A patient presents at an emergency department somewhere in the world. They are feverish and vomiting. Doctors suspect it is influenza, but they are wrong.
When the outbreak of a virulent new disease such as the coronavirus is identified, the starting gun is fired on a vast, multimillion-dollar international effort to try to contain it.
But nothing can start before a health professional determines that, against the odds, they are confronting something exceptional. “You need to work through that process, establish that this is an out-of-the-ordinary disease and say, let’s do lab tests on it,” says Jonathan Quick, an adjunct professor of global health and author of The End of Epidemics.
Sometimes the signs are clear: health workers becoming infected, or patients growing sicker or dying faster than expected.
Other cases rely on a hunch. In 2003, the Italian specialist Carlo Urbani was asked to examine a patient in a Vietnamese hospital with symptoms of influenza. Urbani saw a different pattern. He commissioned tests, reinforced infection controls around the patient and alerted the World Health Organization.
A global alert for a virus named severe acute respiratory syndrome (Sars) was declared 12 days later. Urbani died from it the following month.
Advances in medical science by the late 1960s led some experts to declare that humanity had conquered infectious diseases. It was wishful thinking. Two decades into the 21st century, viruses are breaking out more frequently than in the past, data shows.
One factor is that humans are spreading into territories we have never lived in before, bringing us into contact with animal populations carrying diseases our bodies never learned to fight.
The 2014 Ebola outbreak was formally identified more than two and a half months after it was first detected. The 2015–16 epidemic of Zika,the mosquito-borne virus that led to 3,000 severe birth defects, took 37 days. The disease always gets a head start, and not just for biological reasons. An epidemic may be a medical phenomenon, but it is social and political too.