Tony writes:

Hi TWiV panel!

Here’s a question appropriate for the upcoming World AIDS Day! Does the panel agree it’s appropriate for China to suspend He Jiankui for violating medical ethics for his use of CRISPR to genetically engineer infants immune to HIV?


Nick writes:

I just looked over the most recent TWIV and saw your citation of an article of seeing the moon “upside down” when in the Southern hemisphere.

I only recently noticed, during a birding trip to Guyana, that the moon’s crescent lay at the “bottom” of the moon as it set in the west; here in the Northern hemisphere the crescent is on the moon’s “side”. This is a result of the same phenomenon, but I was unaware until that trip near the equator a couple of years ago (during a magic, clear tropical moonlit night in a small boat in the middle of a lake in southwestern Guyana, with monkeys calling from the shore and nighthawks flitting over the surface gleaning insects). This is about 5 degrees north of the equator.

Of course the crescent, the sunlit part of the moon, faces the sun as seen from the observer; and since the moon circles the earth over the equator, when we are near the equator the moon follows a path from east to west directly overhead, so as it is sinking in the west the lower part of the moon is sunlit as it “follows” the setting sun. Whereas farther north (or south), the moon is not seen from below but from the side, as it lies above the equator, so we see the crescent on the righthand side from the northern hemisphere, or on the lefthand side from the southern hemisphere.

Fascinating, one learns about such simple phenomena at such a late age! We virologists are curious about the world and are always learning new stuff, as shown by the links you guys provide!

Keep up the good work with TWIV and ASV!


Dr. Nicholas H. Acheson

Emeritus Professor

Department of Microbiology and Immunology

McGill University

Rob writes:

Hi Vincent

You fell victim to one of the classic blunders: Mixing up University College London (UCL) and Imperial College London. They are two different Universities. The MSc course in Molecular Biology and Pathology of viruses is at Imperial College, not UCL.

Rob (from Imperial, not UCL)

Rob writes:

Hi Twivvers

I wanted to send a follow-up to address your skepticism about the efficacy of Acyclovir in blocking Alzheimer’s plaque formation (TWiV 519)

First, one oddity of herpesvirus replication is that after reactivation from latency, the viral late genes (including its glycoproteins) can only be transcribed from replicated viral DNA. The evidence for this is good for gamma and beta herpesviruses, less so for alphas, where there are no really reliable latency/reactivation models.

Second, Acyclovir inhibits all herpesviruses: they all make a thymidine kinase (an early gene product) that will activate the molecule.

Third, at least some cases of HSV encephalitis are caused by lack of innate immune signalling (eg TLR3 or TRAF3 mutations – So maybe for most of us (who don’t have defects in innate control of herpesviruses), injecting HSV into the brain would not cause HSV encephalitis. Remember: mice lie!!

So, to my mind, it is entirely logical that occasional HSV particles (or other herpesviruses – HHV6 or 7, or VZV) could stray into the brain without causing disease. Then, if beta amyloid becoming fibrillar is an innate response to having herpesvirus glycoproteins/capsids floating around [which was the implication of the Xandra Breakefield paper], it is entirely logical that acyclovir (which prevents late gene expression by all herpesviruses) would reduce or prevent that from happening, regardless of whether HSV or HHV6/7 is causative.


Jake writes:

Hello Twivsters!

Ever since my first listen and email, I’ve listened to TWiV, TWiP, TWiM and Bacteriofiles on a daily basis with a rotation of each every four days.

It would be safe to say I’m addicted.

After hearing your TWiM and rereading the paper I have to you have changed my view on the fundamentals on the paper but I’m still critical on its coverage, however the findings of the paper are interesting indeed.

Keep up the good work and marking my daily commutes a lot more enjoyable!

Oh, and how could I forget?

It’s a murky 11°C overcast day in Newcastle, United Kingdom.

Anthony writes:

Too despicable NOT to be true? I don’t know.

Jessica writes:

Hi TWiV Team,

Because I have equal passion for social justice and science, I wanted to offer a couple of books that changed my perspective on some of my scientific heroes. I don’t think I’ve heard these books mentioned on the podcast before but the recent discussion of historical figures and early explorers brought this to mind.

While I think it’s important to value their contributions, I learned through these books that many of the scientists I always placed on pedestals and listed among my personal faves (as I guess I should be surprised to find out) often maintained or promoted terrible positions on social issues.  

For example, I learned from first reading “Inferior” by Angela Saini that Charles Darwin used his theories and scientific knowledge to make a case for the inferiority of women (as did many other prominent scientists).

I learned from reading “Stamped from the Beginning” by Ibram Kendi that ancient Greek philosophers (who essentially developed the modern education system) and scientists like Boyle, Darwin, Linnaeus, etc. used their above average intelligence to publicly argue the case for racism, slavery and oppression of black and brown people around the world.  Perhaps more obvious, the founding fathers of the US who are still largely honored as great thinkers/men, followed suit (including Lincoln!). Many of the early explorers were enabled to do their exploration/colonization of “distant lands” thanks to these “philosophical doctrines” about who is superior and inferior around the globe.

While it’s jarring to disrupt the romantic illusion that these great pioneers were also co-signers or creators of modern racism and oppression, it feels better at least to me, to discontinue believing in the lie.  As one who has always studied and worked in science, I found it interesting to read historical accounts and observations through the lens of the “marginalized” because it made me realize how much spin has been applied to even my beloved discipline.

Again, I don’t think being a jerk means scientists like Darwin shouldn’t be acknowledged as paving the way for important ideas, but I don’t believe they should be placed on pedestals either. I also think learning this has broadened my perspective even further by making me question some of the opinions I’ve held in such high esteem for so long–e.g., hard science is superior to soft science etc. There’s a whole gender bias associated with how we do science and as long as we ignore it and ignore the stories of the “non victors” (“history is written by the victors”) we limit our ability to fully understand and appreciate the world.

I respect your openness, intellect and thoughtful discussions which is why I thought this might be of interest to all of you.

Thank you as always,


Fernando writes:

Hi TWiV crew,

A few echoes for your #519 picks and banter:

Rich and voyages of discovery reminded me of two recent readings:

Pathfinders by Felipe Fernández-Armesto is a great global history of discovery, warts and all.

Erebus by Michael Palin (yes, the former Monty Python!) is a can’t-put-it-down history of HMS Erebus, its Antarctic and Arctic (mis)adventures, and English colonial spirit at its most colorful.

Dickson’s coming visit to my hometown Lisbon reminded me that Lisbon is home to a tropical medicine institute, a leftover from Portuguese colonial days, that might be of interest to him. And some outstanding fish restaurants!