Within less than three years, the World Health Organization (WHO) has declared two public health emergencies of international concern: Covid-19 in February 2020 and monkeypox in July 2022. At the same time, extreme weather events are being reported continuously across the world and are expected to become more frequent and intense, writes Arindam Basu, Associate Professor, Epidemiology and Environmental Health, University of Canterbury.
These are not separate issues. We will have a better chance of suppressing infectious diseases only if we adopt what the WHO calls a One Health approach and integrate predictive modelling and surveillance used in both infectious disease control and climate change.
health experts have relied on disease surveillance systems to track emerging
diseases since the 19th century. Their methods have become increasingly
sophisticated, including genomic surveillance to track how pathogens evolve.
as long as these surveillance systems depend on diseases that have already
emerged, they remain behind the curve and we risk “sleepwalking” into the next
the impacts of a changing climate on ecosystems, any surveillance of new disease
outbreaks must include humans, animals and planetary changes.
and re-emerging pathogens
will continue to evolve into new variants despite high vaccination rates in
some countries and the availability of antiviral treatments. At the same time,
new diseases will continue to emerge.
the first week of August, more than 25,000 cases of monkeypox were registered
worldwide and new reports of deaths continue to emerge. Ghana has declared an
outbreak of Marnburg virus disease in July and Mozambique reported its first
case of polio in 30 years in May.
has now also been detected in wastewater samples in New York and public health
authorities in other wealthy countries are racing to head off the re-emergence
of a virus that had been almost eliminated.
the latter is most likely due to a global drop in vaccinations, health experts
are warning that new pathogens, particularly those that jump between animals
and humans, will become more frequent as habitats change in a warming world.
scientists refer to diseases such as Covid-19 and monkeypox as zoonoses –
pathogens known to be transmitted from animals to humans. Close contact between
humans and wild animals is increasing as forests are destroyed to make way for
agriculture and trade in exotic animals continues.
the same time, the thawing of permafrost is releasing microbes hidden beneath
the ice. Taken together, there is an ever growing risk of new pathogens.
link between human, animal and environmental health
climate models are increasingly sophisticated at projecting how climate change
will affect Earth systems and ecosystems. There are efforts to “connect the
dots” by integrating human and animal health and the “sickness of the planet”,
as described by the late Norwegian physician Per Fugelli in his 1994 essay, In
Search of a Global Social Medicine.
steps in integrating disease and planetary surveillance are under way. In 2008,
the WHO, the Food and Agriculture Organization (FAO), the World Organisation
for Animal Health (WOAH) and other organisations jointly drafted a framework
for how best to diminish the risk and minimise the global impact of pandemics.
2014, a manifesto published in the Lancet called for an urgent transformation
in our values, based on the recognition of our “interdependence and
interconnectedness of the risks we face”.
2021, the One Health high level expert panel adopted a definition of an
integrated, unifying approach that aims to balance and optimise the health of
people, animals and ecosystems.
One Health approach to disease surveillance is now used by the African Centers
for Disease Control and the global network to address antimicrobial resistance.
In 2019, the UN’s interagency coordinating group on antimicrobial resistance recognised
that microbes that infect animals and humans share the same ecosystems and
their prevention therefore requires a coordinated approach.
are relatively recent initiatives in our effort to understand and track past,
present and future outbreaks. There may be a long way to go in integrating
disciplines, but the answer to predicting and preempting future outbreaks and
pandemics lies in a One Health approach.