Ecuador Paraiso Escondido virus, a new flavivirus isolated from New World sand flies in Ecuador, is the first representative of a novel clade in the genus flavivirus

A new flavivirus, Ecuador Paraiso Escondido virus (EPEV), named after the village where it was discovered, was isolated from sand flies (Psathyromyia abonnenci, formerly Lutzomyia abonnenci) that are unique to the New World. This represents the first sand fly-borne flavivirus identified in the New World. EPEV exhibited a typical flavivirus genome organization. Nevertheless, the maximum pairwise amino acid sequence identity with currently recognized flaviviruses was 52.8%. Phylogenetic analysis of the complete coding sequence showed that EPEV represents a distinct clade which diverged from a lineage that was ancestral to the nonvectored flaviviruses Entebbe bat virus, Yokose virus, and Sokoluk virus and also the Aedes-associated mosquito-borne flaviviruses, which include yellow fever virus, Sepik virus, Saboya virus, and others. EPEV replicated in C6/36 mosquito cells, yielding high infectious titers, but failed to reproduce either in vertebrate cell lines (Vero, BHK, SW13, and XTC cells) or in suckling mouse brains. This surprising result, which appears to eliminate an association with vertebrate hosts in the life cycle of EPEV, is discussed in the context of the evolutionary origins of EPEV in the New World.The flaviviruses are rarely (if ever) vectored by sand fly species, at least in the Old World. We have identified the first representative of a sand fly-associated flavivirus, Ecuador Paraiso Escondido virus (EPEV), in the New World. EPEV constitutes a novel clade according to current knowledge of the flaviviruses. Phylogenetic analysis of the virus genome showed that EPEV roots the Aedes-associated mosquito-borne flaviviruses, including yellow fever virus. In light of this new discovery, the New World origin of EPEV is discussed together with that of the other flaviviruses

Levels of abstraction and the roles of the organic and value compositions of capital in the transportation problem

SIGLEAvailable from British Library Document Supply Centre-DSC:3597.979570(LU-SBES-DP-E--96/10) / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Evolution of ISFV direct repeats and RNA structures.

<p>The alignment between <i>Aedes</i>-and <i>Culex</i>-associated ISFV 3′UTRs is presented schematically based on the alignment in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0092056#pone.0092056.s004" target="_blank">Figure S4A</a>. The CxFV DRs1-4 are designated as black boxes and <i>Aedes</i>-associated R1/R2 as grey boxes; different box shadows reflect the independent origin of the CxFV DRs as discovered by the alignments in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0092056#pone.0092056.s005" target="_blank">Figure S5A</a>. The regions of very low sequence homology between <i>Aedes</i>- and <i>Culex</i>-associated ISFV are shown as dashed lines and the deletions as gaps. RNA conformations conserved between all ISFV are scheduled and specified based on the MFold-generated images in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0092056#pone.0092056.s003" target="_blank">Figure S3</a>. The RNA structures upstream of DB1 vary significantly between the ISFV and are not presented.</p

Predicted RNA structures for TBFV.

<p>Adapted from the <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0092056#pone.0092056.s001" target="_blank">Figure S1</a> for A) TBEV, B) LGTV and C) OHFV. The 3′UTR and adjacent NS5^pol gene region is shown and annotated with the LRSs, DRs, conserved and variable, enhancer and promoter regions. The areas where LGTV and OHFV show different folding are framed.</p

The sequence identity matrix between DRs of ISFV.

<p>The ISFV and DRs abbreviations were used as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0092056#pone.0092056.s005" target="_blank">Figure S5A</a>. Produced with the use of Bioedit <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0092056#pone.0092056-Hall1" target="_blank">[18]</a>.</p

Diversification of <i>Aedes</i>- and <i>Culex</i>-associated 3′UTRs from the primordial flavivirus precursor.

<p>As previously proposed the primordial 3′UTR formed due to numerous (9 times) duplication of the C-terminal region (LRS) of the NS5^pol gene named the primordial LRS (pLRS) <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0092056#pone.0092056-Gritsun3" target="_blank">[11]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0092056#pone.0092056-Gritsun4" target="_blank">[12]</a>. The remnants of pLRSs are most highly preserved among TBFVs which also developed 6 additional short DRs (dark small grey boxes). The development of the ISFV 3′UTR may have occurred via a primordial precursor that, after significant regression, self-duplicated as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0092056#pone.0092056-Gritsun9" target="_blank">[17]</a>; KRV is one direct extant descendent of the ancient ISFV precursor which also gave rise to CFAV. The CxFV 3′UTR is a second direct descendant which evolved independently from the KRV/CFAV precursor by duplication of the LRS2-like region as revealed by the alignment between TBFV and ISFV in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0092056#pone.0092056.s004" target="_blank">Figures S4B and S4C</a>. Different box shading reflects the evolution of original LRSs and DRs descendants by the accumulation of nucleotide alterations.</p

CD8+ T-cells mediate immunopathology in tick-borne encephalitis

Epidemics of tick-borne encephalitis involving thousands of humans occur annually in the forested regions of Europe and Asia. Despite the importance of this disease, the underlying basis for the development of encephalitis remains undefined. Here, we prove the key role of CD8(+) T-cells in the immunopathology of tick-borne encephalitis, as demonstrated by prolonged survival of SCID or CD8(-/-) mice, following infection, when compared with immunocompetent mice or mice with adoptively transferred CD8(+) T-cells. The results imply that tick-borne encephalitis is an immunopathological disease and that the inflammatory reaction significantly contributes to the fatal outcome of the infection. (C) 2008 Elsevier Inc. All rights reserved