Before the emergence of the new coronavirus, which causes a disease called COVID-19, the world has already confronted a strain of coronavirus starting in 2002, known as severe acute respiratory syndrome (SARS) coronavirus (SARS-CoV). And prior to that, only 12 other animals or human coronaviruses were known.

In a clinical microbiology review published in 2007, members of the American Society of Microbiologists cited SARS as the first known major pandemic caused by a coronavirus. They have also raised red flags about the possible reemergence of SARS and other novel viruses from animals.

Origin of SARS

The disease emerged in late 2002, when an outbreak of acute community-acquired atypical pneumonia syndrome was first noticed in the Guangdong Province, China.

According to the review, the exposure of the first human cases of the disease to wild game animals which suggested that SARS-CoV is zoonotic in origin. It cited palm civets and horseshoe bats, which are common in animal markets in Guangzhou, as the source of the contagion.

During the epidemic in 2003, 8,096 cases with 774 deaths had occurred in over 30 countries among five continents.

Red Flags

Since 2004, no known cases of SARS have been reported, according to the Centers for Disease Control and Prevention.

However, in the review, scientists warned that since coronaviruses are well known to undergo genetic recombination, they may lead to new genotypes and outbreaks.

"The presence of a large reservoir of SARS-CoV-like viruses in horseshoe bats, together with the culture of eating exotic mammals in southern China, is a time bomb."

They advised that with the possibility of the reemergence of SARS and other novel viruses from animals or laboratories, preparedness should not be ignored.

SARS vs COVID-19

According to the World Health Organization (WHO), the fatality rate--percentage of people who contract the coronavirus and then die--of COVID-19 is 3.4 percent. But the rate varies on the countries and the moment: for instance, fatality is 0.6 percent in South Korea, 4.4 percent in Iran, between 3.6 percent and 6.1 percent in China and around 4 percent in Italy.

Dr. Norman Swan, host of the ABC's Coronacast, explained, "COVID-19 has two or three times the transmission rate [compared with the flu] ... and the case fatality rate for COVID-19 is around 30 times higher than the flu."

The COVID-19 appears to be less deadly than SARS, which killed around 10 percent of people who became infected but the SARS outbreak was contained within about six months.

Meanwhile the COVID-19 outbreak is only a few months old at this point. As of writing, there are already more than 380,000 confirmed COVID-19 cases around the globe with more than 16,000 deaths. It is also worthy to note that more than 100,000 COVID-19 patients have recovered from the deadly disease.

Because the latest coronavirus outbreak is still unfolding globally, experts don't have the data about the virus' true fatality rate.

According to Timothy Sheahan, an epidemiologist at the Gillings School of Global Public Health at the University of North Carolina, structurally, the new coronavirus is similar to SARS, with the two viruses sharing about 80 percent of their genomes.

Since it first emerged in Wuhan, the new coronavirus does not have many significant changes, based on genetic analyses. It's the nature of viruses to mutate to avoid dying out after being pass from person to person and spread into new geographical locations.

"It's basically Darwinian evolution, where it's survival of the fittest," Sheahan said. "But if you already have a virus that is good at human-to-human transmission and good at replicating in a person, there's no reason for it to get more fit."

As experts warned in 2007, COVID-19 may have evolved from SARS-CoV and until we do something about it, history would repeat itself.