Global changes in land use are disrupting the balance of wild
animal communities in our environment, and species that carry
diseases known to infect humans appear to be benefiting, finds a
new UCL-led study.
The findings, published in Nature, may have
implications for future spillovers of diseases originating in
animal hosts.
The research team, led by the UCL Centre for Biodiversity
& Environment Research, studied evidence from 6,801
ecological communities from six continents, and found that
animals known to carry pathogens (disease-causing microorganisms)
that can infect humans were more common in landscapes intensively
used by people.
The evidence was sourced from a dataset of 184 studies
incorporating close to 7,000 species, 376 of which are known to
carry human-shared pathogens.
The researchers say we may need to alter how we use land
across the world to reduce the risk of future spillovers of
infectious diseases.
Lead author, PhD candidate Rory Gibb (UCL Centre for
Biodiversity & Environment Research) said: “The way humans
change landscapes across the world, from natural forest to
farmland for example, has consistent impacts on many wild animal
species, causing some to decline while some others persist or
increase.
“Our findings show that the animals that remain in more
human-dominated environments are those that are more likely to
carry infectious diseases that can make people sick.”
Species that host zoonotic pathogens (which can jump from
animals to people) constituted a higher proportion of the animal
species found in human-influenced (disturbed) environments
compared to the ecological communities in more wild
habitats.
The same relationship is seen for animals that tend to
carry more pathogens of any kind – whether or not they can affect
humans.
In comparison, most other wild animal species are found in
lower numbers in disturbed environments compared to natural
habitats. The researchers say this suggests that similar factors
may be influencing both whether a species can tolerate humans and
how likely it is to carry potentially zoonotic diseases.
Co-lead author Dr David Redding (ZSL Institute of Zoology
and UCL Centre for Biodiversity & Environment Research) said:
“Other studies have found that outbreaks of emerging zoonotic
infectious diseases appear to be increasingly common – our
findings may help to explain that pattern, by clarifying the
underlying ecological change processes that are interacting to
drive infection risks.”
Senior author Professor Kate Jones (UCL Centre for
Biodiversity & Environment Research and ZSL Institute of
Zoology) said: “Global land use change is primarily characterised
by the conversion of natural landscapes for agriculture,
particularly for food production. Our
findings underscore the need to manage agricultural landscapes to
protect the health of local people while also ensuring their food
security.”
The researchers say that while there are numerous other
factors influencing emergent disease risks, the findings point to
strategies that could help mitigate the risk of further
infectious disease outbreaks comparable to COVID-19.
Professor Jones said: “As agricultural and urban lands are
predicted to continue expanding in the coming decades, we should
be strengthening disease surveillance and healthcare provision in
those areas that are undergoing a lot of land disturbance, as
they are increasingly likely to have animals that could be
hosting harmful pathogens.”
Dr Redding added: “Our findings provide a context for
thinking about how to manage land use changes more sustainably,
in ways that take into account potential risks not only to
biodiversity, but also to human health.”
The study, by researchers from UCL, ZSL, University of
Oxford and Imperial College London, used data from the Projecting
Responses of Ecological Diversity in Changing Terrestrial Systems
(PREDICTS) biodiversity database. It was supported by the Natural
Environment Research Council, the Medical Research Council,
Wellcome and the Royal Society.
