In-cell Western assay to quantify infection with pathogenic orthohantavirus Puumala virus in replication kinetics and antiviral drug testing.

Hemorrhagic fever with renal syndrome (HFRS) represents a serious zoonotic disease caused by orthohantaviruses in Eurasia. A specific antiviral therapy is not available. HFRS is characterized by acute kidney injury (AKI) with often massive proteinuria. Infection of kidney cells may contribute to the clinical picture. However, orthohantaviral replication in kidney cells is not well characterized. Therefore, we aimed to perform a reliable high-throughput assay that allows the quantification of infection rates and testing of antiviral compounds in different cell types. We quantified relative infection rates of Eurasian pathogenic Puumala virus (PUUV) by staining of nucleocapsid protein (N protein) in an in-cell Western (ICW) assay. Vero E6 cells, derived from the African green monkey and commonly used in viral cell culture studies, and the human podocyte cell line CIHP (conditionally immortalized human podocytes) were used to test the ICW assay for replication kinetics and antiviral drug testing. Quantification of infection by ICW revealed reliable results for both cell types, as shown by their correlation with immunofluorescence quantification results by counting infected cells. Evaluation of antiviral efficacy of ribavirin by ICW assay revealed differences in the toxicity (TC) and inhibitory concentrations (IC) between Vero E6 cells and podocytes. IC5O of ribavirin in podocytes is about 12-fold lower than in Vero E6 cells. In summary, ICW assay together with relevant human target cells represents an important tool for the study of hantaviral replication and drug testing.

An algal lectin griffithsin inhibits Hantaan virus infection in vitro and in vivo.

Hantaan virus (HTNV) is the etiological pathogen of hemorrhagic fever with renal syndrome in East Asia. There are currently no effective therapeutics approved for HTNV and other hantavirus infections. We found that griffithsin (GRFT), an algae-derived lectin with broad-spectrum antiviral activity against various enveloped viruses, can inhibit the growth and spread of HTNV. In vitro experiments using recombinant vesicular stomatitis virus (rVSV) with HTNV glycoproteins as a model revealed that the GRFT inhibited the entry of rVSV-HTNV-G into host cells. In addition, we demonstrated that GRFT prevented authentic HTNV infection in vitro by binding to the viral N-glycans. In vivo experiments showed that GRFT partially protected the suckling mice from death induced by intracranial exposure to HTNV. These results demonstrated that GRFT can be a promising agent for inhibiting HTNV infection.

Novel therapeutic approaches toward Hantaan virus and its clinical features' similarity with COVID-19.

Zoonotic virus spill over in human community has been an intensive area of viral pathogenesis and the outbreak of Hantaan virus and severe acute respiratory syndrome coronavirus 2 (SARS CoV2) after late December 2019 caused a global threat. Hantaan virus is second to the COVID-19 outbreak in China with seven cases positive and one death. Both RNA viruses have opposite sense as in (-) for Hantaan virus and (+) for SARS CoV2 but have similarity in the pathogenesis and relevant clinical features including dry cough, high fever, shortness of breath, and SARS associated with pneumonia and certain reported cases with multiple organ failure. Although COVID-19 has global impact with high death toll, Hantaan virus has varyingly high mortality rate between 1% and 40%. Hence, there is a need to explore novel therapeutic targets in Hantaan virus due to its rapid evolution rate in its genetic makeup which governs virulence and target host cells. This review emphasizes the importance of structural and nonstructural proteins of Hantaan virus with relevant insight from SARS CoV2. The envelope glycoproteins such as Gn, Gc, and nucleocapsid protein (N) direct the viral assembly and replication in host cells. Therapeutic treatment has similarity in using ribavirin and extracorporeal membrane oxygenation but lack of efficacious treatment in both cases of SARAS CoV2 and Hantaan virus. Therefore, potential features regarding therapeutic targets for drug discovery for Hantaan viruses are discussed herewith. The conclusive description highlights that N protein is substantially involved in evoking immune response and induces symptoms and could be precursive target for drug discovery studies.

Therapeutic effect of Xuebijing combined with thymosin on hemorrhagic fever with renal syndrome: A protocol of systematic review and meta-analysis.

BACKGROUND: The goal of this study is to assess the therapeutic effect of Xuebijing combined with thymosin (XBJ-T) for the treatment of patients with hemorrhagic fever with renal syndrome (HFRS). METHODS: We will search the electronic databases of Cochrane Library, PUBMED, EMBASE, PsycINFO, Scopus, Opengrey, Cumulative Index to Nursing and Allied Health Literature, Web of Science, Google scholar, Allied and Complementary Medicine Database, and Chinese Biomedical Literature Database from inception to the present. No language and publication status will be employed in this study. Based on the predefined eligibility criteria, selection of study and data extraction will be performed by 2 researchers independently. Study quality will be assessed using Cochrane risk of bias tool. We will apply RevMan 5.3 software to pool and analyze the extracted data. RESULTS: This study will assess the therapeutic effect of XBJ-T for the treatment of patients with HFRS. CONCLUSION: The findings of this study may provide systematic evidence to judge whether XBJ-T is an effective and safety intervention for HFRS. STUDY REGISTRATION NUMBER: INPLASY202040068.

Peritonitis secondary to hemorrhagic fever with renal syndrome: a case report in GuangZhou China.

BACKGROUND: Hantavirus infection is worldwide epidemic and can cause life-threatening consequences. With more and more cases reported in countries with atypical morbidity, it is necessarily urgent to know some atypical symptoms and signs of Hantavirus infection. CASE PRESENTATION: Here we report the case of a 44-year old male with a complaint of fever and diffuse abdominal pain, initially suspiciously diagnosed with acute peritonitis. The patient was eventually diagnosed as hemorrhagic fever with renal syndrome and enhanced CT scan showed peritonitis. The clinical condition of the patient was relatively mild and he was recovered 9 days later. CONCLUSION: Peritonitis secondary to hemorrhagic fever with renal syndrome is rare in clinically practice. When confronted with atypical celialgia, it is important to make differential diagnosis of hantavirus infection.

Targeted inhibition of hantavirus replication and intracranial pathogenesis by a chimeric protein-delivered siRNA.

Hantavirus (HV) infection, which underlies hantavirus hemorrhagic fever with renal syndrome and hantavirus pulmonary syndrome, remains to be a severe clinical challenge. Here, we synthesized small interfering RNAs (siRNAs) that target the encoding sequences of HV strain 76-118, and validated their inhibitory role in virus replication in HV-infected monkey kidney Vero E6 cells. A chimeric protein, 3G1-Cκ-tP, consisting of a single-chain antibody fragment (3G1) against the HV surface envelop glycoprotein, the constant region of human immunoglobulin κ chain (Cκ), and truncated protamine (amino acids 8-29, tP), was further generated. The fusion protein showed high affinity to HV antigen on the infected cell membrane, and internalized through clathrin-mediated endocytosis; it bound to siRNAs via the basic nucleic acid-rich protamine fragment, leading to their specific delivery into HV-infected cells and efficient inhibition of virus replication. An encephalitis mouse model was established via intracranial HV administration. Intraperitoneal injection of siRNAs complexed with 3G1-Cκ-tP achieved specific distribution of siRNAs in HV-infected brain cells, significantly reduced HV antigen levels, and effective protection from HV infection-derived animal death. These results provide a compelling rationale for novel therapeutic protocols designed for HV infection and related disorders.

In-Cell Western Assays to Evaluate Hantaan Virus Replication as a Novel Approach to Screen Antiviral Molecules and Detect Neutralizing Antibody Titers.

Hantaviruses encompass rodent-borne zoonotic pathogens that cause severe hemorrhagic fever disease with high mortality rates in humans. Detection of infectious virus titer lays a solid foundation for virology and immunology researches. Canonical methods to assess viral titers rely on visible cytopathic effects (CPE), but Hantaan virus (HTNV, the prototype hantavirus) maintains a relatively sluggish life cycle and does not produce CPE in cell culture. Here, an in-cell Western (ICW) assay was utilized to rapidly measure the expression of viral proteins in infected cells and to establish a novel approach to detect viral titers. Compared with classical approaches, the ICW assay is accurate and time- and cost-effective. Furthermore, the ICW assay provided a high-throughput platform to screen and identify antiviral molecules. Potential antiviral roles of several DExD/H box helicase family members were investigated using the ICW assay, and the results indicated that DDX21 and DDX60 reinforced IFN responses and exerted anti-hantaviral effects, whereas DDX50 probably promoted HTNV replication. Additionally, the ICW assay was also applied to assess NAb titers in patients and vaccine recipients. Patients with prompt production of NAbs tended to have favorable disease outcomes. Modest NAb titers were found in vaccinees, indicating that current vaccines still require improvements as they cannot prime host humoral immunity with high efficiency. Taken together, our results indicate that the use of the ICW assay to evaluate non-CPE Hantaan virus titer demonstrates a significant improvement over current infectivity approaches and a novel technique to screen antiviral molecules and detect NAb efficacies.

Insufficient efficacy and safety of intravenous ribavirin in treatment of haemorrhagic fever with renal syndrome caused by Puumala virus.

BACKGROUND: Intravenous ribavirin has been reported to be an effective treatment for haemorrhagic fever with renal syndrome (HFRS) caused by Hantaan virus in Asia. However, its therapeutic benefits for HFRS caused by Puumala virus (PUUV) in Europe are still unknown. METHODS: A randomized, open-label study of efficacy and safety of intravenous ribavirin in the treatment of HFRS was conducted in the European part of Russia. Seventy-three patients with suspected HFRS within 4 d of the onset of the disease were randomized to receive either intravenous ribavirin (33 mg/kg, followed by 16 mg/kg given every 6 h for 4 d and by 8 mg/kg given every 8 h for 3 d) plus standard therapy (n = 37) or standard therapy alone (n = 36). The primary outcome was the average change from baseline in viral load over time estimated as area under the viral load curve minus baseline (AUCMB). Fifty-five patients with HFRS confirmed by nested reverse transcriptase - polymerase chain reaction (PCR) assay were included in the assessment of the efficacy. All patients entered into the clinical trial were included in the assessment of the safety. RESULTS: PUUV was detected in all cases of confirmed HFRS. Viral load kinetics were similar in both treatment groups. Significantly more patients receiving ribavirin than standard therapy experienced low haemoglobin level (95% vs 36%), hyperbilirubinemia (81% vs 3%), sinus bradycardia (43% vs 14%), and rash (19% vs 0%). CONCLUSIONS: Results of the study showed insufficient efficacy and safety of intravenous ribavirin in the treatment of HFRS caused by PUUV.

Cytokine response to Hantaan virus infection in patients with hemorrhagic fever with renal syndrome.

Hantaan virus (HTNV) infection of the human body causes a severe acute infectious disease known as hemorrhagic fever renal syndrome (HFRS). The aim of this study was to correlate patient cytokine profiles to HFRS severity. In this study, we discuss the clinical significance of evaluating HFRS treatment outcomes using cytokine information. The levels of 18 cytokines were quantitatively determined in three groups: 34 HTNV IgM+ cases, 63 HTNV IgM- negative cases, and 78 healthy volunteers. The level of 14 serum cytokines were higher in the patient group than that in the healthy control group. In the 34 HTNV IgM+ patient sera, a set of 27 cytokines was further assessed. The cytokines of TNF-ß, IL-1ra, and IL-6 were detected at higher level in the IgM+ group than that in the IgM- group. The deterioration of HFRS was accompanied with multiple cytokines increased, such as IL-1ra, IL-12p70, IL-10, IP-10, IL-17, IL-2, and IL-6. Our data indicate that serum cytokine levels are associated with the progression of HFRS.

Hemorrhagic Fever with Renal Syndrome: Pathogenesis and Clinical Picture.

Hantaan virus (HTNV) causes hemorrhagic fever with renal syndrome (HFRS), which is a zoonosis endemic in eastern Asia, especially in China. The reservoir host of HTNV is field mouse (Apodemus agraricus). The main manifestation of HFRS, including acute kidney injury, increases vascular permeability, and coagulation abnormalities. In this paper, we review the current knowledge of the pathogenesis of HFRS including virus factor, immunity factor and host genetic factors. Furthermore, the treatment and prevention will be discussed.

Severe Puumala virus infection in a patient with a lymphoproliferative disease treated with icatibant.

Early identification of patients at risk of a severe course of hantaviral disease and lack of effective medication represent a global challenge in the treatment of this emerging infection. We describe a 67-year-old female patient with a history of chronic lymphoproliferative disease involving the spleen and an extremely severe acute Puumala hantavirus infection. She was treated with the bradykinin receptor antagonist icatibant and recovered. She is the second patient with a spleen abnormality and severe Puumala infection treated with icatibant in our hospital. We suggest that patients with spleen abnormalities may be more susceptible to severe hantavirus disease. The activation of the kinin-kallikrein system and the formation of bradykinin in hantavirus-infected endothelial cells indicate that the role of bradykinin receptor antagonist icatibant in the treatment of hantavirus disease is worth studying.

Bilateral simultaneous angle-closure glaucoma associated with septic condition of Korean hemorrhagic fever (KHF).

PURPOSE: To report a case of bilateral simultaneous angle-closure glaucoma caused by septic condition of Korean hemorrhagic fever. METHODS: A 62-year-old man visited our emergency center with signs of sepsis (fever, leukocytosis, and oliguria). After 4 days of hospitalization, the patient reported blurred vision. Upon ophthalmologic examination, elevated intraocular pressure, edematous cornea, closed anterior chamber angle, and shallow anterior chamber without iris bowing were found in both eyes in slit-lamp examination and in Pentacam (Oculus, Wetzlar, Germany) Scheimpflug images. Bilateral choroidal effusion was observed on an ultrasound B scan as well. The serologic test for anti-hantaan virus immunoglobulin G (IgG) was positive. RESULTS: Along with the sepsis treatment, intravenous hyperosmotic agent, antiglaucoma eye drops, and 1% atropine eye drop were administered immediately. To control the choroidal effusion, systemic steroid was also administered. After 4 months, anterior chamber depth and choroidal effusion were normalized. CONCLUSIONS: Systemic causes should be considered in patients with bilateral angle-closure glaucoma, and Korean hemorrhagic fever can be one of the causes in endemic areas.

Pathophysiology of a severe case of Puumala hantavirus infection successfully treated with bradykinin receptor antagonist icatibant.

We recently described a patient with very severe Puumala hantavirus infection manifested by capillary leakage syndrome and shock. He was successfully treated with the bradykinin receptor antagonist, icatibant (Antonen et al., 2013). Here we report analysis of the pathophysiology which indicated pronounced complement activation, prolonged leukocytosis, extensive fibrinolysis, circulating histones, and defects in liver function. The patient had an uncommon HLA-phenotype, which may have contributed to the severe course of the disease.

Human hantavirus infections: epidemiology, clinical features, pathogenesis and immunology.

In humans, hantaviruses can cause haemorrhagic fever with renal syndrome (HFRS) or hantavirus cardiopulmonary syndrome (HCPS). Currently it is estimated that 150,000 to 200,000 cases of hantavirus disease occur each year, the majority being reported in Asia. However, human hantavirus infections are increasingly reported in the Americas and Europe. Although many of the underlying pathogenic mechanisms still remain unclear, recent evidence rather argues against a purely immune-mediated pathophysiology of human disease. Despite the high morbidity and case-fatality rates of HFRS and HCPS, respectively, no vaccine or drug is currently proven to be preventive or therapeutic. This review summarises clinical features and current epidemiological findings, as well as concepts regarding the immunology, pathogenesis and intervention strategies of human hantaviral diseases.

The murine model for Hantaan virus-induced lethal disease shows two distinct paths in viral evolutionary trajectory with and without ribavirin treatment.

In vitro, ribavirin acts as a lethal mutagen in Hantaan virus (HTNV)-infected Vero E6 cells, resulting in an increased mutation load and viral population extinction. In this study, we asked whether ribavirin treatment in the lethal, suckling mouse model of HTNV infection would act similarly. The HTNV genomic RNA (vRNA) copy number and infectious virus were measured in lungs of untreated and ribavirin-treated mice. In untreated, HTNV-infected mice, the vRNA copy number increased for 10 days postinfection (dpi) and thereafter remained constant through 26 dpi. Surprisingly, in ribavirin-treated, HTNV-infected mice, vRNA levels were similar to those in untreated mice between 10 and 26 dpi. Infectious virus levels, however, were different: in ribavirin-treated mice, the amount of infectious HTNV was significantly decreased relative to that in untreated mice, suggesting that ribavirin reduced the specific infectivity of the virus (amount of infectious virus produced per vRNA copy). Mutational analysis revealed a ribavirin-associated elevation in mutation frequency in HTNV vRNA similar to that previously reported in vitro. Codon-based analyses of rates of nonsynonymous (dN) and synonymous (dS) substitutions in the S segment revealed a positive selection for codons within the HTNV N protein gene in the ribavirin-treated vRNA population. In contrast, the vRNA population in untreated, HTNV-infected mice showed a lower level of diversity, reflecting purifying selection for the wild-type genome. In summary, these experiments show two different evolutionary paths that Hantavirus may take during infection in a lethal murine model of disease, as well as the importance of the in vivo host environment in the evolution of the virus, which was not apparent in our prior in vitro model system.

[Acalculous cholecystitis in hantavirus infections]. / Akalkulöse Cholezystitis bei Hantavirusinfektionen.

HISTORY AND ADMISSION FINDINGS: Three men, aged 32, 56 and 41 years, respectively, were hospitalized within two weeks because of flu-like symptoms, limb pain and abdominal pain. Being in a febrile, impaired general condition, pressure pains in the upper abdomen and flank pains were particularly noteworthy. INVESTIGATIONS: The results of the examinations, indicating acute renal insufficiency, thrombocytopenia and elevated lactate dehydrogenase were typical of a hantavirus infection, and positive serology for the puumala virus confirmed this suspicion. Ultrasonography indicated nephritic changes in all cases. Striking and unusual, however, was the finding of an acalculous cholecystitis. TREATMENT AND COURSE: In one of the three cases, antibiotic therapy with ceftriaxone was performed, in the other two cases symptomatic therapy. The cholecystitis was closely monitored sonographically and healed without complications in all cases. CONCLUSIONS: Hantavirus infections are common in an endemic area such as the Swabian Alb in Southern Germany, but an acalculous cholecystitis was rarely described in such a context. This accumulation is very remarkable, and the knowledge about it can both help to detect complications at an early stage and prevent unnecessary cases of cholecystectomy.

[Systemic hantavirus-infection in a comatose HIV patient]. / Systemische Hantavirus-Infektion bei einem komatösen HIV Patienten.

SYMPTOMS: A 40 year old, disoriented, HIV- and Hepatitis B positive male patient was admitted with 40.3 °C. Clinically he presented a sinustachycardia (160/min) and hypotension (70/60 mmHg). INVESTIGATIONS/DIAGNOSIS: Laboratory analyses showed elevated infection parameters, azotemia, proteinuria and thrombopenia. CD(4+)T-helper cells: 320/µl (32 %), HIV RNA: <40 copies/ml, Hepatitis B DNA: 20800 copies/ml. Hantavirus serology (immunofluorescence antibody assay): 1:2048; serotype Puumala. TREATMENT/COURSE: An early-goal-directed therapy and antibiotic treatment with Piperacillin and Tazobactam was initiated. The patient developed a bipulmonal infiltrate and an acute respiratory distress syndrome (ARDS ) requiring tracheal intubation, as well as a triad of fever, renal failure and profound hemorrhagic symptoms. This led to the diagnosis of the Puumala infection. Due to the parallel HIV- and Hepatits B infection an antiretroviral therapy was initiated. CONCLUSION: In summary the Puumala infection bears the potential for a severe multi-organ failure, which is not typical for this usually benign infection.

Establishment of SYBR green-based qPCR assay for rapid evaluation and quantification for anti-Hantaan virus compounds in vitro and in suckling mice.

Hantaan viruses cause two severe diseases lacking efficient treatment, yet no effective prophylactic vaccines are available. Continued exploration of alternative antiviral agents to treat hantavirus-related syndromes remains compulsory. The fluorescence-based quantitative real-time PCR (qPCR) has become the touchstone for target gene quantification. In the present study, standard curves for Hantaan virus (HTNV), mouse, and human glyceraldehyde-3-phosphate dehydrogenase (GAPDH) were generated by serial 10-fold dilutions of the constructed recombinant plasmid pGEM-T/HTNV, pGEM-T/mouse-GAPDH, and pGEM-T/human-GAPDH, respectively. Comparisons between the indirect immunofluorescence assay and qPCR assay in the detection of HTNV-infected Vero E6 cells showed improved detection limit and sensitivity of latter method. To characterize the inhibitory effect of several conventional antivirals (arbidol and ribavirin) and unconventional antivirals (indomethacin and curcumin) on HTNV, the levels of viral RNAs were measured for 4 days post-treatment of HTNV-infected Vero E6 cells and 18 days post-inoculation of HTNV-infected suckling mice. Our results validated that HTNV was sensitive to ribavirin and arbidol treatment, while indomethacin and curcumin may also be therapeutically effective in treating HTNV infection. As a result, the establishment and application of qPCR may be a useful tool for the evaluation of potential antivirals for Hantaan virus infection in vitro and in vivo.

Ibuprofen or diclofenac is associated with more severe acute kidney injury in nephropathia epidemica.

OBJECTIVE: In many parts of Europe, nephropathia epidemica (NE) is an endemic zoonosis. After a flu-like prodrome, this viral disease often manifests with acute kidney injury. Use of non-steroidal anti-inflammatory drugs is discouraged during the disease, but no data from clinical investigations are available on the association between disease course and the use of analgesics. MATERIAL AND METHODS: The charts of 59 patients admitted with NE to a hospital in 2007 were retrospectively analysed. Creatinine levels were compared between users of different analgesics. RESULTS: Patients taking analgesics before admission had higher peak creatinine levels, but not after adjustment for confounders. The subgroup taking ibuprofen or diclofenac had higher initial and peak creatinine levels than the group who did not, even after adjustment for confounders. CONCLUSION: Since NE cannot be accurately diagnosed in the early disease phase, metamizole, acetaminophen or acetylsalicylic acid may be preferable analgesics to ibuprofen or diclofenac for flu-like symptoms in endemic areas.

Hantavirus pulmonary syndrome.

Hantavirus pulmonary syndrome (HPS) is a severe disease characterized by a rapid onset of pulmonary edema followed by respiratory failure and cardiogenic shock. The HPS associated viruses are members of the genus Hantavirus, family Bunyaviridae. Hantaviruses have a worldwide distribution and are broadly split into the New World hantaviruses, which includes those causing HPS, and the Old World hantaviruses [including the prototype Hantaan virus (HTNV)], which are associated with a different disease, hemorrhagic fever with renal syndrome (HFRS). Sin Nombre virus (SNV) and Andes virus (ANDV) are the most common causes of HPS in North and South America, respectively. Case fatality of HPS is approximately 40%. Pathogenic New World hantaviruses infect the lung microvascular endothelium without causing any virus induced cytopathic effect. However, virus infection results in microvascular leakage, which is the hallmark of HPS. This article briefly reviews the knowledge on HPS-associated hantaviruses accumulated since their discovery, less than 20 years ago.