Peter writes:

Good Morning,

I’m a fan of your show, though I admit I haven’t listened in a while.  You probably saw the news:

Here’s the FDA briefing:

Have you guys covered this therapy yet?  My understanding is that Carl June repurposed the HIV virus to modify a patient’s own T-cells to combat their leukemia.  Sounds fascinating, and I would *love* to hear a TWiV discussion on the topic!

Thank you,


Bob writes:

Spotted while browsing news sites:


Anthony writes:


Subject: West Nile and bird population recovery


“It’s like after a flu outbreak,” says Ryan Harrigan, an infectious disease biologist at the University of California, Los Angeles, and one of the authors of the study. “Everyone builds up immunity, and the impact tends to wane.” Eleven of the 23 affected species in the study experienced this type of recovery.


West Nile virus still wiping out birds across North America

Persistent impacts of West Nile virus on North American bird populations

# # #

Has it been determined that there are breeding populations of infection survivors that now have immunity?  Or might it be — as in Fenner’s feral rabbits — that there is a combination of selection of resistant individuals in tandem with reduction  in virus virulence (perhaps just for some species)?

Thank you.


Great question, and certainly not mutually exclusive ideas. The curious thing about WNV as compared to flu, however, is that the strains don’t tend to evolve nearly as fast, so the virulence year-to-year shouldn’t change much, if at all. I know some birds have recently been tested that were healthy but still ended positive on ELISA tests (meaning they had the antibody for WNV) but whether this represents increased immunity or just a recent infection is hard to determine.

The “bad” years for WNV weren’t due to some new strain of WNV hitting the population, which is different than the flu outbreaks that occur. It may be that those outbreaks represent a new crop of immunologically naïve birds hitting the population.



Ryan Harrigan, Ph.D.

Assistant Adjunct Professor

Center for Tropical Research

Institute of the Environment and Sustainability

University of California, Los Angeles

Ashley writes:

Afternoon Dr’s

Long term listener from the outback of South Australia, about 6 hours drive from the state capital, Adelaide.

I happened to hear your comments on several Australian issues and its battle against introduced pests.  Australia has had a habit of not thinking about the long term impacts of introducing exotic animals with several destroying the habitat and causing the extinction of many native animals and plants. Two of the worst, rabbits on the land, and carp in its waterways.

Two viruses have been used against the rabbits with a fair success but the battle continues.

The herpes virus against the carp has not been released yet as there is still no plan on how to deal with estimated 5 million tons of dead fish expected.  Some say it may be more!!

Reports are though that they are aiming for release at the end of 2017.

It would be an interesting show for your listeners on the use of viruses in Australia in its fight against introduced pests. Well worth investigating.

Kind regards.


Mark writes:

Dear Team,

Firstly, thank you Kathy.

Secondly, the following paragraph of my last correspondence should have been less ambiguous

Just a thought on the naming of Myxoma Virus….. I’m not sure if it was a mucous or perhaps pus?

Please note the question mark at the end of the paragraph (inferring my doubt).

The ‘substance’ was coming from the noses of the rabbits (and substances from the mouths and eyes as well) I wasn’t really asking you to make a diagnosis on the show, I was just conveying my observations [vr: really, you expect scientists not to do that?]. Most of the uglier lesions were around the openings of the rabbits body (i.e. mouth, nose, eyes, anus, etc) and did in fact have clear and white substances exuding from the lesions and orifices (from memory). I, in my naiveté,

thought the observations were implied ( in thinking that someone on the team may have seen a rabbit with ‘mixo’). I now know that it obviously wasn’t mucous even though there was a clear viscous substance involved.

Lastly, I had been excited to think that I may have been championing you guys in that your comments on TWiV 457 made it sound (to me) that you thought the experiment to be somewhat sloppy/slipshod in the fact that no useful answers were gained because they had not used rabbits that may have had the requisite mutations i.e. wild rabbits. You also sounded (to me) to be disappointed in other aspects of the research/experiments in the paper. As I said in my initial correspondence, I usually don’t take positions, take up causes or take sides (especially in things I know nothing about, hence all the question marks and the phase “I have written to ask your advice”) in regard to anything much nowadays. Just thought I might be a useful pawn to gather some useful answers on your behalf (I really don’t give a rats arse what kills us all in the end) I just find you (all of your voices) comforting, knowledgeable and interesting as I go to sleep of an evening.

Please don’t interpret this as a ‘poison pen’ letter. I’m just telling it how it is. I obviously misread your concerns in regard to the paper. No malice is intended in my clarification (this letter) I simply wanted to set the record straight (so you don’t think me completely stupid).

I listen to both TWiV and TWiM and enjoy them both very much. Thanks for all the work you put into it. I really do appreciate it.

Sincerely and with warm regards,


Anthony writes:
To: McColl, Ken (AAHL, Geelong AAHL) 
Subject: Using herpes virus to eradicate feral fish

you outline the use of  Cyprinid herpesvirus 3 to control carp.  If the virus is used, are there plans to mirror Dr. Fenner’s research with rabbits?  It will be extremely interesting to see if the virus indeed does evolve to accommodate carp.   

Dr. Lipkin is studying a virus that appears to affect only tilapia:
Is there any possibility of using this virus to control invasive tilapia in Australia?

Thank you.

Hi Anthony,

The answer is ‘Yes’ to both your questions.

We’re planning a study in collaboration with Professor Edward Holmes on the evolution of the host-virus relationship  for CyHV-3 and carp with full genome sequencing of both host and virus.

We’re also exploring the possibility of Tilapia Lake virus as a biocontrol agent for tilapia in Australia.

Best wishes,


Dr Ken McColl  BVSc (Melb) PhD (Cornell)

Principal Research Veterinarian

CSIRO-Australian Animal Health Laboratory

Geelong Vic 3220


Anthony writes:

Re: Fenner myxomatosis paper

Luck favors the prepared mind.  

While searching for Fenner’s papers Online, someone gave me a box of old books. Perhaps from a cleaned out basement.  In it was the Harvey Lectures.  If it wasn’t for your shows, I’d have thought it just a dusty copy of stale material and tossed it.  I’d not have recognized a collection of reports of fundamental research by towering figures.  

Dakoda writes:

Dear TWiV team,

This is mostly meant to be a thank you letter, so I hope that it doesn’t become too self-indulgent. After graduating high school, I still wasn’t quite sure what kind of career I wanted to pursue. Instead of jumping straight into college without a goal in mind, I ended up traveling around the country and participating in environmental activism. Things were great; I had a lot of fun but eventually I realized that I should be thinking a bit more about my future.

In 2014 two important life events happened: Ebola ravaged across West Africa, and I spent a week in a West Virginia hospital with what the doctors (tentatively) diagnosed as Rocky Mountain Spotted Fever. This ignited in me a passion to better understand infectious disease. It was while waiting under observation before they decided whether or not to discharge me that I discovered your podcast. Although I couldn’t fully understand most of what was being discussed, I was immediately interested. After a few more episodes, I felt pretty certain that I would like to study virology.

Once I was discharged with a prescription of antibiotics and the good news of no permanent negative health effects, I bought a plane ticket back to my hometown and enrolled in classes at my local community college. I’m now at Western Michigan University, finishing up my undergraduate degree. Last year I worked in the microbiology teaching lab mostly preparing growth media and pouring plates for students to conduct their experiments. A few weeks ago I was hired into Karim Essani’s virology lab and there’s few times I’ve been as excited. His research was discussed on episode 124. I am currently reading through one of his most recent publications in preparation to assist in researching the oncolytic properties of tanapoxvirus.

The difference between what I’m doing now and what I was doing three years ago is pretty striking. I set out with a pretty specific goal and feel like I’ve accomplished quite a bit toward that in a relatively short period of time. I can’t wait to see what else happens in the near future. Your podcasts are owed some credit for that. Science communication continues to be an important vehicle for the betterment of society as a whole and of individual lives. Keep it up!

Thank you again,


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