The dying at the tin-roofed clinic in the rural Kono district of Sierra Leone comes at a ruthless pace. In the first two weeks of October, 20 out of the 22 patients who sought treatment for Ebola at the center died of the disease. That fatality rate, high even by the lethal standards of Ebola—the virus in the West African outbreak is killing 70% of people it infects, according to the World Health Organization (WHO)—could easily be brought down, says Dan Kelly, an infectious-disease doctor at the University of California, San Francisco who is currently in Kono with the Wellbody Alliance, a medical nonprofit he set up eight years ago. “The ability to test for Ebola, to test quickly, has become ever more important,” says Kelly, who believes the high death toll at the Kono clinic was due in part to the fact that there is no place to test for Ebola in the entire district. Instead, blood samples from suspected Ebola patients have to be sent to the capital over rutted mud roads that are often washed out by rain. By the time the results come back, it is often too late. “Even if we have the best treatments available, without a timely diagnosis people are still going to die,” says Kelly. “It doesn’t even matter if we get a lifesaving drug. If we can’t make the Ebola diagnosis, people won’t get treatment, and they will die.”
Work out quickly who does and does not have Ebola and you’ll go a long way toward stopping the outbreak that has killed at least 4,877 and infected thousands more. Right now, especially in West Africa, that simple proposition feels like some far-off fantasy. In Guinea, Sierra Leone and Liberia, the three countries with the most cases, the need for rapid test results far outpaces capacity, increasing the burden on already overwhelmed Ebola treatment centers. Staff can end up treating people who are suspected to have Ebola but later end up testing negative. The lack of rapid testing also means that patients often aren’t getting treatment until the disease has ravaged their bodies beyond repair and they have already infected friends and family. “If patients are promptly diagnosed and receive aggressive supportive care, the great majority, as many as 90%, should survive,” wrote the global health expert Paul Farmer in a recent issue of the London Review of Books.
Even in a top U.S. laboratory it can take up to eight hours to process a blood sample for Ebola through an expensive and complex polymerase chain reaction (PCR) test. In Liberia, Guinea and Sierra Leone, several factors greatly slow down the time between test and result: patchy communications networks, poor transportation and unreliable power supplies.
The U.S. Centers for Disease Control and Prevention and the U.S. military have helped by setting up, staffing and equipping four additional labs over the past six months—Liberia now has a total of five, Sierra Leone four and Guinea three—but capacity is still limited to about 100 tests per lab per day, not nearly enough to cope with an epidemic that could grow to 10,000 new cases a week by December, according to WHO. Health care workers on the ground say that more PCR labs are urgently needed. “Crushing this epidemic means getting 70% of the population with Ebola into isolation and care,” Kelly says. That could be achieved, he believes, by putting a PCR lab in each of Sierra Leone’s 12 districts and in Liberia’s 15 counties. Ideally, Guinea, where the outbreak started, would have one for each of its eight regional capitals as well. By that measure, the region has a third of the number of PCR labs it needs.
The challenges don’t stop there. Testing can create risks even as it offers solutions. To obtain enough blood for a PCR test, medical personnel must draw blood from patients, a potentially lethal process for caregivers. “Taking samples is extremely dangerous,” says Dr. Estrella Lasry, a tropical medicine adviser in Liberia for Doctors Without Borders/ Médecins Sans Frontières (MSF). “Sometimes the patients are cooperative, but sometimes they are combative. At any time you risk a needlestick injury that can expose you to the virus.” Sample takers must be dressed in full protective gear, including multiple layers of gloves, making the process of drawing blood even more difficult—and more painful for the patient.
And then there’s the threat of patients without Ebola being exposed to patients with the disease. Lasry estimates that 30% to 50% of people coming into the MSF clinics end up testing negative for Ebola and instead have other illnesses like malaria that have similar early symptoms. All those being tested for Ebola must wait in holding centers for their results, to ensure that they don’t have an opportunity to infect others back at home if they test positive. But that period of waiting creates further risk: patients with other illnesses mix with patients with Ebola, increasing the chances of transmission.
Like most health care workers involved in the fight against Ebola, Kelly hopes researchers can develop a test that could give rapid readings at a clinic and wouldn’t require trained technicians to interpret the results. “It would be a game changer if you could immediately identify patients needing quarantine from those who do not,” he says.
Several versions of so-called point-of-care rapid diagnostic tests are already in development, but while some are at the testing stage, it is not clear when they can actually be used on the ground. One U.S. company, Corgenix, received a $2.9 million grant in June from the National Institutes of Health to perfect its prototype, a pregnancy-test-style slip of paper that reveals a dark red line within 15 minutes when exposed to a drop of Ebola-infected blood. Instead of needles and syringes, test takers need only a pinprick to get the sample, much like an insulin test for diabetes patients.
These tests, which could cost anywhere from $2 to $10 each (PCR tests average about $100 each) would have applications far beyond West Africa. They could be used in airports to confirm whether someone with symptoms has Ebola, and they would allow U.S. and European hospitals to do their testing on-site instead of sending samples out to facilities that house expensive PCR systems. If the Corgenix test had been available, says one of its lead researchers, Robert F. Garry, a professor of microbiology and immunology at Tulane University School of Medicine in New Orleans, it might have helped doctors diagnose Amber Vinson, an American nurse infected with Ebola, before she boarded a flight from Cleveland to Dallas on Oct. 13. “This is a test that could be used anywhere you would want to test for Ebola,” says Garry. “Anyone could use it, and anyone could read it.” (The Corgenix test, like the PCR, can only identify Ebola at the onset of symptoms, usually eight to 10 days after exposure. So far, no one has been able to conceptualize a test that would work any earlier.)
With the epidemic worsening in West Africa, medical staff in Ebola-hit countries can’t afford to wait for companies like Corgenix to bring their product to market. Kelly has been hearing about better, faster tests almost since he started working on Ebola in June, and he fears that pinning hopes on future technologies undermines efforts to ramp up testing facilities. “Everyone says they have a new test, but at this point I’m like, ‘Show me the money,’” says Kelly. “We already have a working technology that is deployable. Get me a PCR in every district capital, and then we can start talking about faster tests.”
More help, even if it’s slow and insufficient, may be on the way. The U.S. Department of Defense is considering a request from the Liberian government for three more diagnostic labs in Liberia, and Garry says he has people in every U.S. time zone working “as fast as humanly possible” to get the Corgenix test out. “We want to make an impact on this outbreak,” he says. “With enough tests, we can shut it down.” Without them, Ebola may be here to stay.
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