143 research outputs found
European Bat Lyssavirus Type 2 RNA in Myotis daubentonii
Organ distribution of European bat lyssavirus type 2 viral RNA in its reservoir host, Myotis daubentonii (Daubenton's bat), was measured with a novel quantitative reverse transcription–polymerase chain reaction assay. High levels of genomic RNA were found in the brain and were also detectable in the tongue, bladder, and stomach
Selection of variant viruses during replication and transmission of H7N1 viruses in chickens and turkeys
AbstractThe influence of different glycosylation patterns of the haemagglutinin glycoprotein of H7N1 avian influenza viruses on virus replication in vivo was examined. Experimental infection of chickens and turkeys was carried out with H7N1 avian influenza viruses with alternative sites of glycosylation in the haemagglutinin and infected birds were sampled daily by swabbing the buccal and cloacal cavities. cDNAs of the HA1 coding region of the HA gene were prepared from the swabs and cloned into plasmids. Sequencing multiple plasmids made from individual swabs taken over the period of virus shedding showed that viruses with specific patterns of glycosylation near the receptor binding site were stable when birds were infected with a single variant, but when presented with a mixed population of viruses encoding differing patterns of glycosylation a specific variant was rapidly selected in the infected host
Serologic Cross-Reactivity with Pandemic (H1N1) 2009 Virus in Pigs, Europe
We tested serum samples from pigs infected or vaccinated with European swine influenza viruses (SIVs) in hemagglutination-inhibition assays against pandemic (H1N1) 2009 virus and related North American SIVs. We found more serologic cross-reaction than expected. Data suggest pigs in Europe may have partial immunity to pandemic (H1N1) 2009 virus
Experimental infection of Foxes with European bat Lyssaviruses type-1 and 2
<p>Abstract</p> <p>Background</p> <p>Since 1954, there have been in excess of 800 cases of rabies as a result of European Bat <it>Lyssaviruses </it>types 1 and 2 (EBLV-1, EBLV-2) infection, mainly in Serotine and Myotis bats respectively. These viruses have rarely been reported to infect humans and terrestrial mammals, as the only exceptions are sheep in Denmark, a stone marten in Germany and a cat in France. The purpose of this study was to investigate the susceptibility of foxes to EBLVs using silver foxes (<it>Vulpes vulpes</it>) as a model.</p> <p>Results</p> <p>Our experimental studies have shown that the susceptibility of foxes to EBLVs is low by the intramuscular (IM) route, however, animals were sensitive to intracranial (IC) inoculation. Mortality was 100% for both EBLV-1 (~4.5 logs) and EBLV-2 (~3.0 logs) delivered by the IC route. Virus dissemination and inflammatory infiltrate in the brain were demonstrated but virus specific neutralising antibody (VNA) was limited (log(ED<sub>50</sub>) = 0.24–2.23 and 0.95–2.39 respectively for specific EBLV-1 and EBLV-2). Foxes were also susceptible, at a low level, to peripheral (IM) infection (~3.0 logs) with EBLV-1 but not EBLV-2. Three out of 21 (14.3%) foxes developed clinical signs between 14 and 24 days post-EBLV-1 infection. None of the animals given EBLV-2 developed clinical disease.</p> <p>Conclusion</p> <p>These data suggest that the chance of a EBLV spill-over from bat to fox is low, but with a greater probability for EBLV-1 than for EBLV-2 and that foxes seem to be able to clear the virus before it reaches the brain and cause a lethal infection.</p
Subclinical hepatitis E virus infection in laboratory ferrets in the UK
Ferrets are widely used for experimental modelling of viral infections. However, background disease in ferrets could potentially confound intended experimental interpretation. Here we report the detection of a subclinical infection of ferret hepatitis E virus (FRHEV) within a colony sub-group of female laboratory ferrets that had been enrolled on an experimental viral infection study (non-hepatitis). Lymphoplasmacytic cuffing of periportal spaces was identified on histopathology but was negative for the RNA and antigens of the administered virus. Follow-up viral metagenomic analysis conducted on liver specimens revealed sequences attributed to FRHEV and these were confirmed by reverse-transcriptase polymerase chain reaction. Further genomic analysis revealed contiguous sequences spanning 79-95 % of the FRHEV genome and that the sequences were closely related to those reported previously in Europe. Using in situ hybridization by RNAScope, we confirmed the presence of HEV-specific RNA in hepatocytes. The HEV open reading frame 2 (ORF2) protein was also detected by immunohistochemistry in the hepatocytes and the biliary canaliculi. In conclusion, the results of our study provide evidence of background infection with FRHEV in laboratory ferrets. As this infection can be subclinical, we recommend routine monitoring of ferret populations using virological and liver function tests to avoid incorrect causal attribution of any liver disease detected in in vivo studies
Chicken and duck myotubes are highly susceptible and permissive to influenza virus infection
Skeletal muscle, at 30 to 40% of body mass, is the most abundant soft tissue in the body. Besides its primary function in movement and posture, skeletal muscle is a significant innate immune organ with the capacity to produce cytokines and chemokines and respond to proinflammatory cytokines. Little is known about the role of skeletal muscle during systemic influenza A virus infection in any host and particularly avian species. Here we used primary chicken and duck multinucleated myotubes to examine their susceptibility and innate immune response to influenza virus infections. Both chicken and duck myotubes expressed avian and human sialic acid receptors and were readily susceptible to low-pathogenicity (H2N3 A/mallard duck/England/7277/06) and high-pathogenicity (H5N1 A/turkey/England/50-92/91 and H5N1 A/turkey/Turkey/1/05) avian and human H1N1 (A/USSR/77) influenza viruses. Both avian host species produced comparable levels of progeny H5N1 A/turkey/Turkey/1/05 virus.Notably, the rapid accumulation of viral nucleoprotein and matrix (M) gene RNA in chicken and duck myotubes was accompanied by extensive cytopathic damage with marked myotube apoptosis (widespread microscopic blebs, caspase 3/7 activation, and annexin V binding at the plasma membrane). Infected chicken myotubes produced significantly higher levels of proinflammatory cytokines than did the corresponding duck cells. Additionally, in chicken myotubes infected with H5N1 viruses, the induction of interferon beta (IFN-beta) and IFN-inducible genes, including the melanoma differentiation-associated protein 5 (MDA-5) gene, was relatively weak compared to infection with the corresponding H2N3 virus. Our findings highlight that avian skeletal muscle fibers are capable of productive influenza virus replication and are a potential tissue source of infection
18S rRNA is a reliable normalisation gene for real time PCR based on influenza virus infected cells
Background: One requisite of quantitative reverse transcription PCR (qRT-PCR) is to normalise the data with an
internal reference gene that is invariant regardless of treatment, such as virus infection. Several studies have found
variability in the expression of commonly used housekeeping genes, such as beta-actin (ACTB) and
glyceraldehyde-3-phosphate dehydrogenase (GAPDH), under different experimental settings. However, ACTB and
GAPDH remain widely used in the studies of host gene response to virus infections, including influenza viruses. To
date no detailed study has been described that compares the suitability of commonly used housekeeping genes in
influenza virus infections. The present study evaluated several commonly used housekeeping genes [ACTB, GAPDH,
18S ribosomal RNA (18S rRNA), ATP synthase, H+ transporting, mitochondrial F1 complex, beta polypeptide (ATP5B)
and ATP synthase, H+ transporting, mitochondrial Fo complex, subunit C1 (subunit 9) (ATP5G1)] to identify the most
stably expressed gene in human, pig, chicken and duck cells infected with a range of influenza A virus subtypes.
Results: The relative expression stability of commonly used housekeeping genes were determined in primary
human bronchial epithelial cells (HBECs), pig tracheal epithelial cells (PTECs), and chicken and duck primary
lung-derived cells infected with five influenza A virus subtypes. Analysis of qRT-PCR data from virus and mock
infected cells using NormFinder and BestKeeper software programmes found that 18S rRNA was the most stable
gene in HBECs, PTECs and avian lung cells.
Conclusions: Based on the presented data from cell culture models (HBECs, PTECs, chicken and duck lung cells)
infected with a range of influenza viruses, we found that 18S rRNA is the most stable reference gene for normalising
qRT-PCR data. Expression levels of the other housekeeping genes evaluated in this study (including ACTB and
GPADH) were highly affected by influenza virus infection and hence are not reliable as reference genes for RNA
normalisation
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