Bugabate writes:

Good article on long term Ebola risks:


Sandra writes:

I learned about your podcast at the ASM meeting in Boston last May. Thanks for the tip!

Here is some information that might be applicable to the topic of rapid screening for Ebola in airports or clinics. The FBI has promoted the development of Rapid DNA Analysis for law enforcement. The idea is to quickly generate an STR profile for someone when they are brought into a station for processing/booking and to use the profile to search for a match in CODIS (Convicted Offender DNA Index System) within an hour. Currently, it can take weeks to months for STR profiles to be generated through a crime lab.

A talk this summer at a Forensic DNA conference discussed a launch of the program in Arizona, so it’s now operational.

This technology could, in theory, be used to screen people for anything that can be detected by PCR. It’s not inexpensive like a thermometer, but it’s possible.



Alice writes:

Love them, but they are SO long I just don’t have time to listen.

Alice MD

Mitchell writes:

Hi TWIV folks,

Love your podcast. I’m impressed and appreciate that all of you not only spend the time doing the podcast, but also doing “homework” to prep for them. Also, as an aside, I’m happy to hear that “real scientists” can’t understand and/or read all of the articles in journals such as Science. As a non-scientist, I have trouble reading more than a very few articles in Science. But, enough of that, I’ve got a question.

Can you explain how testing someone for Ebola works. Especially when people going into quarantine, voluntary or otherwise, is such a problematic issue? For example, if someone had contact with an Ebola patient, could they be tested and avoid the quarantine? I’m guessing not, otherwise this wouldn’t be much of an issue. Can you help me to understand this?

New Jersey
Today it’s 40 degrees F, with winds at “really a lot of” mph.

Anne writes:

This is a video prepared by the presenters of the Epidemiology course currently in session on Coursera. It was posted about two weeks ago, so the information is a bit dated (regarding numbers of cases) but it is otherwise a nice summary of what’s been happening, and what needs to happen.


S David writes:

The Dave who wrote the letter read by Kathy on water transmission of Ebola (on 309), is not the Dave from Fresno whose relatively entertaining missives have turned up three or four times in the past year on a TWiX. I might be the Dave who wrote suggesting Ebola survivors as immune nursing helpers in treatment settings, but I don’t remember. I don’t think I’m any of the other Daves either. (But see PS.)

I am the Dave, aka SDH de Lorge, who wrote several comments to NPR stories conveying some useful factual info about Ebola in early weeks, culminating in my impassioned recommendation of all things TWiX in general as well as for reliable discussion of Ebola. A little while after that, I was pleased to hear Vincent interviewed, but have too little grandiosity to suppose I was instrumental in that. It has occurred to me to wonder if there might have been a bump in your podcast download numbers, though. That Dave is here. Since then, I have not felt compelled to comment much further on NPR on that topic, and haven’t lately had much smart to say on other stuff either, despite repeated attempts.

BUT, One respondent there a couple months back informed me in no uncertain terms that Ebola lingered in semen for three months after recovery, but it wasn’t ever clear to me how she knew that. Could there have been more then one of her for you to have heard from too?

It cooled off here, into the 60s F°, and we got a measurable rain! Sleeping much better, which I believe is related.

Haven’t communicated with Robin of Fresno about pulmonary embolism from leg thrombus progressing to clotting in cardiac or brain arteries, but s/he is certainly essentially right that that is very unlikely. I was trying to be dramatic, in pushing for compliance regarding wiggling your feet on long airplane rides. Bloody Marys too.

Warmest regards,
PS Oops! I am the S David whose letter was just read, preemptively bragging about the NPR bump. Did I mention my memory? Now you will be entirely justified in skipping this letter, except for the Fresno part. -d

Alaina writes:

Greetings, TWIVsters, from Toronto, Canada, where it is 12C and cloudy. (I really wanted to wait until next month to write my first letter because it would have been written from Playa Del Carmen, Mexico, where I am spending the winter. 26C and sunny, in case you were curious.)

Last week in TWIV 309, listener Timothy asked if you knew of a place to get information about the number of beds, etc. I can help!

WHO releases an EVD outbreak situation report twice a week. I love referencing it because I get to use the phrase “WHO sitrep” in conversation, which makes me feel cool. In any case, the sitrep has a lot of information, including the number of available and required beds. Here’s the link: http://www.who.int/csr/disease/ebola/situation-reports/en/.

I discovered TWIV back in early August and have been catching up like a mad woman. I’ve been jumping around a lot, but I’m averaging one about every day and a half. I could have listened to more if you hadn’t rekindled my love of molecular biology, which inspired me to join the Coursera Systems Biology specialization!


PS: My undergrad degree is in computer science, but I’ve had a lifelong affair with biology, and am one of the co-founders of DIYbio Toronto. I’d like to suggest another link for the epidemiology data nerds out there: Virginia Tech PhD student Caitlin Rivers’ Github repo, where she and other contributors collect, clean, and post EVD epidemiological data from many different sources: https://github.com/cmrivers/ebola

Dominic writes:

Dear Professor Racaniello and TWiV-colleagues,

I am aware that you and your colleagues screen the current literature intensively, nevertheless I would like to call your attention to a paper our group has published a few days ago describing the treatment of an Ebola-patient with best supportive care: A Case of Severe Ebola Virus Infection Complicated by Gram-negative Septicemia, Kreuels B, Wichmann D, Emmerich P, Schmidt-Chanasit J, de Heer G, Kluge S, Sow A, Renné T, Günther S, Lohse AW, Addo MM, Schmiedel S. N Engl J Med. 2014 Oct 22.

The paper has been published online ahead of print and thus might not have been come to attention to everybody involved in the care of EBVD patients. This might be of interest especially in resource-limited settings.In addition the to this we also provide some evidence (at least on case-report-level) to answer questions like „How long is a patient infectiouse?“. We performed serial PCR-tests from various body fluids (blood, saliva, urine, stool, sweat, teardrops) to detect EBV-RNA after clinical cure but in respect to Linfa Wangs statement “PCR is not virus” (episode 296) we also performed plaque assays.

As a comment to a statement in one of your recent TWiVs, I agree with you that negative pressure rooms and BSL-4-like conditions are not necessarily needed for the protection of medical staff, but it appears to me that especially the decontamination process is a crucial step. Decontamination might be more reliably achieved when showering with 2% peroxyacetic acid. As a result Germany decided to centralize the treatment of patients with viral hemorrhagic fevers in specialized units which have been build in recent years.

Keep up the excellent work!
Best regards,
Dominic – on my way back from a skiing trip at Hintertux Austria (clear blue sky; -6°C; 100cm of fresh powder).

P.S.: Just for your background: I started my carrier in the lab of Heinz Feldmann at the Institute of Virology in Marburg (Germany) working on Hantaviruses (the same institute where Elke Muehlberger comes from). After finishing medical school I ended up as a specialist for Infectious Diseases and Intensive Care Medicine in the Department of Intensive Care Medicine at the University Medical Center Hamburg-Eppendorf (Germany).
PD Dr. Dominic Wichmann MD, DTM
University Hospital Hamburg-Eppendorf
Department of Intensive Care Medicine
Infectious Diseases and Tropical Medicine Branch

John writes:

Dear TWIVbolans,

In TWIV 309, it was stated that Ebola epidemiology was not supportive of sexual transmission. HIV was held up as an exemplar of classic epidemiology for sexual transmission.

Having been in medical school during the early AIDS years, I can assure you that in those years it was not at all clear that AIDS transmission was sexual. Other correlates of the gay lifestyle were considered as possibilities, for example the recreational use of amyl nitrate. It was all extremely confusing.

Nor was it even clear that heterosexual transmission could occur… that knowledge came later, and was for awhile stubbornly resisted. Confusion arose, too, when hemophiliacs and IV drug users started getting the disease, apparently non-sexually.

Thus, the real lesson of HIV/AIDS is that epidemiology is messy. In that sense, HIV/AIDS is a great exemplar for Ebola, because Ebola epidemiology is a very noisy signal right now, far noisier than AIDS ever was. Record keeping in Ebola outbreaks is atrocious — no one wants even to touch paper from the sickroom. Today, no one even knows the correct number of Ebola cases, and the outbreaks of the past were small. Thus, there may very well be other signals lost in the epidemiological noise, as the hemophiliac and IV drug user signals were initially hidden in AIDS noise until they got larger and people started looking at those populations with more diligence.

So I don’t buy your statements that the absence of Ebola in brothels is a major point against sexual transmission. Are you sure that brothels are open? Do you expect that a country with a non-existent public health infrastructure would be able to dispatch public health workers to survey brothels? Do you expect that health workers have been taking an occupational history from Ebola patients when no one is even able to count the patients? Do you expect that sex workers would be honest if asked about their profession? All of these considerations influence the signal to noise ratio.

My prediction is that sexual transmission will become clearly apparent only after the main epidemic subsides, because the small number of such cases are epidemiologically invisible or unclassified at present. I further predict that chronically infected male superspreaders will appear. These would be men who cannot eradicate Ebolavirus from their prostate or testis, both of which are immunologically privileged tissues, i.e. tissues in which the body’s immune response is blunted. See, for example:


So far, in the few men checked, a surprisingly high percentage have demonstrated three-month viral persistence in ejaculate. Given that, if you checked a thousand convalescent men, no one would be surprised if the tail of the bell curve extended to 12 months or beyond. And there may ultimately be tens of thousands of convalescent men. The resulting epidemiology could, therefore, resemble that of Lassa fever, where sporadic cases appear seemingly randomly between larger outbreaks. If sporadic cases of Ebola start appearing, cherchez l’homme.

One other suggestion: In your discussions, why not drop the term “airborne” entirely? You have to explain it every time you introduce it, because your meaning is counter to the public’s intuitive meaning. You cannot win a fight that redefines a word that everyone already knows. Speak instead of aerosol trajectories and ballistic trajectories, like one of the listeners wrote in.

Keep up the great work. I can’t tell you how valuable your Ebola coverage has been to me.


Jacob writes:


Hi all,
There are a lot of TWiV listeners who want to help out with the Ebola virus outbreak, this might be a great way to do it. For every dollar you give, Google will donate two dollars.

Sydney, Australia.

John writes:

Dear Twivvers,

The CDC temperature-monitoring algorithm for Ebola was discussed toward the end of TWIV #309. I’d like to offer an alternate view.

The discussion highlighted the wide range of body temperatures found in normal humans and the resulting difficulty of specifying a single threshold temperature above which a person is considered to have a fever.

The alternative is to monitor for temperature *change* rather than monitor for an absolute temperature. For people who are performing post-exposure self-monitoring of their temperature, this is easy. In almost all such cases, a person’s temperature readings in the initial few days after exposure can be averaged and used as the baseline temperature for that individual. Then we watch for a spike above that temperature, where the size of the spike is greater than some threshold amount.

Using this approach, the bell curve of normal temperatures ceases to be a concern.

With a little extra work, I think that really tight deltas of even one degree Fahrenheit could be used to detect the earliest hours of a fever. Specifically, body temperature has a circadian rhythm, so it would be best to compute separate averages for morning versus evening temperatures. It would also be wise to ensure artifacts were not corrupting the temperature readings. This can happen after drinking hot liquids, exercising, smoking, and so on.

The big problem with building a highly sensitive algorithm is complexity — it becomes impossible for CDC to put the algorithm on a poster. But they could put it into a smartphone app, in which a person enters their self-monitored temperatures longitudinally, and the app decides whether to raise an alarm or not. If there are any medical students listening, this would be a fun algorithm and app to develop. At the least, you’d learn a lot about the practicalities of body temperature that would serve you well during residency.


Elise writes:

Dear TWIV/TWIP/TWIM Collective,

I’ve been listening to you for years (full disclosure: my gateway was through TWIP since I have been intrigued with parasites ever since I was in college) and I have no background in science and medicine (I’m a writer– screenplays and etiquette books) but have a powerful interest in disease, parasites, viruses and bodily phenomena and love hearing about your work. I am sure I have many questions for you all but in this quick note I wanted to thank you all so much for everything you do. I listen to your podcasts really at every opportunity and am really grateful for the careful way you talk, explain your thinking and humor such a wide range of ideas. In moments when I am feeling particularly isolated, it is a pleasure to listen to you all and so nice to hear your camaraderie. Best wishes from a fan in Lower Manhattan where my weather is probably quite similar to yours Uptown.

All best

Chris writes:


My early background is in Biochemistry, so I am not fully informed on Virology, but I heard an MD discussing how there were significant quantities of viruses in body fluids, say sweat, before the 100.4F temperature the CDC establishes for being contagious with Ebola – is that true? So if one is infected with Ebola and runs around NYC subway on a hot day with a temp of 100F and sweats on seats, handles, etc, could infect others?

Wouldn’t it be less of a risk for the American population and Emergency resources if people from west Africa were quarantined 21+ days BEFORE a flight to the US, rather than walking around until one finds one has 100.4F?

Thanks in advance for your thoughts…


Leave a Reply

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

One comment on “TWiV 312 letters