The Loom » The Parasite Files

The French Disease, the Italian Disease, the Christian Disease–the New World Disease?

Carl Zimmer — Mon, 19 Dec 2011 22:35:13 +0000

In 1494, King Charles VIII of France invaded Italy. Within months, his army collapsed and fled. It was routed not by the Italian army but by a microbe. A mysterious new disease spread through sex killed many of Charles’s soldiers and left survivors weak and disfigured. French soldiers spread the disease across much of Europe, and then it moved into Africa and Asia. Many called it the French disease. The French called it the Italian disease. Arabs called it the Christian disease. Today, it is called syphilis.

I’ve been intrigued by the murky history of syphilis for a few years now. The text above is from the start of an article I wrote for Science in 2008. At the time, scientists were split between two explanations for sudden appearance of syphilis at the end of the fifteenth century. According to one, it was caused by bacteria that had evolved in the New World and were brought back to Europe by Columbus’s crew. But other researchers found many skeletons with signs of syphilis in Europe, Africa, and Asia that appeared to have been from long before Columbus’s voyage. They argued that it must ...

There’s just something about him…

Carl Zimmer — Thu, 03 Nov 2011 00:27:05 +0000

If you’re a regular reader of the Loom, you’re no doubt familiar with the parasite Toxoplasma gondii. If you’re not, now is the perfect time to meet this sinister creature which may very well be residing in your brain. It seems like every year or two, it gets more remarkable, and today it’s taken another step into awesomeness.

Here’s a quick Toxoplasma primer. It’s a single-celled protozoan that reproduces inside the digestive tract of cats. The cats poop out egg-like Toxoplasma cells into kitty litter and dirt. Other animals take up the parasite, which makes its way into their tissues, especially the brain. There it forms cysts that can linger for years or decades. Only if that animal gets eaten by a cat can Toxoplasma complete its life cycle.

This life cycle opens up opportunities for Toxoplasma to evolve. For example, natural selection should favor mildness in the parasite in its hosts, because cats do not like to eat corpses. And, indeed, Toxoplasma is fairly harmless, only causing trouble to people with suppressed immune systems. (Hence the rule that pregnant women should not handle kitty litter. If they get infected by Toxoplasma for the first ...

Radiolab and Skeptically Speaking: For Your Listening Pleasure

Carl Zimmer — Tue, 01 Nov 2011 02:01:39 +0000

If you’ve got some free time, here are a couple talks for your listening pleasure.

Radiolab presents a story I told about a fateful trip to Sudan on their latest podcast. I’ve embedded it here:

Last week, I also talked about viruses on Skeptically Speaking, and they’ve posted our conversation here. (If you have trouble at that link, try here.) Among other things, we talk about the unimaginably huge number of viruses on Earth, and I offer my vote for the Worst Virus Ever. Fortunately, if you’re not a catepillar, you don’t have anything to worry about.

Holes in the net: A podcast of my Story Collider tale

Carl Zimmer — Tue, 04 Oct 2011 21:13:19 +0000

Story Collider is a monthly performance where people tell stories about science. (Think The Moth in a lab coat.) The organizer, Ben Lillie, invited me to tell a personal story about the place of science writing in my life. I decided to talk about a memorable night in South Sudan, when I wondered what I was living for.

I told the story to a great crowd at Union Hall in Brooklyn last week. And you can hear the podcast at the Story Collider web site. Check it out.

More on Scientific American Podcast: Science Tattoos and the Myth of the Parasite-Driven Cat Lady

Carl Zimmer — Sun, 28 Aug 2011 02:46:36 +0000

Before Irene takes away my Internet connection, let me point you to part two of my interview on Science Talk, the podcast of Scientific American. (If you missed it, here’s part one.)

Talk you on the other side of the maelstrom.

[Update: Part one linked now fixed]

Fatal Attraction: Sex, Death, Parasites, and Cats

Carl Zimmer — Thu, 18 Aug 2011 03:17:16 +0000

It’s time to revisit that grand old parasite, the brain-infecting Toxoplasma. The more we learn about it, the more marvelously creepy it gets.

Toxoplasma is a single-celled relative of the parasites that cause malaria. It poses a serious risk to people with compromised immune systems (for example, people with AIDS) and fetuses (which is why pregnant women need to avoid getting Toxoplasma infections). If you’ve got a healthy immune system, it doesn’t cause any immediate harm. (Ed Yong has explained why a purported link to brain cancer is very weak.) All told, perhaps a quarter or a third of all people on Earth carry thousands of Toxoplasma cysts in their heads. Most never become aware of their living cargo.

The Toxoplasma life cycle normally takes the parasite from cats to the prey of cats and back again. In the guts of cats, the parasites have sex and produce egg-like offspring which are shed with cat droppings. They can survive in soil for weeks or months. Rats and other mammals ingest the eggs, which produce cysts mainly in the brain. When the cats eat infected prey, they get infected.

For a little over ten years, scientists have been ...

Why is there sex? To fight the parasite army

Carl Zimmer — Thu, 07 Jul 2011 18:02:02 +0000

For several decades now, biologists have been puzzling over sex. In some ways, it seems like a huge waste of effort.

Sexual reproduction requires splitting a species into two sexes, only one of which will be able to produce offspring. There are some species of animals that do without males; the females simply trigger their eggs to develop into embryos without any need for sperm. All the offspring of an asexual animal can produce offspring of their own, instead of just half. So it would make sense that genes that gave rise to asexual reproduction would win out in the evolutionary race.

Clearly that hasn’t happened. The world is rife with sex. Animals do it. Plants do it. Even mushrooms do it. So evolutionary biologists have carried out a number of studies to get an answer to the question, “Why sex?”

In 2009, I wrote an essay for Science about this research. If I had been writing that essay today, I’d have focused some attention on an elegant experiment on the sex life of a humble worm. It gives a big boost to the long-floated idea that ...

How a zombie virus became a big biotech business

Carl Zimmer — Mon, 23 May 2011 19:42:48 +0000

Sometimes a blog must serve as a repository of regrets, a place to atone for not including some perfect fact in a book. While working on my book Parasite Rex, I came across many delicious examples of parasites manipulating the behavior of their hosts for their own benefit. After the book came out, I met scientists who enlightened me about other examples which would have been wonderful to include. A few years back, for example, a Johns Hopkins scientist pointed me to a parasitic wasp that turns cockroaches into zombies.

I’ve recently been wondering about behavior-altering viruses, thanks to an online conversation I had with Ian Lipkin, a virus hunter at Columbia University, about my new book A Planet of Viruses. Lipkin wondered aloud if some viruses would turn out to manipulate their hosts for their own good. Did herpesviruses, for example, increase its transmission by boosting their host’s sexual desire?

Most of the examples I knew about came from parasitic animals and fungi. The only virus that could have this kind of effect that I knew of was rabies, which causes its hosts to become more ...

More eldritch ant horror!

Carl Zimmer — Mon, 09 May 2011 17:40:34 +0000

It’s time to pay another visit to Cordyceps, the fungus that turns its hosts into spore-sprouting zombies.

The fungus, which can be found in many parts of the tropics, penetrates an insect’s exoskeleton and then work its way into its host’s body. At first the ant seems normal to the human eye, but eventually it makes its way to a leaf, where it clamps down with its mandibles. Cordyceps then sprouts out of the ant’s body, lashing it to the leaf’s underside, and producing a long stalk tipped with spores. The spores can then shower down on unfortunate insects below.

David Hughes of Penn State University has been publishing a string of fascinating papers in recent years about this science-fiction-topping parasite. In 2009, I wrote about one study of his on the exquisite precision of the fungus’s manipulations. He and his colleagues found that one species that lives in Thailand almost always causes infected ants to clamp onto a leaf vein about 25 centimeters off the ground–a spot where the humidity and other conditions may be ideal for a fungus to grow. When Hughes and his colleagues moved infected ants higher up into the canopy, the fungus ...

Do we need to welcome our virus overlords? My first guest blog post at University of Chicago Press

Carl Zimmer — Fri, 06 May 2011 18:01:38 +0000

To mark the publication of A Planet of Viruses, the University of Chicago Press asked me to participate in a weekly series of conversations with experts on some of the themes I explore in the book. They’ll be coming out each Friday in May. First up is an exchange between me and Ian Lipkin, a virus hunter at Columbia University and the subject of this 2010 profile I wrote for the New York Times. As if waving a piece of red meat before me, Lipkin wonders if viruses can alter our behavior. I then take the bait. Check it out.

It was just a matter of time: LOL Parasites

Carl Zimmer — Fri, 22 Apr 2011 17:14:32 +0000

Thanks to Joe DeCapo for his response to my offer of an autographed book plate for the new edition of Parasite Rex. And yes, his cat (named μ) does probably haz one.

Celebrating a decade under the influence of parasites: My talk tomorrow (4/15) at SUNY Plattsburgh

Carl Zimmer — Thu, 14 Apr 2011 15:59:07 +0000

I’ll be speaking tomorrow at SUNY Plattsburgh on the occasion of the publication of the new edition of Parasite Rex. I’ll be talking about the many ways in which parasites have infiltrated my mind since the book first came out a decade ago. I hope some Loominaries will be able to attend, and be infiltrated as well.

Where: SUNY Plattburgh, Plattsburgh NY. Room 206, Yokum Hall. (Directions and campus map)

When: Friday, April 15, 12:15 pm.

More details here.

Two Happily Infected Hosts!

Carl Zimmer — Mon, 11 Apr 2011 21:15:21 +0000

Steven Barritz (left) and Travis Bautista pose with their brand new copies of the revised edition of Parasite Rex with a new epilogue. I’ll be sending them an autographed book plate. If you’d like one, here are the steps:

1. Buy a copy.

2. Email me a picture of yourself with the book (it’s marked “with a new epilogue”).

3. I’ll reply to your email and we’ll make arrangements to send you an autographed book plate. (You’ll need to cover the cost of the postage and plate, which should be about a buck.)

Dr. Kiki’s Science Hour video is up. Jackalopes, zombie ants, evolution’s odometer, and more!

Carl Zimmer — Fri, 01 Apr 2011 19:51:59 +0000

Brian Malow and I talked yesterday about some of my favorite things on the latest episode of Dr. Kiki’s Science Hour–including the evolution odometer. You can watch it on Youtube, or you can head over to Dr. Kiki’s Science Hour site to download the video or audio. (The Skype goes berserk briefly, but we get back on track.)

Parasite Rex Redux: Now with a new epilogue

Carl Zimmer — Tue, 29 Mar 2011 13:38:17 +0000

In 1996 I had just turned thirty. If you had told me at the time that parasites were about to become an integral part of my life for years to come, I would have said, “Oh, look at the time! I’ve got to go feed my hyrax!” and headed for the nearest restroom to scrub my hands.

But it would have been true. I just had finished my first book, and I was wondering what to write next. I had a couple vague ideas I bounced around with my agent over lunch. How about an exploration of the intersection of biology and philosophy? A blank look. How about a book about parasites? Boom: my agent sat up.

That decision led me to some interesting places: rebel-held territory in southern Sudan, a Costa Rican jungle, a salt marsh in California, and the official United States Parasite Collection. And not too long afterwards, I finished writing Parasite Rex.

The book has thrived ever since. Recently, my publisher decided to put out a new paperback edition, to celebrate the ten year anniversary of the original paperback. I’ve written an epilogue for ...

Mysterious smiles and single-cell dogs: a double-header in tomorrow’s New York Times

Carl Zimmer — Tue, 25 Jan 2011 04:41:57 +0000

I’ve got two stories in the New York Times tomorrow, at two ends of life’s scales.

In the cover story, I write about smiles. Faces have long fascinated me (see this Discover column on Darwin and Botox), and so I was intrigued to come across this recent paper focusing on smiles in particular. I talked to David Corcoran about the story for the first twelve minutes of the latest Science Times podcast.

Elsewhere in the Science Times, I keep up with the creepiest form of life out there: infectious cancer. Two species–Tasmanian devils and dogs–have given rise to cancer cells that can hop from host to host. I wrote about Tasmanian devils in the Times, and about dogs here at the Loom. Now there’s news that the dog cancer (which I want to call Canis cancer after talking to the scientists who study it) rejuvenates itself from time to time by stealing its host’s mitochondria. This is a story that just keeps going and going…like the cancer themselves.

The Twelve Parasites of Christmas

Carl Zimmer — Sun, 19 Dec 2010 17:57:49 +0000

Susan Perkins at the American Museum of Natural History is almost done with a truly heroic feat: overseeing a blog that features a new parasite every day in 2010. As we glide towards the end of the year, she’s launched “The Twelve Parasites of Christmas.” So far, mistletoe (that botanical equivalent of a tapeworm!), two turtle doves (and their blood parasites), and the cauliflower mushroom, bane of Christmas trees. What gifts await us in the next week?

The Cholera Tree of Life (and Death)

Carl Zimmer — Sat, 11 Dec 2010 02:07:56 +0000

The nightmare that is the cholera epidemic of Haiti (2,100 dead so far) has become a little less mysterious. Haiti has not seen cholera for over a cenutry, and so the emergence of cholera in recent weeks has puzzled scientists and led to riots directed at the U.N. for supposedly bringing Vibrio cholerae to the Caribbean nation. Others have pointed to a New World strain as a potential culprit. It triggered an outbreak in Peru in 1991, and has circulated in Central and South America ever since. Perhaps these bacteria washed up on Haiti’s shores.

In the latest issue of the New England Journal of Medicine, Matthew Waldor of Harvard and his colleagues go some distance to settling the debate by finding the Haitian cholera’s place in the tree of life.

“Collectively, our data strongly suggest that the Haitian epidemic began with introduction of a V. cholerae strain into Haiti by human activity from a distant geographic source,” the scientists write. The bacteria belong to a strain that evolved in South Asia. It was probably introduced onto Haiti by a sick person who flew there. We may never ...

The empire of viruses: my story in tomorrow’s New York Times

Carl Zimmer — Mon, 22 Nov 2010 22:36:45 +0000

Recently I paid a visit to a place where the world’s most mysterious viruses go to find a name. The result was my profile of Ian Lipkin of Columbia University for tomorrow’s New York Times. I first started thinking about this story when I heard Lipkin give a lecture about his work identifying unknown viruses this spring. And when I read this review of Lipkin’s, entitled simply, “Microbe Hunting,” I knew it was time to get cracking.

One thing I didn’t have room for is the fact that Lipkin has gone all Hollywood. By which I mean that he’s helping Steven Soderbergh on a new movie on a virus outbreak called Contagion, starring Matt Damon, Kate Winslet, and other big stars. Lipkin seems pretty stoked about the movie, which is slated for 2011, so I’ll definitely be keeping an eye out for it.

Your inner viruses: the trickle becomes the flood

Carl Zimmer — Thu, 18 Nov 2010 22:00:29 +0000

Scientists have known for decades that the genomes of animals can sometimes harbor DNA from the viruses that have infected them. When I first learned of this fact some years ago, it blew my mind. The notion that any animal could be a little bit viral blurred nature’s boundaries.

The viruses that scientists discovered in host genomes were of a particular sort, known as endogenous retroviruses. Retroviruses, which include HIV and a number of viruses that can trigger cancer, have to insert their genetic material into their host’s genome in order to reproduce. The cell reads their genetic instructions along with its own, and then builds new viruses. It made a certain intuitive sense that retroviruses might sometimes get trapped in their host genomes, to be passed down from one generation to the next.

The first endogenous retroviruses scientists identified were still relatively functional. Under certain circumstances, their genes could still give rise to new viruses that could break out of their host cell. But gradually, scientists identified more and more fossil viruses, which had mutated so much that they could no longer reproduce. As I wrote in the New York Times in 2006, scientists ...

Got satellite radio? I’ll be talking about weird life at 1 pm EST today on XM171 and SR147

Carl Zimmer — Mon, 25 Oct 2010 15:25:09 +0000

I’m going to be a guest on Road Dog Trucking Radio, the satellite radio channel for truckers. I’m going to talk about parasites, viruses, and other weird critters. Even if you don’t drive a big rig, you’re welcome to tune in.

All in the Mind goes all parasitic

Carl Zimmer — Sat, 09 Oct 2010 04:06:25 +0000

I’m a big fan of All in the Mind, a radio program on neuroscience, psychology, and all things brain-ish, produced by Natasha Mitchell for Australia’s ABC Radio National. So it’s a double pleasure to hear her new episode about how parasites alter behavior. Check it out.

Malaria, Sea Grapes, and Kidney Stones: A Tale of Parasites Lost

Carl Zimmer — Tue, 24 Aug 2010 05:58:43 +0000

If you’re looking for a gang of vicious killers, look no further than the Apicomplexans. These single-celled protozoans cause death and destruction across the animal kingdom. They infect everything from butterflies to people. Their diseases include Texas Cattle Fever, toxoplasmosis, and the scourge that makes Plasmodium the baddest Apicomplexan of them all, malaria.

Scientists have named 6,000 apicomplexans, but they estimate there may be anywhere between 1.2 and 10 million species waiting to be identified. Every apicomplexan they’d studied so far is equipped with the same fearsome weaponry. Their cells are shaped like teardrops, and at the pointed end they have a ring of tubes, like the chambers on a revolver. When an apicomplexan prepares to invade a cell, it points those chambers at its prospective host and fires a set of molecules that grab the cell’s surface and stretch it open so that the apicomplexan can slide in. Apicomplexans inherited their weaponry from their common ancestor, which lived several hundred million years ago, and they’ve thrived as pathogens ever since.

Yet in the midst of this brutal dynasty, scientists have now discovered a peacemaker. For the first time, they’ve found an apicomplexan that bestows a biochemical gift to its ...

Now bring me a T. rex tapeworm!

Carl Zimmer — Wed, 18 Aug 2010 12:54:18 +0000

I had planned to spend today NOT writing about parasites, but this morning I’ve already gotten comments and tweets informing me about a very cool new paper that was published today, documenting parasitized zombies 48 million years ago.

All right, then. The parasite overlords cannot be ignored.

The parasite in question is the fiendishly awesome Cordyceps, a fungus that forces its insect hosts to climb up high on plants, clamp down, and hold fast. The fungus then sprouts out of the ant’s body, showering down spores on hapless insects below. I wrote about Cordyceps in my book Parasite Rex, and followed up last year with a blog post on some great work by David Hughes of the University of Exeter and Harvard. Hughes and his colleagues wondered if the fungus was controlling its host in a fine-tuned adaptation, or if the ants were becoming zombies because they were just sick. After all, if your body was shot through with fungus threads, you’d probably feel lousy as well. But Hughes made a strong case that Cordyceps really is in charge, because it so consistently sends its hosts to the ...

Parasitic wasps on Weeds: We have video!

Carl Zimmer — Tue, 17 Aug 2010 18:05:13 +0000

Thanks to Mandarb for posting this clip from Weeds I was wondering about yesterday. I should point out that it’s a very abridged version of my original piece on the radio. For example, it sounds as if I’m giving God my own personal forgiveness for parasitic wasps. I was actually talking about a letter written by Darwin in which the wasps figured in his musings about God.

And I have to say that I’m not much closer to figuring out what parasitic wasps have to do with the show’s plot. I guess I’ll have to watch the whole episode. But–for the record–here it is: