Vincent Racaniello

Vincent Racaniello

Vincent Racaniello, Ph.D. is Professor of Microbiology at Columbia University Medical Center. As principal investigator of his laboratory, he oversees the research that is carried out by Ph.D. students and postdoctoral fellows. He also teaches virology to graduate students, as well as medical, dental, and nursing students.

Vincent entered the world of social media in 2004 with virology blog, followed by This Week in Virology. Videocasts of lectures from his undergraduate virology course are on iTunes University and virology blog. You can find him on WikipediaTwitter, Facebook, and Instagram. His goal is to be Earth’s virology professor. In recognition of his contribution to microbiology education, he was awarded the Peter Wildy Prize for Microbiology Education by the Society for General Microbiology. His Wildy Lecture provides an overview of how he uses social media for science communication.

From ASM Microbe 2017 at New Orleans, Vincent and Rich meet up with Kate Rubins to talk about becoming an astronaut, space travel, and doing science in space.

At Microbe 2017 in New Orleans, the TWiM team speaks with Arturo Casadevall about his thoughts on the pathogenic potential of a microbe, rigorous science, funding by lottery, and moonshot science.

Wednesday, 21 June 2017 09:25

TWiP 135 Letters

Wink writes:

Vincent and Daniel,

I am willing to bet that you would not pass the Toxo/Sex/Internet study if it came through an oversight committee you were on. If so, why give it the TWIP bump?

Wink Weinberg (Atlanta)

Anthony writes:

The (lucky number 7) worms collected by Dickson Despommier (then in his technician phase (1962?)) from the woman in the hospital were tapeworms, not flatworms.


Noah writes:

Chinese text printed on the “sticker test” cellophane


dìyī rì

first day

Day one


náochóng jiǎnchá bōlizhǐ

pinworm check cellophane

Check cellophane for pinworms.

Sincerely, Noah

Case guesses:

David writes:

Dear Hosts,

Although the hiking woman from Colorado featured in the case of TWiP 134 uses iodine tablets while drinking water from streams, the symptoms she presents seem to point to a classic case of giardiasis (or beaver fever). She likely caught the parasite on one of her summer hiking expeditions after drinking stream water contaminated with the infective cyst stage of the Giardia parasite.

The Giardia trophozoites colonize the duodenum and jejunum in the small intestine and prevent host nutrient absorption, which causes gastrointestinal symptoms such as sticky, foul-smelling, fatty diarrhea (or steatorrhea), abdominal pain and nausea. Cysts are then passed into environment along with the feces, and the life cycle can continue.

Diagnosis for this parasite can be obtained through stool examination, ELISA testing, and an entero-test using a thread in a gelatin capsule that has one end taped to the inside of the patients mouth. The thread is later extracted and examined for the presence of trophozoites.

Treatment for the normally self-resolving giardiasis include a nitroimidazole medication (such as metronidazole, which is considered a first-line therapy by the CDC); however there has been recent evidence of drug resistance developing in Giardia.

Thank you once again for the informative and educational podcasts.


David P

Molecular Helminthology Lab at Tufts Cummings School of Veterinary Medicine

Octavio writes:

Dear Professors,

About a month ago, I came across the Podcast “This week in Parasitology”, and it has since become my loyal, entertaining, and extremely educational travel companion during my usual 3 hours-long driving around beautiful Portugal, the place where I send you my warmest regards from.

I am a Veterinarian, after a few other professional sidesteps, and I felt compelled to write you today, after hearing Professor DesPommier introduction in the first episode of TWiP, when he answered to Professor´s Racaniello question on why had he become a Parasitologist; His answer had to do with “doors opening”. A great story with somewhat of an emphasis on the importance of being in the right place at the right time, which in my opinion seemed to neglect all the work, dedication and talent the Professor has. A sentence ascribed to Thomas Jefferson goes like “I’m a great believer in luck, and I find the harder I work the more I have of it” and I believe this is also the case with Professor DesPommier as with illustrious Professor Racaniello and Professor Griffin.

As I said, I had a few other jobs before and in order to become a Veterinarian; I was a tomato paste factory worker, worked in restaurant kitchens, I was (and still am) a certified commercial diver, worked in private security, I held a couple of office clerk jobs, managed a bookstore, among other “survival experiences” that (in some cases thankfully) time ensured to blur out from my memory.

Nowadays and since 2013, I am working for a veterinary pharma company as a lecturer on their products, particularly in ectoparasiticides, the big fat teat on which  40% of all the vet pharmas gladly suck (smile).

As long as there are fleas and ticks in this world, there will be business –  and that’s not only because of the extraordinary biology, adaptation and resilience of these amazing and terrible creatures, but also because of the incredible misinformation, lack of information, or, as I find more frequent, utterly bewildering ignorance of the common citizen on the matters of parasites (parasites of their pets, internal or external, and parasites of their own).

I get a great pleasure and reward from what I do, because even within the constrains of a commercial activity, I feel that, every time I speak with someone (a pet owner, a Pharmacists, a Veterinary colleague, Technician or Nurse, an over the counter retailer, or whomever) I do my best to share with them my knowledge; It is a microscopic knowledge when I compare it with the likes of you three Gentlemen: I just hope it may be a microscopic embryonated egg of knowledge I can lay on my listener’s mind,and that it may hatch onto something useful and with relevance for the “one health”, just as you do with TWiP.

You do a truly great Service, and I learn every single time I listen to you. Please, keep on infecting us with your embryonated eggs of wisdom!

So that this already long message is just not a kilometer-long drooling-over-you exercise, I would like to add my hunch on what may be the cause for TWiP 134 case study – the fatty buoyant feces.

My guess goes to Giardia duodenalis, probably contracted due to consumption of water not completely treated with the iodine tablets this patient referred using, a situation described in the 1997 paper by Gerba, Johnson and Hasan “Efficacy of iodine water purification tablets against Cryptosporidium oocysts and Giardia cysts” (attached).

The epidemiological cycle is another case that reveals the intricate connections between human and wild fauna. In Urquhart’s Veterinary Parasitology it reads “There is evidence from the USA that Giardia from man which gain access to municipal water reservoirs may successfully infect wild animals, especially beavers. These then act as a source of contamination of domestic water supplies.”

Giardia trophozoites (Greek Throphós – the feeding state) should be the responsible for the duodenal, jejuneal (jejunii?) and ileal epithelial villi flattening with compromise of intercellular tight junctions, leading to malabsortion and steatorrhea.

Cryptosporidium would also be a suspect, but it is unusual that immunocompetent individuals should develop clinical disease.

The definitive diagnosis could be established by fresh stool smear examination, despite difficult, because the protozoans are very small (~15 micrometers), may not be passed in every sample, and this sample must be examined within 30 minutes after collection. Patience and systematic methodology are required. They are, nevertheless, very beautiful to watch.

In cats we have an ELISA fast test for Giardiasis, so I imagine quite more sophisticated kits exist for humans, including DNA amplification techniques.

If the diagnosis is confirmed, the anti-flagellated anti protozoan antibiotic metronidazole could be used to the treatment.

That is all for now.

I bid you farewell, and I am

Yours, “parasitophically”

Octávio Carraça Pereira

Post scriptum: “Pereira” is my surname and it means “Pear-tree” – almost a DePommier’s cousin My middle name, nevertheless, “Carraça” (it could be read karrassa) means “tick”.  Yes, I am a Veterinarian named Tick, who works with ectoparasiticides – I would not go so far as to say what Professor said about chance, fortune, fate or “Fado“, but it sure is quite a gag…

John writes:

Dear doctors Twip,

I think that the woman with the lighter-coloured, foul-smelling, sticky, floating stool from twip 134 has giardiasis.

The description of the stool seems to match steatorrhea (presence of excess fat in feces) which is characteristic of giardiasis. She had cramping and nausea which are also associated with the parasite.

She also consumed water from streams during camping trips (which may have been improperly treated)

Diagnosis can be made by direct microscopic observation of the trophozoites or cysts in a stool sample, by ELISA antibody test or by the delightful (though possibly obsolete?) string test.

The string test involves swallowing a gelatin capsule attached to a string. The string is taped to the subject’s cheek and the capsule is digested and travels down the gut. The string remains in place for several hours and is then withdrawn and the absorbent string is examined for trophozoites or cysts. Lovely.

According to Parasitic Diseases 6ed, treatments for giardiasis include metronidazole and  tinidazole, as well as paromomycin for pregnant women.


John in Limerick, Ireland where today the weather is 15° C with torrential rain after a week of clear skies and 23° C

P.S. I was listening to the team on TWiV discussing a paper a few episodes ago and  Vincent mentioned that two of the authors had ascaris. My first thought that flashed into my head was “that’s an odd thing to say but albendazole or ivermectin should clear it up”. Of course, what Vincent actually said was that the authors had asterisks. They were joint first authors. I’ve been infected by Twip.

Marcia writes:

Giardia lamblia

Johnye writes:

Good morning,

As always a pleasure to listen and learn.

As I listened to the Case Study for TWiP 134, it struck me that a more objective description of the patient’s stool might have been helpful. Dr. Griffin do you ever use the Bristol Stool Chart? I’ve found it very helpful in pediatric and adolescent medicine as a way of clarifying what a patient or parent is describing as abnormal. It is also something medical students and residents find interesting and, hopefully useful.

I’ve included 2 examples of the stool chart. There are many others that may be more or less appealing.

Now to think more about the clinical scenario and possibilities.

Best from Boston and Cambridge where it is currently mostly sunny and 18C.


(Your Cambridge Pediatrician)

JB writes:

Hey hey, Doctors!

I’d like to make a guess about the case study from episode number 134, the woman from Colorado experiencing weeks of foul-smelling loose stools.

The duration of her symptoms, as well as a few other facts in the case, has me leaning towards a specific diagnosis.

Floating, light-colored stools sounds like classic steatorrhea, and excess fat could also lead to an increase in “stickiness”. Many parasites can cause malabsorption in the intestines that could lead to steatorrhea, and some of them are water-born. What strikes me is that even though multiple people drank from the same water source, she became ill when her fellow hikers did not.

Had the entire party gotten sick, I would have suspected cryptosporidium. From what I’ve read, standard iodine disinfecting procedures aren’t very good at killing some crypto. If there were a lot of crypto cysts in the water, most everyone would likely have been infected.

The fact that only she got sick (and that only she drank out of her water bottle) leads me to believe that she did not practice sterilization as thoroughly as she may wish she had done.

So a freshwater-borne parasite that is easily killed by thorough iodine sterilization, and causes weeks of foul-smelling steatorrhea? I’m going with a diagnosis of beaver fever, aka giardiasis.

Thanks for all the great work, and here’s to many more wonderful episodes!

JB, Philadelphia

Iosif writes:

Dear Twip Team,

My guess for this week’s case is that our patient has a giardia infection. Cryptosporidium and giardia can both be obtained from dirty stream water and are more resistant to iodine treatment than most organisms. The giveaway is the fact that this diarrhea has been going on for a while and that the stool has turned fatty. The diagnosis can be made with a stool O&P or an ELISA. Treatment is with metronidazole.


Iosif Davidov

Hofstra SoM Class of 2018

P.S. I found this picture of giardia that I think would have been more appropriate a few months ago, but it was too good to pass up.


Mark writes:

Hello to This Week in Parasitology Hosts Vincent and Daniel,

Be nice to Dickson who is away traveling the world.

Below is my diagnosis for the case study presented by Dr. Griffin in episode 133. Late in the show, you, Vincent, requested listeners to send in an audio file with their diagnosis.

I am having fun by generating an audio file for this letter on my Mac using Siri’s voice. Let us see how Siri pronounces the names of worms that are suspected in this case. Those names are taneia solium, taneia saginata, or As-car-is lum-bri-coi-des.

Eggs of these parasites are spread through contaminated water, food, or soil. Daniel’s case notes indicated the young patient lived in a rural area, in a house with dirt floor, and drank untreated water from a stream. This establishes risk factors and possibility of infection.

Given that she is physically smaller than a younger sister indicates a nutrition problem. Her protuberant belly, hard to the touch, is consistent with a large mass of parasites in her intestines.

There are three candidate worms. We need to start to eliminate some. The girl’s diet is described as plantains, rice, beans. This eliminates taneia saginata which passes from cow to human during its life cycle. Taneia solium is eliminated as it passes from pig to human during its life cycle. This leaves ascaris lumbridoides

The final piece of evidence is that the girl’s mother observed a long, moving worm in the girl’s feces. To me, this piece of evidence validates the diagnosis above. As described in “Parasitic Diseases Sixth Edition” T. saginata is a segmented worm and its proglottid pieces may be observed in feces. T. solium is also a segmented worm and can be eliminated for the same reason. This leaves As-car-is lum-bri-coi-des as the parasite infecting the young girl.

The CDC’s website lists treatment with albendazole, mebendazole, or ivermectin as treatments while noting that the FDC has not approved Albendazole for treating ascaris.

In ancient history, when I started listening to TWiP, Dickson described Ascaris lumbricoides in episode 21. The episode’s image was a disgusting looking jar filled with dead worms. For those interested, I found the URL — it is:

Keep up the good work, and be nice to Dickson.


Anthony writes:

Here’s a Believe It or Not feature.  A freshwater mussel produces a fishing lure to attract fish to be infested with the mussel eggs:


Blackalls Park flying fox study to test for waterborne parasites

Wednesday, 21 June 2017 09:18

Embryonated eggs of wisdom - TWiP 135

TWiP solves the case of the Woman from Colorado With Loose Stools, and explains how single-sex infection with female Schistosoma mansoni reduces hepatic fibrosis.

Monday, 19 June 2017 08:40

TWiV 446 Letters

Junio writes:

Re: coccinellae in Japanese

These colorful round small beetles are collectively called Tentou-Mushi in Japanese. “Mushi” is a generic term for insects. “Tentou” is the Sun-God (you can call the Sun “O-Tentou-Sama”).

Wikipedia says they fly towards the Sun hence that name. The most common ones are called Nanahoshi Tentou (Seven-star Sun-God).

There is a less commonly used alternative spelling of the name of the bug, which is Beni-Musume 紅娘. It literally means Red Girl, so in that sense, in Japanese they are also deemed female just like “Lady Bug”implies female, but not many people know that spelling.

Akira Ono writes:

Japanese: Lady beetles

Google translation is helplessly incompetent in this.

It is called “tentou-mushi”. “tentou” means the sun, sun-god, or the path of the sun, and “mushi” means “bug”. So, “sun-bug” or sungod bug would be better translation. These insects are thought to fly towards the sun, hence the name.


Anthony writes:

I found interesting the need for an inverter.  How many devices are not available for 12V?  In addition to space, machines that require 110 will be difficult to use in a remote location on Earth.

It was good to learn that much of a standard lab can be used immediately in space, perhaps with just perhaps just minor adjustments in technique.  Even so, can better tools be designed?  Are comments on experience and limitations encountered being collected and published for manufacturers to review and incorporate in future designs for space applications?

Thank you on a particularly great TWiV episode.  Even though I basically stay put on a side street in Jersey City, through TWiX I learn about topics in a range of the biological sciences, hear Nobel laureates and now find out about living in space from someone who was there.

Let’s imagine BSL-10 as a facility in deep space where nothing but data ever leaves.  What would the space station then be?  BSL-7?

Wytamma writes:

Hi Y’all,

I’m writing this to you on the plane to Hungary, the weather on arrival should be clear skies and 28°C. Two other PhD students and I from James Cook University Australia are on our way to attend back-to-back conferences in Budapest. The international symposium on viruses of lower vertebrates and the international symposium on ranavirus are running from 4th-10th of July. Can you please give a shoutout to all the veterinary and wildlife virologists in Budapest this week and remember it’s not only men and mice that get viruses!

Cheers from a jet lagged student,


Aadra writes:

Dear TwiV: I’m a long-time listener of TwiV, and now, TwiM.

I just read this article in Science, and I am absolutely heartbroken.

There are so many infectious diseases rampant in Nigeria: malaria, measles, polio. Is there any way the TwiV listener community could help out? I don’t really have a solidified suggestion or an idea. I am writing to you in a moment of sadness and wondering if there’s any way, as virologists/microbiologists, we could all help out this humanitarian crisis…it’s one of so many right now in the world.

Anthony writes:

A historical review. Just an excerpt is below



# # #

A passage in Philip Roth’s novel Nemesis describes the horror of catching polio in the US town of Newark in 1944, when outbreaks of the disease were common and each summer was spent in fear of infection.

“Finally the cataclysm began – the monstrous headache, the enfeebling exhaustion, the severe nausea, the raging fever, the unbearable muscle ache, followed in another forty-eight hours by the paralysis,” it says.

Polio, or poliomyelitis, has existed for millennia. There is ancient Egyptian art which depicts a victim of the disease with a frail, deformed limb, using a staff for support.

Now the disease is only endemic in three countries, Pakistan, Afghanistan and Nigeria, and there were just 37 cases last year. Optimistic health workers and organisations such as Rotary International say 2017 could be the year in which the world sees the last case of polio.

Serious challenges, including violent attacks on vaccinators by Islamists and poor routine immunisation coverage, remain.

But one day taking children to the doctor for polio vaccination drops may be a distant memory, and the long list of famous Polio survivors including Francis Ford Coppola, David Starkey and Mary Berry will fade into history.

Anthony writes:

“Linus Pauling is the only person to have been awarded two unshared Nobel Prizes – the 1954 Nobel Prize in Chemistry and the 1962 Nobel Peace Prize.”

Gary writes:

Hello twivers,

I was listening to an old episode today and heard a letter talking about Amizon and how you could not find information about it. I am talking about episode 59 and an outbreak of swine flu in the Ukraine. I decided to see if I could find any information about the medication and I found it. I am curious what you guys think about this drug. Here is the link: I hope you will let us all know what you think.


MaryClare writes:

Hello Vincent and colleagues-

I’m writing to thank you for making such worthy podcasts. I subscribe to all the TWix shows, and I’ve come to expect at least one personal lightbulb moment every week while listening. The papers are always interesting, and the conversations between the hosts are good fun. I’ve learned an enormous amount from your podcasts, and it’s time I thanked you for the exceptional work.

Cheers to the whole team!

MaryClare Rollins

Montana State University

Stephanie writes:


I am not a scientist, but I have the flu and stumbled on your March 31st podcast. I was wondering why I am so sore?  I literally have physical pain up and down my spine like I have been hit by a car.

Please help me understand how a virus can cause physical pain?



Harlan writes:

Dear TWiV,

Thank you kindly for your informative and engaging discussions on virology. As an undergraduate in clinical laboratory science, I’m eager for the sorts of discussions you provide across the whole TWiX spectrum. Seasoned scholars discussing the nuances as you do helps inspire me by elucidating the world that I’m steadily exploring with fun yet deep details of microbial machinery.

Keeping with tradition of mentioning local atmospherics, it is 26 degrees C here in Honolulu. Also in keeping with tradition, I believe that Vincent should also be nicer to Dickson, whose commentary in particular I treasure.

The political commentary is slightly longer than I prefer, if only because the intersection of science and politics at this time is somewhat despair-provoking. I agree with the principles that you’ve mentioned across various episodes, though.

Having been so inspired by TWiV, I’ve just purchased a copy of Principles of Virology that I’ve had my eye on for several months. Should any of you ever grace our tiny island, I’ll happily take whoever makes it for beers.

Warm regards,


Ewa Beach, Hawaii

Laura writes:

Doctors Vincent Racaniello &  Dickson Despommier,

I recently found TWIM, TWIP, TWIV while adding podcasts on aquaculture to my list. I finished my laboratory sciences degree back in 2010 and I’m quite sad I hadn’t come across you sooner!  I find myself addicted to your shows- to now include Urban Agriculture. Despite my addiction and subsequent strife of not having enough time in the day to podcast n’binge I would like to extend my gratitude. I delight in the histories and stories previously unknown to me, as well as your humorous and informative banter.

I read these articles this last week and thought of you two.

Theileria parva-

Yellow Fever-

Rat Lungworm-


Thanks for all that you do,


Raihan writes:

Dear TWIV Hosts (I hope this is gender neutral enough, if not I will use TWIV Hosts(ess)),

I have several comments to the past few TWIVs:

  1. TWIV 437: WWTP is a common abbreviation for wastewater treatment plant. I am currently working as a post doc in the Water Desalination & Reuse Centre in KAUST (King Abdullah University of Science and Technology, Saudi Arabia). One of my projects involves studying the different viruses present in a wastewater treatment plant. We studied the different viral species entering the wastewater treatment plant in human waste, the viruses which are retained in different stations of the wastewater treatment plant, the viruses which are exiting the wastewater treatment plant and the viruses which are inactivated by the wastewater treatment plant. I’m sure by now you must be sick of saying wastewater treatment plant and appreciate the WWTP abbreviation. This is extremely useful in writing manuscripts on WWTP efficiency with really low word count limits.
  2. TWIV 435: You brought up the plaque video which was discussed in TWiV 68 ‘Ode to a Plaque’. I remember hearing this TWiV as a miserable PhD student and showing it to my supervisor. He then used it in a lab practical to teach about plaque formation. Fast forward several years, I was invited to lecture on ‘Introduction to Virology’ in a Public Health Course in my current institute. I used the same video for my lecture and I still get mesmerized by it. In fact, after showing the video I played it again just to observe the awesomeness of the plaque formation
  3. I can’t remember which TWiV where this was discussed, but the topic of digital PCR was brought up. One of the hosts mentioned that the machine is expensive and has to be in a core facility to be shared by different groups because of the cost. I’d like to say that we have a dPCR machine in our lab (not sharing with anyone else). This dPCR machine runs on a different principle than the one discussed on TWiV which is droplet based. Our machine  runs by partitioning the DNA template on a chip . This machine costs approximately 5X less than the droplet-based  digital PCR machine, still rather expensive, but funding is not a big limitation to research in Saudi Arabia. Maybe the United States should follow the same model for research funding as Saudi Arabia, tell that to the far right.
  4. Lastly I’d like to express my appreciation to Prof Rich Condit. Nowadays, it seems like if one want to be successful in research, one should sacrifice family time. But on several occasions, Prof Condit had mentioned how he made sure that he allocates time for work and family even as a young researcher. I specifically remember Prof Condit explaining that he was in charge of baths before bedtime when his children were younger. This meant that he had to return home early and make the time at work really productive. I totally can relate to this as I am in charge of bedtime readings and school lunch preparation and I do not want to push all of this to my poor suffering wife, who also has her own career. I also follow other advice which Prof Condit has given like to put away any frivolous matters at work and focus on research and to come in for a few hours over the weekend to catch up on any work. I feel that young parents should really embrace and enjoy the time with children when they are young, because this time will never come back, and I look to Prof Condit as an inspiration for this. I also hope that in retirement, I can spend time traveling and visiting my children and grandchildren, just like Prof Condit. One can spend time with family and still do well in research. The pressures of publishing can get to a young researcher but spending time with the family, I find, is the best way to beat the stress.

Sorry for the long email

Best Regards,

a huge fan ,


(sadly im not working on influenza B viruses anymore But they’re still my BaBies)

Monday, 19 June 2017 08:35

Old sins die hard - TWiV 446

The TWiV hosts review an analysis of gender parity trends at virology conferences, and the origin and unusual pathogenesis of the 1918 pandemic H1N1 influenza virus.

Monday, 12 June 2017 08:51

A nido virology meeting - TWiV 445

From Nido2017 in Kansas City, TWiV meets up with three virologists to talk about their careers and their work on nidoviruses.

Wednesday, 14 June 2017 18:00

Rigor, lotteries, and moonshots - TWiM 154

TWiM speaks with Arturo Casadevall about his thoughts on the pathogenic potential of a microbe, rigorous science, funding by lottery, and moonshot science.

Monday, 05 June 2017 13:09

Astro Kate, The Right Stuff - TWiV 444

From ASM Microbe 2017 at New Orleans, This Week in Virology talks with Kate Rubins about becoming an astronaut, space travel, and doing science in space.

Thursday, 01 June 2017 16:48

TWiV Special: Trial by Error, Continued

David Tuller returns to discuss the continuing saga of the UK’s PACE trial for chronic fatigue syndrome, including the accusation that he is engaging in libelous blogging.

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