TWiV regularly receives listener email with corrections, comments, suggestions for show topics, requests for clarification, and additional information. All are archived on this page.

TWiV 372 letters

TWiV 371 letters

TWiV 370 letters

TWiV 369 letters

TWiV 368 letters

TWiV 367 letters

TWiV 365 letters

TWiV 364 letters

TWiV 363 letters

TWiV 362 letters

TWiV 361 letters

TWiV 357 letters

TWiV 356 letters

TWiV 355 letters

TWiV 354 letters

TWiV 353 letters

TWiV 351 letters

TWiV 349 letters

TWiV 348 letters

TWiV 347 letters

TWiV 345 letters

TWiV 343 letters

TWiV 342 letters

TWiV 340 letters

TWiV 339 letters

TWiV 336 letters

TWiV 335 letters

TWiV 334 letters

TWiV 331 letters

TWiV 330 letters

TWiV 329 letters

TWiV 328 letters

TWiV 327 letters

TWiV 326 letters

TWiV 324 letters

TWiV 323 letters

TWiV 322 letters

TWiV 321 letters

TWiV 319 letters

TWiV 318 letters

TWiV 316 letters

TWiV 315 letters

TWiV 314 letters

TWiV 313 letters

TWiV 312 letters

TWiV 309 letters

TWiV 307 letters

TWiV 306 letters

TWiV 305 letters

TWiV 304 letters

TWiV 303 letters

TWiV 302 letters

TWiV 300 letters

TWiV 298 letters

TWiV 297 letters

TWiV 295 letters

TWiV 294 letters

TWiV 289 letters

TWiV 288 letters

TWiV 287 letters

TWiV 284 letters

TWiV 283 letters

TWiV 282 letters

TWiV 280 letters

TWiV 279 letters

TWiV 278 letters

TWiV 278 letters

TWiV 276 letters

TWiV 274 letters

TWiV 273 letters

TWiV 272 letters

TWiV 271 letters

TWiV 270 letters

TWiV 269 letters

TWiV 268 letters

TWiV 267 letters

TWiV 266 letters

TWiV 265 letters

TWiV 264 letters

TWiV 263 letters

TWiV 258 letters

TWiV 257 letters

TWiV 256 letters

TWiV 254 letters

TWiV 253 letters

TWiV 252 letters

TWiV 251 letters

TWiV 250 letters

TWiV 249 letters

TWiV 248 letters

TWiV 247 letters

TWiV 246 letters

TWiV 244 letters

TWiV 242 letters

TWiV 241 letters

TWiV 239 letters

TWiV 237 letters

TWiV 236 letters

TWiV 233 letters

TWiV 230 letters

TWiV 229 letters

TWiV 227 letters

TWiV 225 letters

TWiV 224 letters

TWiV 223 letters

TWiV 222 letters

TWiV 221 letters

TWiV 220 letters

TWiV 218 letters

TWiV 217 letters

TWiV 216 letters

TWiV 215 letters

TWiV 214 letters

TWiV 213 letters

TWiV 212 letters

TWiV 211 letters

TWiV 210 letters

TWiV 209 letters

Letters read on earlier episodes of TWiV can be found on this page.

Leave a Reply to Michael Lane Cancel Reply

Your email address will not be published.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

208 comments on “Letters

  1. I am a neuroscientist but have a side interest in germs. I really enjoy your podcasts. Rodney has a lot of opinions that I have been subjected to over the years. I think he would make an interesting guest.

  2. I just finished listening to episode 51 and have a follow up for you on Virogenetics. They were taken over by Sanofi. The technology on which the vaccine was developed goes back to 1995 for the ALVAC-HIV patent. There are 3 people on this patent. Paoletti, who Rich mentioned, Jim Tartaglia who now works for Sanofi and Bill Cox. Bill was the immunologist and he quit science to fly packages between Albany and Newark.

    My understanding, through Bill, is that since the vaccine was designed to work against 2 strains the lack of higher efficacy may be due to other strains. This is quite possible in a place that is known to be a destination for sex tourists. It will be interesting to know which strains the infected people in the vaccinated group were infected with. They must have collected these data and it is not that difficult serotype or genotype, is it? Is the problem that the patients are infected with multiple strains? I feel like the scientists involved in this trial are holding something back. Perhaps they are waiting for a big meeting to have a press release but that is more of a big pharma maneuver.

  3. gtolle Oct 7, 2009

    TWIV 47

    Still catching up! Not rushing through. Savoring each episode. Sorry if this has already been addressed.

    Dick, congrats on your op ed on vertical farming. Keep in mind that the most overall efficient system would be a permaculture (simplified eco-) system so there would really need to be lots of wee beasties running around to balance the resource cycling.

    As for the magic no-virus switch:

    1) Human illness would almost certainly increase almost immediately upon throwing the switch. I can't imagine that bacteriophages are not an essential component of human health. It will be interesting, however, to find out if the human immune system coordinates with some bacteriophages.

    2) Viruses would come back fairly quickly (at least some of them) unless the switch also eliminates retroviruses hidden away in various genomes around the world.

    3) I believe that viruses would probably re-evolve eventually as I believe that they are related to microbial gene transfer systems. I suspect that the reason that we haven't seen novel viruses evolve lately may be related to A) there are a limited number of core viral types (the equivalent to the theoretical minimal genome for microbial life) and B) the niches that they could fill are already occupied. Hence, a novel virus might resemble a pre-existing virus sufficiently to confuse its origin and there is little pressure for one to evolve from current gene transfer systems.

    Keep up the good work.

  4. Daniel Oct 17, 2009

    Hello. I listen regularily to your Podcast, and I've come across a video about FluMist and a conspiracy theory in general. Would you mind watching and commenting it from a scientific point of view (leaving all that conspiracy stuff out).

    Kind regards,

  5. Daniel Oct 17, 2009

    Hello. I listen regularily to your Podcast, and I've come across a video about FluMist and a conspiracy theory in general. Would you mind watching and commenting it from a scientific point of view (leaving all that conspiracy stuff out).

    Kind regards,

  6. euthanasiaforgeezers Feb 9, 2010

    I was just listening to your podcast on plaque and you mentioned how much fun it would be to make time lapse movies.

    You can make your own movies.

    I too wanted to make time-lapse movies and ran across an electronic shutter control that works on regular digital cameras. Reading from their list, their product is compatible with canon, nikon, pentax, samsung, olympus, panasonic, sigma, leica, minolta, sony, fujifilm and kodak.

    With one of these timer/shutter controls all you need to do is scrounge an adapter for your camera lens to fit on the microscope and you're in business. What's really great about it is that it's extremely easy. Even a virologist can do it.

    After you've taken several thousand photos (in JPG format) over a period of several days (you program the interval between shots) you use a shareware program (JPGAvi) to convert them into an AVI format movie. The website for the timer is… and the website for the JPG to AVI converter software I use is

    For about $60 (including shipping) you can make your very own time-lapse movies. If you have any problems you must know some 12 year old kid who can help you get up and running. Maybe Dick can do it.

    If you have a decent camera and can take acceptable quality pictures with it you'll be able to produce a professional quality time-lapse movie on your very first try. I'll say it again – it's easy.

    I enjoy your show.



    • We just had a case of a cheating brain-scientist, who now has been
      convicted of using research money for clothes and stuff, trying to blame
      this on one of her students and faking mouse-experiments results. It
      was quite clear that the system isn’t really geared towards handling
      these cases.

  7. Dear Twiv Guys/virology gurus,

    I really need your help. Let me preface this by saying that I have a slightly exaggerated fear of germs which is probably why virology fascinates me so much. I need your collective brainpower to explain something to me. My question has to do with AAV vectors. I’m specifically wondering about the ones people use in the lab but this also applies to gene therapy vectors. Supposedly these vectors are replication defective. The replication factors are supplied in trans to make the virions, right? In neuroscience this is frequently HSV so I call it AAV in a herpes suitcase. If HSV and AAV can supply factors in trans, why can other related viruses that might be lurking in the mouse or person? I’m sure mutations and recombination figure into this as well but how safe are these vectors? Given the number of viruses in the world and the constant evolution can you really guarantee that a virus is replication defective? I would like someone who knows something to explain the science because I don’t see how you can. Sure, it is a remote chance of replication but it isn’t completely out of the question, right?

    Thanks for the education. I love the podcasts and have even listened to the lectures. It is great to be able to listen to lectures from courses I wish I had the time to take. Hopefully this will catch on and people more people will realize that science education isn’t just facts and lectures. I’ll take TWIV and TWIP over network TV any day.


  8. Wonderingalice1984 Aug 8, 2011

    I just wanted to say thanks! I love TWIV! I’m just interested in virology. (My degrees in K-6 education) I’ve learned so much and spent many an enjoyable hour with you guys! Keep up the good work! – Jocelyn Johnson

  9. Assaf Lowenthal Aug 10, 2013

    Hello TWIV team,

    I am a microbiologist from the Hebrew University in Jerusalem Israel, currently spending my time making wine and beer (not drinking, at least not that much…). Naturally, I started listening to the TWIM podcast, but very quickly ran out of episodes and started listening to TWIV. I was waiting for a good reason to write and unfortunately there’s a good one now. You might have heard that during the last several weeks Polio was detected in Israel. It was first detected in the south, in a town small town where the population is not very strict about getting vaccinated. This week our ministry of health began a campain for vaccinating (OPV) kids in the south and in the center of the country . I’m sure you explained it previous podcasts, but could you please explain why a kid who got the dead vaccine (that would be the vast majority of the population) should get the attenuated one? The ministry of health says that the purpose of this vaccine is to reduce the number of carriers in the population, and that there is absolutly no danger in vaccinating. But, what about vaccine-derived polio? More personally- I’ve got a 11 month baby- her third and last vaccine (dead virus) is schedulaed for next month, my gut feeling tells me not to give her the OPV, would you share your thoughs on the subject? Also, as a microbiologist many of my friends ask my opinion on the subject, I’ll feel much more comfortable answering them after hearing your advice.

    Thank you for many hours of fun and eduction

    Assaf Lowenthal

  10. Ken Kahn Dec 17, 2013

    Just read this Technology Review article about Angela Belcher who is designing viruses to make better batteries, solar cells, cancer diagnostic tools, and more.

    Might be a fun topic for a future episode.

  11. Nicola Cataldo Mar 23, 2014

    Dear Doctors,
    I am among those who wish I had studied virology instead of the direction I did take and I want to thank you for the podcasts that seem to be offering me a second chance, here in my retired years. I started with TWIV Podcast #125 because it was the earliest I could find (why is that, anyway?) and I’m up to Podcast #260 already.

    Given how much viruses effect the daily lives of all of us, it seems like everyone would want to know something about them and the thing that sent me on this quest was the lack of information available to laymen on the subject. In your podcasts you often tsk-tsk the amount of Woo Medicine that circulates and I think I can point you to a very reasonable reason for this: the (clinical) medical community is doing a pretty terrible job of providing consistent information. I think if you review the information websites of even the most progressive major hospitals in the country, you will see a spate of contradiction and outright error.

    Some time ago, I asked a doctor friend of mine whether a person can contract the same virus more than once. Her answer was, “Sure, why not?”

    I pointed out that if that’s true, it is hard to understand why she recommends getting flu vaccinations. And having learned a few things in listening to your podcasts, I know understand now that, depending on the specific virus, correct answers could include Yes, No, Sometimes, and We don’t know. But her glib answer served no purpose at all.

    So this is in defense of the layman who might be suffering from Chronic Fatigue Syndrome or whose children seem to get one virus after another despite the annual vaccines, and who can’t get anything from his doctor but double-talk. You can hardly blame this patient from latching on to something. And if the medical community wants more trust from the patient community and less quack medicine, they need to start taking seriously their obligation to provide intelligent answers. Maybe you have some opportunity to survey the informational sites of legitimate hospitals and review the quality of the information therein.

  12. WanderingGnoma Sep 11, 2014

    Dear TWIV-team,

    Here are a couple notes from a clinician.

    If one considers the entire human organism, there are simple answers to the question in TWIV #295 about the viability of cells missing either the X or Y chromosome.

    The Y chromosome is clearly not required, given that no cell in a woman has a Y chromosome.

    By contrast, the X chromosome clearly *is* required, given the existence of lethal X-linked recessive disorders. For example, ornithine transcarbamylase deficiency is classically lethal in males, but not in heterozygous females. Normal males have one copy of the gene coding for the Ornithine carbamoyltransferase enzyme on their one X chromosome, and this is sufficient for good health. Having zero functional copies, however, results in death neonatally or in utero. The enzyme is essential in the cellular urea cycle.

    Also, in TWIV #298, SPECT (single photon emission tomography) is not the same as CT (computed tomography).

    A CT scanner shoots X-rays through the patient (or sample), which are then collected and processed into an image. In SPECT, however, radioactive elements inside the patient (or sample) emit photons that are collected and analyzed. PET is similar to SPECT, except that PET collects emitted positrons.

    Keep up the great work!

  13. Richard Ocepek Feb 3, 2015

    Greeting men and women of TWIV.

    I listened to your Jan 30 podcast and was a bit surprised you did not discuss the current measles outbreak in the US. I am 70 years old and recall having mumps and chicken pox as a child but do not recall having measles. This has concerned me somewhat over the years but I was not overly worried because the disease was essentially eliminated in the US for a long time. I was a pilot in the USAF and visited a bunch of places in the world that I would never pay to visit. I also lived in the Middle East for 6 years and have visited about 30 countries.

    I have often wondered if I did in fact contract measles as a child and the symptoms were minor and overlooked; or I have a natural immunity to the disease; or I am at risk to contract the disease in my later years? What are your comments on my situation? What are the pros and cons of getting a measles shot at this point in my life.

    P.S. Thanks for the straight info on the Ebola outbreak. Turns out you guys actually knew what you talking about which was quite different from the talking heads on TV.

    It is currently drizzling rain in Houston at 6:20 PM with a temp of 45 degrees.

  14. Katie Jan 15, 2016

    Greetings TWIV,
    I am an Immunology graduate student from Iowa State University that studies coronaviruses in pigs. I have loved listening and reading along with you since I started my graduate career 3 years ago! My friend shared this link with me and I thought other TWIV/TWIM listeners may find this interesting as well! I’ve always wondered what microbes make up my microbiome! There is a special for 5 site microbiome testing. They have a discount special running through 17-Jan-16. See the information below. Thank you providing this wonderful podcast as well as other great resources! I am continuing to explore this wonderful world of infectious diseases.

    5-for-1 Sale!

    Do you track how well your new year’s resolutions are working? Why not get a snapshot of your microbiome today, and see how it changes as you do. Here’s to the very best of health for you in 2016.

    Starting right now, a 5-site microbiome testing kit is just $89 instead of the usual $399.

    You can meet all the bacteria currently living in your gut, and also learn about your mouth, nose, skin, and genital microbiomes at the same time.

    Offer valid until Sunday, 1/17 at midnight, or while supplies last.

    Use discount code 5FOR1JAN when you checkout at

    P.S. The weather is currently -7 degrees Celsius and light snow flurries; a mild winter day for Iowa!


    Apparently drinking moderately boosts monkey immunity and enhances vaccine effectiveness. Any commentary from the TWIV Team?

  16. Michael Lane Oct 25, 2016

    I love TWIB, TWIM and TWIV – I grew up in a medical family – it skipped a generation, cuz I turned down Harvard or Yale for a music education. My mom was a nurse, my son is turn. ONE OF YOU has a Limerick contest – most likely expired, but here’s my entry:

    There once was a virulent virus
    which tried with all might to retire us
    We know it’s a pest
    But hardly the best
    I’m sure that you know Miley Cyrus

  17. Michael Lane Oct 25, 2016

    for the limerick contest going on on TWIM, TWIB or TWIV (all addictive) here is my “I’m sure it’s turned in too late” entry, after a foreward…

    I love TWIB, TWIM and TWIV – I grew up in a medical family – it skipped a generation, cuz I turned down Harvard or Yale for a music education. My mom was a nurse, my son is turn. ONE OF YOU has a Limerick contest – most likely expired, but here’s my entry:

    There once was a virulent virus
    which tried with all might to retire us
    We know it’s a pest
    But hardly the best
    I’m sure that you know Miley Cyrus

  18. Michael Lane Oct 25, 2016

    I love TWIB, TWIM and TWIV – I grew up in a medical family – it skipped a generation, cuz I turned down Harvard or Yale for a music education. My mom was a nurse, my son is turn. ONE OF YOU has a Limerick contest – most likely expired, but here’s my entry:

    There once was a virulent virus
    which tried with all might to retire us
    We know it’s a pest
    But hardly the best
    I’m sure that you know Miley Cyrus

  19. STeven Severance Nov 6, 2017

    COuld you have Nigel Goldenfeld on TWIV? His recent work on phages developing the genomes of bacteria seems facinating.

  20. Hello Dr Racaniello! I am a tenured investigator in the field of viral pathogenesis based in India and recently (through a colleague) heard about Twiv. I’ve decided to listen to every podcast from the first (West Nile) which by the way was broadcast during my post-doctoral stint at NCI-Frederick in Fort Detrick. Congratulations on creating a fun, educative and yet erudite discussion/forum. I was particularly intrigued by your 2nd show, on polio and would’ve loved to hear more about the SV40 contamination issue. Also, India is now polio free and we use the Sabin vaccine. Looking forward to carrying on listening!