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.

Differences in the Susceptibility of Human Tubular Epithelial Cells for Infection with Orthohantaviruses.

Diseases induced by infection with pathogenic orthohantaviruses are characterized by a pronounced organ-specific manifestation. Pathogenic Eurasian orthohantaviruses cause hemorrhagic fever with renal syndrome (HFRS) with often massive proteinuria. Therefore, the use of a relevant kidney cell culture would be favorable to analyze the underlying cellular mechanisms of orthohantavirus-induced acute kidney injury (AKI). We tested different human tubular epithelial cell lines for their suitability as an in vitro infection model. Permissiveness and replication kinetics of highly pathogenic Hantaan virus (HTNV) and non-/low-pathogenic Tula virus (TULV) were analyzed in tubular epithelial cell lines and compared to human primary tubular epithelial cells. Ana-lysis of the cell line HK-2 revealed the same results for viral replication, morphological and functional effects as observed for HTNV in primary cells. In contrast, the cell lines RPTEC/TERT1 and TH1 demonstrated only poor infection rates after inoculation with HTNV and are unusable as an infection model. While pathogenic HNTV infects primary tubular and HK-2 cells, non-/low-pathogenic TULV infects neither primary tubular cells nor the cell line HK-2. Our results show that permissiveness of renal cells varies between orthohantaviruses with differences in pathogenicity and that HK-2 cells demonstrate a suitable in vitro model to study viral tropism and pathogenesis of orthohantavirus-induced AKI.

Liver-Support Therapies in Critical Illness-A Comparative Analysis of Procedural Characteristics and Safety.

Extracorporeal liver-support therapies remain controversial in critically ill patients, as most studies have failed to show an improvement in outcomes. However, heterogeneous timing and inclusion criteria, an insufficient number of treatments, and the lack of a situation-dependent selection of available liver-support modalities may have contributed to negative study results. We retrospectively investigated the procedural characteristics and safety of the three liver-support therapies CytoSorb, Molecular Adsorbent Recirculating System (MARS) and therapeutic plasma exchange (TPE). Whereas TPE had its strengths in a shorter treatment duration, in clearing larger molecules, affecting platelet numbers less, and improving systemic coagulation and hemodynamics, CytoSorb and MARS were associated with a superior reduction in particularly small protein-bound and water-soluble substances. The clearance magnitude was concentration-dependent for all three therapies, but additionally related to the molecular weight for CytoSorb and MARS therapy. Severe complications did not appear. In conclusion, a better characterization of disease-driving as well as beneficial molecules in critically ill patients with acute liver dysfunction is crucial to improve the use of liver-support therapy in critically ill patients. TPE may be beneficial in patients at high risk for bleeding complications and impaired liver synthesis and hemodynamics, while CytoSorb and MARS may be considered for patients in whom the elimination of smaller toxic compounds is a primary objective.

suPAR links a dysregulated immune response to tissue inflammation and sepsis-induced acute kidney injury.

Acute kidney injury (AKI) secondary to sepsis results in poor outcomes and conventional kidney function indicators lack diagnostic value. Soluble urokinase plasminogen activator receptor (suPAR) is an innate immune-derived molecule implicated in inflammatory organ damage. We characterized the diagnostic ability of longitudinal serum suPAR levels to discriminate severity and course of sepsis-induced AKI (SI-AKI) in 200 critically ill patients meeting Sepsis-3 criteria. The pathophysiologic relevance of varying suPAR levels in SI-AKI was explored in a polymicrobial sepsis model in WT, (s)uPAR-knockout, and transgenic suPAR-overexpressing mice. At all time points studied, suPAR provided a robust classification of SI-AKI disease severity, with improved prediction of renal replacement therapy (RRT) and mortality compared with established kidney biomarkers. Patients with suPAR levels of greater than 12.7 ng/mL were at highest risk for RRT or death, with an adjusted odds ratio of 7.48 (95% CI, 3.00-18.63). suPAR deficiency protected mice against SI-AKI. suPAR-overexpressing mice exhibited greater kidney damage and poorer survival through inflamed kidneys, accompanied by local upregulation of potent chemoattractants and pronounced kidney T cell infiltration. Hence, suPAR allows for an innate immune-derived and kidney function-independent staging of SI-AKI and offers improved longitudinal risk stratification. suPAR promotes T cell-based kidney inflammation, while suPAR deficiency improves SI-AKI.

Expression Profile of Human Renal Mesangial Cells Is Altered by Infection with Pathogenic Puumala Orthohantavirus.

Acute kidney injury (AKI) with proteinuria is a hallmark of infections with Eurasian orthohantaviruses. Different kidney cells are identified as target cells of hantaviruses. Mesangial cells may play a central role in the pathogenesis of AKI by regulation of inflammatory mediators and signaling cascades. Therefore, we examined the characteristics of hantavirus infection on human renal mesangial cells (HRMCs). Receptor expression and infection with pathogenic Puumala virus (PUUV) and low-pathogenic Tula virus (TULV) were explored. To analyze changes in protein expression in infected mesangial cells, we performed a proteome profiler assay analyzing 38 markers of kidney damage. We compared the proteome profile of in vitro-infected HRMCs with the profile detected in urine samples of 11 patients with acute hantavirus infection. We observed effective productive infection of HRMCs with pathogenic PUUV, but only poor abortive infection for low-pathogenic TULV. PUUV infection resulted in the deregulation of proteases, adhesion proteins, and cytokines associated with renal damage. The urinary proteome profile of hantavirus patients demonstrated also massive changes, which in part correspond to the alterations observed in the in vitro infection of HRMCs. The direct infection of mesangial cells may induce a local environment of signal mediators that contributes to AKI in hantavirus infection.

Cells of the human respiratory tract support the replication of pathogenic Old World orthohantavirus Puumala.

BACKGROUND: Transmission of all known pathogenic orthohantaviruses (family Hantaviridae) usually occurs via inhalation of aerosols contaminated with viral particles derived from infected rodents and organ manifestation of infections is characterized by lung and kidney involvement. Orthohantaviruses found in Eurasia cause hemorrhagic fever with renal syndrome (HFRS) and New World orthohantaviruses cause hantavirus cardiopulmonary syndrome (HCPS). However, cases of infection with Old World orthohantaviruses with severe pulmonary manifestations have also been observed. Therefore, human airway cells may represent initial targets for orthohantavirus infection and may also play a role in the pathogenesis of infections with Eurasian orthohantaviruses. METHODS: We analyzed the permissiveness of primary endothelial cells of the human pulmonary microvasculature and of primary human epithelial cells derived from bronchi, bronchioles and alveoli for Old World orthohantavirus Puumala virus (PUUV) in vitro. In addition, we examined the expression of orthohantaviral receptors in these cell types. To minimize donor-specific effects, cells from two different donors were tested for each cell type. RESULTS: Productive infection with PUUV was observed for endothelial cells of the microvasculature and for the three tested epithelial cell types derived from different sites of the respiratory tract. Interestingly, infection and particle release were also detected in bronchial and bronchiolar epithelial cells although expression of the orthohantaviral receptor integrin ß3 was not detectable in these cell types. In addition, replication kinetics and viral release demonstrate enormous donor-specific variations. CONCLUSIONS: The human respiratory epithelium is among the first targets of orthohantaviral infection and may contribute to virus replication, dissemination and pathogenesis of HFRS-causing orthohantaviruses. Differences in initial pulmonary infection due to donor-specific factors may play a role in the observed broad variance of severity and symptoms of orthohantavirus disease in patients. The absence of detectable levels of integrin αVß3 surface expression on bronchial and small airway epithelial cells indicates an alternate mode of orthohantaviral entry in these cells that is independent from integrin ß3.

Glomerular filtration barrier dysfunction in a self-limiting, RNA virus-induced glomerulopathy resembles findings in idiopathic nephrotic syndromes.

Podocyte injury has recently been described as unifying feature in idiopathic nephrotic syndromes (INS). Puumala hantavirus (PUUV) infection represents a unique RNA virus-induced renal disease with significant proteinuria. The underlying pathomechanism is unclear. We hypothesized that PUUV infection results in podocyte injury, similar to findings in INS. We therefore analyzed standard markers of glomerular proteinuria (e.g. immunoglobulin G [IgG]), urinary nephrin excretion (podocyte injury) and serum levels of the soluble urokinase plasminogen activator receptor (suPAR), a proposed pathomechanically involved molecule in INS, in PUUV-infected patients. Hantavirus patients showed significantly increased urinary nephrin, IgG and serum suPAR concentrations compared to healthy controls. Nephrin and IgG levels were significantly higher in patients with severe proteinuria than with mild proteinuria, and nephrin correlated strongly with biomarkers of glomerular proteinuria over time. Congruently, electron microcopy analyses showed a focal podocyte foot process effacement. suPAR correlated significantly with urinary nephrin, IgG and albumin levels, suggesting suPAR as a pathophysiological mediator in podocyte dysfunction. In contrast to INS, proteinuria recovered autonomously in hantavirus patients. This study reveals podocyte injury as main cause of proteinuria in hantavirus patients. A better understanding of the regenerative nature of hantavirus-induced glomerulopathy may generate new therapeutic approaches for INS.

Cell Cycle Biomarkers and Soluble Urokinase-Type Plasminogen Activator Receptor for the Prediction of Sepsis-Induced Acute Kidney Injury Requiring Renal Replacement Therapy: A Prospective, Exploratory Study.

OBJECTIVES: Sepsis-induced acute kidney injury is the dominant acute kidney injury etiology in critically ill patients and is often associated with a need for renal replacement therapy. The indication and timing of renal replacement therapy are controversially discussed. We hypothesized that the product of the G1-cell cycle arrest biomarkers tissue inhibitor of metalloproteinase-2 and insulin-like growth factor-binding protein 7 ([TIMP-2] × [IGFBP7]), and the soluble urokinase-type plasminogen activator receptor are of diagnostic value for the prediction of septic acute kidney injury courses requiring renal replacement therapy. DESIGN: In this prospective study, critically ill patients were enrolled immediately after the fulfillment of Sepsis-3 criteria. Urinary [TIMP-2] × [IGFBP7] levels over time and serum soluble urokinase-type plasminogen activator receptor levels once at inclusion were measured. The primary endpoint was the development of septic acute kidney injury with the need for renal replacement therapy. Area under the receiver operating characteristic curves, de Long's tests, and logistic regression models were calculated. SETTING: Two ICUs at Heidelberg University Hospital between May 2017 and July 2018. PATIENTS: One-hundred critically ill patients with positive Sepsis-3 criteria. INTERVENTIONS: None. MEASUREMENT AND MAIN RESULTS: Nineteen patients required renal replacement therapy. Diagnostic performance of urinary [TIMP-2] × [IGFBP7] improved over time with the highest area under the receiver operating characteristic curve of 0.89 (95% CI, 0.80-0.98) 24 hours after study inclusion. Soluble urokinase-type plasminogen activator receptor levels at inclusion showed an area under the receiver operating characteristic curve of 0.83 (0.75-0.92). The best discrimination ability for the primary outcome measure was achieved for [TIMP-2] × [IGFBP7] at 24 hours after inclusion by applying a cutoff value of greater than or equal to 0.6 (ng/mL)/1,000 (sensitivity 90.9, specificity 67.1). Soluble urokinase-type plasminogen activator receptor performed best by using a cutoff value of greater than or equal to 8.53 ng/mL (sensitivity 84.2, specificity 82.7). A combination of newly tested biomarkers with cystatin C resulted in a significantly improved diagnostic accuracy. Cystatin C in combination with [TIMP-2] × [IGFBP7] 24 hours outperformed all standard renal parameters (area under the receiver operating characteristic curve 0.93 [0.86-1.00]). CONCLUSIONS: [TIMP-2] × [IGFBP7] and soluble urokinase-type plasminogen activator receptor are promising biomarker candidates for the risk stratification of septic acute kidney injury patients with the need for renal replacement therapy.

Analysis of the integrin ß3 receptor for pathogenic orthohantaviruses in rodent host species.

Host reservoir specificity of pathogens is complex and may depend on receptor variability. For pathogenic orthohantaviruses, integrin ß3 had been previously identified as entry receptor and the presence of aspartic acid residue at position 39 (D39) in human integrin ß3 was described to be a prerequisite for infection of primate cells with Hantaan virus (HTNV). However, the role of integrin ß3 in orthohantavirus infection of host animals is not completely understood. Therefore, we analyzed the nucleotide sequence of the integrin ß3 gene of Myodes glareolus and Apodemus agrarius, the hosts of Puumala virus (PUUV) and HTNV, respectively. Sequence analysis in tissue samples demonstrated that the amino acid residue D39 is not present in integrin ß3 of these natural orthohantavirus hosts. Furthermore, we analyzed the transcription and protein expression levels of integrin ß3 in the renal cell line BVK168 generated from the PUUV host, bank vole. Transcription level of integrin ß3 was 100-fold lower in BVK168 cells than in Vero E6 cells and integrin ß3 expression was not detectable in BVK168 cells. However, despite the absence of amino acid residue D39 and no detectable integrin ß3 expression, BVK168 cells are susceptible to infection with both PUUV and HTNV. These results indicate that the mechanism of orthohantaviral entry in rodent species does not correspond to the requirements that were described for the entry in primate cells in vitro.

Virus- and cell type-specific effects in orthohantavirus infection.

Orthohantaviruses Hantaan (HTNV) and Puumala (PUUV) virus cause hemorrhagic fever with renal syndrome (HFRS), that is characterized by acute renal failure with often massive proteinuria and by morphological changes of the tubular and glomerular apparatus. Orthohantaviral N protein is found in renal cells and plays a key role in replication. However, the replication in human renal cells is not well characterized. Therefore, we examined the orthohantaviral infection in different human renal cells. Differences in localization of N protein, release of particles, and modulation of the actin cytoskeleton between both virus species are observed in human renal cells. A substantial portion of HTNV N protein demonstrates a filamentous pattern in addition to the typical punctate pattern. Release of HTNV depends on an intact actin and microtubule cytoskeleton. In contrast, PUUV N protein is generally localized in a punctate pattern and release of PUUV does not require an intact actin cytoskeleton. Infection of podocytes results in cytoskeletal rearrangements that are more pronounced for HTNV. Analyzing Vero E6 cells revealed differences compared to human renal cells. The pattern of N proteins is strictly punctate, release does not depend on an intact actin cytoskeleton and cytoskeletal rearrangements are not present. No virus-specific variations between HTNV and PUUV are observed in Vero E6 cells. Using human renal cells as cell culture model for orthohantavirus infection demonstrates virus-specific differences and orthohantavirus-induced cytoskeletal rearrangements that are not observed in Vero E6 cells. Therefore, the choice of an appropriate cell culture system is a prerequisite to study orthohantavirus pathogenicity.

Motility of human renal cells is disturbed by infection with pathogenic hantaviruses.

BACKGROUND: Hemorrhagic fever with renal syndrome (HFRS) caused by pathogenic hantaviruses in Europe and Asia is often characterized by acute kidney injury (AKI) with massive proteinuria. Renal filtration depends on the integrity of epithelial and endothelial monolayers in the tubular and glomerular apparatus. Tubular and glomerular cells represent target cells of hantavirus infection. However, the detailed mechanisms of renal impairment induced by hantaviruses are not well understood. METHODS: We analyzed the cellular consequences of hantavirus infection by measuring adhesion and migration capacity of human renal cells infected with Puumala (PUUV) or Hantaan (HTNV) virus. The impact of hantaviral nucleocapsid proteins (N proteins) on motility was examined by transfection of podocytes. RESULTS: Infection of kidney cells with hantavirus species PUUV and HTNV causes a significant reduction of migration capacity. The impaired motility depends on viral replication and transfection of podocytes with N protein of PUUV or HTNV reveals that the expression of N protein alone is sufficient to deteriorate podocyte function. The cellular effects are more pronounced for the more pathogenic HTNV than for PUUV that causes a milder form of HFRS. CONCLUSIONS: The direct impairment of migration capacity of renal cells by hantaviral N proteins may contribute substantially to proteinuria observed in the clinical picture of hantavirus infection.

Deregulation of levels of angiopoietin-1 and angiopoietin-2 is associated with severe courses of hantavirus infection.

BACKGROUND: Hantavirus disease is characterized by endothelial dysfunction. Angiopoietin-1 (Ang-1) and its antagonist angiopoietin-2 (Ang-2) play a key role in the control of capillary permeability. Ang-1 is responsible for maintenance of cell-to-cell contacts whereas Ang-2 destabilizes monolayers. An imbalance of Ang-1 and Ang-2 levels results in enhanced permeability and capillary leakage. OBJECTIVES: To analyze the involvement of angiopoietins in hantavirus-induced disruption of endothelia, we measured the levels of Ang-1 and Ang-2 in hantavirus infection. STUDY DESIGN: Levels of angiopoietins of 31 patients with acute Puumala virus (PUUV) infection and a patient infected with Dobrava-Belgrade virus genotype Sochi (DOBV-Sochi) were analyzed. An age-matched group of 16 healthy volunteers served as control. The ratios of Ang-2 to Ang-1 levels were calculated and correlated with laboratory parameters. RESULTS: Patients with PUUV and DOBV-Sochi infection exhibited elevated ratios of Ang-2/Ang-1 compared to the control group. The imbalance of Ang-2 to Ang-1 levels was observed early after onset of symptoms and lasted for the acute phase of infection. The deregulation in DOBV-Sochi infection was more prominent than in PUUV infection. Analysis of Ang-2/Ang-1 ratio and laboratory parameters in the PUUV cohort revealed a positive correlation with serum creatinine and a negative correlation with serum albumin and thrombocyte levels. CONCLUSIONS: We observed an imbalance between levels of Ang-1 and Ang-2 in patients infected with PUUV and DOBV-Sochi. Elevated Ang-2/Ang-1 ratios correlate with disease severity. The virus-induced deregulation of angiopoietin levels may enhance capillary permeability and contribute to the pathogenesis of hantavirus disease.

Clinical characterization of two severe cases of hemorrhagic fever with renal syndrome (HFRS) caused by hantaviruses Puumala and Dobrava-Belgrade genotype Sochi.

BACKGROUND: Hantavirus disease belongs to the emerging infections. The clinical picture and severity of infections differ between hantavirus species and may even vary between hantavirus genotypes. The mechanisms that lead to the broad variance of severity in infected patients are not completely understood. Host- and virus-specific factors are considered. CASE PRESENTATION: We analyzed severe cases of hantavirus disease in two young women. The first case was caused by Puumala virus (PUUV) infection in Germany; the second case describes the infection with Dobrava-Belgrade virus (DOBV) in Russia. Symptoms, laboratory parameters and cytokine levels were analyzed and compared between the two patients. Serological and sequence analysis revealed that PUUV was the infecting agent for the German patient and the infection of the Russian patient was caused by Dobrava-Belgrade virus genotype Sochi (DOBV-Sochi). The symptoms in the initial phase of the diseases did not differ noticeably between both patients. However, deterioration of laboratory parameter values was prolonged and stronger in DOBV-Sochi than in PUUV infection. Circulating endothelial progenitor cells (cEPCs), known to be responsible for endothelial repair, were mobilized in both infections. Striking differences were observed in the temporal course and level of cytokine upregulation. Levels of angiopoietin-2 (Ang-2), vascular endothelial growth factor (VEGF), and stromal derived factor-1 (SDF-1α) were increased in both infections; but, sustained and more pronounced elevation was observed in DOBV-Sochi infection. CONCLUSIONS: Severe hantavirus disease caused by different hantavirus species did not differ in the general symptoms and clinical characteristics. However, we observed a prolonged clinical course and a late and enhanced mobilization of cytokines in DOBV-Sochi infection. The differences in cytokine deregulation may contribute to the observed variation in the clinical course.

Old World hantaviruses: aspects of pathogenesis and clinical course of acute renal failure.

Hantavirus-associated diseases represent emerging infections that are ranked in the highest priority group of communicable diseases for surveillance and epidemiological research. In the last years, several novel hantavirus species were described and the number of host reservoir species harboring hantaviruses is also increasing. Reports of cases with severe or atypical clinical courses become also more frequent. These facts raise more and more questions concerning host reservoir specificity, pathogenicity and molecular mechanism of pathogenesis. Hantavirus disease is characterized by vascular leakage due to increased capillary permeability. The infection manifests often in the lung (hantaviral cardiopulmonary syndrome; HCPS) or in the kidney (hemorrhagic fever with renal syndrome, HFRS). The underlying mechanisms of both syndromes are probably similar despite the difference in organ tropism. Characterization of hantaviral replication cycle and of patient-specific determinants will help to identify factors responsible for the clinical symptoms and course.

Mobilization of circulating endothelial progenitor cells correlates with the clinical course of hantavirus disease.

Infections with hemorrhagic fever viruses are characterized by increased permeability leading to capillary leakage. Hantavirus infection is associated with endothelial dysfunction, and the clinical course is related to the degree of vascular injury. Circulating endothelial progenitor cells (cEPCs) play a pivotal role in the repair of the damaged endothelium. Therefore, we analyzed the number of cEPCs and their mobilizing growth factors in patients suffering from hantavirus disease induced by infection with Puumala virus. The numbers of EPCs of 36 hantavirus-infected patients and age- and gender-matched healthy controls were analyzed by flow cytometry. Concentrations of cEPC-mobilizing growth factors in plasma were determined by enzyme-linked immunosorbent assay. Laboratory parameters were correlated with the number of cEPCs. In patients infected with hantavirus, the number of cEPCs was significantly higher than that in healthy controls. Levels of mobilizing cytokines were upregulated in patients, and the mobilization of cEPCs is paralleled with the normalization of clinical parameters. Moreover, higher levels of cEPCs correlated with higher serum albumin levels and platelet concentrations. Our data indicate that cEPCs may play a role in the repair of hantavirus-induced endothelial damage, thereby influencing the clinical course and the severity of symptoms.

No gender-related differences in the severity of nephropathia epidemica, Germany.

BACKGROUND: The number of cases of hantavirus disease caused by Puumala virus is increasing enormously in Germany within the last years. Men are overrepresented in hantavirus disease and differences in course and symptoms in relation to gender were reported from several countries. This study was conducted to define possible gender-specific risk factors and aspects of severity in hantavirus infections occurring in Germany. METHODS: Characteristics, clinical parameters and symptoms were recorded in a retrospective analysis of 108 patients with serologically confirmed hantavirus infection treated in our department. This cohort corresponds in regard to age, time of infection and gender ratio to the characteristics of the overall cases reported in Germany. RESULTS: The frequency of characteristic symptoms of hantavirus disease did not differ between males and females. The median of nadir and peak levels of clinical parameters did not exhibit relevant differences that would point to a more severe course in males or females. The clinical course and duration of hospitalization were similar for both sexes. No relevant differences in renal and pulmonary findings were observed. Males with hantavirus disease exhibited more cardiac findings than females.To compare the unequal gender distribution of the rodent-borne Puumala hantavirus disease with the gender ratio of other infectious diseases, we analyzed the gender ratio for notifiable infections according to their mode of transmission. Our data revealed a general overrepresentation of men in infections carried by arthropods and rodents. CONCLUSIONS: In contrast to reports from other countries, no crucial differences in the symptoms, course or severity of hantavirus disease between infected men and female were observed in our cohort. However behavioural differences may account for the fact that men are more often affected by certain infectious diseases than females.

Hantavirus infection: an emerging infectious disease causing acute renal failure.

The function of the kidney with its highly differentiated and specialized cell types is affected by infection with several viruses. Viral infections of the kidney have a negative impact not only on patients undergoing renal transplantation and immunosuppression. Besides the increasing number of patients suffering from HIV-associated nephropathy, another group of viruses infects immunocompetent patients and induces renal failure. Hantaviruses belong nowadays to the emerging zoonoses that increase in number and geographic distribution. The viruses are distributed worldwide in endemic areas and distribution seems to expand. Together with the increase in the number of cases in the last few years, the understanding of epidemiology and pathology has deepened and some concepts had to be changed. Symptoms and mortality vary between species. The classification refers to geographical distribution: New World hantaviruses causing hantavirus cardiopulmonary syndrome (HCPS) and Old World hantaviruses causing hemorrhagic fever with renal syndrome (HFRS). Indeed, in most HFRS cases, the kidney is mainly affected and HCPS is characterized by cardiopulmonary involvement. But the picture of strict organ tropism is changing and reports of pulmonary findings and nonrenal manifestations in infections with Old World hantaviruses are increasing. However, the overall symptoms-vascular alterations and leakage-that are responsible for organ failure are characteristic for all diseases caused by hantaviruses.

[Hantaviruses in Germany: threat for zoo, pet, companion and farm animals?]. / Hantaviren in Deutschland: Gefahren für Zoo-, Heim-, Haus- und Nutztier?

Hantaviruses are so-called "emerging" and "re-emerging" viruses because of the new and sudden nature of their appearance. Human infections can lead to two distinct disease patterns, the Haemorrhagic Fever with Renal Syndrome and the Hantavirus Cardiopulmonary Syndrome. All known human pathogenic hantaviruses are transmitted through rodent hosts. There are three rodent-associated hantaviruses in Germany. The bank vole-associated Puumala virus (PUUV) is responsible for most of the human hantavirus infections. The Dobrava-Belgrade virus (DOBV) associated with the striped field mouse is causing hantavirus disease in the North and Northeast of Germany. The human pathogenicity of Tula virus (TULV) is still controversially discussed--the virus has been mainly associated with the common vole as the reservoir, but was molecularly detected also in the field and the water vole. More recently, two shrew-borne hantaviruses were described in Germany, i. e. Seewis virus in the common shrew and Asikkala virus in the pygmy shrew. Systematic studies about hantavirus infections of zoo, pet, companion and farm animals are still lacking. Hence, the aim of this review article is to summarise the current knowledge on this topic and raise the attention of veterinarians to potentially overlooked clinical disease patterns.

Polar release of pathogenic Old World hantaviruses from renal tubular epithelial cells.

BACKGROUND: Epithelio- and endotheliotropic viruses often exert polarized entry and release that may be responsible for viral spread and dissemination. Hantaviruses, mostly rodent-borne members of the Bunyaviridae family infect epithelial and endothelial cells of different organs leading to organ dysfunction or even failure. Endothelial and renal epithelial cells belong to the target cells of Old World hantavirus. Therefore, we examined the release of hantaviruses in several renal epithelial cell culture models. We used Vero cells that are commonly used in hantavirus studies and primary human renal epithelial cells (HREpC). In addition, we analyzed MDCKII cells, an epithelial cell line of a dog kidney, which represents a widely accepted in vitro model of polarized monolayers for their permissiveness for hantavirus infection. RESULTS: Vero C1008 and primary HREpCs were grown on porous-support filter inserts for polarization. Monolayers were infected with hantavirus Hantaan (HTNV) and Puumala (PUUV) virus. Supernatants from the apical and basolateral chamber of infected cells were analyzed for the presence of infectious particles by re-infection of Vero cells. Viral antigen and infectious particles of HTNV and PUUV were exclusively detected in supernatants collected from the apical chamber of infected Vero C1008 cells and HREpCs. MDCKII cells were permissive for hantavirus infection and polarized MDCKII cells released infectious hantaviral particles from the apical surface corresponding to the results of Vero and primary human epithelial cells. CONCLUSIONS: Pathogenic Old World hantaviruses are released from the apical surface of different polarized renal epithelial cells. We characterized MDCKII cells as a suitable polarized cell culture model for hantavirus infection studies.