COVID-19 is a disease caused by a coronavirus (CoV) named SARS-CoV-2. They are called coronaviruses because of their characteristic ‘corona’ (crown) of spike proteins that surround their lipid envelope. Coronavirus infections are common in both animals and humans, and some strains of coronaviruses are zoonotic, meaning they can be transmitted between animals and humans.
In humans, coronaviruses can cause illnesses ranging from the common cold to more severe diseases such as Middle East Respiratory Syndrome (caused by MERS-CoV), and Severe Acute Respiratory Syndrome (caused by SARS-CoV). Detailed investigations have demonstrated that MERS-CoV was transmitted from dromedary camels to humans and SARS-CoV from civets to humans.
In 2019, a new coronavirus was identified as the causative agent of human cases of pneumonia by Chinese Authorities. Since then, human cases have been reported by almost all countries around the world and the COVID-19 outbreak has been declared a pandemic by the World Health Organization (WHO). Investigations are on-going to identify the origin of the virus and a possible animal reservoir. For up-to-date information on human health, situation consults the WHO website.
The current pandemic is being sustained through the human-to-human transmission of SARS-CoV-2. Current evidence suggests that SARS-CoV-2 emerged from an animal source. Genetic sequence data reveals that the closest known relative of SARS-CoV-2 is a coronavirus circulating in Rhinolophus bat (Horseshoe Bat) populations. However, to date, there is not enough scientific evidence to identify the source of SARS-CoV-2 or to explain the original route of transmission to humans, which may have involved an intermediate host.
Investigations led by the WHO, and in close cooperation with China, are underway to find the source, to determine how the virus entered the human population, and to establish the potential role of animals in this disease. Recent findings confirmed that infections in mink can result in spill over back into the humans. This is further discussed below.