ViroBlogy

See on Scoop.it – Virology News

Endogenous retroviruses (ERVs) differ from typical retroviruses in being inherited through the host germline and therefore are a unique combination of pathogen and selfish genetic element. Some ERV lineages proliferate by infecting germline cells, as do typical retroviruses, whereas others lack the env gene required for virions to enter cells and thus behave like retrotransposons. We wished to know what factors determined the relative abundance of different ERV lineages, so we analyzed ERV loci recovered from 38 mammal genomes by in silico screening. By modeling the relationship between proliferation and replication mechanism in detail within one group, the intracisternal A-type particles (IAPs), and performing simple correlations across all ERV lineages, we show that when ERVs lose the env gene their proliferation within that genome is boosted by a factor of ∼30. We also show that ERV abundance follows the Pareto principle or 20/80 rule, with ∼20% of lineages containing 80% of the loci. This rule is observed in many biological systems, including infectious disease epidemics, where commonly ∼20% of the infected individuals are responsible for 80% of onward infection. We thus borrow simple epidemiological and ecological models and show that retrotransposition and loss of env is the trait that leads endogenous retroviruses to becoming genomic superspreaders that take over a significant proportion of their host’s genome.

I love it: retroviruses that choose to spread WITHIN a cell’s genome, rather than between cells.  Safe little niche, as long as it keeps dividing!

See on www.pnas.org

See on Scoop.it – Virology News

“Last year was the worst year for measles in the U.S. in 15 years, health officials said Thursday.

There were 222 cases of measles, a large jump from the 60 or so seen in a typical year. Most of the cases last year were imported — either by foreign visitors or by U.S. residents who picked up the virus overseas.

U.S. children have been getting vaccinated against the measles for about 50 years. But low vaccination rates in Europe and other places resulted in large outbreaks overseas last year.

So far this year, 27 U.S. cases have been reported and it’s too early to gauge whether 2012 will be as bad as last year. But with large international events like the London Olympics coming up, health officials are urging everyone — particularly international travelers — to make sure they’re fully vaccinated.”

And so it begins…the collapse of what used to be near-universal anti-measles vaccination, resulting in re-importation of the virus to places where it had almost been eradicated.

See on www.businessweek.com

See on Scoop.it – Virology News

“Hanoi has asked the World Health Organization for help to cure a virulent disease affecting children. Symptoms include blistering on hands, feet and mouths accompanied by high fever and eventual organ failure.

Nineteen children died from the illness in 2011 alone.
The virus spreads through direct contact with an infected person’s oral discharges or saliva, the fluid from burst blisters or the stool of infected persons.
The Red Cross mission in Vietnam reports the disease has already infected over 28,000 children this year, which is more than 10 times the number of infected children in the same period last year.
According to the International Federation of Red Cross and Red Crescent Societies (IFRC), last year a record 110,000 children became infected, with 169 deaths.
The hand, foot and mouth disease (HFMD) disease mostly affects children under three years old (80 per cent of totals cases) the Red Cross said. There is no known treatment for HFMD.”

The virus is EV71, a picornavirus similar to the polioviruses and hepatitis A virus – so hardly a “mystery virus”.  There are also a number of vaccines in the pipeline for the disease, including one highlighted here a while ago.

See on rt.com

See on Scoop.it – Virology News

Usutu virus (USUV) is an African mosquito-borne flavivirus, member of the Japanese encephalitis antigenic group. This avian virus is transmitted by arthropod vectors (mainly mosquitoes of the Culex pipiens complex). It is well known that free-living birds, including migratory species, have the potential to disperse certain pathogenic microorganisms. Usutu virus has recently been introduced to Europe and is spreading through Austria, Hungary, Italy, Spain and Switzerland, causing disease in birds and humans. Like West Nile virus, USUV may become a resident pathogen in Europe and the consequences for public health should be considered. Many different biotic and abiotic factors affect the survival of the virus in a new environment and influence the efficiency of its geographical dispersal

See on www.eurosurveillance.org

See on Scoop.it – Virology News

“I have just created an animation of a rotating influenza virus. The sequence begins with a still of the cutaway virus with various parts labelled. The labels disappear and the virus rotates, then returns to the starting graphic. This is in high definition and looks good full screen on a 27″ iMac. It is the latest addition to my YouTube Channel.”

Definitely, graphics courtesy of Russell Kightley Media…B-)  STRONGLY commended!

See on blog.kightleys.com

See on Scoop.it – Virology News

A new study, published in PLoS Computational Biology, shows how worries over vaccine risks can allow preventable contagious diseases, such as measles and whooping cough, to make a comeback.

I remember commenting, some 17 years ago, that people in Kikwit should be more concerned than people in the urban USA about Ebola risks from the outbreak then occurring – but probably weren’t, largely because they knew that spread required contact, AND they had no internet to spread the panic.  Virally…in fact, one correspondent coined the term “Ebola Preston” to account for the fear-of-virus propagated by Richard Preston, whose book “The Hot Zone” piggy-backed the Ebola epidemic to huge sales.

The bottom line is that people who obsess about safety of vaccines are the ones who are themselves almost certainly protected because THEIR parents followed public health guidleines – but they will be opening their kids up to all of the old scourges that they themselves were protected against.

Because they are functionally STUPID.

See on www.eurekalert.org

See on Scoop.it – Virology News

“HCPro, the RNA silencing suppressor (RSS) of viruses belonging to the Potyvirus genus in the Potyviridae family, is a multifunctional protein presumably involved in all essential steps of the viral infection cycle. Recent studies have shown that Plum pox potyvirus (PPV) HCPro can be successfully replaced by Cucumber vein yellowing ipomovirus P1b, a sequence unrelated RSS from a virus of the same family. In order to gain insight into the requirement of a particular RSS to establish a successful potyviral infection, we tested the ability of different heterologous RSSs from both plant- and animal-infecting viruses to substitute HCPro. Making use of engineered PPV chimeras, we show that PPV HCPro can be functionally replaced by some, but not all, unrelated RSSs, including the NS1 protein of the mammalian-infecting Influenza A virus.”

Fascinating stuff: shows how promiscuois, or possibly how universal, the machinery for avoiding silencing is – and how funadamental to the life cycles of viruses.  One could almost argue “virus altruism”?

See on vir.sgmjournals.org