Science Life - A blog of news and ideas in Biomedicine

Evolution via Cannibalism: The Case of Kuru

Posted at 11:32 am CT on November 19, 2009

prion4In the 1950s and ’60s, several villages in the Oceanic country of Papua New Guinea began to see an odd disease. Villagers of the Fore people in the Eastern Highlands - predominantly women and children - would show an array of frightening symptoms that rapidly worsened over about six months: muscle tremors, uncontrollable laughter, slurring of speech and finally an inability to move and swallow. In the 1960’s, European scientists began to study people with the disease, called kuru for the Fore word for “shiver,” and made two astonishing discoveries. First, that kuru represented a new kind of infectious disease that caused the brain and nervous system to degenerate. Second, that kuru probably resulted from people eating their dead relatives.

Yeah, that’s not a typo. Before the Fore people of Papua New Guinea were known for kuru, they were known for “mortuary feasts,” where villagers would mark the death of a family member by consuming him or her. And not just a nibble here or there - according to a 1979 book by anthropologist Shirley Lindenbaum, “meat, viscera, and brain were all eaten.” That’s a good way to spread a disease caused by prions - the mechanism for kuru eventually discovered by Daniel Carleton Gajdusek in research that won him the 1976 Nobel Prize in Physiology or Medicine. Now, kuru continues to fascinate the scientific community, as a new medical paper presents how the savage disease caused rapid natural selection in Papua New Guinea, selecting for a gene variant that may offer clues to how to treat prion diseases with no known cure.

Prions are also the culprit behind bovine spongiform encephalopathy, better known as Mad Cow Disease, which is thought to have broken out in Britain due to cannibalistic feeding practices in cattle. In short, prion diseases are caused by misshaped proteins that are a bad influence on native prion proteins present in all species, causing them to change shape, clump together, and eventually kill the cell. So when a prion disease enters a person’s nervous system - by, say, eating a person with a prion disease - it tends to wreak havoc in the brain, producing the odd symptoms of kuru or BSE.

At the height of kuru, 1 out of 50 people in some Fore villages succumbed to the untreatable, fatal disease. Women and children tended to die more often from kuru, likely because they usually were given the brains to eat while the men got the good, meaty parts. But what about those who participated in the mortuary feasts, but never contracted the disease? Was there something genetically different about them that made them resistant? Sounds like a case for…evolution!

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Posted by - Rob Mitchum

Global Health: “The Mother of All Ethical Challenges”

Posted at 12:22 pm CT on October 1, 2009

singer2007hrThanks to scientific and medical progress, the average life expectancy of a person in North America is 80 years and increasing. But in sub-Saharan Africa, the average lifespan is half that figure, and dropping. Technology is often said to have made the world a much smaller place, so how can those of us fortunate enough to be in the developed world help close that shocking life expectancy gap? That question, according to the University of Toronto’s Peter Singer, is “the mother of all ethical challenges.”

Singer, a professor of medicine and an internationally-renowned expert on bioethics, returned Wednesday to the University of Chicago, the school where he studied medical ethics 22 years ago. And boy did we put him to work, asking him to deliver the opening speeches for two separate but related launches: this year’s MacLean Center for Clinical Medical Ethics seminar series, and the school’s new Global Health Initiative. In both lectures, Singer drew from vast experience in facilitating efforts to improve health in Africa, India, China and other areas of the developing world, offering valuable advice for what doctors, scientists, and universities could do to help such efforts.

It’s nice to think that simply sending doctors and the fruits of scientific research to needy countries would solve these problems, but as Singer explained, there are several obstacles to merely hoping public health will spread around the globe by osmosis. Singer showed this Nature Review Immunology figure from 2002, which illustrates how developing countries lag behind in vaccinations given to children despite the development of vaccines for more diseases. Lack of scientific discovery relevant to the developing world, ethical and social barriers and a “brain drain” of scientific talent from Africa and Asia have all contributed to these inequalities, Singer said.

But Singer also gave reasons for optimism. In 2003, The Bill and Melinda Gates Foundation (for which Singer serves as an advisor), issued their Grand Challenges in Global Health, funding vaccine research and efforts to limit diseases spread by insects - scientific questions more pressing to to poor countries. Six years later, those projects are already bearing fruit, such as the effort to infuse staple crops of poor populations with nutrients, the creation of genetically modified mosquitos that don’t spread malaria or the combination of several vaccines into a single injection

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Posted by - Rob Mitchum

Linkage: Animal Weirdness, Hubble’s Return and Follow-ups

Posted at 3:14 pm CT on September 11, 2009

Our weekly roundup of science news from around the world that doesn’t easily fit anywhere else.

A cuscus. Crazy. (photo from Wikimedia Commons)

A cuscus. Crazy. (photo from Wikimedia Commons)

Wild Kingdom Gets Weirder

If you’re a fan of weird animal stories, this was a week for you. First, there was the discovery of a never-before-seen giant rat and about 40 other unidentified species by a group of British and American scientists in a volcano crater on the island of Papua New Guinea (they also stumbled upon Doria’s tree kangaroos and cuscuses while they were at it; adorable photo gallery here). Christened the Bosavi woolly rat, it’s 32 inches long and 3.5 pounds, and was completely friendly to humans, having never really seen them before.

Then a report came out in Biology Letters about a group of birds called tits in Hungary that were forced to add an unusual menu item when food became scarce: bats. These cute little birds apparently get on a real mean streak when they’re hungry, attacking hibernating bats (small ones - only 4cm) and dragging them out of their caves for dinner. The paper’s authors found that the tits (okay, stop giggling) would only go for bat meals when other food wasn’t available, which they proved by satiating the carnivorous birds with…bacon. I’d provide some more links on this story, but it’s not exactly the kind of topic you want to be caught Googling at work.

Finally, in a study that will probably end up on some politician’s pork-barrel list, NASA revealed this week they can now make mice float with magnets. The superconducting magnet is powerful enough to use a mouse’s natural water content to cause its entire body to float, an unusual sensation that the mice apparently get used to fairly quickly (3-4 hours). Why levitate mice? To study the effects of microgravity on astronauts, of course, though Switched points out rightly that NASA has already been bringing rodents for ride-alongs into space for decades. Alas, there is nary a video of levitating mice to be found, and the article is accompanied only by terrible overhead pictures. C’mon, NASA. read more

Posted by - Rob Mitchum

Linkage: “Swine Flu” Special

Posted at 3:55 pm CT on September 4, 2009

48446046With the weather cooling and the kids back in school, the media coverage of the H1N1 flu - last spring’s “swine flu” - is building back to a fever pitch, if you’ll pardon the pun. As expected, colleges immediately found themselves dealing with campus outbreaks, and elementary and high schools have also already seen flu cases in the first few days of the school year.

In April, scientists knew very little about the nature of this novel H1N1 strain, and the worst-case scenarios suggested by some flu experts fueled the frenzy over whether this virus could be as deadly as the 1918 pandemic that killed as many as 100 million people worldwide. Now, six months later, there has been a lot more time to study the virus, observe its movements through the Southern Hemisphere’s flu season, develop and test vaccines and estimate the damage us citizens of the Northern Hemisphere can expect as a our flu season traditionally begins in October.

Because the novel H1N1 pandemic is such a fast-developing and important topic, much of the research into it is happening at an accelerated pace and is being disclosed to the public more quickly and openly than is typical for the traditionally slow march of science. Other sites have done excellent overviews of influenza in general and what we know about this particular strain or have followed every turn of this story. Below are summaries for a few of the main H1N1 subtopics.

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Posted by - Rob Mitchum

Who Gets Dibs on H1N1 Vaccines?

Posted at 10:15 pm CT on July 29, 2009

Much of the latest news on the H1N1 virus, colloquially known as swine flu, indicates that the next flu season has the potential to be unusually rough. In some ways the last flu season never really ended; the Centers for Disease Control and Prevention report that 20 states are still seeing widespread or regional flu activity, with H1N1 accounting for the vast majority of cases.

The coming flu season could fall within normal ranges, but CDC planners are bracing in case it resembles an especially bad pandemic year, such as 1957. The details on how H1N1 affects patients are still coming in. Certain populations appear to be at high risk for severe symptoms and, occasionally, death. Widely covered today was a Lancet report that suggested pregnant women may be more susceptible to the virus, with a higher rate of hospitalization and an elevated death rate in the pandemic’s early days. Between mid-April and mid-June, six pregnant women (including one in Chicago) died from the novel flu strain, 13% of the 45 American deaths reported during that time period.

The authors of the Lancet paper recommend that pregnant women receive antiviral medication, such as Tamiflu, as soon as possible after developing flu symptoms - none of the six deceased patients addressed in the paper received antivirals until at least 48 hours after illness onset.

But the best way to protect pregnant women from the flu strain when it likely returns in force this fall is through vaccination. The H1N1 story of the summer has been the frantic race by governments and scientists around the world to have a vaccine against the strain ready in time for the Northern Hemisphere’s next flu season. Manufacturers told an FDA panel last week that about 100 million vaccines could be ready in the U.S. by mid-October, but with roughly 300 million Americans, not everyone is going to be immediately vaccinated and priorities will have to be set.

That sober reality set the stage for a fascinating meeting today in Atlanta, where the federal Advisory Committee on Immunization Practices - a panel of doctors, scientists and public health experts - attempted to pick and choose which groups deserved the first crack at the limited vaccine supply. Given the numbers released yesterday, it was no surprise to find pregnant women in the top priority group for this fall’s vaccinations. Also given priority in the ACIP’s recommendations were caregivers for children younger than 6 months (who cannot themselves be immunized), healthcare and emergency medical personnel, children and young adults from 6 months to 24 years old and adults with chronic medical conditions.

Added together, that’s about 150 million people, roughly half the U.S. population. But with compliance among the priority groups expected to be far below 100% (it’s only around 40% for the regular old seasonal flu), it’s thought that the initial batch of 100 million will suffice, even if each person needs two doses to be fully protected, which experts predict may be necessary. As more vaccines become available, people between 25 and 64 will get it next. Those above 65 years old, who have seemed less affected by H1N1, are in the third, lowest priority group.

Much of the debate Wednesday (helpfully webcast on the government’s flu.gov website) centered over whether the younger population targeted in the first wave of vaccinations should be capped at age 19 or age 24. The argument of some panelists: college kids are as good at spreading viruses as they are at sleeping in late. Others argued that colleges are also an excellent distribution system for getting vaccines to this particular population. So young adults will join the front of the queue for the first batch.

The effects of H1N1 on different age groups appear to vary in a striking way, according to epidemiology discussed at the meeting. With nearly 44,000 American cases of H1N1 now documented, elderly folks appear to be less susceptible to the strain than younger populations. That observation runs counter to the pattern in most flu seasons, when senior citizens are more sensitive to the effects of seasonal strains and thus are heavily encouraged to get the yearly vaccine. At a CDC press conference announcing the panel’s recommendations, Assistant Surgeon General Anne Schuchat urged American seniors to get the seasonal flu vaccine as usual this coming fall. But for the H1N1 vaccine, they’ll be at the back of the line behind their children and grandchildren.

(Not to be a scaremonger, but for a gripping tale of H1N1 overseas, see this article by New York Times reporter Sheryl Gay Stolberg and her daughter Olivia Robinson, who contracted the virus while on a school trip to China)

Posted by - Rob Mitchum

Flu scare prompts “emergency science”

Posted at 4:38 pm CT on May 8, 2009

Ever since the swine flu outbreak hit, Patrick Wilson has been immersed in what he calls “emergency science.”

The emergency may have abated thanks to the low mortality rate observed from the H1N1 strain, but Wilson’s group is working with scientists at Emory University and the Centers for Disease Control and Prevention to help combat the novel flu variety.

Wilson’s skills suddenly are in high demand because of a paper he co-authored in the journal Nature last year, demonstrating a rapid method of making antibodies to specific types of flu. The technique one day could help protect against new pandemic strains for which a vaccines do not yet exist. In the short term, the method offers a new way of rapidly diagnosing cases of H1N1 flu.

“The first application the CDC wants is to make a rapid diagnostic,” said Wilson, an assistant professor in the department of medicine at the University of Chicago.

The method that Wilson’s team published last year could be a new chapter for an old way of dealing with infection through “passive immunization.” The idea of harvesting antibodies for sick patients began in 1891, when Emil von Behring and Shibasaburo Kitasato cured a patient with diptheria by injecting serum from sheep that had antibodies to the disease. Von Behring later won a Nobel Prize as “The Founder of Serum Therapy.”

Before the advent of antibiotics, such treatments with antibodies became widely used for many infections, including anthrax and Streptococcus pneumoniae.

“Doctors used to keep vials of antibody serum that they could use off the shelf for various infections,” Wilson said.

The risk of anaphylactic shock and other drawbacks of antibody serum made doctors turn to antibiotics and vaccines once they became widely available. But even today, the idea of using antibodies has appeal for emerging viral infections, for which scientists have not yet developed a vaccine.

Flu vaccines typically take months to make, but the technique that Wilson devised with colleagues from Emory and the University of Oklahoma Health Sciences Center can produce monoclonal antibodies to a specific strain of flu in just a few weeks.

No one knows yet if the flu antibodies would offer meaningful protection in the case of an emerging pandemic. Wilson said it’s possible that the technique would prevent infection in people at high risk of exposure during the period when scientists are still working on a vaccine.

“It’s controversial how useful antibodies would be in treating this kind of infectious disease,” Wilson said.

But using the antibodies to develop a rapid diagnostic tool could be almost as valuable. Currently, most hospitals use an antibody-based test to see if a patient has influenza, then they ship samples to state labs or the CDC for further testing, which usually takes several days. The new method of producing monoclonal antibodies would allow for faster and more widespread testing of new flu viruses as they emerge.

Posted by - Jeremy Manier

Why swine flu is still important

Posted at 10:18 am CT on May 5, 2009

This may be the best expression I’ve seen yet of why swine flu still is a source of concern, even though it’s looking about as severe as normal influenza. From the Wall Street Journal’s coverage of a press conference today with Keiji Fukuda of the World Health Organization:

The reason why we’re paying so much attention to this virus is that the seasonal flu viruses have been around and circulating for many years. We understand their behavior and know most people have had previous infections and some immunity to them. When a new virus enters the human population and people do not have immunity to this virus, then the levels of serious illness and the levels of death can be higher than what we see with regular seasonal influenza.

…In the past, we’ve seen pandemics cause relatively fewer deaths, and some cause relatively huge amounts of death. One of them started out mild in the spring and over the course of several months became a severe illness. This is a situation in which things can evolve, and can do so quite differently. That’s why so much attention is being paid to what’s going on and why we’re jumping so hard on it. If it stays mild and people stay healthy, then that is great. But if it turns severe, then it’s something we have to know about, be prepared for and jump on.

Posted by - Jeremy Manier

Answers to Common Questions About Swine Flu, Pt. 2

Posted at 2:37 pm CT on April 28, 2009

Here’s Part 2 of our conversation with Kenneth Alexander, M.D., chief of pediatric infectious diseases. In this second and last installment, we discuss what ordinary people can do to avoid getting or spreading swine flu, some steps that medical professionals can take, and what would constitute a flu pandemic.

Posted by - Jeremy Manier

Answers to Common Questions About Swine Flu, Pt. 1

Posted at 2:20 pm CT on April 28, 2009

Here’s a video we shot yesterday of Kenneth Alexander, M.D., chief of pediatric infectious diseases, answering common questions about swine flu.

Posted by - Jeremy Manier

How would Obama respond to a flu pandemic?

Posted at 3:51 pm CT on April 24, 2009

The news of unusual swine flu cases in Mexico and the American southwest has raised concerns that the outbreaks could herald a new flu pandemic - though the anxiety level in this AP story on today’s news seems just a bit too high at this stage. Something about the tone smacks of that movie “The Andromeda Strain” - “it’s something we’ve never seen before…”

It’s important to be vigilant, but overreaction also can have costs. In 1976, the CDC instituted an emergency immunization program in response to an outbreak of swine flu. The vaccine they used may or may not have been the cause of an uptick that year in cases of Guillain-Barre Syndrome (see this for an account of the 1976 experience by the former directors of the CDC and the immunization program).

President Obama has a history of interest in flu pandemic preparedness. He co-wrote a 2005 op-ed in the New York Times on pandemic measures, and later that year I interviewed him on that subject for the Chicago Tribune. You can see the transcript here. Two passages from that interview may offer clues about how Obama’s administration will handle the latest outbreak: 

Even when the SARS scare struck, the losses were in multiple billions of dollars. And that proved to be a false alarm essentially. If something like this genuinely occurred, you’d see global trade come to a standstill. And in addition to obviously the loss of life, the breakdown of our health systems, the economic consequences would be huge.

…you hate to be Chicken Little on this thing - no pun intended. But this is actually one of those situations where getting people a little scared, and certainly getting our government a little scared is probably a useful thing. And as I said, whatever investments we make are not going to be wasted, because the likelihood of pandemic is so high, even if it isn’t this particular pandemic. 

Perhaps Obama will see the issue differently as president than he did as a senator. But his instincts seem similar to those of the people who ran the 1976 immunization program - “When lives are at stake, it is better to err on the side of overreaction than underreaction.” If this outbreak continues, we may see another test of that idea.

Posted by - Jeremy Manier