With Covid-19 still an issue of global concern, for an international group of researchers, the focus is on preventing the next pandemic – and after studying more than two decades of data on bats, their conclusion is that the more we invade animal habitats, the more zoonotic diseases we are likely to encounter.
Seventy scientists from seven countries have collaborated to explore how bats transmit viruses, with the hope it will help predict how and when the next pandemic might strike, reports TimesLIVE Premium.
Known as BatOneHealth, the group is focusing on spillover (of viruses from animals to humans) as “landscapes change to meet the growing demands of people, resulting in animal populations being forced to adapt and find new places to live and feed”.
This can “bring them closer into contact with people”.
Professor Wanda Markotter, a virologist and director of the University of Pretoria Centre for Viral Zoonoses and who sits on several international virology panels, including at the World Health Organisation, said the group’s work would be valuable.
“History has shown most outbreaks and pandemics have an animal origin, with the majority spilling over from wildlife. Bats have been implicated in several of these, which is why several studies globally are focusing on understanding the presence of the viruses in bats first but also how these infections work.”
The opportunity for contact between humans and bats needs to be understood, she said, citing examples like the wildlife trade, bush-meat and human behaviour.
It is also useful to understand the characteristics of a virus.
“For example, most bat viruses are adapted to bats and cannot infect human cells. They will first have to adapt, which will take a long time and many opportunities for contact with other species.”
She said BatOneHealth would look at “all these factors” and lauded the proposed studies as representing “essential approaches to understanding and preventing spillover from animals to humans from happening in the future”.
She said there are several studies such as this across the globe, including in South Africa.
In their recent publication in Nature, the scientists at BatOneHealth said that “pathogens originating in bats have become an increasing concern”.
Many studies associate spillover with changes in land use and other human-induced stressors, but “the mechanisms” underlying the correlations had not been identified.
The paper in Nature, which collated 25 years of data on land-use change, bat behaviour, and spillover, “show that bats are responding to environmental change by persistently adopting behaviours that were previously transient responses to nutritional stress”.
“Interactions between land-use change and climate now lead to persistent bat residency in agricultural areas, where periodic food shortages drive clusters of spillovers.”
The long-term study identifies the mechanistic connections between habitat loss, climate and increased spillover risk, providing a framework for examining causes of bat virus spillover and for developing ecological counter-measures to prevent pandemics.
Up to 70% of human infectious diseases are zoonotic in nature.
Study details
Pathogen spillover driven by rapid changes in bat ecology
Peggy Eby, Alison Peel, Andrew Hoegh, Wyatt Madden, John Giles, Peter Hudson & Raina Plowright.
Published in Nature on 16 November 2022
Abstract
During recent decades, pathogens that originated in bats have become an increasing public health concern. A major challenge is to identify how those pathogens spill over into human populations to generate a pandemic threat. Many correlational studies associate spillover with changes in land use or other anthropogenic stressors, although the mechanisms underlying the observed correlations have not been identified.
One limitation is the lack of spatially and temporally explicit data on multiple spillovers, and on the connections among spillovers, reservoir host ecology and behaviour and viral dynamics.
We present 25 years of data on land-use change, bat behaviour and spillover of Hendra virus from Pteropodid bats to horses in subtropical Australia. These data show that bats are responding to environmental change by persistently adopting behaviours that were previously transient responses to nutritional stress. Interactions between land-use change and climate now lead to persistent bat residency in agricultural areas, where periodic food shortages drive clusters of spillovers. Pulses of winter flowering of trees in remnant forests appeared to prevent spillover.
We developed integrative Bayesian network models based on these phenomena that accurately predicted the presence or absence of clusters of spillovers in each of the 25 years. Our long-term study identifies the mechanistic connections between habitat loss, climate and increased spillover risk. It provides a framework for examining causes of bat virus spillover and for developing ecological countermeasures to prevent pandemics.
See more from MedicalBrief archives:
Russian bats carry vaccine-resistant virus capable of infecting humans
Zoonotic diseases: Sindbis, Langya and monkeypox outbreaks keep scientists on alert
Wuhan scientists planned to release coronavirus into bat caves: Leaked papers
85% of Cameroonian respondents eat bush meat
Bats responsible for recent West African Ebola epidemics