Scientists Discover AIDS-like Disease in Chimps
Tanzania's Gombe National Park is where Jane Goodall began her famous research on wild chimpanzees. Scientists have been keeping tabs on those chimps ever since. Elizabeth Lonsdorf of the Lincoln Park Zoo helps run a team monitoring the chimps' long-term health. They observe chimp behavior, analyze their leavings, and they track chimps to their nests up in trees, in order to collect their urine.
LONSDORF: In the morning they do what many of us do, they go right to the bathroom. And then you can hold out a plastic bag on the end of a stick or something like that. Urine is actually not our preferred substance because it can be quite messy because it's usually coming from above.
Feces, it turns out, is way easier. So, one thing they can learn from those samples is which chimps are infected with Simian Immunodeficiency Virus - the precursor to HIV. Not that Lonsdorf's team was paying a whole lot of attention. Everybody thought SIV didn't do much of anything to wild chimps - it was just a benign germ a lot of them carry.
But then a few researchers discovered something: the SIV-positive chimps were dying much faster than non-infected chimps: The death rate is 10-to-16 times higher.
LONSDORF: At first it was really hard for all of us to buy it. We just said, you know, are we doing this analysis right? But we went over everything with a fine tooth comb. And the real kicker was when Karen started looking at those samples.
TERIO: I'm Dr. Karen Terio, I'm a veterinary pathologist with the University of Illinois's zoological pathology program.
At the moment, Terio is sitting outside the chimp enclosure at Lincoln Park Zoo. The zoo sends her tissue samples to necropsy - that's an animal autopsy. In the spring of '08, she was looking at a bunch of organ slivers from a female chimp sent from Gombe.
TERIO: Every time I was coming across sections of tissues that were part of the immune system, I couldn't find any lymphocytes. And then I pretty much immediately go on the phone.
LONSDORF: Karen called me, and said, Elizabeth, they don't have any lymphocytes. And I said, that's white blood cells, right? And she said, Yeah, that's white blood cells.
TERIO: I actually didn't believe what I was seeing at first, I called a couple of my colleagues in to look at it and say, do you see what I'm seeing? Is this really true?
LONSDORF: And I said, does that mean what I think it means? And she said, yeah.
TERIO: It looked like what you see with AIDS.
LONSDORF: An advanced, end-stage AIDS patient. I think we gotta call some people.
TERIO: We needed to chat. This was gonna change what we knew about SIV in chimpanzees.
Namely: chimps, apparently, can get AIDS. It's the first discovery of AIDS-like disease in a wild primate -- the findings are published in today's issue of the journal, "Nature." Now, scientists have several different SIV strains - some benign, one deadly. By looking at minute variations, they hope to find the molecular keys to what makes the human versions so dangerous.
Some specialists say animal models aren't exactly the center of the action in HIV research these days. But Terio says the chimp studies could make a real contribution.
TERIO: Absolutely, it could have implications for therapy. Management of the disease, our understanding of the disease, but also therapy. Because the more we understand about why the disease progresses, we can look at different areas we want to target for therapy.
That could be a way's off, and these findings still need to be duplicated. But Lonsdorf says this discovery is the payoff from years of dogged research.
LONSDORF: There's often times when people say, well gosh, don't we know everything there is to know about those chimps? But obviously, this is good evidence that we don't, and it's still incredibly valuable to have long-term studies on wild ape communities.
This is, after all, the same chimp community Jane Goodall was studying when she discovered that apes can make tools. That breakthrough taught us that chimpanzees are even closer to humans than we had thought. And for good or ill, this revelation about AIDS holds the same lesson.
Music Button: Chris Joss, "Night Scare", from the CD Sticks, (ESL records)