased aHRs for all types of solid organ cancer.

CONCLUSIONS

Patients with HFRS are at increased risk of both haematologic and solid organ malignancies compared with the general population, and this increased proportionally over time. Careful monitoring for malignancy after the onset of HFRS may be necessary.

Puumala Virus Variants Circulating in Forests of Ardennes, France: Ten Years of Genetic Evolution

In Europe, Puumala virus (PUUV) transmitted by the bank vole (Myodes glareolus) is the causative agent of nephropathia epidemica (NE), a mild form of haemorrhagic fever with renal syndrome. In France, very little is known about the spatial and temporal variability of the virus circulating within bank vole populations. The present study involved monitoring of bank vole population dynamics and PUUV microdiversity over a ten-year period (2000–2009) in two forests of the Ardennes region: Elan and Croix-Scaille. Ardennes region is characterised by different environmental conditions associated with different NE epidemiology. Bank vole density and population parameters were estimated using the capture/marking/recapture method, and blood samples were collected to monitor the overall seroprevalence of PUUV in rodent populations. Phylogenetic analyses of fifty-five sequences were performed to illustrate the genetic diversity of PUUV variants between forests. The pattern of the two forests differed clearly. In the Elan forest, the rodent survival was higher, and this limited turn-over resulted in a lower seroprevalence and diversity of PUUV sequences than in the Croix-Scaille forest. Uncovering the links between host dynamics and virus microevolution is improving our understanding of PUUV distribution in rodents and the NE risk.

The surface glycoproteins of hantaviruses

Hantaviruses are rodent-borne viruses distributed worldwide, transmitted through the air and with the ability to spread from person to person. They maintain a non-symptomatic persistent infection in their rodent hosts, but their spillover to humans produces a renal or pulmonary syndrome associated with high fatality rates. Hantavirus particles are lipid-enveloped and display a characteristic surface lattice built up of tetragonal spikes composed of two glycoproteins, Gn and Gc. The pleomorphism of these particles has hindered cryo-EM efforts to obtain detailed structural information and only by using a combination of X-ray crystallography and cryo-electron tomography it was possible to build an atomic model of the surface lattice. Here we review these structural efforts and the unanticipated evolutionary relations between hantaviruses and alphaviruses highlighted by these studies.

Inhibition of interferon I induction by non-structural protein NSs of Puumala virus and other vole-associated orthohantaviruses: phenotypic plasticity of the protein and potential functional domains

The orthohantavirus Puumala virus (PUUV), which is transmitted by bank voles (Clethrionomys glareolus), and other vole-borne hantaviruses contain in their small (S) genome segment two overlapping open reading frames, coding for the nucleocapsid protein and the non-structural protein NSs, a putative type I interferon (IFN-I) antagonist. To investigate the role of NSs of PUUV and other orthohantaviruses, the expression pattern of recombinant NSs constructs and their ability to inhibit human IFN-I promoter activity were investigated. The NSs proteins of PUUV and related cricetid-borne orthohantaviruses showed strong inhibition of IFN-I promoter induction. We identified protein products originating from three and two methionine initiation codons in the NSs ORF of PUUV during transfection and infection, respectively. The three putative start codons are conserved in all PUUV strains analysed. Translation initiation at these start codons influenced the inhibitory activity of the NSs products, with the wild-type (wt) construct expressing two proteins starting at the first and second methionine and showing strong inhibition activity. Analysis of in vitro-generated variants and naturally occurring PUUV NSs proteins indicated that amino acid variation in the NSs protein is well tolerated, suggesting its phenotypic plasticity. The N-terminal 20-amino-acid region of the NSs protein was found to be associated with strong inhibition and to be highly vulnerable to amino acid exchanges and tag fusions. Infection studies using human, bank vole, and Vero E6 cells did not show obvious differences in the replication capacity of PUUV Sotkamo wt and a strain with a truncated NSs protein (NSs21Stop), showing that the lack of a full-length NSs might be compensated by its N-terminal peptide, as seen in transfection experiments. These results contribute to our understanding of virus-host interactions and highlight the importance of future innate immunity studies in reservoir hosts.

Epidemiological Characteristics and Regional Risk Prediction of Hemorrhagic Fever with Renal Syndrome in Shandong Province, China

BACKGROUND

Hemorrhagic fever with renal syndrome (HFRS), a rodent-borne disease caused by different species of hantaviruses, is widely endemic in China. Shandong Province is one of the most affected areas. This study aims to analyze the epidemiological characteristics of HFRS, and to predict the regional risk in Shandong Province.

METHODS

Descriptive statistics were used to elucidate the epidemiological characteristics of HFRS cases in Shandong Province from 2010 to 2018. Based on environmental and socioeconomic data, the boosted regression tree (BRT) model was applied to identify important influencing factors, as well as predict the infection risk zones of HFRS.

RESULTS

A total of 11,432 HFRS cases were reported from 2010 to 2018 in Shandong, with groups aged 31-70 years (81.04%), and farmers (84.44%) being the majority. Most cases were from central and southeast Shandong. There were two incidence peak periods in April to June and October to December, respectively. According to the BRT model, we found that population density (a relative contribution of 15.90%), elevation (12.02%), grassland (11.06%), cultivated land (9.98%), rural settlement (9.25%), woodland (8.71%), and water body (8.63%) were relatively important influencing factors for HFRS epidemics, and the predicted high infection risk areas were concentrated in central and eastern areas of Shandong Province. The BRT model provided an overall prediction accuracy, with an area under the receiver operating characteristic curve of 0.91 (range: 0.83-0.95).

CONCLUSIONS

HFRS in Shandong Province has shown seasonal and spatial clustering characteristics. Middle-aged and elderly farmers are a high-risk population. The BRT model has satisfactory predictive capability in stratifying the regional risk of HFRS at a county level in Shandong Province, which could serve as an important tool for risk assessment of HFRS to deploy prevention and control measures.

Rodent host population dynamics drive zoonotic Lyme Borreliosis and Orthohantavirus infections in humans in Northern Europe

Zoonotic diseases, caused by pathogens transmitted between other vertebrate animals and humans, pose a major risk to human health. Rodents are important reservoir hosts for many zoonotic pathogens, and rodent population dynamics affect the infection dynamics of rodent-borne diseases, such as diseases caused by hantaviruses. However, the role of rodent population dynamics in determining the infection dynamics of rodent-associated tick-borne diseases, such as Lyme borreliosis (LB), caused by Borrelia burgdorferi sensu lato bacteria, have gained limited attention in Northern Europe, despite the multiannual abundance fluctuations, the so-called vole cycles, that characterise rodent population dynamics in the region. Here, we quantify the associations between rodent abundance and LB human cases and Puumala Orthohantavirus (PUUV) infections by using two time series (25-year and 9-year) in Finland. Both bank vole (Myodes glareolus) abundance as well as LB and PUUV infection incidence in humans showed approximately 3-year cycles. Without vector transmitted PUUV infections followed the bank vole host abundance fluctuations with two-month time lag, whereas tick-transmitted LB was associated with bank vole abundance ca. 12 and 24 months earlier. However, the strength of association between LB incidence and bank vole abundance ca. 12 months before varied over the study years. This study highlights that the human risk to acquire rodent-borne pathogens, as well as rodent-associated tick-borne pathogens is associated with the vole cycles in Northern Fennoscandia, yet with complex time lags.

Hantavirus Replication Cycle-An Updated Structural Virology Perspective

Hantaviruses infect a wide range of hosts including insectivores and rodents and can also cause zoonotic infections in humans, which can lead to severe disease with possible fatal outcomes. Hantavirus outbreaks are usually linked to the population dynamics of the host animals and their habitats being in close proximity to humans, which is becoming increasingly important in a globalized world. Currently there is neither an approved vaccine nor a specific and effective antiviral treatment available for use in humans. Hantaviruses belong to the order Bunyavirales with a tri-segmented negative-sense RNA genome. They encode only five viral proteins and replicate and transcribe their genome in the cytoplasm of infected cells. However, many details of the viral amplification cycle are still unknown. In recent years, structural biology methods such as cryo-electron tomography, cryo-electron microscopy, and crystallography have contributed essentially to our understanding of virus entry by membrane fusion as well as genome encapsidation by the nucleoprotein. In this review, we provide an update on the hantavirus replication cycle with a special focus on structural virology aspects.

Coagulopathy in Acute Puumala Hantavirus Infection

Puumala hantavirus (PUUV) causes a hemorrhagic fever with renal syndrome (HFRS), also called nephropathia epidemica (NE), which is mainly endemic in Europe and Russia. The clinical features include a low platelet count, altered coagulation, endothelial activation, and acute kidney injury (AKI). Multiple connections between coagulation pathways and inflammatory mediators, as well as complement and kallikrein–kinin systems, have been reported. The bleeding symptoms are usually mild. PUUV-infected patients also have an increased risk for disseminated intravascular coagulation (DIC) and thrombosis.

Hantavirus Research in Finland: Highlights and Perspectives

Finland has the highest incidence of hantavirus infections globally, with a significant impact on public health. The large coverage of boreal forests and the cyclic dynamics of the dominant forest rodent species, the bank vole Myodes glareolus, explain most of this. We review the relationships between Puumala hantavirus (PUUV), its host rodent, and the hantavirus disease, nephropathia epidemica (NE), in Finland. We describe the history of NE and its diagnostic research in Finland, the seasonal and multiannual cyclic dynamics of PUUV in bank voles impacting human epidemiology, and we compare our northern epidemiological patterns with those in temperate Europe. The long survival of PUUV outside the host and the life-long shedding of PUUV by the bank voles are highlighted. In humans, the infection has unique features in pathobiology but rarely long-term consequences. NE is affected by specific host genetics and risk behavior (smoking), and certain biomarkers can predict the outcome. Unlike many other hantaviruses, PUUV causes a relatively mild disease and is rarely fatal. Reinfections do not exist. Antiviral therapy is complicated by the fact that when symptoms appear, the patient already has a generalized infection. Blocking vascular leakage measures counteracting pathobiology, offer a real therapeutic approach.

Hanta hemorrhagic fever with renal syndrome: A pathology in whose diagnosis kidney biopsy plays a major role (Review)

Hantavirus infection belongs to a group of zoonoses rare in the Balkan Peninsula, causing two major syndromes, depending on the viral serotype involved: Hemorrhagic fever with renal syndrome (HFRS) also known as endemic nephropathy and cardiopulmonary syndrome (CPS). Because there is no specific treatment or vaccine for this condition approved in the USA or Europe, the key to minimizing the risk of adverse progression to chronic kidney disease, secondary hypertension or even death is primarily the recognition and early diagnosis of this condition with prompt therapeutic intervention. The aim of this study was to review the literature data on the epidemiology, pathogenesis and management of this disease and to identify several aspects related to the difficulties encountered in diagnosing this pathology, taking into consideration that the disease is not endemic in this geographical area.

Hantavirus infections in humans in Poland-current state of knowledge and perspectives for research

BACKGROUND

In Europe, hantaviruses cause serious human disease, hemorrhagic fever with renal syndrome (HFRS). The geographic distribution of human cases of HFRS is a consequence of distribution of reservoir host species. Epidemiology of HFRS is well-studied in Western Europe, while data from Central and Eastern Europe are poor or unavailable.

METHODS

The data on hantavirus infections in humans during 2007-2017 were gathered to distinguish pattern of HFRS occurrence and characterize potential factors shaping HFRS epidemiology in Poland.

RESULTS

The south-eastern part of Poland (Podkarpackie voivodeship) was recognized as endemic area of hantavirus prevalence. Incidence rate of HFRS in Poland was positively correlated with mast years and higher abundance of rodents, urbanization index, and forest cover, while the climatic factors (average temperatures in January and July and average annual precipitation) have had no significant impact.

CONCLUSIONS

In Poland, HFRS is still not recognized entity. Further studies on hantavirus infection rate in reservoir host species (rodents, shrews, and bats) and virus transmission to humans are needed to prevent outbreaks of HFRS in the future.

Antiviral Efficacy of Ribavirin and Favipiravir against Hantaan Virus

Ecological changes, population movements and increasing urbanization promote the expansion of hantaviruses, placing humans at high risk of virus transmission and consequent diseases. The currently limited therapeutic options make the development of antiviral strategies an urgent need. Ribavirin is the only antiviral used currently to treat hemorrhagic fever with renal syndrome (HFRS) caused by Hantaan virus (HTNV), even though severe side effects are associated with this drug. We therefore investigated the antiviral activity of favipiravir, a new antiviral agent against RNA viruses. Both ribavirin and favipiravir demonstrated similar potent antiviral activity on HTNV infection. When combined, the efficacy of ribavirin is enhanced through the addition of low dose favipiravir, highlighting the possibility to provide better treatment than is currently available.

HTNV infection of CD8+ T cells is associated with disease progression in HFRS patients

Hantaan viruses (HTNVs) are zoonotic pathogens transmitted mainly by rodents and capable of infecting humans. Increasing knowledge of the human response to HTNV infection can guide the development of new preventative vaccines and therapeutic strategies. Here, we show that HTNV can infect CD8+ T cells in vivo in patients diagnosed with hemorrhagic fever with renal syndrome (HFRS). Electron microscopy-mediated tracking of the life cycle and ultrastructure of HTNV-infected CD8+ T cells in vitro showed an association between notable increases in cytoplasmic multivesicular bodies and virus production. Notably, based on a clinical cohort of 280 patients, we found that circulating HTNV-infected CD8+ T cell numbers in blood were proportional to disease severity. These results demonstrate that viral infected CD8+ T cells may be used as an adjunct marker for monitoring HFRS disease progression and that modulating T cell functions may be explored for new treatment strategies.