Trudy writes:

Dear TWiVers,

In answer to your question about who else out there has listened to all of the episodes, the answer is me. I have listened to all of the episodes of TWiV, TWiM and TWiP. As a result, I’m very familiar with TWiX culture. I also tried Urban Agriculture, but it’s not my cup of tea. I like infectious disease.

Keep it up!

Lisa writes:

Dear TWiV team,

I teach English as a Second Language and many of my students are living and working in South Korea. These days, they have become very distracted from their English studies over concerns about the recent MERS outbreak. I have run out of things to say to them to assuage their fears — such as it is spread through direct contact and it is very unlikely they will contract MERS if they are not health care workers. I have suggested taking Vitamin C and extra hand washing, but most of my students are freaking out and I feel that, while their concerns are valid, they have reached peak panic mode. Lately, they have told me that they don’t understand why their government will not release the names of the hospitals where MERS patients are being treated, and I have tried to explain that it is probably due to patient privacy among other mitigating factors. South Koreans are very distrustful of their current government, and they are habitual users of social media, where it seems rumors are spreading faster than the virus itself. They have blamed their government for the fact that their “Patient Zero” went from hospital to hospital before anyone diagnosed him with MERS.

Can you please do a show about MERS or speak about the South Korean outbreak during a portion of one of your upcoming episodes? I would really like to hear your take on this outbreak and hopefully you can give me some information about MERS that will help me to talk my students off the ledge. I majored in English literature and psychology, so this is not exactly my area of expertise, although I do enjoy virology and your show.

It’s a sunny 65 degrees Fahrenheit today in Cincinnati, Ohio, with an expected high this afternoon of 84. We have 87% humidity with winds at 2 mph.

Thank you,


Todd writes:

Dear TWiVers,

While listening to Ep. 339, I was so disappointed that Alan missed a great pun opportunity while discussing the Herpesvirus paper. Vincent brought up Viral Host Shutoff protein. As soon as I heard it, I was certain Alan would make some sort of VHS joke. Ah well.

Thanks for taking a complex paper and putting it into terms that a layperson like myself can (sort of) follow.

Todd W.

Suellen writes:

I listen to your podcasts (all 3 of them!) every week, and I just love all the science. I am pro-vaccine, but of course like just about everyone these days I have anti-vaccine friends. One posted this on FB:

“Amount of mercury allowed in drinking water: 2 parts per billion. Amount of mercury in a vaccine: 51,000 parts per billion”

Now, I just know this can’t be true, but don’t know how to respond to it in a responsible, science-based manner. What are the facts? Can you help me correct this — and I sure hope it is wrong! I looked online but can’t find official numbers from the industry, only crazy numbers from the anti-vaccine people.

Harpocrates writes:

Hi, Kathy,

Thanks for your question. I haven’t done a full post on thimerosal in vaccines yet. However, I do have some info on my other site: Part of the problem with their comment is that they are likely citing the EPA guidelines on methylmercury, which limits amounts to 0.0001mg/kg/day. Methylmercury tends to stick around for weeks, while ethylmercury (in thimerosal) has half-life of around a week. Second, they’re confusing something people are exposed to multiple times every day (drinking water, using water to cook/clean) to a one-time, acute exposure (a vaccine). Then there’s the fact that, at least in the U.S., only some flu vaccines contain thimerosal; the rest of the childhood schedule has either no or only trace amounts of thimerosal in the final formulation. And in California, no vaccine given to a child or pregnant woman can contain thimerosal, by law.

Hope that helps.

Peter writes:

Hi TWiVers
Not sure if this recent Nature Communications paper is within the remit of TWiV as it is immunology rather than virology but I think it could be worth a mention. The authors highlight many seasonal changes in the immune cells, immune and inflammatory responses, with a more inflammatory response predominating in winter months.

It was also found that the antibody responses to several vaccines were influenced by the month in which the vaccinations were given.

The paper is open access but I found it rather heavy going and feel I would gain more from a discussion of the paper by people with a better understanding of the subject than me.

Widespread seasonal gene expression reveals annual differences in human immunity and physiology

Reed writes:

Dear Vincent and friends,

I came across this recent article in this week’s Nature ( and was curious about the TWiV team’s opinion, especially regarding the ideas about new policies for antibody production and validation (another related article:

How feasible do you think these suggestions would be? How much of a reproducibility problem would be fixed?

Thanks for your time,


Katie writes:

Dear TWIV team,

I am a PhD. candidate at Cornell University, studying coinfections between plant viruses, and I wanted to provide some information about prunus necrotic ringspot virus and cherry leaf roll virus if no one has yet written in. I’m a bit behind in my podcast listening, since I only listen when doing lab work alone. The epidemiology of both viruses relies heavily on pollen and seed transmission, to the point where prunus necrotic ringspot virus has no known insect vector. Prunus necrotic leafspot virus is an Ilarvirus that packages its segmented, tripartite genome into single capsids. Like many Nepoviruses, cherry leaf roll virus packages its bipartite RNA genome into separate capsids. RNA-1 and RNA-2 are packaged into B and M particles, respectively, and both are needed to infect a plant. While there is some evidence that certain strains of cherry leaf roll virus can be transmitted by nematodes, a 2006 paper in the Journal of Virology by Rebenstorf et al. provides evidence that this is unlikely to be the major form of transmission. The authors examined a number of strains isolated from different host species in several countries around the world, and found that the population structure of cherry leaf roll virus is strongly correlated with host species rather than country of isolate origin. The majority of Nepoviruses, like cherry leaf roll virus, are seed and/ or pollen transmitted, so isolates are very likely to be transmitted within a host species. One way that cherry leaf roll virus and other Nepoviruses may be able to survive with separately packaged genomes is that ovules can likely hold more virions than could be transmitted by an insect vector, such that the probability of only containing one virus particle type is low. Remember also that plant virus particles do not use cellular receptors to enter cells, and RNA is actively transported between plant cells through plasmodesmata (cytoplasmic bridges between plant cells).

I find all of this infinitely fascinating, and would love to hear more TWIV podcasts about plant virology. Living in Ithaca, NY, I’m often extremely jealous whenever Rich gives his weather reports, but today is a beautiful 63F (17.2C) day with clear skies.

Thanks for all of the work you do to put out these podcasts.



Judi writes:

​a map of the us by most common ca​use of death…

Not sure what this says about the US — most common cause in Texas is TB?!?

and why are people in Utah dying from undetermined events and their sequelae?

Here in California we die from hyperplasia of the prostate, so I guess women will live forever!

Thanks for all you do…
Judi (the retired science teacher in San Diego)

weather — cloudy, cool (high 60s), calm winds, 62% relative humidity – a wonderful relaxing day

Pritesh writes:

Hi TWIV team,

Here is my pick of the week – amazing video on how killer T cells kill cancer cells!

Pritesh Desai
Graduate Student
University of Florida

Ramon writes:

Maybe you could find this TED Talk interesting as listener pick of the week:
Romina Libster: The power of herd immunity

Ramón Canet, MD
Internal Med Chief
H Can Misses
Ibiza (Spain)

Leave a Reply

Your email address will not be published. Required fields are marked *