In its daily report on incidences of the Ebola virus, the World Health Organization quietly published today a disturbing statistic – more than 10,000 people are believed to have died from Ebola in West Africa in the outbreak that started last year. As the rate of new Ebola infections continues to decline (Liberia has had no new infections for several weeks) reaching this death total punctuates an epidemic that took West Africa to the brink of collapse, and had the entire waiting to see if they were next.
Research has shown that humans have difficulty comprehending large numbers, and it’s even harder to think about each number of a total being a living, breathing human being who had his or her own dreams, sadness and joy. According to the latest U.S. Census, more than 80% of American cities and towns have less than 10,000 people living in them. Think of your hometown, or that suburban city, or even your high school or university. That many people have died in just three countries from one epidemic.
On the scale of epidemics, this outbreak of Ebola is mercifully small. It never reached “pandemic” status, meaning it never became a global epidemic, and seems not so deadly when compared to the world’s assorted outbreaks of flu, such as the 2009 “swine flu” outbreak that killed nearly 300,000 people, or the 1918 flu pandemic that killed more than 75,000,000 (nearly 5% of the entire human population). This disparity comes from Ebola’s low contagiousness – unlike flu, it cannot spread through the air. In fact, Ebola comes in near the bottom of lists of diseases’ basic reproduction rates, or number of people each infected person will go on to infect in an unvaccinated population. An Ebola victim will infect 2 people on average, while individuals with the once-common childhood diseases mumps or pertussis will infect 12-17 people on average.
What Ebola lacked in numbers, it made up for in lethality, though. The 10,000 deaths came out of a total of about 24,350 known infections, meaning Ebola killed about 40% of people who caught it. The heroic interventions of local and international medical professionals brought this epidemic’s fatality rate down from the 80-90% death rate observed in other outbreaks. Ebola has one of the highest fatality rates ever observed in a human disease. Even the 1918 flu pandemic had a fatality rate of only 2.5%.
It’s still too early to tell what the world will learn from this outbreak. There was a lot of fear, a lot of incompetence and a lot of tragedy. But there was also a lot of bravery, survival and determination to keep going. Humanity has recovered and thrived after much worse, and hopefully the health knowledge and infrastructure put in place in West Africa will prevent another epidemic from spreading so violently. But as epidemiology professor Tara Smith so eloquently wrote in an article last October, “We will never be free of epidemics.”