Cross-reactivity of hantavirus antibodies after immunization with PUUV antigens.

Nephropathia epidemica (NE), caused by Puumala (PUUV) orthohantavirus, is endemic in the Republic of Tatarstan (RT). There are limited options for NE prevention in RT. Currently, available vaccines are made using Haantan (HNTV) orthohantavirus antigens. In this study, the efficacy of microvesicles (MVs) loaded with PUUV antigens to induce the humoral immune response in small mammals was analyzed. Additionally, the cross-reactivity of serum from immunized small mammals and NE patients with HNTV, Dobrava, and Andes orthohantaviruses was investigated using nucleocapsid (N) protein peptide libraries. Finally, the selected peptides were analyzed for allergenicity, their ability to induce an autoimmune response, and their interaction with Class II HLA. Several N protein peptides were found to be cross-reactive with serum from MVs immunized small mammals. These cross-reactive epitopes were located in oligomerization perinuclear targeting and Daxx-interacting domains. Most cross-reactive peptides lack allergenic and autoimmune reactivity. Molecular docking revealed two cross-reacting peptides, N6 and N19, to have good binding with three Class II HLA alleles. These peptides could be candidates for developing vaccines and therapeutics for NE.

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.

Serum Concentrations of TIM-3, LAG-3, and PD-1 in Patients with Hemorrhagic Fever with Renal Syndrome.

Hemorrhagic fever with renal syndrome (HFRS) is a rodent-borne disease widespread in Europe and Asia. HFRS is caused by negative-sensed single-stranded RNA orthohantaviruses transmitted to humans through inhaling aerosolized excreta of infected rodents. Symptoms of HFRS include acute kidney injury, thrombocytopenia, hemorrhages, and hypotension. The immune response raised against viral antigens plays an important role in the pathogenesis of HFRS. Inhibitory co-receptors are essential in regulating immune responses, mitigating immunopathogenesis, and reducing tissue damage. Our research showed an increased soluble form of inhibitory co-receptors TIM-3, LAG-3, and PD-1 in HFRS patients associated with disease severity. Our study aimed to investigate the impact of HFRS on the concentrations of soluble forms of inhibitory receptors TIM-3, LAG-3, and PD-1 in the patient's serum and the potential correlation with key clinical parameters. Our study aimed to investigate the impact of HFRS on the concentrations of soluble forms of inhibitory receptors TIM-3, LAG-3, and PD-1 in the patient's serum and their possible association with relevant clinical parameters. Using multiplex immunoassay, we found elevated levels of TIM-3, LAG-3, and PD-1 proteins in the serum of HFRS patients. Furthermore, increased levels were associated with creatinine, urea, lactate dehydrogenase concentrations, and platelet count. These findings suggest that these proteins play a role in regulating the immune response and disease progression.

A fatal case of haemorrhagic fever with renal syndrome in Kursk Region, Russia, caused by a novel Puumala virus clade.

Haemorrhagic fever with renal syndrome (HFRS) is the most widespread natural-focal human disease in the Russian Federation. In this study, we report virological assessment of a fatal case of HFRS-PUUV (Puumala virus) in the Kursk Region. The infection caused severe multiorgan failure and the maximum viral load was detected in the tissue of the spleen. Viral sequences were obtained from the patient's autopsy material and lung tissues of bank voles captured in the region. These sequences formed a new clade in the PUUV phylogenetic tree, an outgroup to all known Russian (RUS) lineage sequences. On the other hand viruses collected in the Kursk Region grouped with the RUS lineage and are separated from all other PUUV linages. We propose to nominate this novel group as W-RUS as the identified viruses were collected near the western Russian boundary. The recombination signals between their ancestors and RUS lineage representatives from the Volga region were revealed. The strain Samara_94/CG/2005 suggestively emerged as the result of reassortment between the ancestors of W-RUS and DTK-Ufa-97.

Cocirculation of Two Orthohantavirus Species in Small Mammals of the Northwestern Ukraine.

Rodent-borne hantaviruses have been reported in many of the countries surrounding Ukraine; however, to date we have no knowledge of the viral strains circulating in Ukraine within reservoirs such as the striped field mouse (Apodemus agrarius), the yellow-necked field mouse (Apodemus flavicollis), and the bank vole (Myodes glareolus). To determine the prevalence of hantaviruses in Ukraine, we captured 1,261 mammals, of which 1,109 were rodents, in 58 field sites within the province of Volyn in western Ukraine. Foci of the striped field mouse tended to occur in the eastern and southern parts of the province, whereas the bank vole were clustered in western and northern regions. The striped field mouse and bank vole had detectable serum antibodies to Puumala virus (PUUV) or Dobrava virus (DOBV) antigens at 7% or 2%, respectively, using an indirect immunofluorescence assay. Antibody prevalence among the bank vole males and females was equivalent, whereas for the striped field mouse, the prevalence among males was 5% versus 1% for females. In two bank vole specimens, we were able to detect partial nucleotide sequences that showed identity to PUUV. In summary, this study suggests that two human pathogens, PUUV and DOBV, cocirculate in the bank vole and the striped field mouse, respectively, in Ukraine. Future studies will focus on new rodent collections that will enable obtaining the complete genome sequences of the PUUV and DOBV strains circulating in Ukraine to provide guidance on the design of optimal molecular diagnostics that can enable insight into the potential contribution of hantaviruses to human disease in Ukraine.

Zoonotic Viruses in Three Species of Voles from Poland.

Rodents are known to be reservoir hosts for a plethora of zoonotic viruses and therefore play a significant role in the dissemination of these pathogens. We trapped three vole species (Microtus arvalis, Alexandromys oeconomus and Microtus agrestis) in northeastern Poland, all of which are widely distributed species in Europe. Using immunofluorescence assays, we assessed serum samples for the presence of antibodies to hantaviruses, arenaviruses and cowpox viruses (CPXV). We detected antibodies against CPXV and Puumala hantavirus (PUUV), the overall seroprevalence of combined viral infections being 18.2% [10.5-29.3] and mostly attributed to CPXV. We detected only one PUUV/TULV cross-reaction in Microtus arvalis (1.3% [0.1-7.9]), but found similar levels of antibodies against CPXV in all three vole species. There were no significant differences in seroprevalence of CPXV among host species and age categories, nor between the sexes. These results contribute to our understanding of the distribution and abundance of CPXV in voles in Europe, and confirm that CPXV circulates also in Microtus and Alexandromys voles in northeastern Poland.

Seroprevalence of Old World Hantaviruses and Crimean Congo Hemorrhagic Fever Viruses in Human Populations in Northwestern Ukraine.

In Ukraine, a retrospective review of clinical case reports by public health officials suggest that human cases of febrile illnesses associated with hemorrhage may be due to infections of Crimean-Congo hemorrhagic fever virus (CCHFV) and Old World hantaviruses. In a serosurvey of 966 healthy individuals in the Lviv Oblast, Ukraine, bordering Poland, we found that 1.6% showed cross-reactivity to hantaviral antigens by an immunofluorescence assay (IFA) and 1.7% of the study participants had antibodies cross-reactive to CCHFV by enzyme-linked immunosorbent assay (ELISA). Demographic variables and history of exposures obtained through questionnaires were assessed by logistic regression models for association with seroprevalence for both viruses with no significant risk factors found. Analysis of spatial distribution identified two clusters of samples positive for antibodies to both hantaviruses and CCHFV, which, however, were not statistically significant (p > 0.05). In general, the study results suggest that the population of the study area is exposed to hantaviruses and CCHFV. Further surveillance for respective pathogens in Ukraine is warranted and prospective surveillance of febrile patients with unidentified febrile illness.

Characterization of the Puumala orthohantavirus Strains in the Northwestern Region of the Republic of Tatarstan in Relation to the Clinical Manifestations in Hemorrhagic Fever With Renal Syndrome Patients.

Over 1,000 cases of hemorrhagic fever with renal syndrome (HFRS) were recorded in the Republic of Tatarstan (RT) in 2015. HFRS is a zoonotic disease caused by several different Old World hantaviruses. In RT, Puumala orthohantavirus (PUUV) is a prevalent etiological agent of HFRS. We looked for the genetic link between the PUUV strains isolated from the bank voles and from the infected humans. In addition, possible correlation between the genetic makeup of the PUUV strain involved and different clinical picture of HFRS was investigated. Partial PUUV small (S) genome segment sequences were retrieved from 37 small animals captured in the northwestern region of RT in 2015. Phylogenetic analysis revealed that 34 PUUV sequences clustered with strains of the previously identified "Russia" (RUS) genetic lineage, while 3 remaining PUUV sequences clustered with the known lineage from Finland (FIN). Sequence comparisons showed that the majority of the S-segment sequences isolated in the current study displayed 98.2-100.0% sequence identity when compared with the strains isolated earlier from the HFRS patients hospitalized in Kazan city. HFRS patients infected with PUUV strains of either RUS or FIN genetic lineages were observed to have consistent differences in clinical presentation of the disease and laboratory findings. These findings indicated a strong genetic link between the infected bank voles and human HFRS cases from the same localities. Thus, S-segment sequences of the PUUV strains isolated from HFRS patients could serve as a molecular marker for determining the likely geographic area where infection occurred.

Hemorrhagic Fever with Renal Syndrome in the New, and Hantavirus Pulmonary Syndrome in the Old World: paradi(se)gm lost or regained?

Since the first clinical description in 1994 of the so-called "Hantavirus Pulmonary Syndrome" (HPS) as a "newly recognized disease", hantavirus infections have always been characterized as presenting in two distinct syndromes, the so-called "Hemorrhagic Fever with Renal Syndrome" (HFRS) in the Old World, with the kidney as main target organ, in contrast to HPS in the New World, with the lung as main target organ. However, European literature mentions already since 1934 a mostly milder local HFRS form, aptly named "nephropathia epidemica" (NE), and caused by the prototype European hantavirus species Puumala virus (PUUV). Several NE reports dating from the 1980s and early 1990s described already non-cardiogenic HPS-like lung involvement, prior to any kidney involvement, and increasing evidence is now mounting that a considerable clinical overlap exists between HPS and HFRS. Moreover, growing immunologic insights point to common pathologic mechanisms, leading to capillary hyperpermeability, the cardinal feature of all hantavirus infections, both of the New and Old World. It is now perhaps time to reconsider the paradigm of two "different" syndromes caused by viruses of the same Hantavirus genus in the same Bunyaviridae family, and to agree on a common, more logical disease denomination, such as simply and briefly "Hantavirus fever".

Production and biomedical applications of virus-like particles derived from polyomaviruses.

Virus-like particles (VLPs), aggregates of capsid proteins devoid of viral genetic material, show great promise in the fields of vaccine development and gene therapy. These particles spontaneously self-assemble after heterologous expression of viral structural proteins. This review will focus on the use of virus-like particles derived from polyomavirus capsid proteins. Since their first recombinant production 27 years ago these particles have been investigated for a myriad of biomedical applications. These virus-like particles are safe, easy to produce, can be loaded with a broad range of diverse cargoes and can be tailored for specific delivery or epitope presentation. We will highlight the structural characteristics of polyomavirus-derived VLPs and give an overview of their applications in diagnostics, vaccine development and gene delivery.