Project description:We present the molecular identification of Apodemus agrarius (striped field mouse) as reservoir host of the Dobrava-Belgrade virus (DOBV) lineage DOBV-Aa in 3 federal states of Germany. Phylogenetic analyses provided evidence for multiple spillover of DOBV-Aa to A. flavicollis, a crucial prerequisite for host switch and genetic reassortment.
Project description:Hantaviruses are endemic in the Balkans, particularly in Serbia, where sporadic cases and/or outbreaks of hantaviral human disease have been reported repeatedly, and evidenced serologically. Here, we present genetic detection of Dobrava-Belgrade virus (DOBV) hantaviral sequences in wild rodents trapped in central Serbia. All the animals were pre-screened serologically by indirect immunofluorescence (IF) test and only those with a positive finding of hantaviral antigens were further tested by polymerase chain reaction. Of the total of 104 trapped animals, 20 were found to be IF positive and of those three were positive for hantaviral RNA: one Microtus arvalis for Tula virus, and one each of Apodemus agrarius and Glis glis for DOBV. Phylogenetic analysis of the obtained sequences implies putative DOBV spillover infection of A. agrarius and G. glis from Apodemus flavicollis. However, future investigations should help to identify the most common natural host and geographical distribution of DOBV in its reservoir hosts in Serbia.
Project description:In 2009, human Dobrava-Belgrade virus (DOBV) infections were reported on the Black Sea coast of Turkey. Serologic and molecular studies of potential rodent reservoirs demonstrated DOBV infections in Apodemus flavicollis and A. uralensis mice. Phylogenetic analysis of DOBV strains showed their similarity to A. flavicollis mice-borne DOBV in Greece, Slovenia, and Slovakia.
Project description:We used an in vitro model to study the impact of hantavirus infection on the cellular gene expression profile. To do so, A549 cells were infected with pathogenic DOBV genotypes Dobrava, Kurkino, and Sochi and less-pathogenic TULV . A549 cells were chosen because of their high susceptibility towards hantavirus infection and because many fundamental studies on hantavirus biology and on host gene expression changes following infection have been performed with this cell line. Cells were infected at a high multiplicity of infection of 5 focus forming units (FFU) per cell to guarantee uniform infection of all cells. Total RNA from infected and mock-infected control cells was isolated at 12 h post infection. This point of time was chosen to allow enough time for establishment of infection and progression to early viral gene expression but to avoid the risk of missing gene expression changes associated with the onset of the cellular innate immune response towards infection. The distinct modulation of cellular transcription of A549 cells was analyzed by means of a whole genome cRNA microarray. All experiments were performed in duplicate using RNA samples from two independently infected cell cultures for each analysis. To compare the gene expression profiles, ratios were calculated by dividing the merged normalized signal intensities of infected samples by mock-control signal intensities. Genes that exhibited a ≥2-fold change (FC) in gene expression and signal intensities that were significantly above the background with p-values ≤ 0.01 were chosen for further analysis. The successful infection of A549 cells with all viruses and the uniform progression of infection were confirmed by immunofluorescence microscopy of cells infected in parallel. At 12 h post infection with each virus nearly all cells were infected without showing cytopathic effects. Since different clinical courses are caused by infection with distinct DOBV genotypes, genotype-specific regulation of cellular transcripts were investigated that may be crucial for pathogenesis in vitro. Selected infection regulated candidates were verified by qPCR at different time points after infection.
Project description:Acute kidney injury (AKI) caused by hantavirus infections is rare but should be suspected in any patient presenting with flu-like symptoms, signs of haemolytic-uraemic syndrome or presence of anti-glomerular basement membrane (anti-GBM) antibodies. We report the first case of Dobrava-Belgrade virus in France imported from southeastern Europe. The characteristic macroscopic appearance of the fresh renal biopsy specimen, displaying a haemorrhagic appearance of the medulla, suggested hantavirus infection. AKI caused by hantavirus infections remains a diagnostic challenge, especially outside endemic areas.
Project description:Dobrava-Belgrade virus (DOBV) is a human pathogen that has evolved in, and is hosted by, mice of several species of the genus Apodemus. We propose a subdivision of the species Dobrava-Belgrade virus into four related genotypes - Dobrava, Kurkino, Saaremaa, and Sochi - that show characteristic differences in their phylogeny, specific host reservoirs, geographical distribution, and pathogenicity for humans.
Project description:We used an in vitro model to study the impact of hantavirus infection on the cellular gene expression profile. To do so, A549 cells were infected with pathogenic DOBV genotypes Dobrava, Kurkino, and Sochi and less-pathogenic TULV . A549 cells were chosen because of their high susceptibility towards hantavirus infection and because many fundamental studies on hantavirus biology and on host gene expression changes following infection have been performed with this cell line. Cells were infected at a high multiplicity of infection of 5 focus forming units (FFU) per cell to guarantee uniform infection of all cells. Total RNA from infected and mock-infected control cells was isolated at 12 h post infection. This point of time was chosen to allow enough time for establishment of infection and progression to early viral gene expression but to avoid the risk of missing gene expression changes associated with the onset of the cellular innate immune response towards infection. The distinct modulation of cellular transcription of A549 cells was analyzed by means of a whole genome cRNA microarray. All experiments were performed in duplicate using RNA samples from two independently infected cell cultures for each analysis. To compare the gene expression profiles, ratios were calculated by dividing the merged normalized signal intensities of infected samples by mock-control signal intensities. Genes that exhibited a â¥2-fold change (FC) in gene expression and signal intensities that were significantly above the background with p-values ⤠0.01 were chosen for further analysis. The successful infection of A549 cells with all viruses and the uniform progression of infection were confirmed by immunofluorescence microscopy of cells infected in parallel. At 12 h post infection with each virus nearly all cells were infected without showing cytopathic effects. Since different clinical courses are caused by infection with distinct DOBV genotypes, genotype-specific regulation of cellular transcripts were investigated that may be crucial for pathogenesis in vitro. Selected infection regulated candidates were verified by qPCR at different time points after infection. We analyzed the gene expression profile of A549 cells wich were either mock-infected or infected with Dobrava Virus (DOBV) Dobrava, Kurkino or Sochi, or with Tula Virus (TULV) at a multiplicity of infection of 5. Experiments were performed in duplicate. At 12 h post infection total RNA was isolated from infected cells and used for microarray analysis.
Project description:BACKGROUND: Dobrava-Belgrade virus (DOBV) is a European hantavirus causing hemorrhagic fever with renal syndrome (HFRS) in humans with fatality rates of up to 12%. DOBV-associated clinical cases typically occur also in the northern part of Germany where the virus is carried by the striped field mouse (Apodemus agrarius). However, the causative agent responsible for human illness has not been previously isolated. METHODOLOGY/PRINCIPAL FINDINGS: Here we report on characterization of a novel cell culture isolate from Germany obtained from a lung tissue of "spillover" infected yellow necked mouse (A. flavicollis) trapped near the city of Greifswald. Phylogenetic analyses demonstrated close clustering of the new strain, designated Greifswald/Aa (GRW/Aa) with the nucleotide sequence obtained from a northern German HFRS patient. The virus was effectively blocked by specific antibodies directed against ?3 integrins and Decay Accelerating Factor (DAF) indicating that the virus uses same receptors as the highly pathogenic Hantaan virus (HTNV). In addition, activation of selected innate immunity markers as interferon ? and ? and antiviral protein MxA after viral infection of A549 cells was investigated and showed that the virus modulates the first-line antiviral response in a similar way as HTNV. CONCLUSIONS/SIGNIFICANCE: In summary, our study reveals novel data on DOBV receptor usage and innate immunity induction in relationship to virus pathogenicity and underlines the potency of German DOBV strains to act as human pathogen.
Project description:Using nested polymerase chain reaction, we sequenced Dobrava virus (DOB) from the rodent Apodemus agrarius in Hungary. The samples we isolated group with DOB samples previously isolated from A. flavicollis. This grouping may indicate host switching.
Project description:We report complete coding sequences of Orthohantavirus dobravaense (Dobrava virus) Igneada strains and phylogenetic characterization of all available complete coding sequences. Our analyses suggested separation of host-dependent lineages, followed by geographic clustering. Surveillance of orthohantaviruses using complete genomes would be useful for assessing public health threats from Dobrava virus.