Coronaviruses are a large family of single stranded RNA viruses that cause diseases in
animals and humans. In humans, the viruses usually cause mild to moderate upper-
respiratory tract illnesses such as the common cold. In the last two decades, more
aggressive coronaviruses have emerged that are capable of causing serious illness and even
death in humans. These include SARS-CoV, MERS and now SARS-CoV-2.
Human coronaviruses were first characterised in the mid-1960s and they are mostly
considered to be responsible for causing upper respiratory tract infections in children. In
1965, scientists DJ Tyrrell and ML Bynoe were the first ones to identify a human
coronavirus, which they isolated from the nasal washing of a male child who had symptoms
of common cold. They termed the strain B814 and later in 1968 the term “coronavirus” was
accepted. These viruses are named so because of spikes found on their surface that give
them the appearance of a crown when looked through an electron microscope.
In animals, coronaviruses can cause diarrhea in cows and pigs and upper respiratory tract
disease in chickens. The first coronavirus was isolated in 1937 and it was the infectious
bronchitis virus (IBV) that caused respiratory disease in chickens.
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