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Stopping Ebola Before the Virus Goes Viral

By Michael J. Armstrong

The Ebola outbreak in the Democratic Republic of the Congo (DRC) remains relatively small. The World Health Organization (WHO) reports 53 people with confirmed, probable, or suspected infections, including 25 deaths thus far.

But despite the modest numbers, other countries should not be complacent. It’s in everyone’s interest to help WHO and the DRC bring this outbreak under control in a timely manner. Ebola virus disease is not as contagious as influenza or measles. But it can still spread exponentially quickly.

Viruses Spread Exponentially

Many things grow along “linear” patterns. They increase by constant amounts each period. Consider a worker paid $15 per hour. They’ll have $15 after one hour’s work and $30 after two.

Other quantities grow “exponentially.” They increase by constant proportions. Imagine a $100 investment earning compound interest of 10 percent annually. It’ll be worth $110 after one year but $121 after two. That’s because the first year’s interest earns interest in the second year. The compounding lets $100 double to $200 in about 7.3 years, rather than 10.

Ideas can also spread exponentially quickly. Suppose each person reading this article sends it to several friends. And each friend sends it to several more, and so on. The total number of people seeing this article would then grow exponentially. That was the concept behind a popular 1980s shampoo commercial. It’s what “going viral” means: news spreading exponentially fast — like a virus.

The West Africa Epidemic in 2014

But Ebola infections are far more serious than internet memes or hair-care products. The 2014 Ebola outbreak in West Africa was the largest in history. It began with one sick person in Guinea, then spread into nearby Liberia and Sierra Leone.

Impoverished local health services could not cope, and wealthier countries were slow to help. Consequently, the disease spread exponentially quickly. From March to September 2014, the number of confirmed, probable, or suspected Ebola cases grew 2.35 percent per day on average. The total count roughly doubled each month.

Cumulative confirmed, probable, and suspected Ebola cases in West Africa from March to September 2014. Figure courtesy of Michael Armstrong, using data from the Centers for Disease Control and Prevention.

This meant that medical workloads also doubled monthly. Every patient needed quarantine and care. Each one’s recent contacts required tracing and monitoring; that was labour-intensive. The case growth became more linear in October and November as international aid caught up with the virus. But there were still about 160 new cases daily.

The daily patient additions finally began declining around December 2014, but the outbreak didn’t end until June 2016. It ultimately involved 28,616 patients, 11,310 of whom died. It also cost regional economies US$2.2 billion.

This potential for exponential spread and enormous tragedy explains why reacting quickly to Ebola is key. The healthcare demands and human costs are far smaller with 10 cases than with 10,000.

Cumulative confirmed, probable, and suspected Ebola cases in West Africa from March 2014 to April 2016. Red indicates exponential growth, orange indicates roughly linear growth, and blue indicates slower-than-linear growth. Figure courtesy of Michael Armstrong, using data from the Centers for Disease Control and Prevention.

Congo 2018

Fortunately, health agencies are responding quickly to the current outbreak in the DRC. Unlike West African countries, the DRC has experience handling Ebola. And an experimental vaccine developed in Canada and produced in the United States should help contain the disease.

But the outbreak is not yet under control. If it grows as it did in 2014, it could exceed 100 cases by late June and 200 cases before the end of July. Those figures can be smaller if health workers contain the disease — or larger if they uncover new infections in remote villages.

The Need for International Funding

Success depends on how quickly other countries send help. It’s easier and cheaper to handle 56 cases than 200. Neighbouring African nations are alerting their own health defenses. But WHO needs international funding for its US$57 million DRC campaign.

So far, Canada has promised CDN$2.5 million and the United Kingdom has pledged £5 million. The U.S. has sent US$1 million and promised up to US$7 million more. Conversely, the Trump administration recently dropped its global health security adviser. It also wants to cancel US$252 million the government previously set aside for future epidemics like this one.

Passengers wait to have their temperature taken by healthcare workers at Ngobila Beach in Kinshasa, Democratic Republic of the Congo, May 24, 2018. AP Photo/John Bompengo.

Germany, Italy and Norway are also contributing. Many other countries with large economies or high per-capita incomes remain conspicuously absent thus far. If world officials need added motivation, they can simply look to their phones. The DRC mines half the world’s cobalt, an ingredient in many rechargeable batteries. An epidemic (or fear of one) that shuts down the DRC’s economy could cripple world battery production. That could hinder the manufacture of everything from cellphones to electric cars.

Individuals can help too. They can donate to groups like Doctors Without Borders, the Red Cross, or the United Nations Central Emergency Response Fund.

We Must ‘Go to the Gemba’

With the world just a plane ride away, no one can hide from viruses. Airport thermometers and border restrictions help little, as neither measure addresses the problem’s source.

Consider a business analogy. If a company has quality problems, it could hire inspectors to test outgoing products. But they cannot catch every defect or fix the underlying cause. Alternatively, its spokespeople could deny that anything is wrong. But such Twitter noise merely lets the problem grow. 

Successful businesses instead “go to the gemba” — the scene of the action. They find the problem’s source and help workers there solve it. That is what the world should do to beat the DRC’s Ebola outbreak. Helping them stop it early “over there” helps protects us all “over here.”

This article is republished with permission from The Conversation.

Michael J. Armstrong is an associate professor of operations research in the Goodman School of Business at Brock University. He uses mathematical models to analyze historic battles, such as Gettysburg, Balaclava, and Coral Sea; and to understand modern missile combat, as in naval warfare and Israeli rocket defenses.