Mortality rate patterns for hemorrhagic fever with renal syndrome caused by Puumala virus

Smoking Is a Risk Factor for Severe Acute Kidney Injury in Hantavirus-Induced Nephropathia Epidemica

BACKGROUND/AIMS

Hantaviruses are zoonotic pathogens causing emerging diseases worldwide. Patients typically present with fever, acute kidney injury (AKI) and thrombocytopenia. Puumala virus (PUUV) that causes nephropathia epidemica (NE) is common in Germany. Recently, a study from Finland revealed an association between nicotine consumption and the severity of AKI in NE. Differences between individuals in Finland and Germany might modulate the effect; therefore, the aim of our study was to prove that smoking is a risk factor for a severe course of NE in Germany.

METHODS

A cross-sectional prospective survey of 485 patients with hantavirus infections was performed. Clinical and laboratory data during the acute course of the disease were obtained from medical reports and files, while follow-up (including smoking status) data were collected prospectively.

RESULTS

Smoking information was available for 298 out of 485 patients (61%). Male was the predominant gender (67%), median age at the time of diagnosis was 50 (interquartile range, IQR 41-60) years and 34% of patients were current smokers during the phase of acute NE. Patients in the smoking group were significantly younger than in the non-smoking group (p < 0.0001). Peak serum creatinine levels were significantly higher in the smoking group than in the non-smoking patients (median 301 (IQR 186-469 μmol/l) vs. median 240 (IQR 137-469 μmol/l), p < 0.05). In addition, severe AKI (stages 2 and 3 using KDIGO criteria) was more common in current smokers (80%) than in the non-smokers (68%, p < 0.05).

CONCLUSION

Current smoking is a risk factor for severity of AKI in patients with acute PUUV infection in Germany. Therefore, information about smoking habits needs to be an integral part of the documentation in patients with suspected acute PUUV infection, and increased monitoring of kidney function should be done in NE patients who are current smokers.

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.

Clinical course and long-term outcome of hantavirus-associated nephropathia epidemica, Germany

The consequences of associated hematuria may be long-lasting, and hantavirus IgG is detectable years after acute infection.

Human infection with Puumala virus (PUUV), the most common hantavirus in Central Europe, causes nephropathia epidemica (NE), a disease characterized by acute kidney injury and thrombocytopenia. To determine the clinical phenotype of hantavirus-infected patients and their long-term outcome and humoral immunity to PUUV, we conducted a cross-sectional prospective survey of 456 patients in Germany with clinically and serologically confirmed hantavirus-associated NE during 2001–2012. Prominent clinical findings during acute NE were fever and back/limb pain, and 88% of the patients had acute kidney injury. At follow-up (7–35 mo), all patients had detectable hantavirus-specific IgG; 8.5% had persistent IgM; 25% had hematuria; 23% had hypertension (new diagnosis for 67%); and 7% had proteinuria. NE-associated hypertension and proteinuria do not appear to have long-term consequences, but NE-associated hematuria may. All patients in this study had hantavirus-specific IgG up to years after the infection.

Human hantavirus infections in the Netherlands

We report the recent epidemiology and estimated seroprevalence of human hantavirus infections in the Netherlands. Sixty-two cases were reported during December 2008-December 2013. The estimated seroprevalence in the screened municipalities in 2006-2007 was 1.7% (95% CI 1.3%-2.3%). Findings suggest that hantavirus infections are underdiagnosed in the Netherlands.

Smoking is associated with aggravated kidney injury in Puumala hantavirus-induced haemorrhagic fever with renal syndrome

BACKGROUND

Previous studies indicate that smoking affects the outcome of some infections and is a risk factor for Puumala virus (PUUV) infection. The aim of this study was to assess the effect of smoking on the clinical severity of PUUV infection and the prevalence of smoking in patients with PUUV infection.

METHODS

A questionnaire on smoking habits was sent to 494 patients in 2012, who had been treated in Tampere University Hospital, Finland, for serologically confirmed PUUV infection during years 1982-2012.

RESULTS

Of all patients, 357 (72%) participated. Maximum plasma creatinine level measured during acute illness was significantly higher in current smokers than in non-smokers (median: 273 versus 184 µmol/L, P < 0.001). Current smokers had a higher maximum blood leucocyte count than non-smokers (median: 10.8 versus 8.9 × 10(9)/L, P < 0.001) and they were younger than non-smokers (38 versus 45 years, P < 0.001). There were no differences between current smokers and non-smokers in the other variables reflecting the severity of PUUV infection. Altogether 51% were current smokers at the time of onset of the illness, 57% of males and 36% of females. During these years in Finland, smoking among males in the same aged population has decreased from 33 to 22% and among females, smoking has varied between 14 and 20%.

CONCLUSIONS

Smoking is common in patients with PUUV infection. Current smokers suffer from more severe acute kidney injury (AKI) and they have higher leucocyte count than non-smokers in PUUV infection. Smoking cessation decreases the risk of severe AKI to the same level as observed in never-smokers.

Determination of procalcitonin levels in patients with nephropathia epidemica - a useful tool or an unnecessary diagnostic procedure?

BACKGROUND/AIMS

Puumala virus causes nephropathia epidemica (NE), a milder form of hemorrhagic fever with renal syndrome that occurs in Central and Northern Europe. Several studies have sought to identify risk factors for severe NE. However, elevated procalcitonin (PCT) levels have not previously been investigated as a predictive marker for a severe course of NE.

METHODS

A cross-sectional prospective survey of 456 adults with serologically confirmed NE was performed.

RESULTS

PCT levels at the time of diagnosis were available for 43 out of 456 patients, and in 24 of these patients (56%) PCT levels were elevated ("PCT positive"). C-reactive protein (CRP) levels at admission to hospital and peak CRP levels during the acute course of the disease were higher in the PCT-positive compared with the PCT-negative group (p<0.05). Severe acute kidney injury (AKI) (RIFLE I and F) was present in similar numbers of PCT-positive and -negative patients (p=0.7), but antibiotics were more frequently used in the PCT-positive than the PCT-negative group (p<0.05). Within the PCT-positive group, PCT levels were similar among those receiving and not receiving antibiotics (p=0.13), and neither the duration of hospital stay nor CRP peak levels were lower in those treated with antibiotics (p=0.12 and p=0.13, respectively).

CONCLUSIONS

Elevated PCT levels are common in patients with acute NE. There was no association between PCT levels and severity of disease, including AKI or thrombocytopenia. It is important to distinguish Puumala virus infection from other causes of AKI with thrombocytopenia. However, PCT might not be useful in differentiating hantavirus infection from bacterial infection.

Single-Stranded RNA Viruses

In this chapter, we describe 73 zoonotic viruses that were isolated in Northern Eurasia and that belong to the different families of viruses with a single-stranded RNA (ssRNA) genome. The family includes viruses with a segmented negative-sense ssRNA genome (families Bunyaviridae and Orthomyxoviridae) and viruses with a positive-sense ssRNA genome (families Togaviridae and Flaviviridae). Among them are viruses associated with sporadic cases or outbreaks of human disease, such as hemorrhagic fever with renal syndrome (viruses of the genus Hantavirus), Crimean–Congo hemorrhagic fever (CCHFV, Nairovirus), California encephalitis (INKV, TAHV, and KHATV; Orthobunyavirus), sandfly fever (SFCV and SFNV, Phlebovirus), Tick-borne encephalitis (TBEV, Flavivirus), Omsk hemorrhagic fever (OHFV, Flavivirus), West Nile fever (WNV, Flavivirus), Sindbis fever (SINV, Alphavirus) Chikungunya fever (CHIKV, Alphavirus) and others. Other viruses described in the chapter can cause epizootics in wild or domestic animals: Geta virus (GETV, Alphavirus), Influenza A virus (Influenzavirus A), Bhanja virus (BHAV, Phlebovirus) and more. The chapter also discusses both ecological peculiarities that promote the circulation of these viruses in natural foci and factors influencing the occurrence of epidemic and epizootic outbreaks

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.

Acute kidney injury and tools for risk-stratification in 456 patients with hantavirus-induced nephropathia epidemica

BACKGROUND

Puumala virus (PUUV) is the most common species of hantavirus in Central Europe. Nephropathia epidemica (NE), caused by PUUV, is characterized by acute kidney injury (AKI) and thrombocytopenia. The major goals of this study were to provide a clear clinical phenotyping of AKI in patients with NE and to develop an easy prediction rule to identify patients, who are at lower risk to develop severe AKI.

METHODS

A cross-sectional prospective survey of 456 adult patients with serologically confirmed NE was performed. Data were collected from medical records and prospectively at follow-up visit. Severe AKI was defined by standard criteria according to the RIFLE (Risk, Injury, Failure, Loss, End-stage kidney disease) classification. Fuller statistical models were developed and validated to estimate the probability for severe AKI.

RESULTS

During acute NE, 88% of the patients had AKI according to the RILFE criteria during acute NE. A risk index score for severe AKI was derived by using three independent risk factors in patients with normal kidney function at time of diagnosis: thrombocytopenia [two points; odds ratios (OR): 3.77; 95% confidence intervals (CI): 1.82, 8.03], elevated C-reactive protein levels (one point; OR: 3.02; 95% CI: 1.42, 6.58) and proteinuria (one point; OR: 3.92; 95% CI: 1.33, 13.35). On the basis of a point score of one or two, the probability of severe AKI was 0.18 and 0.28 with an area under the curve of 0.71.

CONCLUSION

This clinical prediction rule provides a novel and diagnostically accurate strategy for the potential prevention and improved management of kidney complications in patients with NE and, ultimately, for a possible decrease in unnecessary hospitalization in a high number of patients.

Increased risk of acute myocardial infarction and stroke during hemorrhagic fever with renal syndrome: a self-controlled case series study

BACKGROUND

We recently observed that cardiovascular causes of death are common in patients with hemorrhagic fever with renal syndrome (HFRS), which is caused by hantaviruses. However, it is not known whether HFRS is a risk factor for the acute cardiovascular events of acute myocardial infarction (AMI) and stroke.

METHODS AND RESULTS

Personal identification numbers from the Swedish HFRS patient database (1997-2012; n=6643) were cross-linked with the National Patient Register from 1987 to 2011. Using the self-controlled case series method, we calculated the incidence rate ratio of AMI/stroke in the 21 days after HFRS against 2 different control periods either excluding (analysis 1) or including (analysis 2) fatal AMI/stroke events. The incidence rate ratios for analyses 1 and 2 for all AMI events were 5.53 (95% confidence interval [CI], 2.6-11.8) and 6.02 (95% CI, 2.95-12.3) and for first AMI events were 3.53 (95% CI, 1.25-9.96) and 4.64 (95% CI, 1.83-11.77). The incidence rate ratios for analyses 1 and 2 for all stroke events were 12.93 (95% CI, 5.62-29.74) and 15.16 (95% CI, 7.21-31.87) and for first stroke events were 14.54 (95% CI, 5.87-36.04) and 17.09 (95% CI, 7.49-38.96). The majority of stroke events occurred in the first week after HFRS. Seasonal effects were not observed, and apart from 1 study, neither sex nor age interacted with the associations observed in this study.

CONCLUSIONS

There is a significantly increased risk for AMI and stroke in the immediate time period after HFRS. Therefore, HFRS patients should be carefully monitored during the acute phase of disease to ensure early recognition of symptoms of impending AMI or stroke.

Vascular events in viral hemorrhagic fevers: a comparative study of dengue and hantaviruses

Viral hemorrhagic diseases are a group of systemic viral infections with worldwide distribution and are significant causes of global mortality and morbidity. The hallmarks of viral hemorrhagic fevers are plasma leakage, thrombocytopenia, coagulopathy and hemorrhagic manifestations. The molecular mechanisms leading to plasma leakage in viral hemorrhagic fevers are not well understood. A common theme has emerged in which a complex interplay between pathogens, host immune response, and endothelial cells leads to the activation of endothelial cells and perturbation of barrier integrity. In this article, two clinically distinct viral hemorrhagic fevers caused by dengue viruses and hantaviruses are discussed to highlight their similarities and differences that may provide insights into the pathogenesis and therapeutic approach.

Co-circulation of multiple hemorrhagic fever diseases with distinct clinical characteristics in Dandong, China

Hemorrhagic fevers (HF) caused by viruses and bacteria are a major public health problem in China and characterized by variable clinical manifestations, such that it is often difficult to achieve accurate diagnosis and treatment. The causes of HF in 85 patients admitted to Dandong hospital, China, between 2011–2012 were determined by serological and PCR tests. Of these, 34 patients were diagnosed with Huaiyangshan hemorrhagic fever (HYSHF), 34 with Hemorrhagic Fever with Renal Syndrome (HFRS), one with murine typhus, and one with scrub typhus. Etiologic agents could not be determined in the 15 remaining patients. Phylogenetic analyses of recovered bacterial and viral sequences revealed that the causative infectious agents were closely related to those described in other geographical regions. As these diseases have no distinctive clinical features in their early stage, only 13 patients were initially accurately diagnosed. The distinctive clinical features of HFRS and HYSHF developed during disease progression. Enlarged lymph nodes, cough, sputum, and diarrhea were more common in HYSHF patients, while more HFRS cases presented with headache, sore throat, oliguria, percussion pain kidney area, and petechiae. Additionally, HYSHF patients displayed significantly lower levels of white blood cells (WBC), higher levels of creations kinase (CK) and alanine aminotransferase (ALT), while HFRS patients presented with an elevation of blood urea nitrogen (BUN) and creatinine (CREA). These clinical features will assist in the accurate diagnosis of both HYSHF and HFRS. Overall, our data reveal the complexity of pathogens causing HFs in a single Chinese hospital, and highlight the need for accurate early diagnosis and a better understanding of their distinctive clinical features.

The major cellular sterol regulatory pathway is required for Andes virus infection

The Bunyaviridae comprise a large family of RNA viruses with worldwide distribution and includes the pathogenic New World hantavirus, Andes virus (ANDV). Host factors needed for hantavirus entry remain largely enigmatic and therapeutics are unavailable. To identify cellular requirements for ANDV infection, we performed two parallel genetic screens. Analysis of a large library of insertionally mutagenized human haploid cells and a siRNA genomic screen converged on components (SREBP-2, SCAP, S1P and S2P) of the sterol regulatory pathway as critically important for infection by ANDV. The significance of this pathway was confirmed using functionally deficient cells, TALEN-mediated gene disruption, RNA interference and pharmacologic inhibition. Disruption of sterol regulatory complex function impaired ANDV internalization without affecting virus binding. Pharmacologic manipulation of cholesterol levels demonstrated that ANDV entry is sensitive to changes in cellular cholesterol and raises the possibility that clinically approved regulators of sterol synthesis may prove useful for combating ANDV infection.

As obligate, intracellular parasites viruses are dependent upon the host cell for numerous factors and processes. However, for many important viruses few of the required host factors have been identified. Hantaviruses are rodent-borne viruses that are associated with severe human disease. Transmission to humans occurs sporadically with a recent notable example in Yosemite National park. In the present study, we utilized two independent genetic strategies to discover cellular factors needed for replication of the highly pathogenic hantavirus Andes virus. We found that four genes, encoding components of a complex involved in regulation of cholesterol synthesis and uptake, were critical for Andes virus infection. Drugs that inhibit an enzyme in this complex or that reduce cellular cholesterol levels effectively blocked Andes virus infection, suggesting new ways for combating this pathogenic virus.

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.

Seroprevalence of hantavirus infections in Switzerland in 2009: difficulties in determining prevalence in a country with low endemicity

Binary file ES_Abstracts_Final_ECDC.txt matches

Ongoing spillover of Hantaan and Gou hantaviruses from rodents is associated with hemorrhagic fever with renal syndrome (HFRS) in China

BACKGROUND

Longquan City, Zhejiang province, China, has been seriously affected by hemorrhagic fever with renal syndrome (HFRS) since the first cases were registered in 1974. To understand the epidemiology and emergence of HFRS in Longquan, which may be indicative of large parts of rural China, we studied long-term incidence patterns and performed a molecular epidemiological investigation of the causative hantaviruses in human and rodent populations.

METHOD/PRINCIPAL FINDINGS

During 1974-2011, 1866 cases of HFRS were recorded in Longquan, including 20 deaths. In 2011, the incidence of HFRS remained high, with 19.61 cases/100,000 population, despite the onset of vaccination in 1997. During 1974-1998, HFRS cases in Longquan occurred mainly in winter, while in the past decade the peak of HFRS has shifted to the spring. Notably, the concurrent prevalence of rodent-borne hantaviruses in the region was also high. Phylogenetic analyses of viral sequences recovered from rodents in Longquan revealed the presence of novel genetic variants of Gou virus (GOUV) in Rattus sp. rats and Hantaan virus (HTNV) in the stripe field mice, respectively. Strikingly, viral sequences sampled from infected humans were very closely related to those from rodents.

CONCLUSIONS/SIGNIFICANCE

HFRS represents an important public health problem in Longquan even after years of preventive measures. Our data suggest that continual spillover of the novel genetic variant of GOUV and the new genetic lineage of HTNV are responsible for the high prevalence of HFRS in humans. In addition, this is the first report of GOUV associated with human HFRS cases, and our data suggest that GOUV is now the major cause of HFRS in this region.

The pathogenesis of nephropathia epidemica: new knowledge and unanswered questions

Puumala virus (PUUV) causes an acute hemorrhagic fever with renal syndrome (HFRS), a zoonosis also called nephropathia epidemica (NE). The reservoir host of PUUV is the bank vole (Myodes glareolus). Herein we review the main clinical manifestations of NE, acute kidney injury, increased vascular permeability, coagulation abnormalities as well as pulmonary, cardiac, central nervous system and ocular manifestations of the disease. Several biomarkers of disease severity have recently been discovered: interleukin-6, pentraxin-3, C-reactive protein, indoleamine 2,3-dioxygenase, cell-free DNA, soluble urokinase-type plasminogen activator, GATA-3 and Mac-2 binding protein. The role of cytokines, vascular endothelial growth hormone, complement, bradykinin, cellular immune response and other mechanisms in the pathogenesis of NE as well as host genetic factors will be discussed. Finally therapeutic aspects and directions for further research will be handled.

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.

Viral load and humoral immune response in association with disease severity in Puumala hantavirus-infected patients--implications for treatment

Hantaviruses are the causative agents of haemorrhagic fever with renal syndrome (HFRS) in Eurasia and of hantavirus cardiopulmonary syndrome (HCPS) in the Americas. The case fatality rate varies between different hantaviruses and can be up to 40%. At present, there is no specific treatment available. The hantavirus pathogenesis is not well understood, but most likely, both virus-mediated and host-mediated mechanisms are involved. The aim of the present study was to investigate the association among Puumala hantavirus (PUUV) viral RNA load, humoral immune response and disease severity in patients with HFRS. We performed a study of 105 PUUV-infected patients that were followed during the acute phase of disease and for up to 1–3 months later. Fifteen of the 105 patients (14%) were classified as having moderate/severe disease. A low PUUV-specific IgG response (p <0.05) and also a higher white blood cell count (p <0.001) were significantly associated with more severe disease. The PUUV RNA was detected in a majority of patient plasma samples up to 9 days after disease onset; however, PUUV RNA load or longevity of viraemia were not significantly associated with disease severity. We conclude that a low specific IgG response was associated with disease severity in patients with HFRS, whereas PUUV RNA load did not seem to affect the severity of HFRS. Our results raise the possibility of passive immunotherapy as a useful treatment for hantavirus-infected patients.

Puumala virus infections associated with cardiovascular causes of death

We studied the causes of death of patients in Sweden with diagnoses of hemorrhagic fever with renal syndrome (HFRS) during 1997–2009. Cardiovascular disorders were a common cause of death during acute-phase HFRS and were the cause of death for >50% of those who died during the first year after HFRS.

Sex differences in prophylaxis and therapeutic treatments for viral diseases

The intensity and prevalence of viral infections are typically higher in males than in females. In contrast, disease outcome can be worse for females. Males and females also differ in their responses to prophylaxis and therapeutic treatments for viral diseases. In response to vaccines against herpes viruses, hepatitis viruses, influenza viruses, and others, females consistently mount higher humoral immune responses and experience more frequent and severe adverse reactions than males. Males and females also differ in the absorption, metabolism, and clearance of antiviral drugs. The pharmacological effects, including toxicity and adverse reactions, of antiviral drugs are typically greater in females than males. The efficacy of antiviral drugs at reducing viral load also differs between the sexes, with antiviral treatments being better at clearing HIV and hepatitis C virus in females, but showing greater reduction of herpes simplex virus and influenza A virus loads in males. Biological variables, including hormone and genes, as well as gender-specific factors related to access and compliance to drug regimens must be considered when evaluating male-female differences in responses to treatments for viral diseases. Clinicians, epidemiologists, and basic biomedical scientists should design experiments that include both males and females, develop a priori hypotheses that the sexes will differ in their responses to and the outcome of vaccines and antiviral treatments, and statistically analyze outcome data by sex. Knowledge that the sexes differ in response to prophylaxis and therapeutic treatments for viral diseases should influence the recommended course of treatment differently for males and females.

A severe case of Puumala hantavirus infection successfully treated with bradykinin receptor antagonist icatibant

A patient with severe capillary leakage syndrome caused by a Puumala hantavirus infection was treated with a single dose of icatibant, a bradykinin receptor antagonist, with a dramatic positive response. We suggest that this drug should be tested in a larger number of patients with severe hantavirus infection.

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.

Hantavirus infections in Europe and their impact on public health

Hantaviruses (genus Hantavirus, family Bunyaviridae) are enveloped tri-segmented negative-stranded RNA viruses each carried by a specific rodent or insectivore host species. Several different hantaviruses known to infect humans circulate in Europe. The most common is Puumala (PUUV) carried by the bank vole; another two important, genetically closely related ones are Dobrava-Belgrade (DOBV) and Saaremaa viruses (SAAV) carried by Apodemus mice (species names follow the International Committee on Taxonomy of Viruses nomenclature). Of the two hantaviral diseases, hemorrhagic fever with renal syndrome (HFRS) and hantaviral cardiopulmonary syndrome, the European viruses cause only HFRS: DOBV with often severe symptoms and a high case fatality rate, and PUUV and SAAV more often mild disease. More than 10,000 HFRS cases are diagnosed annually in Europe and in increasing numbers. Whether this is because of increasing recognition by the medical community or due to environmental factors such as climate change, or both, is not known. Nevertheless, in large areas of Europe, the population has a considerable seroprevalence but only relatively few HFRS cases are reported. Moreover, no epidemiological data are available from many countries. We know now that cardiac, pulmonary, ocular and hormonal disorders are, besides renal changes, common during the acute stage of PUUV and DOBV infection. About 5% of hospitalized PUUV and 16%-48% of DOBV patients require dialysis and some prolonged intensive-care treatment. Although PUUV-HFRS has a low case fatality rate, complications and long-term hormonal, renal, and cardiovascular consequences commonly occur. No vaccine or specific therapy is in general use in Europe. We conclude that hantaviruses have a significant impact on public health in Europe.

Sex differences in the incidence and case fatality rates from hemorrhagic fever with renal syndrome in China, 2004-2008

BACKGROUND

Differences between male and female individuals in response to infectious diseases are an overlooked global health problem.

METHODS

The relationship between sex and disease outcome was examined in populations of patients with hemorrhagic fever with renal syndrome (HFRS) in mainland China, where most cases of hantavirus exposure occur. HFRS in China is diagnosed on the basis of symptoms and is confirmed with serological testing. The geographical distribution, incidence, and case fatality rates (CFRs) of HFRS in China were estimated and compared by patient sex and age. In a subset of patients with HFRS, clinical manifestations of HFRS were assessed using latent class analysis and compared by sex.

RESULTS

There were 80,671 HFRS cases reported during the period 2004-2008, with a majority of HFRS cases (39.2%) occurring among individuals 20-39 years of age. The incidence of HFRS was higher among male patients than among female patients for all individuals >10 years of age. There were 945 deaths (CFR, 1.17%) due to HFRS in China during the period 2004-2008. CFRs were higher among women than among men between the ages of 20-39 and ≥ 50 years of age. There were no sex differences in the geographical distribution of HFRS cases or deaths. Although the prevalence of each clinical marker did not differ by sex, 2 profiles of clinical markers were identified that were related to both severity of disease and sex.

CONCLUSIONS

These data illustrate a paradox in which the incidence of disease is greater for males, but the severity of disease outcome is worse for females. Several behavioral, societal, and biological factors are hypothesized to be involved.

The fecal viral flora of wild rodents

The frequent interactions of rodents with humans make them a common source of zoonotic infections. To obtain an initial unbiased measure of the viral diversity in the enteric tract of wild rodents we sequenced partially purified, randomly amplified viral RNA and DNA in the feces of 105 wild rodents (mouse, vole, and rat) collected in California and Virginia. We identified in decreasing frequency sequences related to the mammalian viruses families Circoviridae, Picobirnaviridae, Picornaviridae, Astroviridae, Parvoviridae, Papillomaviridae, Adenoviridae, and Coronaviridae. Seventeen small circular DNA genomes containing one or two replicase genes distantly related to the Circoviridae representing several potentially new viral families were characterized. In the Picornaviridae family two new candidate genera as well as a close genetic relative of the human pathogen Aichi virus were characterized. Fragments of the first mouse sapelovirus and picobirnaviruses were identified and the first murine astrovirus genome was characterized. A mouse papillomavirus genome and fragments of a novel adenovirus and adenovirus-associated virus were also sequenced. The next largest fraction of the rodent fecal virome was related to insect viruses of the Densoviridae, Iridoviridae, Polydnaviridae, Dicistroviriade, Bromoviridae, and Virgaviridae families followed by plant virus-related sequences in the Nanoviridae, Geminiviridae, Phycodnaviridae, Secoviridae, Partitiviridae, Tymoviridae, Alphaflexiviridae, and Tombusviridae families reflecting the largely insect and plant rodent diet. Phylogenetic analyses of full and partial viral genomes therefore revealed many previously unreported viral species, genera, and families. The close genetic similarities noted between some rodent and human viruses might reflect past zoonoses. This study increases our understanding of the viral diversity in wild rodents and highlights the large number of still uncharacterized viruses in mammals.

Rodents are the natural reservoir of numerous zoonotic viruses causing serious diseases in humans. We used an unbiased metagenomic approach to characterize the viral diversity in rodent feces. In addition to diet-derived insect and plant viruses mammalian viral sequences were abundant and diverse. Most notably, multiple new circular viral DNA families, two new picornaviridae genera, and the first murine astrovirus and picobirnaviruses were characterized. A mouse kobuvirus was a close relative to the Aichi virus human pathogen. This study significantly increases the known genetic diversity of eukaryotic viruses in rodents and provides an initial description of their enteric viromes.

Evidence of disseminated intravascular coagulation in a hemorrhagic fever with renal syndrome-scoring models and severe illness

BACKGROUND

Viral hemorrhagic fevers (VHF) are considered to be a serious threat to public health worldwide with up to 100 million cases annually. The general hypothesis is that disseminated intravascular coagulation (DIC) is an important part of the pathogenesis. The study objectives were to study the variability of DIC in consecutive patients with acute hemorrhagic fever with renal syndrome (HFRS), and to evaluate if different established DIC-scores can be used as a prognostic marker for a more severe illness.

METHOD AND FINDINGS

In a prospective study 2006-2008, data from 106 patients with confirmed HFRS were analyzed and scored for the presence of DIC according to six different templates based on criteria from the International Society on Thrombosis and Haemostasis (ISTH). The DIC-scoring templates with a fibrinogen/CRP-ratio were most predictive, with predictions for moderate/severe illness (p<0.01) and bleeding of moderate/major importance (p<0.05). With these templates, 18.9-28.3% of the patients were diagnosed with DIC.

CONCLUSIONS

DIC was found in about one fourth of the patients and correlated with a more severe disease. This supports that DIC is an important part of the pathogenesis in HFRS. ISTH-scores including fibrinogen/CRP-ratio outperform models without. The high negative predictive value could be a valuable tool for the clinician. We also believe that our findings could be relevant for other VHFs.

Infection of human monocyte-derived dendritic cells by ANDES Hantavirus enhances pro-inflammatory state, the secretion of active MMP-9 and indirectly enhances endothelial permeability

Background

Andes virus (ANDV), a rodent-borne Hantavirus, is the major etiological agent of Hantavirus cardiopulmonary syndrome (HCPS) in South America, which is mainly characterized by a vascular leakage with high rate of fatal outcomes for infected patients. Currently, neither specific therapy nor vaccines are available against this pathogen. ANDV infects both dendritic and epithelial cells, but in despite that the severity of the disease directly correlates with the viral RNA load, considerable evidence suggests that immune mechanisms rather than direct viral cytopathology are responsible for plasma leakage in HCPS. Here, we assessed the possible effect of soluble factors, induced in viral-activated DCs, on endothelial permeability. Activated immune cells, including DC, secrete gelatinolytic matrix metalloproteases (gMMP-2 and -9) that modulate the vascular permeability for their trafficking.

Methods

A clinical ANDES isolate was used to infect DC derived from primary PBMC. Maturation and pro-inflammatory phenotypes of ANDES-infected DC were assessed by studying the expression of receptors, cytokines and active gMMP-9, as well as some of their functional status. The ANDES-infected DC supernatants were assessed for their capacity to enhance a monolayer endothelial permeability using primary human vascular endothelial cells (HUVEC).

Results

Here, we show that in vitro primary DCs infected by a clinical isolate of ANDV shed virus RNA and proteins, suggesting a competent viral replication in these cells. Moreover, this infection induces an enhanced expression of soluble pro-inflammatory factors, including TNF-α and the active gMMP-9, as well as a decreased expression of anti-inflammatory cytokines, such as IL-10 and TGF-β. These viral activated cells are less sensitive to apoptosis. Moreover, supernatants from ANDV-infected DCs were able to indirectly enhance the permeability of a monolayer of primary HUVEC.

Conclusions

Primary human DCs, that are primarily targeted by hantaviruses can productively be infected by ANDV and subsequently induce direct effects favoring a proinflammatory phenotype of infected DCs. Finally, based on our observations, we hypothesize that soluble factors secreted in ANDV-infected DC supernatants, importantly contribute to the endothelial permeability enhancement that characterize the HCPS.

Maporal virus as a surrogate for pathogenic New World hantaviruses and its inhibition by favipiravir

BACKGROUND

Pathogenic hantaviruses geographically distributed in the Old World cause haemorrhagic fever with renal syndrome (HFRS), whereas New World hantaviruses are the aetiological agents of hantavirus cardiopulmonary syndrome (HCPS). Ribavirin, a drug associated with toxicities, is presently indicated for treatment of HFRS, whereas treatment of the more frequently lethal HCPS is limited to supportive care. Because of the need for safe and effective antivirals to treat severe hantaviral infections, we evaluated favipiravir (T-705) against Dobrava and Maporal viruses as representative Old World and New World hantaviruses, respectively. Dobrava virus causes HFRS in Europe. Maporal virus (MPRLV), recently isolated from western Venezuela, is phylogenetically similar to Andes virus, the principal cause of HCPS in Argentina.

METHODS

Hantavirus replication in the presence of various inhibitors was measured by focus-forming unit assays and quantitative reverse transcriptase PCR. Phylogenetic relationships were assessed by the neighbour-joining and bootstrap consensus methods.

RESULTS

Here, we show that infection of Vero E6 cells with MPRLV is dependent on β3 integrins, similar to that reported for pathogenic hantaviruses. Furthermore, by analysis of molecular determinants associated with the G1 glycoprotein cytoplasmic tail, we show the close genetic proximity of MPRLV to other HCPS-causing hantaviruses in these regions predictive of pathogenicity. We also demonstrate anti-hantavirus activity by favipiravir with inhibitory concentrations ranging from 65 to 93 μM and selectivity indices>50.

CONCLUSIONS

Our data suggest that MPRLV may serve as a safer alternative to modelling infection caused by the highly lethal Andes virus and that hantaviruses are sensitive to the effects of favipiravir in cell culture.

Hantavirus protein interactions regulate cellular functions and signaling responses

Rodent-borne pathogenic hantaviruses cause two severe and often lethal zoonotic diseases: hemorrhagic fever with renal syndrome (HFRS) in Eurasia and hantavirus cardiopulmonary syndrome (HCPS) in the Americas. Currently, no US FDA-approved therapeutics or vaccines are available for HFRS/HCPS. Infections with hantaviruses are not lytic, and it is currently not known exactly why infections in humans cause disease. A better understanding of how hantaviruses interfere with normal cell functions and activation of innate and adaptive immune responses might provide clues to future development of specific treatment and/or vaccines against hantavirus infection. In this article, the current knowledge regarding immune responses observed in patients, hantavirus interference with cellular proteins and signaling pathways, and possible approaches in the development of therapeutics are discussed.