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TWiV 84 letters

TWiV 84 letters

Matthew writes:

Hi Twiv,

Firstly, love the podcast, I listen to it on my way to work. Don't change a thing!

I recently wrote to you asking about the possible link between a high-arginine diet and herpes simplex outbreaks in humans (does lysine prevent outbreaks?). While researching I found this study which to my untrained eye seems to be saying that HSV-1 DNA in the neuron nucleus is histone-bound and folded into chromatin when it is it latent. This suggests an epigenetic control pathway via HDAC inhibitors. Perhaps diet could play a role in the suppression of HSV-1, as diet is linked to epigenetic silencing of genes in animal DNA.
Please could you talk a little about the epigenetics of viruses ?


Jesper writes:

Dear professors,

A while back you discussed the idea of applying mutations to computer viruses to see how they evolved. Someone wrote in and explained that it simply doesn't work that way in machine code.

I am currently reading The Red Queen by Matt Riddley. Great book, I must say. On the discussion of sex as a means to out-evolve the threat from parasites he mentioned a computer program named Tierra.

Tierra is a virtual environment where programs compete for resources (mainly by copying themselves and thus their 'species' would occupy more of the environment). The author of Tierra threw in a small randomization in the copying algorithm, to simulate mutations. As in the biological world, most mutations were detrimental and caused program malfunctioning and thus death, but somewhat to his surprise, some mutations appeared that didn't kill the host. First, they had no impact at all. Then suddenly "parasitic" programs came into being. These programs had no code for reproduction, but used the required instructions from other programs. Some of the initial mutated programs were immune to the parasites. And on it went.

I found a nice article on the project on http://www.infidels.org/library/modern/meta/getalife/coretierra.html (continues onhttp://www.infidels.org/library/modern/meta/getalife/epgp.html and http://www.infidels.org/library/modern/meta/getalife/resources.html).

All the best, and I thoroughly enjoy both twiv and twip. In terms of podcast competiveness for attention resources, you rock!

Keep up the good work!


Jim writes:

Wanted to make sure you didn't miss this.


New handheld HIV detector fits into your iPod case
By Bryan Nelson
The portable device takes less than 10 minutes to perform the test, and it could revolutionize how HIV is monitored in remote regions of Africa.

Bill writes:

Journal of Clinical Investigation -- Antiangiogenic cancer therapy combined with oncolytic virotherapy leads to regression of...

Drs: I'm still hooked on TWIV. Are you still thinking about a TWIV episode focused on this cool emerging virus based cancer therapy?

The company is now about to enroll its first patient to a Phase 3 "registration" trial focused on head and neck cancers, but there are many studies being conducted in and around the principal discovery that reovirus exploits the RAS flaw that is common to 70% of all tumor cell lines....It is shaping up to be a huge story...time for you guys to get on it.

Best Regards,


Lenn sent:


Date: Thu 1 Apr 2010

Source: APP.Com [edited]

A total of 6 New Jersey non-racing horse farms, including 5 in
Monmouth County, were under quarantine Thursday [1 Apr 2010] because
of a possible outbreak of a deadly equine virus.

Except for a farm in Millstone, the Monmouth County farms are all in
Howell according to the state Department of Agriculture, whose
Division of Animal Health announced the quarantine Thursday [1 Apr
2010]. The 5th farm is in Gloucester County, according to the
agriculture department.

The disease, called the [equine herpes], is not harmful to humans and
other animals, but it can spread quickly to horses and is often fatal
to them, according to the agriculture department.

"Quarantines are necessary to ensure that this serious disease does
not spread,'' said state Secretary of Agriculture Douglas H Fisher.
"Our investigation is continuing as we work to protect the health and
safety of horses in New Jersey and other states.''

The agriculture department noted tests, so far, have not confirmed the
disease. But the quarantines went into effect after 2 horses showed
clinical signs of the disease and were euthanized and another with
similar signs died, according to the department.

One of the farms is connected in some way to all the other farms under
quarantine, Lynn Richmond, an agriculture department spokeswoman. The
quarantines were put in place over various days within the last week
or so, and are expected to remain in place for weeks, Richmond said.

[Byline: Joe Sapia]

Communicated by:

[Equine herpesvirus 1 (EHV-1) and EHV-4 comprise 2 antigenically
distinct groups of viruses previously referred to as subtypes 1 and 2
of EHV-1. Both viruses are ubiquitous in horse populations worldwide
and produce an acute febrile respiratory disease upon primary
infection, characterized by rhinopharyngitis and tracheobronchitis.
Outbreaks of respiratory disease occur annually among foals in areas
with concentrated horse populations. Most of these outbreaks in
weanlings are caused by strains of EHV-4. The age, seasonal, and
geographic distributions vary and are determined by immune status and
horse population. In individual horses, the outcome of exposure is
determined by viral strain, immune status, pregnancy status, and
possibly age. Infection of pregnant mares with EHV-4 rarely results in

Outbreaks with specific strains of EHV-1 infection result in
neurologic disease. Clinical signs vary from mild incoordination and
posterior paresis to severe posterior paralysis with recumbency, loss
of bladder and tail function, and loss of sensation to the skin in the
perineal and inguinal areas. In exceptional cases, the paralysis may
progress to quadriplegia and death. Prognosis depends on severity of
signs and the period of recumbency. Neurologic disease associated with
EHV-1 is thought to occur more commonly in mares after abortion
storms, but it has been reported in barren mares, stallions, geldings,
and foals after an outbreak of EHV-1 respiratory infection.

For prevention and control of EHV-4- and EHV-1-related diseases,
management practices that reduce viral spread are recommended. New
horses (or those returning from other premises) should be isolated for
3-4 weeks before commingling with resident horses, especially pregnant
mares. Management-related stress-inducing circumstances should be
avoided to prevent recrudescence of latent virus. Pregnant mares
should be maintained in a group away from the weanlings, yearlings,
and horses out of training. In an outbreak of respiratory disease or
abortion, affected horses should be isolated and appropriate measures
taken for disinfection of contaminated premises. No horse should leave
the premises for 3 weeks after recovery of the last clinical case.

Parenterally administered modified live vaccines are licensed in some
countries but banned in others. An inactivated vaccine is the only
product currently recommended by the manufacturer as an aid in
prevention of EHV-1 abortion. Vaccine should be administered during
moths 3, 5, 7, and 9 of pregnancy. Humoral immunity induced by
vaccination against EHV-1 and EHV-4 generally persists for only 2-4
months. Antigenic variation within each virus type means that
available vaccines do not cover all strains to which horses can be
exposed. Vaccination should begin when foals are 3-4 months old and,
depending on the vaccine used, a 2nd dose given 4-8 weeks later.
Booster vaccinations may be indicated as often as every 3-6 months
through maturity. Vaccination programs against EHV-1 should include
all horses on the premises.

Gary writes:

The original version of the “I’m positive!” joke (TWIV 78), as I heard it, is an atomic physics joke:

Two atoms are talking and one says to the other, “I think I lost an electron.”

“Are you sure!?!”

“I’m positive!”

Thanks for the excellent podcasts!



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