Archive for August 9th, 2012

Schmallenberg virus: A new Shamonda/Sathuperi-like virus on the rise in Europe

9 August, 2012

See on Scoop.itVirology News

“In the summer-fall of 2011, a nonspecific febrile syndrome characterized by hyperthermia, drop in milk production and watery diarrhea was reported in adult dairy cows from a series of farms located in North-West Europe. Further, in November 2011, an enzootic outbreak of abortion, stillbirth and birth at term of lambs, kids and calves with neurologic signs and/or head, spine or limb malformations emerged throughout several European countries. Both syndromes were associated with the presence in the blood (adults) or in the central nervous system (newborns) of the genome of a new Shamonda-Sathuperi reassortant orthobunyavirus provisionally named Schmallenberg virus after the place where the first positive samples were collected. The clinical, pathological, virological and epidemiological facts that were made publicly available during the first 6 months after the emergence are presented here. Current knowledge of the epidemiology of the phylogenetically closest relatives of the newcomer (Shamonda, Sathuperi, Aino and Akabane viruses) is not exhaustive enough to predict whether the current outbreak of Schmallenberg virus is the prelude to endemicity or to a 2 years long outbreak before the infection burns out when serologically naïve animals are no longer available. In the future, cyclic epizootic reemergences are a possibility too, either synchronized with a global decrease of herd immunity or due to antigenic variants escaping the immunity acquired against their predecessors. The latter hypothesis seems unlikely because of the wide array of biologic constraints acting on the genome of viruses whose life cycle requires transmission by a vector, which represses genetic drift. The remarkable stability of the Shamonda virus genome over the last forty years is reassuring in this regard.”

See on www.sciencedirect.com

Evaluation of methods to concentrate and p… [Environ Microbiol. 2012] – PubMed – NCBI

9 August, 2012

See on Scoop.itAquatic Viruses

“Viruses have global impact through mortality, nutrient cycling and horizontal gene transfer, yet their study is limited by complex methodologies with little validation. Here, we use triplicate metagenomes to compare common aquatic viral concentration and purification methods across four combinations as follows: (i) tangential flow filtration (TFF) and DNase + CsCl, (ii) FeCl(3) precipitation and DNase, (iii) FeCl(3) precipitation and DNase + CsCl and (iv) FeCl(3) precipitation and DNase + sucrose. Taxonomic data (30% of reads) suggested that purification methods were statistically indistinguishable at any taxonomic level while concentration methods were significantly different at family and genus levels. Specifically, TFF-concentrated viral metagenomes had significantly fewer abundant viral types (Podoviridae and Phycodnaviridae) and more variability among Myoviridae than FeCl(3) -precipitated viral metagenomes. More comprehensive analyses using protein clusters (66% of reads) and k-mers (100% of reads) showed 50-53% of these data were common to all four methods, and revealed trace bacterial DNA contamination in TFF-concentrated metagenomes and one of three replicates concentrated using FeCl(3) and purified by DNase alone. Shared k-mer analyses also revealed that polymerases used in amplification impact the resulting metagenomes, with TaKaRa enriching for ‘rare’ reads relative to PfuTurbo. Together these results provide empirical data for making experimental design decisions in culture-independent viral ecology studies.”

 

Things just keep getting easier and easier…now to do some work!

Mimivirus graphic courtesy of Russell Kightely Media

See on www.ncbi.nlm.nih.gov