COVID-19 WHEN VIRUSES CROSS OVER

AS COVID-19 spreads worldwide, humanity faces a crisis on a previously unimaginable scale. But, like many other recent outbreaks, this disease began as a virus in animals that jumped across to people. Data suggest, in fact, that about 70 per cent of novel infectious human diseases originated in other animals. A surprising number, including many of the deadliest – such as rabies, SARS-CoV-2 (coronavirus), SARS (severe acute respiratory syndrome), Ebola, Marburg, Hendra and lyssavirus – appear to have come from bats.

Some move directly from these flying mammals to people. Australian bat lyssavirus, for example, can spread to people from bat saliva, causing an often fatal rabies-like disease. Discovered in 1996, it is extremely rare: only three cases are known,