Biology

An immune system for the planet: Exclusive interview with Nathan Wolfe

Posted by: Matthew Trost

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Using genetic sequencing, needle-in-a-haystack research, and dogged persistence (crucial to getting spoilage-susceptible samples through the jungle and to the lab), Nathan Wolfe has proven what was science-fiction conjecture only a few decades ago — not only do viruses jump from animals to humans, but they do so all the time. Along the way Wolfe has discovered several new viruses, and is poised to discover many more.

The TED Blog interviewed Wolfe over the phone shortly before his appearance at the Skoll World Forum on Social Entrepreneurship. He discusses the fact that vaccines often act as a crutch after the failure of preventative measures against disease, the need for a “global immune system” implemented through communication technologies such as SMS, and occasions when it’s professionally acceptable — and socially crucial — to eat rodents. Here’s a snippet:

I think about the secondary effects of diseases like AIDS that cause a population’s immune system to be suppressed, as a whole. I think of this as a tear in the planet’s meta-immune system. This tear increases the possibility that a new virus will enter. With immunosuppressed hunters, a virus that normally couldn’t survive or adapt to human populations might get a few extra generations and be permitted to adapt to these individuals and humanity.

Read the full interview, after the jump >>Transcript of interview with Nathan Wolfe (3/27/09):

Given an extra couple of minutes on the TED stage, what might you have said?

I talked about bushmeat, and obviously I feel strongly about how hunting wild game in central Africa and elsewhere is a crisis for humanity — a conservation crisis, a public health crisis in relation to diseases like HIV that came about through that sort of activity — and also a food security crisis.

I also emphasized that it’s unfair to ask one small, impoverished population to take on the burden of addressing the behavior change and the economic costs associated with diminishing those risks. But I didn’t really talk about how we’d go about doing it.

One interesting approach is developing domesticated wild game. Grasscutters — large grass-eating rodents that you find throughout West and Central Africa — are easy to grow, non-endangered and tasty. They have the potential to provide livelihoods for rural populations. At the same time, they’ll decrease hunting of wild animal populations, such as species of non-human primates.

Do you partake of the bushmeat?

Bien sûr! J’aime beaucoup la viande de brousse. Yeah, I definitely do. Let’s say you show up in a rural village, and somebody who normally would not even be indulging in meat serves something in honor of your visit. You’re often in a very complicated situation, personally and professionally.

I avoid taxa of species that are endangered or those for which I feel like I really need to make a point about the health risks in eating them. But I’ve eaten a whole range of things, from snake to rodent to you-name-it. I’ve eaten much of it in the field.

Tell me about some new places your research is going.

At GVFI we’ve had some interesting findings that tell us how pandemics enter human populations. A smaller and smaller percentage of the world’s population is responsible for the majority of human-animal contact. We can create the equivalent of a safety net — an equivalent of an immune system for the planet — by having these particular sentinel populations telling us what’s pinging us from these animals, and documenting this viral chatter.

We need to move from this point where we have four or five pilot sites to 20 or 30 around the world. We’ll work with WHO, CDC and bring it up to scale.

What or who inspires you to do this work?

Many of my heroes are those who discovered new life on the planet, the unseen microscopic world.

Anthony Leeuwenhoek, by inventing the first optical microscope in the 17th century, transformed the way we think about biology on the planet, for the first time recognizing bacteria and microorganisms. And subsequently we’ve realized that these are the dominant forms of life on our planet.

There’s Martinus Bejernek, a Dutch microbiologist, one of those credited with the discovery of viruses at a time when only bacteria were known. He was fascinated by tobacco diseases. His father had been a tobacco merchant who had gone bankrupt because of tobacco diseases. He was interested in what we now know as the tobacco mosaic virus. He simply strained the juices of infected tobacco plants through a filter with holes so small he knew it would block out all bacteria. Even after that filtration, he could still infect new plants with the juices. He recognized there was an organism that must be smaller than bacteria that was still infectious.

Another person who’s not often credited is a woman named Tikvah Alper, who was key to the discovery of prions. It was unclear what was causing diseases which we now know of as prion diseases. She subjected them to intense UV radiation and found that they still survived. That meant they could include no DNA or RNA, and so she postulated that what they must be is transmissible protein agents — which is of course what they ended up being.

What’s next? What are you excited about?

If the Internet is the global nervous system, and you have companies like Google pushing forward its evolution, part of what we’re trying to do is create the equivalent of the global immune system.

One thing I’m excited about is mobile phones. How are we going to work with populations that are in geographically distant spots and link them together, to know when they’re sick?

I’m fascinated by revolutions that come from adapting technologies like text messaging. For example, people can text message surveillance information, and we can respond and put credit on their phone, which means even populations that are very poor, if they have proximity to cell phones, can have access to healthcare.

What worries you?

People often ask me what keeps me up at night. Not much keeps me up at night, because I’m a fairly good sleeper and I don’t get upset about these things.

I do think about the secondary effects of diseases like AIDS that cause a population’s immune system to be suppressed, as a whole. I think of this as a “tear” in the planet’s “meta-immune system.” This tear increases the possibility that a new virus will enter. With immunosuppressed hunters, a virus that normally couldn’t survive or adapt to human populations might get a few extra generations and be permitted to adapt to these individuals and humanity.

What are your thoughts on the possibility of an HIV vaccine?

Vaccines are and always will be a critical element for human disease control and public health efforts. But, having said that, I do think we rely on them as a crutch. We very much think, “We’re going to wait until diseases occur and then create vaccines and drugs against them.”

HIV has been a perfect example of how vaccine development is by no means an eventuality or a rapid inevitability. AIDS was first noted as a syndrome in 1981. The virus that causes AIDS was first identified in late 1983. The Deputy of Health and Human Services pretty much said “We’ll have a vaccine within a year.” Here we are, 30 years later, and arguably we’re not necessarily much closer to a vaccine than we were then.

Global disease control should be pushed to an earlier point. Instead of waiting for these viruses, we need to catch them earlier.

HIV existed in human populations in the early 20th century, and yet it took 70 years to know about it. Had we been studying in the right places, the world would have been a very different place in the ’70s when the virus started going global. We would have seen that it was a syndrome, that it was transmitted in a number of ways — also heterosexually, which would have changed the entire political dynamic of the outbreak. Reagan didn’t even say the word AIDS until ’86 or ’87. We would have known about the global distribution, about the ways to stop it, control it.

Is there a virus you would characterize as “good”?

I would call Vaccinia a good virus.

Here’s a useful metaphor to think of the world of viruses. There’s the universe of viruses — even just pathogens or microbes — in general. You have known galaxies, say retroviruses. That’s a known galaxy. Or orthopoxviruses, such as smallpox. Those are known galaxies. Part of our job is to look for unknown galaxies. Or to look for unknown stars in known galaxies.

Obviously, galaxies that we would label pathogenic are important. In the orthopox galaxy, we have smallpox, which is one of the deadliest pathogens of human history. If you move out a little bit from that star and look for neighboring stars, what you’ll see is Vaccinia, which is cowpox. That virus is actually the smallpox vaccine. It’s sufficient to cause immunity but does not cause disease. Viruses that are very close to deadly ones can act as vaccines. We can use proximity to help identify possible vaccine candidates, or new microorganisms that might point the way towards new vaccines.

There is a large DNA virus which works in a symbiotic relationship with a parasitic wasp. This is a wasp that makes its living by laying its eggs on the backs of caterpillars. There is an evolutionary tension between the caterpillar and the wasp, because the caterpillar’s defenses change against the wasp eggs, and then the wasp eggs develop the capacity to counteract or work around those caterpillar defenses. But then a third player in this is a virus that coats the wasp’s eggs. That virus limits the ability of the caterpillar’s immune system to detect those wasp eggs.

This is a microbe’s world. The majority of the mass and diversity of life on our planet is made up of microorganisms. It would be odd to imagine all these viruses and bacteria that are part of our bodies are exclusively negative. We know that’s not the case, but we haven’t been on this systematic search for them. If we did, we would likely find a whole range of mutualistic viruses.

What’s going to be the next big thing to come from this field of work?

Finding a new HIV in humans. That’s something I think we — or another group — will find in the coming years. To date, we haven’t seen it.

Watch Nathan Wolfe’s 2009 TEDTalk >>

Image credit: TED.com / Asa Mathat
Interview credit: TED.com