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TWiP 71 letters

Heather writes:

Hi Dr.s R&D,

I thought you might be interested in this news article about aquaculture in Hong Kong. Perhaps it's time for another fish parasite episode? I love the podcast, keep up the great work.


Bill writes:

Trichinella (1835-2007)

After a long and productive life, I am sad to tell you, poor Ella is gone, it seems she was always around, that she had such an infectious nature that she would never fade into history in this manner... needs an update datewise...

Your web guy can set an autoupdater for dates and copyright notices etc, so as each year passes, the year is incremented upwards. Each date you update needs to be told to the web guy, so it is included in the update and does not change the font or color.

It makes the website look fresh.

Ellen writes:

Thought you'd enjoy this :-)

Alicia Watkins' Etsy shop has many cross stitched bacteria and viruses too!

Fishpathologist writes:

Dear Doctors R&D,

I'm catching up on old episodes and I very much enjoyed Dr. D's reading from his new book. I see that his vertical farm book is in audio format, will the new book also be available in audio format? Dr. D telling "stories" is one of my favorite parts of TWiP and I would love a whole book of them.

I also wanted to tell you how far-reaching your podcasts are. My husband works coordinating volunteers for a state park. A science club from a community college in Tennessee came to volunteer in the park during their spring break. My husband was very taken with how industrious and intelligent the group was. I work managing chemistry and microbiology labs for undergraduates at a state college, so I was naturally slightly suspicious of these assertions. The students and their advisor invited us to have dinner with them and I must admit I found them very engaging young people. Due to my interests and previous work with parasites and microbiology the conversation naturally turned in that direction. One of the young ladies, who couldn't have been more than 18 years old, mentioned that she absolutely LOVED all the TWiP, TWiV, and TWiM podcasts and is pursuing microbiology as a field with an interest in cyanobacteria. I thought you would enjoy hearing how your work inspires some of the youngest of the new generation of scientists. Thank you for the excellent podcast. I look forward to more "stories" and I really like having guests like Sagi on TWiP.

Ellen writes:

Hi Vincent and Dickson,

I enjoy the TWIP podcast as someone who's interested in science so please excuse me if bubonic plague isn't a parasite. But if it is... did you see the 3/29 article in The Guardian where archaeologists and forensic scientists say "only an airborne infection could have spread so fast and killed so quickly"?

What do you think? Does this make more sense than transmission by rat fleas?

Jody writes:


Just a couple of corrections for when the discussion veered off into climatology.

La Niña is only the opposite case of El Niño and has nothing to do with the Atlantic. There are how ever oscillations in the ocean and atmosphere in the Atlantic as well, such as the North Atlantic Oscillation (NAO). It has been partly implicated in this cold winter in the US and the warm wet winter in Europe.

El Niño/La Niña also have nothing to do with undersea volcanos. At the most basic they are caused by changes in the trade winds affecting the depth and warmth of the upper layers of the Pacific. When the trade winds flow in one direction they expose cold currents (rich in nutrients) off the coast of South America and build up warmer water above Australia. The other way the warm water covers up the cold South American currents, cutting off the important marine food sources, and reducing the sea temps above Australia.

As a New Zealander I am very familiar with the Southern Oscillation Index which is one of the main measures of El Niño intensity. As a resident of Finland I am now learning of the effects of the NAO. Wikipedia as always has quite good descriptions of both and as well as other regional phenomenon.

And as a side note, I would say that human caused climate change is about as controversial among climate scientists as HIV causing AIDS is amongst virologists.

Thanks for the great podcasts. Even as a software developer I enjoy the whole TWiX series, although it is only TWiP that makes my skin crawl :-).


PS. Has Vincent thought of giving all the regular TWiX hosts the interview treatment like his recent podcast? I'm sure many are also interested in everyone else's backgrounds.

Scott writes:


As always I listened with considerable interest to your discussion of malaria, having had it many times. But when you got to the discussion of El Niño, that's where things went wrong.

El Niño is not the result of oceanic volcanism as you were speculating in the TWIP podcast of late March.

The El Niño and La Niña pattern is the result of the interaction of persistent trade wind patterns and surface water temperatures in the Pacific Ocean.

In normal years, the trade winds, which blow persistently from east to west, push surface waters in the Pacific towards the west. Current (last three hours) trade wind activity in the Pacific can be seen dramatically in this graphic:,-0.62,441

So ocean water that is pushed to the west by the trade winds, has to be replaced, and it is replaced by water rising from the depths along the west coast of South America. That water is extremely cold - and hence, the penguin populations in the Galapagos, which are located on the equator - the last place you'd expect to see penguins, and hence the chilly climate of Lima, on the tropical Peruvian coast. The penguins feed on herring and sardines, both cold water species, which flourish along the west coast of South America, in the upwelling cold water. The cold water generates little evaporation, hence the coastal deserts.

As the surface waters are pushed to the west, they accumulate around Indonesia/Malaysia, where they are pushed down into the depths. That deep, warm water is why that region is one of the most active thunderstorm regions in the world and the world's most active typhoon region - and, with global warming, becoming increasingly active.

On occasion, and for various reasons, the trade winds die down over a period of time, and the accumulated warm water in the western Pacific comes sloshing back to the east. Once it arrives in the eastern Pacific, the surface waters warm substantially, the sardine and herring fisheries die off, and the Peruvian fishermen starve. This usually happens around Christmastime, and hence, the Peruvians gave this phenomenon the name, "El Niño" referring to the Christ Child - in reference to Christmas. When this occurs, the warm water leads to increased precipitation, hence the flash floods in the Peruvian and Ecuadorian coastal deserts in El Niño years.

When the trade winds increase above normal, the pushback to the west is increased, and the opposite hydrologic effects occur. The cold water upwelling along the South American west coast is enhanced, and the herring/sardine fishery flourishes. This is a "La Niña."

Here in Costa Rica, our climate is dominated by the El Niño/La Niña cycle, so we watch it very closely (our worst drought on record by far was in the Great El Niño of 1984). So here is the current forecast for the "El Niño 3.4 index" for the next year, based on current climate models. A +0.5 or greater indicates an El Niño, and a -0.5 or greater indicates a La Niña. Close to the centerline has been dubbed "La Nada" The Nothing. The red line is the most watched model, the cyan line is the model consensus:

I hope this clears things up for you.

Regards from sunny and abnormally dry Costa Rica (77º as I write this),
Cartago, Costa Rica

Stacey writes:

Hi Vince and Dickson,

I came across this article on the IFLS website on facebook and thought it was really interesting. I do confess that I dont listen to TWIP as often as I listen to TWIV, but would love to hear your thoughts about this study (I promise to listen to the episode!). I can’t seem to download the article yet, apologies for only sending the link:

The weather here in sunny Pirbright is 16C and partly cloudy, quite a nice day in England lets be honest!

All the best,

Arbovirus Pathogenesis

Robin writes:

Homo sapiens is mostly an invasive species.

The species is adapted to life in tropical climates: any place that it needs clothes, it is an invasive species. Its natural migratory spread from Africa was through the (now) Middle East and South Asia to the Indonesian archipelago and thence to Australia. It did not need clothes for this.

Spencer Wells:
The Journey of Man PBS (playlist)

Everywhere else, it is an invasive species, needing clothing (and shelter) to survive. This includes the migration to the New World which passed through Beringia.

Gnathostomata are the "jaw-mouthed" vertebrates, as distinguished from the Agnatha, the jawless vertebrates (fish). The jaw is derived from the second branchial arch anlage. The clade includes the Sarcopterygia, the "flesh-finned" fish (with muscles in their fins) which in turn cladistically extends to the Tetrapoda: so, Gnathostomata 'R Us!

Thanks as usual for these most entertaining hours+. A whole lot more interesting because the subjects are intellectually stimulating. Dr. Dickson's resolve to stay at the tiller till the stars guide him elsewhere is much appreciated.



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