Wednesday 16 November 2022 06:05 PM Climate change is 'driving the spillover of pathogens from bats', study says trends now
Changes to land and climate caused by humans are to blame for the ongoing spread of dangerous pathogens from bats, a new study says.
The international team of authors have presented a stark warning for humanity if we want to avoid another viral pandemic similar to Covid.
The experts studied 25 years of data on land-use change and bat behaviour in subtropical Australia, between 1996 and 2020.
A scarcity of food for bats and the loss of their natural habitats, partly triggered by human activity, causes the movement of bats to more populated areas, they say.
This leads to spillover of Hendra virus – an infectious bat-borne virus – to its intermediate host, the horse, from which it can jump to humans.
Therefore, preserving and restoring natural habitats for bats could keep them away from such populated areas – and help avoid another lethal pandemic.
The black flying fox (Pteropus alecto) is the species most likely to excrete Hendra - an infectious bat-borne virus. Pictured, a black flying fox (Pteropus alecto) takes flight in an urban flying fox roost in Queensland, Australia
The researchers noted a high rate of spillover events during the Australian winter. A spillover is a virus's jump from another species
The new study was led by Raina Plowright at Cornell University in Ithaca, New York, and published today in Nature.
It refers to 'spillovers' (a virus's jump from another species), which contrasts with a 'spillback' (a virus going from humans back into wild animals).
SARS-CoV-2 (the virus that causes Covid), SARS-CoV-1, Nipah, Hendra and possibly Ebola are all examples of viruses that fatally spill from bats to humans, sometimes after transmission through an intermediate host.
'Zoonotic spillover is the transmission of a pathogen from a non-human vertebrate to a human,' say Plowright and colleagues in their paper.
'Spillovers of viruses from bats have resulted in the emergence and spread of viruses in the human population.
'We observed rapid changes in bat behaviour that coincided with the emergence of Hendra virus.'
The black flying fox (Pteropus alecto) is the species most likely to excrete Hendra virus, although the virus infects other bats in the Pteropus genus too, such as the grey-headed flying fox.
The Hendra virus is not fatal to bats, nor does it cause 'discernible disease' in bats, but it can cause a highly fatal infection in horses and humans.
Researchers say it has a case fatality rate of 75 per cent in horses (with 84 fatalities documented) and 57 per cent in humans (four fatalities documented).
Amazingly, the Hendra virus has probably circulated in bats far longer than Europeans have occupied Australia, they add.
The grey-headed flying fox, a bat species native to Australia, are hosts of the Hendra virus, a deadly virus capable of spreading to humans. Pictured, a black flying fox (Pteropus alecto) hangs on a branch in an urban
