*1.2. The Highly Pathogenic Coronaviruses*

The other three coronavirus species are zoonotic in origin and have been associated with severe, life-threatening respiratory disease outbreaks. The first was Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV), leading to an outbreak in 2002 and 2003 in Guangdong Province (China). It was initiated by a zoonotic transmission (likely from bats via palm civets), and infected 8098 people, leading to an overall case fatality rate of 11% [11]. This was followed by the Middle East Respiratory Syndrome Coronavirus (MERS-CoV) outbreaks in 2012 (Saudi Arabia) and 2015 (South Korea), probably originating from bats via dromedary camels. Unlike SARS, the infection with MERS-CoV is generally mild in healthy individuals, but very severe in patients with underlying comorbidities, such as chronic lung diseases, diabetes, renal failure and a weakened immune system. It infected 2994 people, with a case fatality rate of 34% [12]. The third zoonotic coronavirus is the recent 2019 novel coronavirus SARS-CoV-2, which originated in Wuhan (South China). The recent outbreak of the SARS-CoV-2 has been linked to the Huanan Seafood Wholesale Market in Wuhan. This market sold a variety of both live and dead animals of wild and domesticated origin in over one thousand stalls. There is some debate about whether this market is the true origin of the outbreak, but it certainly was one area of early transmission in the 2020 pandemic.
