SARS-2 began with a few infections in Wuhan but quickly got out of control.

December 26, 2019. Dr. Jixian Zhang, a doctor at the Hubei Provincial Hospital in Wuhan, China, reports a troubling trend. There’s been a sudden surge in cases of severe acute respiratory syndrome, or SARS. By the end of the month, there are 104 SARS patients. And there have already been 15 deaths. 

At first, the Chinese health authorities are reluctant to raise any alarms. But patients keep being admitted, and the doctors are soon overwhelmed. In January, Beijing sends teams of expert epidemiologists to study the outbreak and orders local governments to close schools, businesses, and other public spaces. By January 25, nearly all of China shuts down to stop the spread of the disease.

On January 27, the Chinese Center for Disease Control identifies the culprit behind all this chaos: a new strain of coronavirus, dubbed SARS-CoV-2 or SARS-2 for short. In a few months, it will transform the world.

The key message here is: SARS-2 began with a few infections in Wuhan but quickly got out of control.

The first people to catch SARS-2 were most likely infected at the Huanan Seafood Wholesale Market, a “wet market” in the heart of Wuhan. Like many markets around the world, this bustling bazaar offers freshly butchered wildlife. This close contact between humans and animals makes it easy for diseases to jump from one species to another. 

The SARS-2 virus likely originated in bats. However, it only became a threat to humans when it evolved the ability to infect people. This small mutation enabled it to spread among human populations with incredible speed. This type of person-to-person transmission is dangerous because the virus causes a sometimes deadly disease named COVID-19. 

Scientists are still studying exactly how COVID-19 works. Its varied symptoms include cough, fever, fatigue, and – strangest of all – anosmia, the loss of one’s sense of smell. For some patients, the virus attacks the alveoli, a part of the lungs responsible for oxygen exchange, which can lead to severe breathing problems and, ultimately, death. Around 50 percent of patients display no symptoms at all, while an estimated 1 to 1.2 percent of people die from the virus.

Since its initial outbreak, SARS-2 has spread to nearly every country on earth. Along the way, governments have tried to control the spread with rigorous regulations while everyday people have adapted their work and social lives to accommodate the new threat. Still, as of July 1, 2020, more than a million people have died from the disease worldwide, and there’s no end in sight.