Hantaan Virus Research Articles

Distinct Genotype of Hantavirus Infection in Rodents in Jiangxi Province, China, in 2020–2021

Background: Hantavirus causes hemorrhagic fever with renal syndrome, thus posing a major threat to human health in Jiangxi Province, China. Both Hantaan virus (HTNV) and Seoul virus (SEOV) have been found to be endemic in the province. Methods: Rodents were trapped from Gaoan Anyi and Tonggu counties in Jiangxi Province in 2020–2021. Hantavirus specific antibodies in the blood and RNA in the lung samples from the captured mammals were detected and analyzed. Results: A total of 889 small mammals from seven species were collected. Positive detection was observed for hantavirus antibodies in 9.8% (87/889), SEOV RNA in 1% (9/889) and HTNV RNA in 2.6% (23/889). The difference in detection rates between regions was significant. Phylogenetic analysis of the obtained partial sequences of M and S segments revealed that two distinct genotypes of HTNV and three genotypes of SEOV were co-circulating in the captured mammals, with a regionally specific distribution. Conclusion: Multiple distinct genotypes of hantavirus are co-circulating in the province. Further studies in broader areas remain needed to reveal the diversity of hantaviruses.

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.

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.

Urinary genome detection and tracking of Hantaan virus from hemorrhagic fever with renal syndrome patients using multiplex PCR-based next-generation sequencing.

BackgroundHantavirus infection occurs through the inhalation of aerosolized excreta, including urine, feces, and saliva of infected rodents. The presence of Hantaan virus (HTNV) RNA or infectious particles in urine specimens of patient with hemorrhagic fever with renal syndrome (HFRS) remains to be investigated.Methodology/Principal findingsWe collected four urine and serum specimens of Republic of Korea Army (ROKA) patients with HFRS. We performed multiplex PCR-based next-generation sequencing (NGS) to obtain the genome sequences of clinical HTNV in urine specimens containing ultra-low amounts of viral genomes. The epidemiological and phylogenetic analyses of HTNV demonstrated geographically homogenous clustering with those in Apodemus agrarius captured in highly endemic areas, indicating that phylogeographic tracing of HTNV genomes reveals the potential infection sites of patients with HFRS. Genetic exchange analyses showed a genetic configuration compatible with HTNV L segment exchange in nature.Conclusion/SignificanceOur results suggest that whole or partial genome sequences of HTNV from the urine enabled to track the putative infection sites of patients with HFRS by phylogeographically linking to the zoonotic HTNV from the reservoir host captured at endemic regions. This report raises awareness among physicians for the presence of HTNV in the urine of patients with HFRS.

Computational vaccinology guided design of multi-epitopes subunit vaccine designing against Hantaan virus and its validation through immune simulations.

The Hantaan virus belongs to Bunyaviridae family, an emerging virus that is responsible for hemorrhagic fevers. The virus is distributed worldwide and as of now there is no successful antiviral drug or vaccine developed to protect against the viral infections. Immunization or vaccination is an alternative approach for the protection against viral infections. A cost effective and thermodynamically stable vaccine should be developed to prevent a future possible pandemic. In this study a vaccine candidate was designed against the Hantaan virus, multiple immunoinformatics and reverse vaccinology tools were utilized for the prediction of both B and T cell epitopes for Nuceloprotein, RNA dependent RNA polymerase L and Envelope protein of the Hantaan virus. The individual epitopes were modeled for docking with respective HLAs and a multi-epitopes subunit vaccine candidate was constructued by joining together carefully evaluated B and T cell epitopes with suitable linkers. The vaccine model was evaluated for several physiochameical parameters i.e. Molecular weight, instability index and aliphatic index among the others, followed by 3D modeling of the vaccine for docking with TLR-4. Based on previous studies, Human beta-defensin was liked at the N-terminus of the vaccine sequence as an adjuvant to enhance immunogenicity. The docked complexes of vaccine-TLR-4 were then evaluated for residual interactions. Moreover, to validate final vaccine construct, immune simulations was carried out by C-IMMSIM server. A natural immune reponse was predicted by the immune simulation analysis. In-silico cloning was carried out using E. coli as host resulting in 0.93 CAI value, which suggests that the vaccine construct will attain maximal expression in E. coli host. The vaccine designed in this study needs experimental verification to confirm the immunogenicity and efficacy of the vaccine and ultimately used against Hantaan virus associated infections.

Elevated Plasma Fractalkine Level Is Associated with the Severity of Hemorrhagic Fever with Renal Syndrome in Humans.

Hantaan virus infection may cause severe lethal hemorrhagic fever with renal syndrome (HFRS) in humans. The chemokine fractalkine (CX3CL1) acts as a proinflammatory cytokine, and it is elevated in several infectious diseases. However, little is known about the contributions of CX3CL1 to HFRS pathogenesis. Present study detected plasma CX3CL1 levels and expression of the receptor CX3CR1 in HFRS patients and discussed the possible effects of CX3CL1 on pathogenesis of HFRS. Plasma CX3CL1 in acute phase and Critical/Severe groups of HFRS patients were significantly increased compared to that in normal controls (p < 0.001 and p < 0.01, respectively). High plasma CX3CL1 was negatively correlated with platelet count (r = -0.5844, p < 0.0001) and positively correlated with blood urea nitrogen (r = 0.3668, p = 0.0039), creatinine (r = 0.42, p = 0.0008), and white blood cells (r = 0.2646, p = 0.0411). Expression of CX3CR1 on nonclassical and intermediate monocytes was also increased in the acute phase (p < 0.01 for both the cells) and Critical/Severe groups (p < 0.05 and p < 0.01, respectively) of HFRS patients compared to that in normal controls. Taken together, elevation of plasma CX3CL1 in HFRS patients and expression of CX3CR1 on nonclassical and intermediate monocyte subsets might provide new insights into the potential role of CX3CL1/CX3CR1 in pathogenesis of HFRS.

Integrative Analysis of HTNV Glycoprotein Derived MHC II Epitopes by In Silico Prediction and Experimental Validation.

Hantaan virus (HTNV), the causative pathogen of hemorrhagic fever with renal syndrome (HFRS), is a negative RNA virus belonging to the Orthohantaviridae family. HTNV envelope glycoprotein (GP), encoded by the genomic medium segment, is immunogenic and is therefore a promising vaccine candidate. Major histocompatibility complex class I (MHC-I) epitopes derived from HTNV has been extensively studied, but little is known of MHC-II epitopes. In silico predictions based on four databases indicated that the full-length HTNV GP has 1121 15-mer epitopes, of which 289 had a high score for binding to the human and murine MHC-II superfamily. It found that epitope ILTVLKFIANIFHTS could potentially bind most MHC-II molecules covering human and murine haplotypes. Dominant epitopes were validated by enzyme-linked immunospot assay of splenocytes from immunized mice; 6 of 10 epitopes supported the predictions including TATYSIVGPANAKVP, TKTLVIGQCIYTITS, FSLLPGVAHSIAVEL, CETYKELKAHGVSCP, CGLYLDRLKPVGSAY, and NLGENPCKIGLQTSS. Conservation analysis of dominant epitopes revealed host–virus interactions without geographic stratification, thus meeting the requirements of candidate vaccines for large-population prophylaxis. These findings provide insight into hantavirus antigenicity and suggest that vaccines targeting MHC-II could provide immune protection in large population to complement symptomatic therapies for the treatment of HFRS.

Nlrc3 Knockout Mice Showed Renal Pathological Changes After HTNV Infection.

Hantaan virus (HTNV) infects humans and causes hemorrhagic fever with renal syndrome (HFRS). The development of well-characterized animal models of HFRS could accelerate the testing of vaccine candidates and therapeutic agents and provide a useful tool for studying the pathogenesis of HFRS. Because NLRC3 has multiple immunoregulatory roles, we investigated the susceptibility of Nlrc3−/− mice to HTNV infection in order to establish a new model of HFRS. Nlrc3−/− mice developed weight loss, renal hemorrhage, and tubule dilation after HTNV infection, recapitulating many clinical symptoms of human HFRS. Moreover, infected Nlrc3−/− mice showed higher viral loads in serum, spleen, and kidney than wild type C57BL/6 (WT) mice, and some of them manifested more hematological disorders and significant pathological changes within multiple organs than WT mice. Our results identify that HTNV infected Nlrc3−/− mice can develop clinical symptoms and pathological changes resembling patients with HFRS, suggesting a new model for studying the pathogenesis and testing of candidate vaccines and therapeutics.

Structural Basis for a Neutralizing Antibody Response Elicited by a Recombinant Hantaan Virus Gn Immunogen.

ABSTRACTHantaviruses are a group of emerging pathogens capable of causing severe disease upon zoonotic transmission to humans. The mature hantavirus surface presents higher-order tetrameric assemblies of two glycoproteins, Gn and Gc, which are responsible for negotiating host cell entry and constitute key therapeutic targets. Here, we demonstrate that recombinantly derived Gn from Hantaan virus (HTNV) elicits a neutralizing antibody response (serum dilution that inhibits 50% infection [ID50], 1:200 to 1:850) in an animal model. Using antigen-specific B cell sorting, we isolated monoclonal antibodies (mAbs) exhibiting neutralizing and non-neutralizing activity, termed mAb HTN-Gn1 and mAb nnHTN-Gn2, respectively. Crystallographic analysis reveals that these mAbs target spatially distinct epitopes at disparate sites of the N-terminal region of the HTNV Gn ectodomain. Epitope mapping onto a model of the higher order (Gn-Gc)4 spike supports the immune accessibility of the mAb HTN-Gn1 epitope, a hypothesis confirmed by electron cryo-tomography of the antibody with virus-like particles. These data define natively exposed regions of the hantaviral Gn that can be targeted in immunogen design.

Edging on Mutational Bias, Induced Natural Selection From Host and Natural Reservoirs Predominates Codon Usage Evolution in Hantaan Virus.

The molecular evolutionary dynamics that shape hantaviruses’ evolution are poorly understood even now, besides the contribution of virus-host interaction to their evolution remains an open question. Our study aimed to investigate these two aspects in Hantaan virus (HTNV)—the prototype of hantaviruses and an emerging zoonotic pathogen that infects humans, causing hemorrhagic fever with renal syndrome (HFRS): endemic in Far East Russia, China, and South Korea—via a comprehensive, phylogenetic-dependent codon usage analysis. We found that host- and natural reservoir-induced natural selection is the primary determinant of its biased codon choices, exceeding the mutational bias effect. The phylogenetic analysis of HTNV strains resulted in three distinct clades: South Korean, Russian, and Chinese. An effective number of codon (ENC) analysis showed a slightly biased codon usage in HTNV genomes. Nucleotide composition and RSCU analyses revealed a significant bias toward A/U nucleotides and A/U-ended codons, indicating the potential influence of mutational bias on the codon usage patterns of HTNV. Via ENC-plot, Parity Rule 2 (PR2), and neutrality plot analyses, we would conclude the presence of both mutation pressure and natural selection effect in shaping the codon usage patterns of HTNV; however, natural selection is the dominant factor influencing its codon usage bias. Codon adaptation index (CAI), Relative codon deoptimization index (RCDI), and Similarity Index (SiD) analyses uncovered the intense selection pressure from the host (Human) and natural reservoirs (Striped field mouse and Chinese white-bellied rat) in shaping HTNV biased codon choices. Our study clearly revealed the evolutionary processes in HTNV and the role of virus-host interaction in its evolution. Moreover, it opens the door for a more comprehensive codon usage analysis for all hantaviruses species to determine their molecular evolutionary dynamics and adaptability to several hosts and environments. We believe that our research will help in a better and deep understanding of HTNV evolution that will serve its future basic research and aid live attenuated vaccines design.

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.

Establishment of a Lethal Animal Model of Hantaan Virus 76-118 Infection

Establishment of a Lethal Animal Model of Hantaan Virus 76-118 Infection

The Presence of Circulating Nucleated Red Blood Cells Is Associated With Disease Severity in Patients of Hemorrhagic Fever With Renal Syndrome.

Hemorrhagic fever with renal syndrome (HFRS) is a regional infectious disease of epidemic potential caused by the Hantaan virus (HTNV). Red blood cells (RBCs) are the major components of peripheral blood. However, pathological changes in RBCs and the underlying mechanisms during HTNV infection remain largely unclear. Therefore, this study sought to explore changes in RBCs in the peripheral blood of HFRS patients. We isolated PBMCs from HFRS patients and performed single-cell RNA sequencing. The results showed that clusters of RBCs in the peripheral blood of HFRS could be classified as nucleated red blood cells (NRBC) based on their cellular components, gene expression profiles and cell surface markers. In addition, it was shown that the higher the count of NRBC in peripheral blood, the more severe the disease status was. Moreover, hematological indices related to RBCs were analyzed and the results showed that impairment in the folate pathway might be the possible reason behind the presence of NRBCs. This study, for the first time showed that the presence of NRBCs in the peripheral blood of HFRS patients was associated with disease severity. This was also the first study to show that infection with the HTNV virus hindered the maturation of RBCs. Therefore, this work provides further insights on the role of and pathological changes in RBCs during HTNV infection.

Predictive value of pentraxin-3 on disease severity and mortality risk in patients with hemorrhagic fever with renal syndrome

BackgroundHemorrhagic fever with renal syndrome (HFRS) caused by Hantaan virus is characterized by systemic immunopathological injury. Pentraxin-3 is an acute-phase reactant involved in the processes of inflammation and infection. This study aimed to investigate the levels of plasma pentraxin-3 and evaluate its predictive value on disease severity and mortality risk in patients with HFRS.MethodsThis was a prospective real-world observational study. The concentrations of plasma pentraxin-3 were measured by enzyme linked immunosorbent assay (ELISA) in 105 HFRS patients and 27 healthy controls. We analyzed the clinical relevance between pentraxin-3 and clinical subtyping, hospital stay and conventional laboratory parameters of HFRS patients. Considering the prognosis (death) as the primary endpoint, the levels of pentraxin-3 between survivors and non-survivors were compared, and its association with mortality was assessed by Kaplan-Meier survival analysis. The predictive potency of pentraxin-3 for mortality risk in HFRS patients was evaluated by receiver operating characteristic (ROC) curve analysis.ResultsThe levels of pentraxin-3 during the acute phase were increased with the aggravation of the disease, and showed the highest expression in critical-type patients (P < 0.05). Pentraxin-3 demonstrated significant correlations with conventional laboratory parameters (WBC, PLT, AST, ALB, APTT, Fib) and the length of hospital stay. Compared with the survivors, non-survivors showed higher levels of pentraxin-3 and worse expressions of conventional laboratory parameters during the acute phase. The Kaplan-Meier survival curves showed that high levels of pentraxin-3 during the acute phase were significantly associated with the death in HFRS patients. Pentraxin-3 demonstrated significant predictive value for the mortality risk of HFRS patients, with the area under ROC curve (AUC) of 0.753 (95%CI: 0.593 ~ 0.914, P = 0.003).ConclusionsThe detection of plasma pentraxin-3 might be beneficial to the evaluation of disease severity and to the prediction of mortality risk in HFRS patients.

A novel genotype of Hantaan orthohantavirus harbored by Apodemus agrarius chejuensis as a potential etiologic agent of hemorrhagic fever with renal syndrome in Republic of Korea.

Orthohantaviruses, causing hemorrhagic fever with renal syndrome (HFRS) and hantavirus cardiopulmonary syndrome, pose a significant public health threat worldwide. Despite the significant mortality and morbidity, effective antiviral therapeutics for orthohantavirus infections are currently unavailable. This study aimed to investigate the prevalence of HFRS-associated orthohantaviruses and identify the etiological agent of orthohantavirus outbreaks in southern Republic of Korea (ROK). We collected small mammals on Jeju Island during 2018-2020. We detected the Hantaan virus (HTNV)-specific antibodies and RNA using an indirect immunofluorescence assay test and reverse transcription-polymerase chain reaction on Apodemus agrarius chejuensis (A. chejuensis). The prevalence of anti-HTNV antibodies among rodents was 14.1%. A total of six seropositive mouse harbored HTNV RNA. The amplicon-based next-generation sequencing provided nearly full-length tripartite genomic sequences of six HTNV harbored by A. chejuensis. Phylogenetic and tanglegram analyses were conducted for inferring evolutionary relationships between orthohantaviruses with their reservoir hosts. Phylogenetic analysis showed a novel distinct HTNV genotype. The detected HTNV genomic sequences were phylogenetically related to a viral sequence derived from HFRS patient in southern ROK. Tanglegram analysis demonstrated the segregation of HTNV genotypes corresponding to Apodemus spp. divergence. Our results suggest that A. chejuensis-borne HTNV may be a potential etiological agent of HFRS in southern ROK. Ancestral HTNV may infect A. chejuensis prior to geological isolation between the Korean peninsula and Jeju Island, supporting the co-evolution of orthohantaviruses and rodents. This study arises awareness among physicians for HFRS outbreaks in southern ROK.

Multiplex PCR-Based Nanopore Sequencing and Epidemiological Surveillance of Hantaan orthohantavirus in Apodemus agrarius, Republic of Korea.

Whole-genome sequencing of infectious agents enables the identification and characterization of emerging viruses. The MinION device is a portable sequencer that allows real-time sequencing in fields or hospitals. Hantaan orthohantavirus (Hantaan virus, HTNV), harbored by Apodemus agrarius, causes hemorrhagic fever with renal syndrome (HFRS) and poses a critical public health threat worldwide. In this study, we aimed to evaluate the feasibility of using nanopore sequencing for whole-genome sequencing of HTNV from samples having different viral copy numbers. Amplicon-based next-generation sequencing was performed in A. agrarius lung tissues collected from the Republic of Korea. Genomic sequences of HTNV were analyzed based on the viral RNA copy numbers. Amplicon-based nanopore sequencing provided nearly full-length genomic sequences of HTNV and showed sufficient read depth for phylogenetic analysis after 8 h of sequencing. The average identity of the HTNV genome sequences for the nanopore sequencer compared to those of generated from Illumina MiSeq revealed 99.8% (L and M segments) and 99.7% (S segment) identities, respectively. This study highlights the potential of the portable nanopore sequencer for rapid generation of accurate genomic sequences of HTNV for quicker decision making in point-of-care testing of HFRS patients during a hantavirus outbreak.

To the History of the Discovery and Research into Hemorrhagic Fever with Renal Syndrome

Background: Hemorrhagic fever with renal syndrome (HFRS) is a viral, natural focal infection that is currently relevant for many countries of the world and ranks high among zoonotic viral infections in the Russian Federation. The purpose of our work was to present the main stages of the discovery and study of HFRS: from registration of the first clinical cases of the disease by military doctors in the east of our country to the current level of research. Materials and methods: We analyzed scientific literature devoted to the discovery of HFRS and further studies of this natural focal disease. Results: The discovery of many natural focal infections that are still relevant today in the Russian Federation coincided with the beginning of the rapid exploration and development of the Far East in the 1930s. Long-term studies of Soviet and foreign scientists helped systematize knowledge about viral etiology, clinical picture, pathophysiology, and pathomorphology of hemorrhagic nephrosonephritis and isolate the Hantaan virus, the etiological agent of HFRS (Lee HW, 1978). World famous Soviet virologists A.A. Smorodintsev and M.P. Chumakov, local scientists, doctors, and employees of the Federal Service for Surveillance on Consumer Rights Protection and Human Wellbeing made a significant contribution to the research into etiology, terminological consistency, epidemiology, and epizootology of HFRS. Conclusion: At present, the study of various aspects of hantavirus infections is one of the main tasks of the Research Institute of Epidemiology and Microbiology named after G.P. Somov. The research continues to establish the mechanisms of functioning of the natural foci of orthohantaviruses at different phases of the population cycles of their main carriers and in different landscape zones of the Russian Far East. A search for new species of orthohantaviruses, their natural reservoirs, and novel antiviral biologically active substances of natural and synthetic origin against orthohantaviruses is going on.

Synthesis and Antiviral Activity of Camphene Derivatives against Different Types of Viruses.

To date, the ‘one bug-one drug’ approach to antiviral drug development cannot effectively respond to the constant threat posed by an increasing diversity of viruses causing outbreaks of viral infections that turn out to be pathogenic for humans. Evidently, there is an urgent need for new strategies to develop efficient antiviral agents with broad-spectrum activities. In this paper, we identified camphene derivatives that showed broad antiviral activities in vitro against a panel of enveloped pathogenic viruses, including influenza virus A/PR/8/34 (H1N1), Ebola virus (EBOV), and the Hantaan virus. The lead-compound 2a, with pyrrolidine cycle in its structure, displayed antiviral activity against influenza virus (IC50 = 45.3 µM), Ebola pseudotype viruses (IC50 = 0.12 µM), and authentic EBOV (IC50 = 18.3 µM), as well as against pseudoviruses with Hantaan virus Gn-Gc glycoprotein (IC50 = 9.1 µM). The results of antiviral activity studies using pseudotype viruses and molecular modeling suggest that surface proteins of the viruses required for the fusion process between viral and cellular membranes are the likely target of compound 2a. The key structural fragments responsible for efficient binding are the bicyclic natural framework and the nitrogen atom. These data encourage us to conduct further investigations using bicyclic monoterpenoids as a scaffold for the rational design of membrane-fusion targeting inhibitors.

Chloroquine, an Anti-Malaria Drug as Effective Prevention for Hantavirus Infections

We investigated whether chloroquine can prevent hantavirus infection and disease in vitro and in vivo, using the Hantaan virus newborn C57BL/6 mice model and the Syrian hamster model for Andes virus. In vitro antiviral experiments were performed using Vero E6 cells, and Old World and New World hantavirus species. Hantavirus RNA was detected using quantitative RT-PCR. For all hantavirus species tested, results indicate that the IC50 of chloroquine (mean 10.2 ± 1.43 μM) is significantly lower than the CC50 (mean 260 ± 2.52 μM) yielding an overall selectivity index of 25.5. We also investigated the potential of chloroquine to prevent death in newborn mice after Hantaan virus infection and its antiviral effect in the hantavirus Syrian hamster model. For this purpose, C57Bl/6 mother mice were treated subcutaneously with daily doses of chloroquine. Subsequently, 1-day-old suckling mice were inoculated intracerebrally with 5 x 102 Hantaan virus particles. In litters of untreated mothers, none of the pups survived challenge. The highest survival rate (72.7% of pups) was found when mother mice were administered a concentration of 10 mg/kg chloroquine. Survival rates declined in a dose-dependent manner, with 47.6% survival when treated with 5 mg/kg chloroquine, and 4.2% when treated with 1 mg/kg chloroquine. Assessing the antiviral therapeutic and prophylactic effect of chloroquine in the Syrian hamster model was done using two different administration routes (intraperitoneally and subcutaneously using an osmotic pump system). Evaluating the prophylactic effect, a delay in onset of disease was noted and for the osmotic pump, 60% survival was observed. Our results show that chloroquine can be highly effective against Hantaan virus infection in newborn mice and against Andes virus in Syrian hamsters.

New class of hantaan virus inhibitors based on conjugation of the isoindole fragment to (+)-camphor or (−)-fenchone hydrazonesv

This work presents the design and synthesis of camphor, fenchone, and norcamphor N-acylhydrazone derivatives as a new class of inhibitors of the Hantaan virus, which causes haemorrhagic fever with renal syndrome (HFRS). A cytopathic model was developed for testing chemotherapeutics against the Hantaan virus, strain 76–118. In addition, a study of the antiviral activity was carried out using a pseudoviral system. It was found that the hit compound possesses significant activity (IC50 = 7.6 ± 2 µM) along with low toxicity (CC50 > 1000 µM). Using molecular docking procedures, the binding with Hantavirus nucleoprotein was evaluated and the correlation between the structure of the synthesised compounds and the antiviral activity was established.