With news that another animal virus has made the leap to humans in China, it's perhaps not surprising the world's fourth-biggest country is being singled out as the most likely source of the next pandemic.
The rare H10N3 strain of bird flu put a man in hospital, China confirmed this week, the first-ever such infection in humans.
While the strain only causes mild illness in poultry and the threat of another pandemic is thankfully considered low, China is also where both of the SARS coronaviruses originated - the first killing hundreds in the early 2000s, the second behind the COVID-19 pandemic that's killed millions in the past 18 months.
A report from United Nations' Intergovernmental Platform on Biodiversity and Ecosystem Services last year concluded there were nearly a million viruses out there that could make the jump to humans, and there was "no great mystery" what would be the cause - human encroachment on wildlife habitats.
"Diseases that we get like COVID come from wildlife - and so the more that we encroach and go into habitats where wildlife are, the more complex they are and the more likely that these emergent events will happen," David Hayman of Massey University's School of Veterinary Science told Newshub in October.
Now Dr Hayman has teamed up with researchers from Italy and the US to figure out the most likely source of the next potential coronavirus pandemic.
It's generally believed both SARS viruses originated in horseshoe bats (also known as rhinolophid bats) before making the leap to humans (perhaps via a secondary animal).
The researchers mapped where rhinolophid bats live - stretching from the UK, Spain and northern Africa in the west, across southern Europe, through the middle East and south Asia, through to Japan in the east and the eastern coast of Australia.
In that area, they looked at "forest cover, cropland distribution, livestock density, human population, human settlements and land-use changes" to find "hotspots" where the chance of an outbreak - known as a 'spillover event' - are more likely to occur.
"These are the places where we should be doing both disease surveillance to ensure that early cases are identified, as well as trying to reduce the risk to prevent future outbreaks and pandemics," said Dr Hayman.
"We identified hotspots, along with what changes, such as increased population, livestock farming or forest fragmentation might change a location from medium to high risk."
Unsurprisingly, most were located in China - which has the world's biggest population and a growing demand for meat, the vast majority of which is produced locally.
"Intensive livestock production keeps a large number of animals - often immunosuppressed, with low genetic diversity and in poor conditions - in close proximity to one another, making them vulnerable to the emergence and spread of epidemics," the study, published in the journal Nature Food, says.
Other hotspots were located in Java, Bhutan, east Nepal, northern Bangladesh and northeastern and western India.
"This loss of habitat is increasing the chances that humans interact with bats harbouring potentially pathogenic SARS-related coronaviruses," said Dr Hayman. "Understanding the circumstances under which coronaviruses can jump from wildlife to humans is crucial for predicting, and avoiding, future epidemics or pandemics, such as COVID-19."
Despite our large agriculture industry, Dr Hayman said New Zealand has "little chance" of being the source of the next global pandemic.
