Taylor writes:

Hi Dr. Spindler,

I was hoping you might be able to clear up a few things that have been bothering me lately. In keeping up with the Ebola outbreak I have been considering the nature of negative sense RNA viruses. Is this a particularly nasty group or is my judgment biased in light of the current epidemic? As a quick aside, why isn’t it sufficient to target viral RDRPs? Is it a matter of drug delivery?

I’ve been wondering about the evolutionary relationship between this group with their hosts- and given the nature of the necessary transcriptional machinery it seems quite unique. Do you think that viruses share a common ancestor? If so, would it be nonsensical to assume the ancestor to be negative sense RNA viruses in light of the RNA world hypothesis?

Thanks for your time and consideration,


Adam writes:

Hello TWiVsters,

Last week, you discussed a study that found that 2% of sampled dogs in France were seropositive for anti-ebolavirus antibodies. Like you mentioned on the show, this is almost certainly cross-reactivity. What you might not know, however, is that there may well be filoviruses in Europe, just not ebolaviruses. Lloviu virus (LLOV) was discovered in 2002 in dead insect-eating bats in Spain, Portugal, and most importantly for us, France. Though it has not yet been isolated, the genome has been sequenced with the exception of the 3′ and 5′ UTRs, and it has been proposed for inclusion in the family Filoviridae in the genus Cuevavirus. It is not conclusively known to cause disease in bats or humans, though there is some weak evidence suggesting pathology in bats. Interestingly, humans frequently visit the caves in which the dead bats have been found, without any known cases of disease. It may well be that the seropositive dogs were exposed to LLOV and the antibody used for the study cross-reacts with LLOV to some extent. I’ve included a link to a relevant paper in PLoS Pathogens, which, of course, is open-access (like everything should be).




Alan writes:

Hello TWiV doctors,

I listen to many podcasts, but never miss a TWiV. Thank you for your excellent work.

I do have a couple of questions… (Up ’till now you’ve answered them all).

Estimating CFR:
Please use something other than naive CFR when characterizing the threat of Ebola infection.

Maybe we need a new number based on the facts. Since we do know the number of deaths and the number of recoveries but not the outcomes for current patients, why not use those 2 numbers alone ie deaths/deaths+recoveries = estimated mortality rate (EMR)? This number would be a new patient’s true risk as opposed to naïve CFR which is misleading at best during an exponential outbreak.

When discussing prognosis with patients should the doctor use CFR or EMR?

This Lancet article discusses the problem: http://www.thelancet.com/journals/laninf/article/PIIS0140-6736%2814%2961706-2/fulltext

However, I don’t see the utility of trying to estimate future CFR by using average time lag between infection (or admission) and outcome. Just use the known numbers! In Ebola’s case it’s only 7.5 days away.

I do see the usefulness of knowing the EMR for hospitalized patients vs untreated cases outside the fence. For instance when deciding whether to pay for a taxi ride to the other hospital across town when turned away from this one vs just walking back home. Uninfected members of the community might be interested in their odds of contracting Ebola from taking the same taxi to go shopping etc. http://www.independent.co.uk/news/world/africa/ebola-virus-spread-by-taxi-passengers-says-who-9719478.html

Meanwhile CNN will continue to use the “up to 90%” number for the ratings bump.

Amplification vs Attenuation
What would cause amplification vs attenuation of virulence and morbidity for a rapidly mutating virus such as Ebola? I listen to TwiV, so I understand that viruses tend to reach a truce with their hosts by becoming less lethal but often more virulent. On the other hand I’m aware of laboratory studies that pass infections thru multiple generations of hosts to amplify the infectious agent’s ability to infect enormously. Ebola already seems able to infect with just 1 or 2 infectious particles, so where does it go from here?

Listener Pick:
Updated daily, linking to articles and giving brief summaries and some commentary.
Started during H5N1 outbreak and expanded to include all disease outbreaks. Excellent site!
H5N1 Blog : http://crofsblogs.typepad.com/h5n1/

Best Regards,
Retired Engineer

Wink writes:

It sounds like the panel assumes that public health interventions are known to be effective. I do not believe that has ever been the case. Please consider the following:
1. cholera was waning in London before John Snow’s intervention. Dr. Snow wrote: “the attacks had so far diminished before the use of the water was stopped, that it is impossible to decide whether the well still contained the cholera poison in an active state [Wickepedia].”
2. deaths from influenza the year of novel H1N1 were the same as usual, ~36,000, despite enhanced public health efforts.
3. polio was controlled thanks to university research and ethical pharmaceutical production.
4. the incidence of HIV in the United States is remarkably constant, about 60,000 new cases, while prevalence steadily rises.
If I knew of any clear public health success stories, I would list them, but I can’t think of any.
Winkler G. Weinberg, MD
Infectious Diseases
Atlanta, GA

Topher writes:

Greetings TWiVers,
My name is Topher, and I’m writing in response to Dawn’s email on episode no.304.

It seems to me that you haven’t listened to TWiV very much. It is also very apparent that you haven’t listened to episode no.297. If you had, you would have heard their well researched and in-depth discussion of Ebola.

Additionally, you mistook a desire for accuracy for a complete lack of knowledge. I’m 100% sure they could have all given you an estimate of the incubation period pretty darn close to what it is. (Which Vincent actually did.)
There is a difference between not remembering what kind of fruit a tomato is, and not knowing what a tomato is at all.

In the desire for an accurate statement, he asked if they remembered, which led to them looking it up. This desire for accuracy, even in an off-the-cuff statement, should be applauded not denounced.

(It also seems that you might have a certain expectation of what the discussion of Ebola should sound like, one that is likely informed by media coverage that is all too often suffused with misinformation.)

You really should have listened to more TWiV before you wrote in.

I might have been more inclined to agree with you…

Except – DAMN – for you not to know the difference between a lack of precision and complete ignorance – simple things that YOU DON’T EVEN KNOW …. maybe you should stick to writing in to podcasts that you know more about. (i.e. NOT TWiV.)

Peter writes:

Dear TWIVers
Many thanks for the excellent podcasts. I’ve only relatively recently been switched onto them and am still catching up. I have really been impressed with the way you have covered ebola or should I say Ebola Virus Disease (EVD). When I say “impressed” I don’t mean to give the impression I’m an expert, but rather I can appreciate how you strike a balance in your discussions.

I’m not part of any response to EVD, but I do, as one part of my day job, give infection prevention and control advice to care homes. As we are approaching Norovirus season and following your discussions on EVD transmission, I got to wondering what allows some viruses to gain entry to the body via mucosal membranes like Hepatitis B &C and others to stick to a faecal-oral or vomitus-oral pathway like Norovirus and how EVD can do both?

Whilst I am clear and agree with you about EVD transmission, that is no evidence of airborne transmission, maybe using the terms vomitus-oral or vomitus–mucosal pathway allows people to draw a clearer mental picture.

And on the subject of vomit, may I suggest the following video clip as a listener’s pick of the week, which shows on two levels why viruses in vomit are so transmissible (their spread and difficulties in cleaning up).


Keep up the great work

By the way: the sun has just broken through the clouds and it is a pleasant 20 Celsius and 75% relative humidity

Lead Health Protection Practitioner. Devon, Cornwall and Somerset PHE Centre
Public Health England

Cameron writes:


Ebola ‘could become airborne’: United Nations warns of ‘nightmare scenario’ as virus spreads to the US – Telegraph
Exclusive: Anthony Banbury, chief of the UN’s Ebola mission, says there is a chance the deadly virus could mutate to become infectious through the air

Hi again guys and gals,

I can’t believe the media!!

How irresponsible is this! Nothing to say how this could actually happen, other than viruses mutate! I assume it is scare tactics to make the authorities take the epidemic seriously. My worry is that this kind of public panic will create far worse problems than the Ebola virus ever could.

Also, in seeing the response in Texas, one case of Ebola and an ambulance is taken off the road (don’t they know about bleach?) if they use up an ambulance every time they have a patient infected with a virus, they better buy a whole lot more ambulances!!!! Do they do that when they transport a patient that turns out to have Hepatitis C???

Keep up the great work guys, it seems that the world needs some common sense more than ever! and you guys are the voice of reason when it comes to virology!

Cameron Rogers MSc

Tom writes:

Today’s NY Times [2 Oct 2014] had a front page article on Ebola. Interesting to note that first USA victim of Ebola was symptomatic, told the staff he had recently been in Liberia, was sent home anyway. He returned two days later and was then admitted and diagnosed with Ebola.

Government and health officials seem more interested in CYA than public health. The public should demand the dismissal of any such officials knowingly lying about this event.

While “experts” claim that Ebola is only transmitted by contact with body fluids from an Ebola victim actually demonstrating symptoms, they also claim to be running around wiping down surfaces with what is apparently an alcohol based hand cleaner. From what I have read these hand cleaners are effective for bacteria and “some” viruses. I think even you and your guests will admit that our real knowledge of Ebola is limited, at best.

The fact that there is no quarantine on people leaving countries that are currently undergoing epidemics of Ebola is inexcusable. The front page of today’s NY Times shows a 4-year old girl lying on a floor covered by body fluids from Ebola victims. It shows exactly how far all America’s well publicized efforts to help deal with Ebola in Africa have progressed. What are the thousand people we sent to help doing? Have they even left yet? What is their mission, outside of propaganda showing our efforts to help Africa and the Ebola epidemic?

While I agree that there is apparently no evidence to indicate the Ebola virus can be spread by airborne droplets I certainly claim some of the statements such as the disease can only be transmitted while the victim is symptomatic is probably based on a too limited data sample to be taken as ground truth.

While USA Today [2 Oct 2014] lacks the reputation of the NY Times, it already is indicating we are possibly up to two USA Ebola victims, the second stemming from the so-called first victim of Ebola here in the USA. With the incubation period being as long as three weeks [sic?] who knows what awaits us. Let me reiterate the “first” USA Ebola victim was obviously symptomatic when he first went to the hospital and was turned away.

Your team isn’t among the crowd who dismisses Ebola by saying more people die in car wrecks or the flu than Ebola, this misses the point. And yes, millions more die of malaria in Africa, so Ebola is a joke in terms of sheer numbers. Americans don’t care about that because malaria is no threat to the average American. This isn’t a criticism, just a fact.

Is the Ebola cat out of the bag? I suspect it is, yet the public has been fed a lot of malarky based on practically no thorough scientific investigation or knowledge of Ebola.

Poo-pooing “idiots” who don’t know squat about Ebola and make claims about aerosol spreading of the disease is all well and good but I think you also should address the fact that almost no body of substantial knowledge exists on this disease because up till now it has been a relatively limited in numbers “African” problem. This is, even you must admit, no longer the case and we are already learning of lies spread by officials about the first victim.

By the time of you next podcast, who knows what the USA Ebola victim count will be. Please, let’s be sure your podcast doesn’t change the statement the truism that “In time of war, the first victim is truth”, to “In the case of Ebola, the first victim is truth,


Tom writes:

While there seems to be no evidence that AIDS can be transmitted by a mosquito bite from someone infected with AIDS to someone not infected, AIDS certainly can be transmitted from a hypodermic needle used by someone infected by AIDS. Since, I believe, far more blood is injected into a potential AIDS victim by a mosquito than a hypodermic needle, I conclude there must be some factor inherent to a mosquito that prevents transmission.

I wonder if any research was ever done to see if there is some component in a mosquito that kills or renders the AIDS virus harmless. If so, perhaps this information could be used to produce a vaccine.

Are you aware of any such study, or of interest to me why a mosquito does not appear capable of spreading AIDS?

Tom writes:

Matthias writes:

Dear TWIV,

I was wondering if you want to talk about the Ebola conspiracy theories in a future episode, the accusation that Ebola was created and patented by the US government to be precise. I’ve seen this nonsense going around for months now and two weeks ago the Daily Observer, Liberia’s largest newspaper, published an article claiming exactly that (and was dutifully quoted by All the Virology on the Face book , which, despite the name, was a reliable page until then). What the conspiracy theory refers to is this patent for Bundibugyo, which was applied for but never granted (if it had been, the patent number would end in B, not A1): http://www.google.com/patents/US20120251502

The application obviously refers to an isolated strain and methods to detect it, not some way of creating the virus itself. The problem is that it is unsurprisingly written in a very dense and technical style and laypersons will almost certainly get the wrong impression from it – that is if they even bother to read beyond the headline. To find out that the patent was never granted in the first place takes active research that nobody is going to do either. I found only one article where a life sciences patent lawyer explicitly debunks all this, unfortunately it’s in German: http://www.zeit.de/wissen/gesundheit/2014-09/ebola-patent-jan-krauss-interview

I would be happy to translate the relevant parts if you decide to do this and want to cite him regarding the legal aspects. Have a nice weekend!


Cheryl writes:

Hi TWIV! Fantastic podcast. You guys are truly amazing.

Question: why does the U.S. government have a patent on ebola? Why would it want to do that? http://www.google.com/patents/US20120251502

Sincerely, Cheryl

Dara writes:

Hi TWIVvers,,=

PhD student in Immunology at Stanford and big TWiV fan here. I wanted to share an outreach project that I and some colleagues recently put together as an immunologists’ response to the anti-vaccine movement. It’s a music video called “I Just Can’t Wait For My Vaccine” set to “I Just Can’t Wait To Be King” from the Lion King. It’s a fun and informative explanation of a lot of commonly misunderstood vaccine-related concepts. Would love it if you wanted to share – we’re hoping it’ll prove to be a useful educational tool.

Thanks so much for your consideration,
Dara (Dara rhymes with Sarah)
Palo Alto, CA
70 degrees and sunny, like yesterday and tomorrow

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