TWiM v3 275

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Vincent Racaniello

Vincent Racaniello

Vincent Racaniello is a virologist at Columbia University and science communicator. He is using Zika Diaries to communicate the personal and behind the scenes experiences of his laboratory as it moves from working on poliovirus (for 35 years) to Zika virus.

Tuesday, 28 March 2017 17:49

Live long and pupate - TWiV 434

The discovery of a new negative stranded RNA virus of wasps that regulates longevity and sex ratio of its parasitoid host.

Tuesday, 28 March 2017 17:26

TWiV 434 Letters

Eric writes:

Dear Vincent et al.,

As a long-time fan of TWiV, it was a real delight to hear our work on “superspreader” phages profiled in a recent episode (TWiV 428: “Lyse globally, protect locally”).  Thank you for choosing to highlight our paper and, as usual, for superbly explaining the underlying science and its implications.  

With best regards,

Eric Keen

Thursday, 23 March 2017 18:01

TWiM 148 Letters

Sol writes:

Oh I hope I win!

I love your podcast...

I listen to all these kind of science podcasts.

Like are we there yet? Planetary radio, star talk, science Friday, etc

 

Dale writes:

Hi TWIM Team

I am a graduate student of medical microbiology in Port Elizabeth, South Africa.

At the moment I study antimicrobial resistance in hospital acquired infections...

Thursday, 23 March 2017 17:04

Neanderthal Dentistry - TWiM 148

Vincent, Elio, and Michael reveal what Neanderthals ate from analysis of DNA in their teeth, and new CRISPR-Cas systems found in the genomes of uncultured microbes.

Monday, 20 March 2017 09:36

TWiV 433 Letters

Maryam writes:

Dear Vincent and all the lovely TWiV team

It’s me again, your Iranian TWiV Addict. The weather here in Gorgan is 11 Celsius and mostly cloudy. When I heard your reply I couldn’t stop smiling, it made me so happy. Don’t think I’m crazy but I was walking in the house with a smile on my face, I wanted to wake up everyone and tell them about it but I couldn’t cause they were my guests and I wanted to be polite. Thank you so much.

You asked me to tell you about Iran. You’re right there are so many great people here for example I think my mother is the kindest person I’ve ever seen. I’m sorry that you hear only the bad things but the truth is Iran is a beautiful country full of great people and great cultures. Every city here has its own unique culture. I think what you hear the most is about our government which to be honest nobody likes them here as well and that’s actually the first reason I want to leave this beautiful country.

I envy you having the freedom to talk about everything you want I mean we can’t talk about politics here cause it’s too dangerous. We have to be careful all the time.

You asked me what’s it like to be a student here it’s a little complicated. We have a barrier called “konkur” (Iranian University Entrance Exam). taking this exam is the only way someone can go to the university in any level of education so I think, no!! we can’t study whatever we want because of this “konkur” thing. it’s worked out well for me though. I mean maybe in my first University or my first major (Microbiology) I was accepted by chance (cause Believe me I didn’t know a thing about it) but for my MSc “konkur”, it was different. it’s more specific I mean I decided to study Virology myself. (The Virology exam is in combination with bacteriology, parasitology and mycology). The only way to study Virology is to take that exam and there are only eight Universities that have the Virology program. I’m glad that I’ve accepted to the field I love.

In our MSc program we learn how to be a researcher in the field of Medical Virology. In the first three semesters we have some virology courses, virology lab training programs, seminars, lab meetings and etc. but it’s not satisfying me enough so I’m watching online courses and I asked the lab manager to help her in the lab. I’m trying to learn as much as I can. While we take our classes we have to write our proposal and defend it. If our proposal is approved then we can work on it and do our experimentations and stuff. after we’re done, we have to write our thesis and then we’re gonna defend it. That’s it.

Right now I’m searching in the all databases and reading articles to find my subject. Actually it’s too hard for me to come up with an idea. The only thing I know is that I want to work on Polio and Cancer! I’m very confused these days and I don’t have an advisor professor to help me yet.

Both my Universities were out of my hometown. My hometown is Tehran. It’s too far from where I am now.

PPS. I learned English myself that’s why I thought I had problems. I think I learned it mostly from movies and radio. glad that I’m fine. 

Thank you for everything

Love you all

Maryam

Asal writes:

Hi TWiV team,

As I was listening to TWiV 430, I was excited to hear Maryam’s email from Iran and decided to reveal my nationality since you all seemed to be curious how education would be in the Persian land! I am an Iranian female, a long-time TWiV listener, and a Patreon supporter!

I have written to TWiV a couple of times before. My husband and I had the pleasure to meet Vincent, Kathy, and Rich at ASV 2016. I am also looking forward to meeting Alan and Dickson some day.

I live in Texas now.

Iranians are pretty much science enthusiasts and math lovers. During my undergrad studies in Iran I had the chance to sit  in virology classes taught by some great Iranian virologists, Dr. Nategh and Dr. Mokhtari-Azad, both of whom are females.– Dr. Mokhtari-Azad also led the polio eradication program in Iran.

As a female scientist, you barely feel suppressed at any levels of education in Iran. It is not rare to be a female leader in Iran either.

After finishing my undergraduate degree in Microbiology and Molecular Biology in Tehran and before I came to the US, I worked in a molecular diagnostics lab specialized for clinical virology. I had realized out of all microbes there was some strong affinity for viruses in me. Tehran was where I learned many of the molecular skills in this area.

In the US, Texas, I finished my graduate studies in clinical lab sciences with emphasis in Molecular diagnostics while working as a supervisor of the Molecular ID department in a reference lab.

Just recently, I have assumed the same role in a Pediatrics Hospital lab. I sometimes teach molecular diagnosis of clinical viruses to graduate students in the field.

I usually tend to be laconic in my writing, but since you were wondering Vincent, I wanted to be thorough. 

It’s never enough to say how informative your show is!

Thanks to all of you wonderful hosts!

Julie writes:

Dear TWiV,

I have been a faithful listener for several years now, and I could elaborate extensively on The value of this podcast and all the TWiX podcasts. Now more than ever, we need solid scientific education and dialogue. I genuinely appreciate all you do, and I cheered out loud alone in my car while listening to Vincent’s rant last week.

I do hope I’m the 27th emailer, as the 23rd was my birthday,  and I love books. It’d be cool to say I got a birthday present from TWiV  (though I think the podcast itself is quite a lovely gift as it is).

Thanks again for doing such important work. If I ever win the lottery, TWiX is at the top of my Donate-To List.

Signing off from rainy, dreary, 6C North Alabama,

Jules

Jarrett writes:

Hello Vincent et al,

I’m writing to secure a copy of Emerging Infections, and also to echo sentiments that have been aired on TWIV about the creepiness of prions. It wigs me out to think that something as simple a mis-folded protein could cause death in a complex vertebrate organism. Tonight the weather in Austin is cloudy, 11 C, and is certainly nothing to write home about. Loving the prion papers, nothing like a good mystery to keep the mind engaged!

Best

-Jarrett H.

Austin, TX

Kim writes:

Hello,

Take this as my entry to the book contest, but I actually also have a topic you’d like to discuss.

You, and specifically Vincent, has frequently criticized the “luxury journals” such as Nature/Science/Cell, and I completely agree with all the criticism. In TWIV 426, which by the way has, once again, a hilarious title, Vincent spoke about the Cell Reports paper and it’s layout as being “not good” or “bad”. I completely agree with everything said in the episode regarding the small figure legends and a lot of figures in the supplementary. I, myself, actively avoid reading papers from these really compressed journals as it is so tough to read such papers. I prefer formats where the authors are given more space to write and explain, which makes the papers so much more comfortable to read.

However, in Vincent’s recent Zika Diary post “A Zika Paper” he explains once again why he doesn’t support these luxury journals, but also highlights the dilemma he’s in with knowing that the best way to further the careers of the people working in his lab is to try to publish in the highest impact journal as possible. Vincent ends the post with:

“My lab wants to publish their Zika virus paper in a high-impact journal, and I can’t deny them that wish. My job is to nurture their careers, not jeopardize them because I think that these journals are damaging science.”

My question to you, as a group, is: Whose responsibility is it to take this fight against this broken system of publishing and impact factor nonsense?

This Zika Diary post really made me depressed. Vincent, as one of the greatest advocates of bioRxiv, open-access, and non-luxury journals, is now not putting his money where his mouth is. I completely, and 100%, understand the dilemma written in the “A Zika Paper” post and understand Vincent’s decision to not jeopardize their careers, but at the same time isn’t this action a bit hypocritical?

I’d love for you to have a discussion on this, and for Vincent to maybe expand on his thinking, although I already completely understand his stance.

In addition, I’d also like to make a “pick of the week”. My pick would be TWiEVO number 7 “Pigeon Fashion Week”. If you want to hear Vincent being giddy about something, listen to this podcast. The science in the episode is amazing and the guest, Mike Shapiro, is great.

I’d probably rank TWiEVO 7 among the best episodes ever together with TWiM 51 “Cave Science with Hazel Barton”. Both episodes will surely give you new eyes regarding how you look at both caves and pigeons.

Best regards from a snowless crappy winter in Stockholm, where it is 0 celsius.

Richard DDS writes:

Check out “aeroMorph” from Tangible Media Group on Vimeo.

The video is available for your viewing pleasure at https://vimeo.com/194560714

And

I came across this project on the MIT Media Lab Webpage. You may have already seen it.

I continue to follow and recommend your podcasts.

Foggy this morning in LA…Bundle up, hope the snow is not as bad as was predicted for your region.

Best wishes,

Rich

https://www.media.mit.edu/projects/understanding-molecular-evolution/overview/

Johnye writes:

Before spring’s warmth takes the beauty that can be found and made in winter’s frigid cold…

http://thekidshouldseethis.com/post/ice-music-made-on-hand-carved-ice-instruments

Gentle Folks,

There are perhaps two videos in this link from The Kid Should See This. One is about the invention of the Fahrenheit thermometer and the other about how the Celsius scale came about.

In a very early communication with TWiV Prof. R politely corrected my error when I referred to the temperature as something “centigrade”, stating it was so many degrees “Celsius” (how embarrassing!).

Best to all and stay appropriately dressed as our bipolar winter races away! Currently, it is an unseasonable 10 degrees Celsius in Boston.

Johnye
http://thekidshouldseethis.com/post/the-stories-behind-fahrenheit-and-celsius-veritasium

Monday, 20 March 2017 09:19

Poops viruses and worms - TWiV 433

TWiV explores the evolution of our fecal virome, and the antiviral RNA interference response in the nematode C. elegans.

Thursday, 16 March 2017 09:34

TWiP 129 Letters

Case guesses:

Peter writes:

Greetings  TWiP team

The patient  is suffering from a generalized muscle weakness that as this is TWiP I will assume is the result of a parasitic infection.

Myopathy refers to a muscle fiber disorder.

This myopathy present as pure motor syndromes without any disturbance of sensory or autonomic function, deep tendon reflexes are preserved.

The high muscle enzyme levels are the result of damaged muscle tissue releasing enzymes into the blood. So whatever the parasite is appears to invade the muscles.

A search of Parasitic Diseases volume six found no mention of myopathy other than cardiomyopathy from Chagas disease.

Well you said it was a rare parasite, it is not even in your textbook!

What could this be, a nematode, something like similar to Trichinella? Maybe a strange Australian Apicomplexan? Onto Google with a search for  Australian  parasitic myopathy.

The search results look encouraging.

The patient  is suffering from Australian parasitic myositis caused by the muspiceoid nematode Haycocknema perplexum

The second item in the search result is the actual case mentioned in TWiP, hers was only the ninth recorded case of Haycocknema perplexum:

https://www.health.gov.au/internet/main/publishing.nsf/Content/cda-cdi4004-pdf-cnt.htm/$FILE/cdi4004g.pdf

Haycocknema perplexum is a rare parasitic nematode infection, believed to be zoonotic in origin though the primary host species is not known. The patient  was treated with albendazole, which was ineffective at preventing continued decline in her muscle strength.  Very little is known about this parasite, more research is needed:

https://www.wildlifehealthaustralia.com.au/Portals/0/Documents/FactSheets/Public%20health/Haycocknema%20perplexum%20Mar%202008%20(1.1).pdf

Regards,

Peter

Peter writes:

Diagnosis:

infection caused by Sarcocystitis species, possibly S. lindemanni

Best wishes

Peter

Cavan

Ireland

John writes:

TWIP Trio,

Greetings from Omaha, NE where it’s a pleasant 19 degrees Celsius. Having been to Australia (including Darwin) this past summer, I want to submit a guess to case study #128. I stumbled upon this review paper about Nonbacterial Myositis:

about https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3043460/

The paper reports that Haycocknema perplexum, a nematode, can cause myositis and cases from Australia and Tasmania have been described. Patients experience muscle weakness, eosinophilia and elevated creatine kinase levels. Diagnosis is made by muscle biopsy and treatment is made with albendazole.

I’m teaching Parasitology this semester at Creighton University and I play your Case Studies during lab. The students get a bonus point on their lab quiz if they guess correctly. They’ve been doing fairly well so far. If I guess correctly on this Case Study, I won’t get any bonus points, but I’ll look really good in front of my students 

Sorry I didn’t snag any pictures of parasites while in Australia (except for some fungi), but attached is a picture of the cane toad and Galah bird mentioned on the last episode.

Keep up the good work.

peace

Trudy writes:

Dear TWiPpers,

I am so excited to learn that I won a copy of the 6th Edition of Diagnostic Medical Parasitology!  Thank you!

I am currently on a flight back to Atlanta from Tokyo, where I was fortunate to be able to visit the Meguro Parasitological Museum.  While I did find it interesting, I do regret to say that the museum is disappointingly small and that most of the labels and descriptions are in Japanese, which unfortunately is not part of my trilingual repertoire.  However, admission is free, I picked up a t-shirt, and at least this particular curiosity has been quenched, so there’s that.

Sooo, since I am already writing to you, and since I’m at the beginning of a 12-hour flight, I suppose I should venture a guess at this week’s case study.  I think the 80-year-old lady has Paragonimiasis. This is a mostly food-borne infection caused by the lung fluke Paragonimus westermani, however, domesticated animals may also harbor the fluke and transmit the disease to humans.  That being said, I believe her contact with marsupials to be a red herring.  Nice try, Dr. Griffin!!  Diagnosis would require demonstration of P. westermani eggs in CSF or brain biopsy material.  But because neurological symptoms occur during the chronic phase of disease, CSF examination may not be as helpful as neuroimaging or other diagnostic testing, which may reveal characteristic lesions.  If the lady is indeed infected with P. westermani, she should be treated with praziquantel.  According to the literature, bithional and triclabendazole are also effective, but may require repeat or prolonged therapy.  

Well, there you have it, my uneducated, and probably entirely incorrect guess, but hey!  At least I tried!

Regards,

Trudy.

Mycheala writes:

Dear TWIP masters

Thank you for all your hard work as always.

For this week’s Parasite guess:

After all the testing mentioned the only test I can think of next is a muscle biopsy!

I’m going to go with the Parasite Haycocknema perplexum. It is a Parasite that has cocked it’s parasitic head in Australia a few times. You mentioned that she recently traveled to Tasmania, which is where this Parasite had been first discovered in 1998.

Also my Dr Google game is very strong and I found her exact case study, here is the link.

https://www.health.gov.au/internet/main/publishing.nsf/Content/cda-cdi4004-pdf-cnt.htm/$FILE/cdi4004g.pdf

Stay parasitic,

Lots of love from

Mycheala, Cork Ireland.

P.s a fun fact, in the link I have provided states that a Haycocknema like nematode has been identified in muscle fibres from a horse imported to Switzerland from Ireland, good to know we’re on the parasitic map haha

Thanks again! Please don’t stop the case studies :3

Fredrik writes:

Hello twip team!

The initial workup seems to point at a myositis rather Than neurologic disease (elevated muscle enzymes, normal neurography etc). Further investigation therefore should be focused on muscle. Autoimmune and paraneoplastic aetiology should be considered. If myoglobin is very elevated hydration may be called for to protect the kidneys.

Some aspects here are less typical for autoinflammatory myositis. I think EMG usually show fibrillation, and eosinophilia is not typical. Physical exam and ANA pattern can give more insight into aetiology. As with all myopathies however muscle biopsy should be considered, which is probably the next important diagnostic measure in this case, possibly guided by MRI to point out active muscle group.

In this case I would expect to see Worms in the muscle (trichinella or taenia of course being to common in this case). A Google search leads me to a couple of Australian case studies where the causative agent turns out to be Haycocknema perplexum, a nematode, that occurs in some of the animals to which the lady had been exposed. This will be my guess.  Mechanism is possibly through skin penetration, though this is not known for sure.

Treatment in those cases was with albendazole, possibly ivermectin could be effective as well. As the treatment for autoimmune myositis is high-dose steroids this patient would fare well from a correct diagnosis (I guess most patients do), since immunosuppression could put the infection in high-speed. However if you do suspect autoinflammatory myositis and treat with steroids, you would monitor CK to evaluate effect and discontinue treatment when it goes up rather than down!

Great case!

Regards,

Fredrik Bäckström

Resident in Pediatrics at University hospital of Northern Sweden, Umeå

Daniel writes:

Dear crepuscular professors

Despite my ill-informed kava konfusion last time, I’m back for more…

This week’s case was – as promised – mysterious. The 80-year-old Australian lady has clinical and EMG evidence of myopathy. Tests for other causes of eosinophilia and autoimmune myositis are negative. The next investigation should be a muscle biopsy, which (this being TWiP) might reveal some kind of parasite 

Although she has an extensive travel history, her long history of close contact with indigenous wildlife puts her at risk of zoonotic infection. Parasitic causes of myositis include trichinosis, cystericercosis and toxoplasmosis. After googling for parasites, myopathy and Australia I found some interesting case studies of eosinophilic myositis caused by the nematode Haycocknema perplexum.

It’s a long shot, but it fits Daniel’s description of “a rare parasite”. A few cases of human infection with H. perplexum  have been reported in Tasmania and tropical Queensland. The natural host and mode of transmission are unknown. Treatment with albendazole for at least 8 weeks is recommended and recovery may be incomplete. Presumptive use of corticosteroids (standard therapy for polymyositis) led to clinical deterioration and ICU admission in one reported case.

I have to add that I really enjoyed Dickson’s impromptu superhero segment in TWiP 127. Parasitology has such a rich history. More of these, please!

Best wishes

Dan

Reference: https://www.mja.com.au/journal/2008/188/4/parasitic-myositis-tropical-australia

Kadhum writes:

Good afternoon!

The case is Trichinella spiralis!

This parasite induces the formation of a collagen capsule and lead to eosinophilia!

Thank you

Kadhum

Wink writes:

Dear TWIP Professors,

I am going to take a shot at the case of proximal muscle weakness and eosinophilia in the wild animal rehabilitator from tropical Australia. My approach was to search on DuckDuckGo for parasites in echidnas, cockatoos, and marsupials that could infect human muscle. A cockatoo site led me to Sarcocystis and in the 6th Edition of Parasitic Diseases I found this reference:

Fayer, R.; Esposito, D. H.; Dubey, J. P., Human infections with Sarcocystis species. Clin Microbiol Rev 2015, 28 (2), 295-311.

which said that “by ingesting sporocysts from feces-contaminated food or water and the environment; infections have an early phase of development in vascular endothelium, with illness that is difficult to diagnose; clinical signs include fever, headache, and myalgia. Subsequent development of intramuscular cysts is characterized by myositis. Presumptive diagnosis based on travel history to tropical regions, elevated serum enzyme levels, and eosinophilia is confirmed by finding sarcocysts in muscle biopsy specimens.”

Got my fingers crossed!

Wink Weinberg

Atlanta

Nicholas writes:

Scholarly gentlemen,

Thank you for your continued efforts in the production of such an intellectually stimulating podcast.

For this week’s case study involving the 80-year-old Australian wildlife carer, Dr. Griffin provided what I believe is sufficient evidence to arrive at an etiologic diagnosis. I will be the first to admit I had to search through current literature to reach a conclusion, but the following statements outline my thought process along the journey.

The EMG and neurologic exam results suggest myopathic rather than neuropathic origin to the clinically described progressive limb weakness. These findings eliminated the nervous system as the source of this woman’s clinical signs and indicate a myopathic origin, which was further fortified by elevated creatine kinase, an indicator of ongoing muscle damage.

Parasites can result in tissue damage either directly through aberrant tissue migration, or secondary to a robust host inflammatory response targeted against foreign parasitic antigens (i.e., parasitic myositis).

Although there is a laundry list of parasites including cestodes (Echinococcus spp., Spirometra spp. Taenia solium), trematodes (Schistosoma spp.), nematodes (Trichinella spp., Toxocara spp., Hayococknema perplexumOnchocerca volvulusWuchereria bancrofti and Brugia malayi), and protozoa (Toxoplasma gondii,Sarcocystis spp., Trypanosoma cruziLeishmania spp.) documented to cause myositis.  To the best of my knowledge, only Haycocknema perplexum is capable of causing diffuse wasting of major muscle groups. Furthermore, this organism has only been diagnosed in patients from Queensland and Tasmania, consistent with this case study.

Definite diagnosis depends on histopathology with demonstration of the characteristic nematode in the muscle fibers. Treatment with albendazole may improve muscle strength if instituted early enough in the disease process, although recovery is slow and often incomplete due to extensive tissue fibrosis.

Recently, PCR-based sequencing and phylogenetic analysis has revealed this organism to belong to the nematode phylum, positioned between the Oxyurida and Ascaridida orders. Even with this information, much of this nematodes biology (e.g., life cycle and host animal/s) and epidemiology (host range/s and transmission) remains mysterious.

Additional research is needed to allow for implementation of appropriate preventative health strategies, however the inherent rarity of this disease (currently 9 case reports documented in humans) will continue to limit our understanding of Hayococknema perplexum

Keep up the excellent work,

Nick Crossland

DVM DipACVP

Iosif writes:

Dear Twip,

For our 80 yo Australian patient, I would first want a history of treatments that she has already tried. If certain tests or lab values came up with abnormal values before, I would want to take that into account before doing anything. Also, how does she know she is allergic to doxycycline? Is it because she was being treated for Chronic Q fever or lyme disease already? Chronic Q fever can present with pneumonia, hepatitis, or pericarditis and I would do my best to look out for those things. It takes about 2 years of treatment with doxycycline and hydroxychloroquine to treat the infection.

Trichinella is a parasite that actually fits well with her presentation. The eosinophilia and myopathy can be signs of trichinosis. The signs pointing away from this diagnosis are the lack of fever, or lack of mention of a pro-dromal phase with GI symptoms before the parasites extravasate and spread. I would want to know if she has ever eaten undercooked meat anywhere on her travels and I would normally want an ELISA screening for diagnosis, but in this case I would want a muscle biopsy.

The muscle biopsy would also to be to rule out any autoimmune conditions. Dermatomyositis, Polymyositis and Inclusion-Body myositis would need a biopsy to be definitive. I heard no mention of a rash of any sort so dermatomyositis is most likely out, but polymyositis and inlusion-body myositis are definitely part of my differential. Polymyositis generally presents with a proximal symmetrical muscle weakness like our patient and inclusion-body myositis predominantly affects those over 50. The eosinophilia does not fit with either of them and makes me think of eosinophilic granulomatosis with polyangiitis, but once again I don’t see much to suggest that diagnosis such as kidney problems, GI symptoms and most importantly a rash. I would lastly also order many autoimmune markers such as anti-dsDNA, ANA, anti-SCl, anti-CCP, etc. to rule out some autoimmune conditions such as SLE, Scleroderma, and rheumatoid arthritis.

But there is another reason for the muscle biopsy, and that’s because I believe she is infected with Haycocknema perplexum. Dr. Griffin stated that this was a rare parasite and you know what that means… that case reports would be abundant and from these reports I have found at least 3 cases of Haycocknema infection within Queensland Australia and that seems plenty rare for me. The symptoms match up pretty well: chronic myositis, eosinophilia, right geography; the only thing that doesn’t fit very well is that in the case reports the patients all developed some form of dysphagia.

It is not fully known how this infection is obtained or spread and treatment so far has been with several weeks of Albendazole. In terms of outcome, of the 6 cases I found there were 1 death, 2 chronically weakened, and 3 with full/near-full recovery. I hope our patient was able to improve.

Sincerely,

Iosif Davidov

P.S. I am a fan of DBZ and I appreciate the meme jokes!

Gavin writes:

Dear TWIP team,

Alright, confession time: I cheated. I was able to find the case report from the team at Cairns Hospital. This is the 9th ever recorded case of myositis caused by the nematode Haycocknema perplexum. That being said, Dr. Griffin was more interested in what tests we would order.

The workup for eosinophilia is extensive, and this diagnosis was far from obvious (at least to me). In the last case I was justified in making the assumption that our young and healthy traveler with exposure and eosinophilia probably had a helminth. That assumption is not necessarily justified in the case of our puggle-loving octogenarian, and I would perform a full laboratory evaluation.

The EMG and symptoms would warrant a muscle biopsy (which clenched the diagnosis in our case). However, it seems to me that you could easily overlook this infection, considering the tissue sample saved for EM did not contain any parasites. Do you think the physicians suspected H. perplexum based on the CK and eosinophilia? I’d be willing to bet that this was yet another case of luck favoring the prepared mind. A faulty diagnosis of polymyositis + prednisone could have killed this patient. Kudos to her physicians!

Thanks for the truly interesting case! I find it perplexing that so little is known of the life cycle and prevalence of this parasite. I’d be willing to bet that subclinical cases are exceedingly common!

I’m in the process of choosing a medical school. Any advice from Dr. Griffin on what factors he thinks are important would be greatly appreciated!

Cheers,

Gavin

Stuart writes:

Dear Twipsters,

Haycocknema perplexum. Boom.

Stuart

Gold Coast, Australia

Dr Stuart Aitken MB BS, Dip Ven, FAChSHM

Sexual Health Physician

David writes:

Dear Professors Twip,

I am an Infectious Diseases registrar down in Melbourne, Australia and your podcast has served the dual purpose of keeping me thoroughly engrossed and awake at the wheel along my 150km daily return commute to work as well as preparing me for the DTM&H exam through the LSHTM. Thank you for bringing your case down under and making it irresistible for me to respond.

Clinically, this patient has a chronic myositis, eosinophilia and lives in Queensland. We are told that they have a rare parasite. This instantly introduces the diagnosis of Australian Parasitic Myositis – an uncommon conditon associated with residence in Queensland and caused by the (rare) nematode Haycocknema perplexum – it is usually diagnosed on muscle biopsy and treated with albendazole, expecting some improvement in muscle function. Otherwise, it seems little is known about this organism except that it can complete its entire life-cycle in humans and maybe associated with animal exposure.

However, as a physician, it would be remiss of me to not include a long list of investigations and differential diagnoses. My investigation would initially seek to localise an affected area to target for biopsy, either in muscle or central nervous system. This can be accomplished in the resource rich setting through MRI scanning of brain, spine and affected muscle groups. Biopsy and histology should then reveal the diagnosis. Serology, particularly for parasitic diseases endemic to Australia such as strongyloides, echinococcus and (very rarely, but perhaps in proliferative form) sparganosis/spirometrosis may be helpful to explain this presentation. The travel to Tasmania introduces the interesting prospect of trichinella pseudospiralis, however this should not cause such widespread muscle involvement and would most likely require consumption of a Tasmanian Devil or Eastern Spotted Quoll, both of which I imagine to be unpalatable and difficult to catch.

Thank you for your fascinating and addictive podcasts!

Zac writes:

Hello TWiP Hosts,

As a second-year medical student, with my first board examination in just under three months, I couldn’t help but use test-taking strategy for finding the next step in treatment. History provided us with vital information, the patient handles animals and travels to many tropical areas, thus, making her more susceptible to zoonoses and tropical diseases. The neurologic exam was normal but muscle strength was reduced. This makes disease of the muscle, and not the nerves, the most likely. The tests support this with normal nerve conduction and myopathic changes on EMG. Elevated muscle enzymes also support damage directed toward muscle cells. One side effect of statins is  rhabdomyolysis. No improvement was seen when withdrawing this drug from the patient, meaning that this is probably not the etiology of the muscle weakness. Lastly her eosinophilia and the name of this podcast led me to an initial diagnosis of helminthic myositis. Because there were no ova nor parasites in the stool, the last test needs to find the culprits. The answer to the question is “B,” perform a muscle biopsy.

Thanks again,
Zac from Milwaukee

email

Becca writes:

Vince, Dick, and Daniel,

Over the past few weeks, I’ve learned so much from your podcasts! I got into parasitism while reading a fiction book called “Peeps” by Scott Westerfield. I loved learning about the parasites in the book so much that I bought “Parasite Rex” by Carl Zimmer, which I’m very glad to have heard you reference on the podcasts.

Currently, I’m a senior in high school, and, come september, I’ll be a freshman at Colby-Sawyer College in New Hampshire studying environmental science. I know it seems a little early to be doing so, but I’m already thinking about grad school. I guess my question for you gentlemen is if there are any graduate schools that you would recommend for a degree in parasitology?

Thanks, and keep doing what you’re doing!

Sincerely,

Becca (an inspired youth)

Biomicgirl writes:

Re: canning it

Don’t go anywhere! We’re out there and listening, even when we don’t write in. Thanks for this podcast.

David writes:

Dear Twip wise-guys,

Based on the eosinophilia, I went through the available worms that may cause this, and strongyloides stercoralis seems to be the most realistic option.  The cough would be caused by the parasite traveling through the lungs, diarrhea is a common symptom, the rash manifests where the unfortunate volunteer sat down in faeces. The duration also fits, with Parasitic diseases mentioning on page 245 a typical duration of 6 weeks. The larvae in the stool should confirm this diagnosis, and I expect the patient to have to been cured by either albendazole or ivermectin.

I actually did go through a differential diagnosis, but other options seemed so unlikely and the source of the infection so obvious that I looked no further, and I therefore hope my guess is right.

Let me finish by expressing once more my admiration for your efforts, I know very well that it takes a long time to come up with even mediocre products, and to offer a top class podcast of over an hour (or in Vincent’s case: several of them) on a weekly basis is more than a hobby, it is a mission.

Kind regards from a windy Nicaragua with just 31 C,

David

Lela writes:

Hello TwiP team,

I have been enjoying the Peace Corps cases. My husband and I were in the Peace Corps in northern South Africa about ten years ago. We were north and east of Thohoyandou (https://en.wikipedia.org/wiki/Thohoyandou). Luckily the only parasitism we suffered (at least as far as we know) were bot flies. Our host family had several mango trees in the backyard next to the clothesline. I was very happy to return to my washer and dryer and stop ironing all my underwear! I attached a picture of us in our village.

For the current case, I’m making a guess of strongyloidiasis. Although I may be wrong since spell check seems to think this is not a word. These roundworms are transmitted through contaminated soil, thus the direct contact with stool as well as the initial rash and eosinophilia fit with this diagnosis.

Thanks to all of you for your hard work making TwiP such a fabulous podcast!

Adam writes:

Dear Vincent, Dickson and Daniel,

It is cold and wet in Belfast. My guess for this week’s case study is strongyloidiasis which should be remedied by treatment with ivermectin, but only if there are no relevant co-infections.

I have been unable to get a decent diagnosis for the case studies recently and I was particularly stumped by the relevance of cava to the previous case and the hypocrisy of an aid worker living with such expensive tastes. I think I have this week’s though.

I am now the proud owner of a TWiP colour changing mug, and although I’m doubtful of being the fourteenth emailer, I am happy to push someone else into that place.

Many thanks for your work,

Adam Bennett

PhD Student

School of Biological Sciences

Medical Biology Centre

Queen’s University Belfast

Kala writes:

Dear TWIP team,

I love all your podcasts!!!

From not so sunny Ireland:)

From mycheala a long time listener

David writes:

Dear hosts of my favorite podcast(s),

As long as there will be free books filled with biological scientific knowledge I will keep on participating, so keep up the giving mood.  Just heard the latest TWIP, and as it has been from the 14th, I realize I am probably too late.  Still, I should take a chance.

Will also try to find some time for a guess in the eosinophilia case today, sincere greetings from Nicaragua,

David

Mike writes:

Greetings to the TWIP team!

This letter is to take a chance on the free book, but more importantly, to answer Vincent’s concern that no one was listening. I don’t know who isn’t, but I know that I am. I listen to the podcasts after the fact on my ipod, and usually the cases and contests are old, so there is not much point to guess at the diagnosis when the following episode is already out.

Regardless, keep up the good work.

I am listening to TWIP and TWIV, though not in real time. So this is a letter from the past to the past, I guess.

Best regards to you all.

Mike Martin

General pediatrician, Rochester, NY.

Thursday, 16 March 2017 09:22

Human kindness, river blindness - TWiP 129

TWiP solves the case of the Australian Wildlife Carer, and review evidence that nodding syndrome may be caused by an autoimmune reaction to the parasitic worm that causes river blindness.

Monday, 13 March 2017 08:48

TWiV 432 Letters

Joel writes:

Seconding the vote on dumping politics as a continuous subject on TWIV. How about if you bring it up again when you have a genuinely new idea on it and not the same old tired complaints. Act as if I’m as bright as you, I get it the first time.

Thanks,

Joel

Anthony writes:

Should scientists be involved in politics?

Today, it is no longer the cholera or plague bacillus that threatens us, but the traditional, cynical reasoning of politicians, the indifference of the masses, and the physicists’ and other scientists’ evasion of responsibility.

Max Born, 1964

http://tinyurl.com/zjvry3c

# # #

Scientists don’t have the right; they have the obligation.

Adam writes:

Greetings Leaders of the TWiVites,

I am writing in strong disagreement to Hanna from Boulder’s email on TWIV 431 regarding the discussion of politics on TWiV. I enjoy the great balance that TWiV provides between both cool virology and the surrounding nontechnical aspects that affect virology. Many great benefits come from hearing you talk about subjects falling in the latter category: for example, “TWiV 385: Failure” is among my favorite episodes.

I am a senior undergraduate student who has tailored my undergraduate experience primarily to pursuing a career in research. However, years of aggressive funding cuts and other deleterious policies affecting scientific research in my home state of Kansas drove me to become involved in writing and influencing public policy on the state level while still a student. I believe that we as young scientists cannot remain disengaged with this reality, and this especially includes those of us pursuing research careers.

There was an excellent interview in ASM’s career newsletter written by Adriana Bankston (see link below) about Dr. Kate Stoll, who is the Senior Policy Advisor for the MIT Washington Office. Fellow students, many of whom likely share my discouragement yet strong call to action in light of current political events, may find it interesting and helpful if you had another science policy expert on the show who can talk about opportunities for engagement specifically in the context of the current situation.

It is currently 46°F and clear skies after a day scattered with heavy winds, golf ball-sized hail, a confirmed tornado, and what would have been in previous decades considered to be an uncharacteristic high of 79°F in Manhattan, KS (fondly known as “The Little Apple”).

http://www.asm.org/index.php/careers-blog/item/5931-navigating-a-science-policy-career-interview-with-kate-stoll-senior-policy-advisor-for-the-mit-washington-office

Trudy writes:

Dear TWiVvers,

I apologize in advance, as I am going to be ranting a little in this email. However, I am sick and tired of people complaining about the politics on TWiV, at work, in social circles, and on social media. The truth is that we live in a political world. Everything we do is affected by politics! Every privilege that you enjoy today in this free country you live in, has been brought about by some political movement or other. The moment you force scientists to ask the government for funding in order to do their work, you have politicized science. Accordingly, if something happens in the political world, which threatens or diminishes that financial supply, scientists will (AND SHOULD!) complain. Why? Because we live in a free country where we are allowed to practice freedom of speech!  You DO not want to know what it’s like to not have that right! I grew up in such a country, and it really made me appreciate true freedom. We must fight to protect that freedom! So if you don’t like what you see or hear, then don’t look and don’t listen! I’ve certainly had to drive past many anti-abortion rallies by people holding up grotesque photographs and had to remind myself of the same thing! No progress of real value in the history of this planet has been effected by people who were quiet, or even “politically correct”. All progress in every facet of life has occurred due to the acts of people who were courageous enough to insist on change in spite of the consequences. In some cases these consequences were imprisonment, or even death. Here are a few people who said or did things that at the time were considered extremely controversial, but in retrospect literally changed the world: Rosa Parks, Martin Luther King Jr., Sojourner Truth, Charles Darwin, Galileo, Abraham Lincoln, and Harvey Milk, just to name a few. My point is that if you believe passionately in a cause, you SHOULD talk about it, no matter how controversial it is or how many people you might offend.

That being said, to all the people who are expressing their disgust, fears, and disappointment about our new administration, you have my support! And if you are marching in Atlanta on April 22, please come find me!  I’ll be the one in the TWiV T-shirt.

Kind Regards,

Trudy

Margaret writes:

Hello TWIVers,

Since we’re all happy in our pedantry, I’ll point out that orzo (as discussed in relation to a Blue Apron ad in episode 431) is NOT rice! It is a rice-shaped PASTA. I’m really sort of shocked that none of the five of you knew this.

Here are two other podcasts that I listen to, showing my nerdiness in other arenas besides science:

Pod Save America (politics, current events, lots of snark and a good bit of swearing from several of President Obama’s speechwriters)

The SweetGeorgia Show (fiber arts, especially knitting, and color)

To bring two of my loves together, here’s my self-serving pick of the week: my knitting patterns for socks and fingerless gloves featuring a DNA cable that I designed. The cable is pretty accurate in both major/minor groove ratio and in number of bases per full twist of the helix. In addition, the sock pattern features a visual pun on a historic style of knitted socks, where a band of pattern runs down the side of the sock and splits so that half runs down the side of the heel flap and half runs down the foot. In my socks, the double-stranded DNA denatures so that one strand that runs down the heel and one down the foot (giving the pattern its name, Denature). The fingerless glove pattern features the DNA denaturing around the thumb and annealing to keep running up the hand. These pieces aren’t really bold enough to be perfect for the Science March, but if you are knitters or know knitters (e.g., Dickson’s wife, when she finishes Dickson’s brain hat) I hope you’ll enjoy combining your love of science with fiber!

http://www.ravelry.com/patterns/sources/denatureanneal

Thanks for your great podcasts (and I’m bummed that the ant one has fallen through). They make my 2 hour commute (each way) between Tacoma and Seattle much more tolerable, and keep my brain engaged while I knit on the bus. Currently it’s 4oC and raining, somewhere along that route.

Margaret

Ted Diehl writes:

Hi Vincent,

I just listened to your most recent TWIV episode featuring the paper from Jim Cunningham’s lab (TWIV 431). I wanted to clarify a couple of points that were discussed during the show.

1) You refer to the assays done in figures 2A, 2C, 3A, and 3C as binding assays. But truly those assays measure GP “triggering” eg. exposure of the fusion loop and insertion of this into membranes. True binding assays (in the form of ELISAs) were performed by the Cunningham group and included as Figure 4A. That assay showed absolutely no difference between the ancestral GP and A82V.

2) In regard to our paper (and/or the associated TWIV episode), you said that we found evidence for the A82V mutation resulting in an enhanced binding to NPC1. In our paper we presented no data either way as to GP-NPC1 interactions and in fact we had heard of the data presented by the Cunningham group as Figure 4A. Rather, in the discussion of our paper we explored both the possibility that the mutation enhances NPC1 binding as well as the possibility that it increases “triggering”. Additionally, toward the end of our TWIV conversation Rich Condit asked us about performing such a binding assay. After my circumspect response, Jeremy chimed in and shared that our current  belief was that the A82V mutation resulted in a GP that was more predisposed to conformational changes resulting in exposure of the fusion peptide. Indeed, this is exactly what the Cunningham report found!

Best Regards,

Ted Diehl

William Diehl

Postdoctoral Fellow

Program in Molecular Medicine

UMass Medical School

James Cunningham writes:

Thank very much for choosing our paper for your podcast and for providing such a thorough and positive discussion.

All of us, but particularly the graduate students May Wang and Soo Mi Li who carried out the studies, were very flattered. They have been bombarded with congratulatory texts, emails from their peers in the Virology Program, which is the ultimate form of validation for young scientists.

So thanks again—it means a lot. And I hope we can discuss some of the details in the future.

Best regards,

Jim

Jory writes:

Hey TWiVoyagers,

This is in response to Rich’s comment that the differing divergence patterns of cifA or cifB compared to core wolbachia genes implies that the selective pressures driving the evolution of this system were likely acting specifically on the prophage. I took a look at the paper, and while the analysis did show this, it also showed that the divergence pattern for a phage structural protein was different from those of cifA/cifB. Thus, it seems the differing divergence patterns are gene- and not organism-specific (although I’d expect correlation to some extent within a genome), and so I don’t think you can say which organism the selective pressure is acting on based on such a difference. Please let me know if I’m missing a key point in yours or the authors’ argument.

My two cents is that the selective pressures driving the evolution of this particular system act on the holobiont. The function of this system appears to be to ensure the propagation of wolbachia, so it seems there must necessarily be a selective pressure acting on the host, which of course is a selective pressure acting on the prophage as well (it needs a place to live). I’m not sure you can really subdivide which component of the holobiont feels the selective pressure in this case.

On a somewhat related note, I keep running into an issue when trying imagine how this system could have evolved, namely that it only works when all/most of the males are already implementing it (i.e. females only require a wolbachia infection for reproduction when males are providing cifA/cifB in the sperm). In that case, it is a self-sustaining system in that cifA/cifB-expressing wolbachia drive selection of their own retention by killing progeny of uninfected mothers. However, if only a small number of cifA/cifB variants were present, it would be highly unlikely that one of them would infect a male arthropod that would go on to breed with a female arthropod variant that preferred to keep the wolbachia, and extremely unlikely that there would be enough to kill all the progeny of females that lacked this tendency. Thus, it seems you would require the result of the selection to perform the selection. Does anyone have any idea for a possible scenario that could explain the initial propagation of this system? Is it likely that this system arose out of genetic drift, and could then sustain itself?

Also, would any of you care to speculate about the wolbachia/WO factor that suppresses the embryonic lethality? I’m wondering whether it could be any old wolbachia gene, or if it must be one specific to the strains that use the embryonic lethality strategy. The latter case seems unlikely given that the authors’ search for genes specific to such strains returned only cifA and cifB. I wouldn’t expect that oocyte-derived cifA/cifB could suppress the effect of those same proteins derived from sperm, but it’s technically possible that they could interact differently with the chemical environment of the sperm vs. the egg. An experiment where cifA/cifB transgenic males were crossed to cifA/cifB transgenic cifA/cifB females would have been nice.

 

I think it’s more likely that the suppressor is a common wolbachia protein rather than cifA/cifB, but this also raises questions about how this system could have evolved. If there was a subpopulation of rare variants that had acquired cifA/cifB, why weren’t they simply diluted out through matings with non-cifA/cifB wolbachia-containing arthropods? If the suppressor is a common wolbachia protein, there would have been no selective pressure to force reproduction specifically from cifA/cifB females, which would be required to propagate these alleles since the female arthropod transmits the parasite.

By contrast, if cifA/cifB were indeed the suppressors, initial rare variants would have formed an instant bottleneck as they would only be able to mate with each other. Could that explain the evolution of this system? This also seems like an easier path to speciation, but it is quite biochemically dubious.

I’d love to hear your thoughts on all this.

Thanks again for the great podcast,

Jory

Montreal, QC (it’s cold here)

Diane writes:

Hi all!

This is my second attempt at a book giveaway and I hope I’m more successful this time around! TWIV and TWIM are still two of my favorite podcasts, and I’m still hoping to be able to add more to my ever-expanding playlist. I’m looking to keep one step ahead of some very bright undergraduate students in my Microbiology course here at Louisburg and your discussions definitely help me with that! The last time I wrote we were expecting wintry weather; that has come and gone and we are anticipating a return to the balmy 60s in the next few days. Keep up the great and lively discussions!

Jen writes:

Hello TWIV team,

Long time listener first time writer. I began listening when writing a paper about Autism, I’m an elementary school teacher for Chicago Public Schools. I was looking for active discussion debunking the myths around vaccines and you folk fit the bill.

I  enjoy your discussions of virology. The way your podcasts intertwines the papers, politics, and real world discussion is both user friendly, informative and fun. I frequently find myself citing information from your podcast when talking with parents and coworkers.

Keep up the great work and the weather in Chicago is a balmy 29F with some flurries.

I hope I win!

Jen

Tim writes:

Hey TWIV friends,

You said to write in immediately to get the contest done quickly so I’m doing so. It’s a pleasant -9C early morning listening to you folks and feeding my dairy cattle.

Jess writes:

Hello everyone!

Hello again from Philadelphia! I was unsuccessful in winning a previous book, but I am determined to be the 27th email! I would love to learn as much as I can about new topics in science since I am currently deciding whether to go for my Master’s and what to study. Maybe one of your books will give me the inspiration I need to pursue my next degree.

The weather today in Philadelphia is pleasant for February! We have mostly cloudy skies with a high of 48F and a low of 32F, though it feels much colder with the wind blowing in between all the buildings!

Thank you for all you do!

Jess

Bib writes:

I happened across this article today:

http://www.aaha.org/blog/NewStat/post/2016/12/14/216057/Getting-to-the-bottom-of-border-collie-collapse.aspx

> Border Collie Collapse, or BCC, is recognized as a form of exercise intolerance in Border collies, Kelpies, and related breeds in the United States, Canada, and Australia. Dogs with BCC are normal at rest, but after 5–15 minutes of strenuous exercise can develop incoordination and altered mentation. Recently, JAAHA posted an exercise study on dogs with BCC in issue 52.5 and a survey on observations of dogs with BCC in issue 52.6.

It struck me that the exercise intolerance here seems to resemble the description of exercise intolerance associated with ME/CFS. Animal model?

—bib

Tubby writes:

While I’m sure I’m not writer number 27, I can at least bump you one closer to getting Emerging Infections sent on its way to the lucky listener who wins it. I appreciate your podcasts and try to make sure I can squeeze in TWIV, TWIM, and TWIP into my listening schedule.

Be nice to Dickson!

Marianne writes:

Good day TWiV hosts!

I’d love to be the winner of your latest book contest on Emerging infections. This semester I am one of the instructors of an undergraduate virology course and the topic I selected was Emerging Viral infections thus this book may come in handy! As always I put in a plug for the TWiX podcasts in my lectures.

I would also like to put in a positive review for the writing of Mary Roach, who you also mentioned you had on your shelf. I’ve read most of her books and she takes a very fresh and funny look at the science around some pretty interesting topics such as the use of human cadavers in research (Stiff), sex research (Bonk), food science (Gulp), and space exploration (Packing for Mars). I have yet to read Grunt, but it’s on my list!

Have a great day!

Cheers

Anthony writes:

Ursula LeGuin on alternative facts

http://www.oregonlive.com/opinion/index.ssf/2017/02/ursula_leguin_on_fiction_vs_al.html

recent letter in The Oregonian compares a politician’s claim to tell “alternative facts” to the inventions of science fiction. The comparison won’t work. We fiction writers make up stuff. Some of it clearly impossible, some of it realistic, but none of it real – all invented, imagined —  and we call it fiction because it isn’t fact. We may call some of it “alternative history” or “an alternate universe,” but make absolutely no pretense that our fictions are “alternative facts.”

Facts aren’t all that easy to come by. Honest scientists and journalists, among others, spend a lot of time trying to make sure of them. The test of a fact is that it simply is so – it has no “alternative.”  The sun rises in the east. To pretend the sun can rise in the west is a fiction, to claim that it does so as fact (or “alternative fact”) is a lie.

A lie is a non-fact deliberately told as fact. Lies are told in order to reassure oneself, or to fool, or scare, or manipulate others. Santa Claus is a fiction. He’s harmless. Lies are seldom completely harmless, and often very dangerous. In most times, most places, by most people, liars are considered contemptible.

TWiV discusses Zika virus seroprevalence in wild monkeys, Zika virus mRNA vaccines, and a gamete fusion protein inherited from viruses.

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