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Why isn’t there a better test to detect Ebola?

June 5, 2015 at 6:35 PM EDT
In Sierra Leone, health care workers use infrared thermometers to monitor those who may have come in contact with Ebola. It takes 21 days before they can be deemed virus-free. That’s why researchers are trying to create more precise infection detection. In the second in the series, science correspondent Miles O’Brien looks at the efforts to create faster, more reliable testing for the virus.

JUDY WOODRUFF: We continue now our series of reports on Ebola by science correspondent Miles O’Brien.

Tonight, Miles looks at efforts to create faster, more reliable testing for the virus.

MILES O’BRIEN: In the dusty, crowded alleys of this market town near Kambia, Sierra Leone, people stick close together and rely on each other. Here, there is no mistaking where Ebola has taken its deadly toll. The quarantines are marked by rope and plastic bags, enforced by soldiers, and monitored by people like this man.

DR. PATRICK OTIM, World Health Organization: I owe it to the people of Sierra Leone to give any help that I can.

MILES O’BRIEN: DR. Patrick Otim is an epidemiologist, a disease detective from South Sudan, a volunteer for the World Health Organization. He helps by doing these crucial house calls.

DR. PATRICK OTIM: Where we can closely monitor them, so that the moment the person becomes symptomatic, we’re able to detect that and we pick them out from the community.

MILES O’BRIEN: Eleven days ago, the mother of these two boys, 3 and 5, was transported to an Ebola treatment center. The virus claimed her life a few days later. Just yesterday, their father also got sick and was also taken away. No one here, the boys and their aunt and uncle, will be deemed Ebola-free until 21 days after they were in contact with someone carrying the virus and showing symptoms.

MAN (through interpreter): They say that’s how they have the contain this outbreak. We wish to do it that way. But it’s been really hard for me and my family.

MILES O’BRIEN: For 11 days, they have been unable to leave here, and now they are in need of supplies, food and water. The delivery is carefully placed just outside the cordon. Everyone, including the boys, pitches in to get it inside. We, too, must keep our distance as we speak with them.

MAN (through interpreter): We’re not sure about what happens tomorrow, but for, now we’re, not feeling any illness at all.

MILES O’BRIEN: Using an infrared thermometer, they check for fevers; 37 degrees Celsius is 98.6 Fahrenheit. So far, so good.

But then we get a scare. It’s a 102-degree Fahrenheit fever. The second reading is no better. Then a new infrared thermometer, still high, so finally they pass along a traditional thermometer. With it tucked inside the boy’s armpit, we all hold our breath.

DR. PATRICK OTIM: And, usually, if we detect any fever, and then immediately for anyone in a quarantine house, the moment they have a fever, we have to take them for testing.

MILES O’BRIEN: The final reading is borderline. But, remember, the boy had been toting water bottles in the hot sun, so Dr. Otim doesn’t think drastic action is warranted. But he vows to give both boys extra scrutiny.

DR. PATRICK OTIM: The moment they have any other symptoms, just fever or a headache, joint pain or sore throat, then you need to be very proactive.

MILES O’BRIEN: It’s an educated guess, but a guess just the same.

Basically, you’re fighting Ebola with a thermometer…


MILES O’BRIEN: … which seems like you could do — we could do better in this day and age, right?

DR. PATRICK OTIM: Yes. Yes. Yes. It seems we could do better, but, unfortunately, that’s all we have for now.

MILES O’BRIEN: So, on the front lines, the simple thermometer remains the primary, really the only way to sort out people who might have Ebola, and is, of course, terribly inaccurate and doesn’t differentiate between Ebola and any number of other diseases.

What health care workers tell us time and again is they need something in between the thermometer and the cumbersome and expensive genetic testing. Not far from the cordoned home, an old customs building near the Ghanaian border is now a makeshift genetic testing facility. Blood from the boys’ father comes here. Workers handle the samples with great care and multiple safeguards.

WOMAN: This bench is the extraction bench.

MILES O’BRIEN: The genetic test is called polymerase chain reaction, or PCR, where machines repeatedly heat and cool the blood sample, causing the RNA in the virus to replicate itself over and over again. It’s a precise way to determine if a person has Ebola, but the machines are expensive, complex and they don’t provide quick answers.

WOMAN: And if you look at it, it’s almost the same curve as this patient that is positive.

MILES O’BRIEN: While they wait for results, the father is taken to an Ebola treatment center run by the International Medical Corps. Doctors here must assume and dress for the worst. And, unfortunately, in this case, that is warranted. The genetic test confirms the father has Ebola.

The grim verdict comes 48 hours after the ambulance took him away from his boys. And with Ebola, any delay can be deadly. It’s either two extra days for the virus to spread or it means a person without Ebola might wait two days near patients who are very sick and extremely contagious.

In Kenema, a few hundred miles away, they’re using a prototype Ebola test that is fast and simple.

MAN: Sample for Ebola.

MILES O’BRIEN: The rapid test was developed by a Colorado company called Corgenix. Instead of looking for genetic material, the Corgenix test looks for antigens, proteins on the Ebola virus surface. It’s not as accurate as the genetic technique, but it is as easy as a home pregnancy test.

Two lines on the left means positive for Ebola, one line on the right negative, no Ebola. It is a low-tech solution, to be sure. But, as it turns out, low tech is the cutting edge in the world of rapid diagnostics.

LEE GEHRKE, Massachusetts Institute of Technology: It’s very simple, requires no refrigeration, no power, no special training.

MILES O’BRIEN: At MIT, biologist Lee Gehrke leads a team that is creating, assembling and shipping do-it-yourself diagnostic kits designed to give health workers in the field the ability to make their own tests for multiple pathogens at once, Ebola, yellow fever and dengue, for starters.

The solutions contain antibodies to these diseases, our natural defenses. They have found a novel way to color-code them using gold nanoparticles of varying size. So, whichever antibodies are engaged in battle with the disease will leave telltale proof of what ails a patient.

It’s all open-source, no patents. Gehrke says the test costs $5 now and could get cheaper.

Why haven’t we had an easier test for Ebola sooner?

LEE GEHRKE: That’s a very important question. And I think, unfortunately, part of the answer is economics. It boils down to whether there are markets for these devices because many of these viruses appear as hot spots and then go away. There’s no constant market.

MILES O’BRIEN: But an entrepreneur in Cambridge with MIT and Harvard lineage believes there is a market for a device that strikes a balance between low tech and high accuracy.

ANITA GOEL, CEO, Nanobiosym: Drop of blood here to the chip.

MILES O’BRIEN: Anita Goel is CEO of a startup called Nanobiosym. Her device is called Gene-RADAR.

ANITA GOEL: So, now what is happening is, it’s processing the blood and it’s getting ready to get the RNA of the virus. Once it gets that, then it’s going to start copying it.

MILES O’BRIEN: She claims the device is nearly as accurate as traditional genetic testing, but that it will be 10 times cheaper. The idea is to detect the Ebola virus before it reaches the threshold when symptoms appear.

ANITA GOEL: Whether they have the Ebola virus or not and quantify what that viral load is.

MILES O’BRIEN: It sounds great, but it isn’t ready for prime time yet, not enough proof that it works. MIT biologist Lee Gehrke is skeptical.

LEE GEHRKE: The disadvantage with fancy technologies is that they are fancy technologies. And the question is, if they’re sent to these countries, if they break, what will happen? Can they be fixed?

MILES O’BRIEN: A good question in places like Kambia, where the poverty is crushing. For now, Dr. Otim and colleagues keep visiting the boy and his family once, sometimes twice a day, wielding only thermometers.

MAN (through interpreter): I feel very confident that we will survive this. We will pull through. We are really optimistic that we will end up free of Ebola.

MILES O’BRIEN: Sadly, his brother, the father of the boys, died, leaving them orphaned. Their quarantine clock is reset, another 21 days of constant surveillance and temperature checks, waiting to learn if they have been spared.

But, long after we leave, we get the word they’re all OK. Maybe next time, the tools will be better and the answers will come sooner.

Miles O’Brien, the PBS NewsHour, Kambia, Sierra Leone.

JUDY WOODRUFF: Miles’ next two reports in his Ebola series air next week. Tune in Thursday and Friday.