Nathan writes:

Dear TWIV team,

Thank you for featuring our paper on TWIV 451. I thought that you did a wonderful job of describing our experiments and findings as well as navigating through our jargon. After hearing non-mosquito folks talk about our paper, I now recognize how strange some of our approaches must seem and I should improve my writing for a broader audience. Your discussions were very helpful, so thank you.

In response, I thought that y’all might appreciate some additional details. These experiments were very difficult and tedious. Our initial goal was to construct a model natural transmission cycle using multiple rounds of mosquito and bird infection. The first issue was getting individual mosquitoes to infect birds without wasting any 1 to 2 days old chicks with mosquitoes incapable of transmitting West Nile virus. If the chicks do not get infected, we cannot reuse them because they are either too old to become infected and it throws off the timing of our experiments. Hence the development of using the filter paper to test for transmission without sacrificing the mosquito. Compounding the issue was that our Culex mosquitoes did not feed well alone, they needed to get into a feeding frenzy with their friends. Many other mosquitoes, like Aedes aegypti, have no issue feeding alone in the lab. It might even be that our particular Culex colonies are picky. To overcome this, we sprayed our transmitting mosquito with fluorescent powder and put her into a 64 oz ice cream carton with mosquitoes that were unexposed to the virus. Then we restrained the chick, placed it on the carton, and waited for the pink mosquito to get fat with blood.

The real hard part was orchestrating the timing of hatching chicks and mosquitoes to be of a particular age and screening the exposed animals for West Nile virus as close to the transmission day as possible. Sometimes this would require collecting filter paper, extracting RNA, and screening for virus from >500 mosquitoes starting at 5am, marking mosquitoes pink powder and combining into cartons in the evening, and transmission experiments going past midnight. I owed my lab lots of beers, to say the least! This was a ton of work to have the main objective not quite work out, mainly because of the mosquito death issue. The consolation prize was using the filter paper saliva collection method to track West Nile virus populations over time – which turned out to be quite surprising.

The discovery of unique virus populations spit out by individual mosquitoes over time is a nice extension of our previous work examining the random bottlenecks that West Nile virus must overcome within the mosquito before transmission. See our graphical abstract in the attached paper for an overview:

In summary, only a few randomly selected viruses make it into and out of the major barriers for transmission: the midgut and salivary glands. It’s the constant bottlenecks at these sites that, in my opinion, contributes to the unique virus populations in the saliva.

Considering how much y’all appreciate semantics, I should comment about the quasispecies theory. Quasispecies is not synonymous with genetic diversity, as it is often used. Rather, quasispecies is a form of mutation-selection balance where the entire mutant spectrum behaves as a single unit and collectively determines fitness (i.e. group selection). It is quite difficult to demonstrate that this form of selection is actually happening during infection, thus it is still very much a theory and not absolute. We did not mention quasispecies in our paper because we did not investigate how the virus behaves as a group, only how drift and selection act to reorganize virus populations.

Anyways, thank you again for presenting our paper. I’d be happy to address any follow-up questions.



P.S. I live in San Diego, so I won’t upset you with the weather details. Trust me, it’s nice.


Nathan D. Grubaugh, Ph.D., M.S.  

Post Doctoral Fellow

Andersen Lab

The Scripps Research Institute

Greg Ebel writes:

Dear TWiV hosts,

Thanks so much for the nice discussion of our recent paper on TWiV.  You all do such a great service to our field through this podcast, and although I’ve never really thought to thank you for it, it’s now high time . . . so, really, thanks a lot.

The phenomenon about group feeding in mosquitoes is pretty strange, and it may be that someone understands it somewhere, but I don’t.  It does make for some experimental headaches, though.  I’m sure that Nate has emailed you a lot (he’s a huge fan) to answer and clarify, but if any questions remain don’t hesitate to contact me.



Gregory D. Ebel

Professor, Department of Microbiology Immunology and Pathology

Director, Arthropod-Borne and Infectious Diseases Laboratory

College of Veterinary Medicine and Biomedical Sciences

Colorado State University

Paul writes:

Dear TWiVians

A quick message to correct (as you predicted we would) your musings on the origin of the style of map used to produce the wonderful Roman roads graphic in one of the week’s picks.

The origin is, of course, the London Tube map and not that of the New York underground. The London map was designed by Harry Beck and first printed in the UK in 1931. A brilliant, original piece of graphical design that has been co-opted around the world for a wide range of network representations.

The New York underground version was produced in 1955 by George Salomon and was the official NYC map from 1958 to 1967. Salomon was a German immigrant and proposed route names and colours that mirrored those of the Berlin U-Bahn. He knew of Beck’s London map from time spent in London and adapted the same modernist style.

A cool morning here in Brisbane of 6degC but warming up to a sunny 26degC later in the day. Might go for a wander around the university lake.



Professor Paul R Young | Head of School |

School of Chemistry and Molecular Biosciences (SCMB) | The University of Queensland | Brisbane | Queensland | Australia |

Australian Infectious Diseases Research Centre (AID) | The University of Queensland | Brisbane | Queensland | Australia |

Maureen writes:

I am a clinical research nurse with NIAID at the NIH. I work with infectious disease patients of many types and we run the Special Studies Unit where the Ebola virus patients were treated. The director has put out an article in his blog on some findings from the research done from the Ebola patients. I thought you might be interested in the paper. Thanks for all the informative podcasts that you present each week and for the summaries now of the papers you are presenting. The intelligent discussion among all of you is such an inspiration. It is 95 degrees (35 C) and sunny now in Bethesda, Maryland.

Ebola Virus: Lessons from a Unique Survivor

Steve writes:

Hi Vincent,

I wonder if you might be able to discuss this idea of a ‘newly discovered branch to the enterovirus tree’, and if Byron Hyde’s theorising is likely to stand up in the case of M.E.

He weaves a rather flowery story/case history, here, but I have little doubt, from my own experience of what passes for ‘diagnostic procedure’ in the UK, that the majority of cases of ‘CFS’ really are just patients who used up their ‘three strikes and you’re a hypochondriac’ allocation of tests or consultants, and were simply never taken seriously again–until an acute crisis like a minor stroke happens, as in my own case.

Here the case history develops around what should have been an easily diagnosed case of ‘hand, foot, and mouth’ disease, but I’d be interested if you could fill us in with an up to date, state of the knowledge on enteroviruses and the diseases they may cause, on TWiV.

I’ve been interested in your case histories as enthusiastically described by Daniel, on TWiP, and, the way he describes his working collaborations with what seems to be a diagnostic team, which is a marked contrast to the process of serial short interviews with solo ‘consultants’ whose relevance has only been guessed at, at widely separated intervals of months, that passes for a diagnostic effort here in the UK. With our system it seems to me that diagnosing any non-obvious illness can only ever happen by sheer fluke. Dr Hyde’s example of the ‘diagnostic’ process applied to the poor patient ‘Amy’, in the above account, is, I’m sorry to say, very familiar.

The ‘closing of ranks’ by the UK professionals that Dr Hyde experienced when he tried to advise them of the more appropriate diagnosis for ‘Amy’, you should be already familiar with, as it closely parallels, and partly stems from, the same culture that David Tuller has been investigating over the PACE trial, and the closing of ranks against anyone who dares to question it.

All the best; and many thanks for the continuing free education on all things microbiological that you and your colleagues are providing to the World.

Anthony writes:

And perhaps monitor the winds and clouds for microbes, too?



# # #


Ultimately, stratollites could prove a boon to atmospheric and astronomical research, serving as platforms for long-term observations. Downward-looking radar could provide data to generate earlier and more precise storm warnings. Other stratollites could serve as internet relays over remote parts of the world.

Kenneth Howard, a research meteorologist at the National Oceanic and Atmospheric Administration, said that although computer models that predict hurricanes and tornadoes have improved, “they’re data-starved.”

Ground-based weather radar is blocked by mountains. The curvature of the Earth limits the area that a radar station can monitor. And there is no radar coverage at all for weather over vast stretches of the oceans.

Mr. Howard envisioned stratollites loitering over Tornado Alley, the slice of the Central United States where the storms strike most often. Weather models can point out two or three days in advance where storms could spawn tornadoes. A stratollite could then be sent to that location to quickly spot tornadoes as they begin to spin and perhaps give people a half-hour or more of warning to seek shelter. (Current warning times are less than 10 minutes on average, Mr. Howard said.)

Mr. Howard said the agency hoped to fly several demonstrations of radar and other weather instruments on World View stratollites in the coming


Connor writes:

Hi all,

Thought you and your listeners might appreciate the virology colouring book that we at the CVR produced as part of the MRC Festival of Medical Research.

Follow this link:

It is free to download and distribute. There is also a competition running to win a hardcopy of the book.


Torma writes:

Dear World of Virology Professors!

First thing first, I would like to express my huge appreciation for your great work and for the really stimulating and informative podcasts. I write from the oven hot Budapest where is curently 34 °C or 93.2 °F, all blue sky, no cloud, no sign of redeeming rain… During the previous podcast there was a conversation about the Japanese term for ladybug and about the urge for the more pronounced presence of women at scientific events. Speaking of urges I cant help to share with you the hungarian word for ladybug. It is spelled „katicabogár” more specifically „hétpettyes katicabogár” ( the seven speckled, which brings one’s good luck). The first part “Katica” is nick/ pet name for Kathy or Kate and the second part “bogár” means bug, so it also has a feminine character to it in Hungarian. With being said that that, big shout out for all the dedicated Women Scientists for their great contribution for building the Tower of Science higher and higher. Btw Prof. Spindler, great video about the pipette washer and the “AstroKate interview”  was just over the top! Thank you all for making science soo Cool! 😀

I wish you all the best!

Tomra Ferenc from the Research Center of Sport and Natural Sciences

Ps:. I was really impressed with Prof. Despommier’ pronunciation of ‘Budapest’. It almost sounded native! Probably a heritage from Miklós Müller.

Seweryn writes:

Dear weekly virtual bus companions,

In the most recent TWiV episode 447, there was a discussion about science communication, including an example of new ways of engaging with the public through “tea and science” sessions. Here in Australia (as well as the UK and possibly other places?) there has been something similar going on for a few years… but in a pub (they say that many great ideas come from discussions over a drink or two, right?) It’s called Pint of Science and has sessions held around the country about a wide variety of topics. Check them out, and keep up the wonderful work.



Seweryn Bialasiewicz, PhD  | Senior Supervising Scientist

QPID Queensland Paediatric Infectious Diseases Laboratory

CCHR Centre for Children’s Health Research | Children’s Health Queensland Hospital & Health Service

CHRC Child Health Research Centre | The University of Queensland

Kasey writes:


I wrote in a few weeks ago regarding the gender parity paper that was discussed with interest in the gender parity of TWiV. I wanted to follow up because after hearing it read, I realized I broke rule#1 of giving feedback, which is that you should always start by describing the things you like. I must’ve been in a rush so I’ll try to remedy that now. I’m a big fan of the show and love being able to listen to descriptions of interesting virology papers while walking my dog in the morning. Listening to your podcast really helps to motivate me to try to do more science communication. I’m an Assistant Professor at Georgia College & State University (a public liberal arts college in central Georgia) and am trained as a molecular virologist. I mostly studied adenovirus although I worked on an adenovirus-vectored malaria vaccine during my postdoc. I teach the Molecular Virology course here and just used the Principles of Virology textbook and loved it. I also like supplementing it with some of these podcasts and Vincent’s blog posts. I started and am the current faculty advisor for our GC STEM club, which hosts monthly Science Cafes during the Fall and Spring semesters. I’ve facilitated a couple of them so far – one on vaccines and another one on Zika (we did that one trivia style). I also do some radio interviews on our local NPR station about the upcoming Science Cafes. And we have Times Talks every week in our library where a NY Times article is picked and we facilitate a discussion with students regarding that topic. I’ve done a couple of those on CRISPR technologies and issues with the anti-vaxx movement.

I also want to clarify a couple things. Sometimes I try to be succinct, but end up not explaining my ideas thoroughly enough and misunderstandings occur. A) I didn’t mean to suggest that Vincent only knew male virologists. It was more that if you’re picking from a limited pool of colleagues and compound that by the small sample size, it is reasonable to expect gender disparity without sexism being a cause. And B) I did not mean to suggest that any of the current hosts should stop being hosts. I love everyone’s contributions. I understand not wanting more than 5 hosts, but I didn’t want to suggest ways to achieve more gender parity since you all would know the logistics better. I think you ended up coming up with some great ideas. It does seem like a lot of work so I can see why several people have turned you down. I myself would love to be a host if I had more time: case in point, it’s taken me a few weeks just to write this follow up email and it’s during the summer. The timing also coincides with the first real day of my “vacation” (I used quotes because I still have several work-related items I want to accomplish during my “vacation”).

I’m actually on Long Island visiting family for my vacation so the weather is a beautiful 28˚C and partly cloudy. Much more pleasant than Georgia this time of year.

Thank you everyone for all that you do. Keep up the good work!

Kasey Karen, Ph.D.

Assistant Professor of Biology

Biological & Environmental Sciences Department

Georgia College & State University

Stig writes:

Hello Professors

At the moment it is hot for Danish standards, and my guess would be that it is around 20 degrees C, and mostly clear skies. I am still not using a weather app, so that is about as precise as I can be.

Unfortunately I can’t really enjoy it seeing as I have my master thesis to hand in at the end of August, feels like I am working around the clock.

I just finished reading “Ignorance” by Stuart Firestein as recommended by someone from TWiV, I don’t remember who, sorry !

This is my 3rd e-mail to the TWiV podcast, but this is the first time not trying to win a book.

I listen to TWiV when I can, while working at the bench and usually while pipetting and it seems that I almost have lot of stuff to e-mail in about but I never get it done. So now was the time to do so …. agin.

I would like to hear your opinion on the matter of sci-hub. I have included some links outlining what it is and how it works. I hope you will take the time to discuss it among you. I don’t think that it have been discussed in any of the TWi(X) podcasts, if so I apologise. As I have “only “ been listening to TWiV and TWiM, TWiEVO and sometimes TWiP for a little over a year now (I think). / /

If you want to get a bit further into it, the level1techs news/podcast talks about it as well: @ 53:28

Thank you for a fantastic podcast, keep scienceing !

Finally I would like to make a pick of the week. And I think Vincent, your son might like it, being in cyber security. If you are like me and value online privacy I can recommend this podcast.

Security now! With Steve Gibson @

Oh, one more pick, if Vincent can have two picks, so can the listeners 😛

“The Gene: An Intimate History” by Siddhartha Mukherjee an Indian MD. I am reading it now, just about halfway through – I find it really interesting.

Best regards

Ricardo writes:

Hello TWIV Friends.

Long time no writing, but I’m listening.

Here I send a link for a listeners pick.

It is a movie from Last Week Tonight with John Oliver about Vaccines.

He uses several communication techniques to pass the message, and ends with a very nice touch.

My best regards my friend and keep the beautiful work.

Ricardo Magalhães

Universidade Fernando Pessoa


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