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How Fast Can An Outbreak Be Detected?

Mar 23, 2018

How do you stop an outbreak from becoming an epidemic?

You catch it early, of course – a task that requires rapid response and coordination. That's a tough mission in any country, especially a nation lacking in resources.

Uganda is proving that it's absolutely doable, even in a low-income country.

Since 2010, a first-of-its-kind program has helped Ugandans quickly detect and respond to deadly viral hemorrhagic fevers (VHFs) – like Ebola, Marburg, Rift Valley fever and Crimean-Congo hemorrhagic fever. It's run by the Ministry of Health, the Uganda Virus Research Institute and the U.S. Centers for Disease Control and Prevention (CDC), which started up the endeavor.

Because of the program, Uganda has cut the time it takes to confirm an outbreak from an average of two weeks to an average of 2.5 days.

"Informally, it was probably a lot longer than two weeks before," says Trevor Shoemaker, the CDC epidemiologist who led the program for six years. "It was maybe a three- [or] four-week average, but we had to go by what was published in literature."

Regardless, early detection and responses have led to a "significant decrease in the overall intensity and duration" of outbreaks, according to a CDC report published Wednesday in The Lancet Infectious Diseases.

"Days really matter," says Dr. Tom Frieden, president and CEO of Resolve to Save Lives and director of the CDC from 2009 to 2017. "Every hour and day is more time the disease has a chance to spread within a community and move to other communities."

Uganda got a bitter taste of that in 2000, when 425 cases of Ebola erupted in Gulu district. It was the largest Ebola outbreak ever recorded – until 2014, when the virus killed more than 11,000 people in West Africa and was carried to the U.S. and Europe.

So Ugandans were aware of these devastating diseases. But protocols for sample collection, transportation and diagnosis were mostly for HIV and tuberculosis. Also, exiting systems were only being used on an "as-needed" basis. No operations were in place to constantly monitor and address viral hemorrhagic fevers specifically.

But the threat of more outbreaks was constant, because the diseases exist in Uganda without outside transmission. So in 2010, the CDC sent Shoemaker to help the Uganda Virus Research Institute (UVRI) and the Ministry of Health improve protocol for effective surveillance, early detection and rapid response.

Shoemaker and UVRI scientists went to districts to help surveillance officers, hospitals and health centers identify suspect patients. If the patients met certain criteria, these health-care workers would collect a sample and send it not to a diagnostic lab in another country as before, but to UVRI in Uganda, where Shoemaker had helped build an isolated lab specifically to test for these fevers. So they would no longer need to wait two to four weeks for specimen results. Instead, they could get a confirmation in one to three days usually, then launch a response within 24 hours.

The accomplishments of UVRI and CDC influenced another new initiative to set up a pilot program in Uganda in 2012. The pilot, which would soon become the basis for the Global Health Security Agenda significantly expanded the country's ability to safely transport even the most transmissible types of specimens, not just HIV and TB. Text-message updates also allowed lab staff to track the samples as they made their way on motorcycles and through the national postal service to UVRI's improved facilities.

The Global Health Security Agenda formally launched February 2014 and is now a partnership of almost 50 nations and organizations, including the CDC. It aims to improve the capacities of all countries to prevent, detect and respond to infectious disease threats.

According to Shoemaker, this kind of collaboration – between a U.S. agency, the most renowned medical research facility in Uganda, a willing government and a globe-spanning partnership – is what has underpinned Uganda's success with viral hemorrhagic fevers.

Shoemaker returned to the U.S. in 2016, and UVRI and the Ministry of Health have taken over 100 percent of the program's management, though the CDC remains a dedicated partner, providing technical support and diagnostic supplies.

The program is carrying on with continued success. So much so, that last fall, Uganda was able to control a Marburg virus outbreak while hosting the annual high-level ministerial meeting of the Global Health Security Agenda. UVRI diagnosed the first confirmed case, then public authorities promptly identified any individuals who might have come into contact with the known cases.

Jennifer Nuzzo, a senior scholar at the Johns Hopkins Center for Health Security and director of the Outbreak Observatory, attended the meeting. She described the outbreak response as "remarkable" and a "well-oiled machine."

"Uganda really does show what's possible in establishing a strong tracking system to find and stop outbreaks when and where they emerge," she said, adding that Ugandan specialists are now sharing their best practices with the U.S. and other global health security actors.

Nuzzo did raise one concern, though – the amount of time it took health workers to recognize the initial cases as Marburg. The weak link in Uganda and most places, she says, is on the health-care side.

Shoemaker says that's because early-stage cases don't always look like Ebola or Marburg or other viral hemorrhagic fevers.

"But if you can catch these within the first two or three cases, I think that's still extremely ahead of where you need to be in order to have an effective response," he said.

That's why Shoemaker, Nuzzo and Frieden all stress the importance of continued investment from the international community in health security.

"We know what it looks like when countries don't have capacities, like what we saw in West Africa. It's not just a problem for those countries; it's a problem for the rest of the world," Nuzzo said. "Preparedness is always cheaper than response."

Joanne Lu is a freelance journalist who covers global poverty and inequity. Her work has appeared in Humanosphere, The Guardian, Global Washington and War is Boring. Follow her on Twitter @joannelu.

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