RACHEL MARTIN, HOST:
Scientists don't know all the conditions Zika might be causing. And they're racing to figure out how the virus works. NPR's Nurith Aizenman takes us now to a lab in the Colombian city of Cali, where they're trying to prove a link between Zika and a neurological condition that causes temporary paralysis.
NURITH AIZENMAN, BYLINE: Researcher Beatriz Parra Patino opens the freezer section of a white refrigerator and takes out a tray of test tubes.
BEATRIZ PARRA PATINO: I have the samples that I need to test today. So we have one, two, three, four, five, six, seven, eight, nine, 10 - like 14 samples to test.
AIZENMAN: The tubes are mostly filled with diluted blood or saliva. Parra says to her, each one represents a human being.
PARRA: A human being, that's right. And I treat the tubes like if I was treating the person, so with respect and trying to do my best.
AIZENMAN: Because the fact that a person's body fluids are in one of these tubes means there's a good chance that right now that person is suffering the excruciating effects of Guillain-Barre syndrome. It's a temporary condition in which your immune system starts attacking your nerve cells. People can lose the ability to walk, to smile, even to breathe. You get a sense of just how bad it can get at one of the hospitals that is sending these fluid samples to Parra. It's about 400 miles on the other side of Colombia in a city called Cucuta, an area with a lot of Zika cases.
UNIDENTIFIED WOMAN: (Speaking Spanish).
AIZENMAN: The head of neurology, Dr. Jairo Lizarazo, is visiting some of his latest Guillain-Barre patients.
JAIRO LIZARAZO: (Speaking Spanish).
AIZENMAN: "One of them is a young doctor," he says, "one of my own students." He finds Dr. Karina Luque collapsed in her hospital bed. Her face muscles are so stiff, it's hard for her to speak.
KARINA LUQUE: (Speaking Spanish).
AIZENMAN: "When I sit up or when I talk a lot, I have to stop for awhile because I get really tired," she says. Lizarazo pulls back a curtain to reveal another patient, an older woman hooked up to breathing tubes. She's been on them for several days, he says.
LIZARAZO: (Speaking Spanish).
AIZENMAN: This is the most serious case.
Guillain-Barre is usually rare. At this hospital, Lizarazo sees about half a dozen cases a year. But he says since the Zika outbreak started...
LIZARAZO: (Speaking Spanish).
AIZENMAN: "Every one or two days, we get a new case." It's a pattern not just across Colombia, but in four other countries where Zika is spreading in a big way, which is where Carlos Pardo, an expert on neurology and neuroimmunology, comes in.
CARLOS PARDO: I got a call from one of my colleagues in Colombia who was telling me about this initial outbreak of cases of Guillain-Barre.
AIZENMAN: Pardo grew up in Colombia. But he's currently a professor at Johns Hopkins University School of Medicine in Baltimore, where I reached him by phone.
PARDO: I immediately made the connection that this may be related with Zika.
AIZENMAN: He moved fast to set up a study, getting not just Dr. Lizarazo but doctors at four other hospitals in Colombia to collect fluid samples - blood, saliva, urine and spinal fluid, from their Guillain-Barre patients. Pardo wants to analyze the antibodies these patients have produced because he thinks that at the same time that those antibodies are fighting the virus, they're also latching onto nerve cells that have a component that look like Zika.
PARDO: So in other words, the immune attack is confusing elements of the nervous system.
AIZENMAN: Confusing it for Zika. But that's just a theory. First, Pardo and his collaborators need to prove something more basic. They need to show these Guillain-Barre patients really did have Zika. The challenge, Zika virus can only be found in the blood during an active infection. But it might linger longer in other body fluids, which brings us back to researcher Beatriz Parra Patino at that lab in Cali. She's testing not just blood but all those other fluids. Pardo knew Parra from his medical school days in Colombia.
PARRA: Carlos just called me. Hey, what are you going to do with this? What is the plan? (Laughter).
AIZENMAN: Pardo arranged for funding to buy Parra the ingredients to do the testing. She's measuring them out with a pipette now, getting ready to drop them into the test tubes with the patient samples.
PARRA: I'm going to be quiet because I need to concentrate and put in the samples.
AIZENMAN: Then Parra pops the tray of tubes into a machine that will run them through various temperature cycles. The results will be ready in two hours. Thanks to this extraordinary mobilization of research, proving the Zika connection to Guillain-Barre could take just a few more weeks. Nurith Aizenman, NPR News, Cali, Colombia.
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