COVID-19 infection
Nucleic acid sequences of viruses taken from pangolins have been found to be a 99% match to those of the virus which causes COVID-19, SARS coronavirus 2 (SARS-CoV-2) and is responsible for the 2019–20 coronavirus outbreak. The working theory of researchers in Guangzhou, China is that SARS-CoV-2 originated in bats and, prior to infecting humans, was circulating among pangolins. The illicit Chinese trade of pangolins for use in traditional Chinese medicine is suggested as a vector for human transmission. Pangolins were eventually ruled out as the definitive source, namely the bridge that the virus used to jump from bats to humans.
Two strains of the virus have caused outbreaks of severe respiratory diseases in humans: SARS-CoV, which caused an outbreak of severe acute respiratory syndrome (SARS) between 2002 and 2003, and SARS-CoV-2, which since late 2019 has caused an outbreak of coronavirus disease 2019 (COVID-19). There are hundreds of other strains of SARSr-CoV, all of which are only known to infect non-human species: bats are a major reservoir of many strains of SARS-related coronaviruses, and several strains have been identified in palm civets, which were likely ancestors of SARS-CoV.
The SARS-related coronavirus was one of several viruses identified by the World Health Organization (WHO) in 2016 as a likely cause of a future epidemic in a new plan developed after the Ebola epidemic for urgent research and development before and during an epidemic towards diagnostic tests, vaccines and medicines. The prediction came to pass with the 2019–20 coronavirus outbreak.
In the SARS outbreak of 2003, about 9% of patients with confirmed SARS-CoV infection died. The mortality rate was much higher for those over 60 years old, with mortality rates approaching 50% for this subset of patients.
