A world where animals and people thrive on a healthy planet

November 3rd is One Health Day.  Each year this date is dedicated to raising global awareness about the importance of One Health collaborations, and the vital role this approach takes in ensuring the health of humans, animals and the environment.  At Vets for Climate Action, we strive for a world where animals and people thrive together on a healthy planet, and we know how important One Health is in seeing that vision come to life.

But what is One Health, and where does climate change come into it?  There’s no-one better qualified to answer those questions than Professor Martyn Jeggo, who has worked in research and management of infectious diseases for many years, in Australia and abroad, in developing countries and with the UN.  Professor Jeggo has been instrumental in the global development of One Health. He explains that One Health “seeks to integrate the sciences of animal, human and environmental health, recognising the interconnected nature of these three disciplines. One Health embraces the concept that by working across these disciplines, health problems can be better understood, and more effective and sustainable solutions developed.”

Climate change is an essential piece of this complex picture.  “From an environmental health viewpoint, climate change is easily recognised as a major factor driving significant change to our environmental well-being,” Professor Jeggo says.  “However, climate change also significantly and directly impacts animal and human health in a myriad of ways.”

He cites the example of vector borne diseases, those infections that are carried and transmitted by insect hosts.  There are many examples of vector borne diseases both here in Australia and across the globe. Some are mainly of concern to human health, such as malaria, while others such as bluetongue virus, a disease spread by culicoides midges which affects sheep and other ruminants, only infect animals.  There are also others, such as Rift Valley Fever, which can impact on both human and animal health.

According to Professor Jeggo, vector borne diseases are governed by the distribution of the vector, and climate plays a crucial role in this distribution.  “But climate change has significantly altered vector distribution both in timing and location,” he tells us, with the result that diseases are now occurring outside of their previously normal ranges and seasons, making control and prevention by strategies such as vaccination increasingly difficult.  “Understanding the dynamics of this interaction between the climate, vector distribution, host disease occurrence and vaccination scheduling thus becomes crucial for the control of diseases – and a One Health approach, alongside climate modelling, is ideally suited to this task.”

In a recent interview on behalf of Vets for Climate Action with 3CR Community Radio in Melbourne, Dr. Ron Glanville gave a very topical example of this while talking about an outbreak of Japanese Encephalitis, another mosquito borne disease.The disease affects both pigs and people. When transmitted to humans, in rare instances it causes serious neurological disease.  “We had a huge outbreak in Australia last year, which affected a lot of piggeries,” Dr Glanville said.  “This really caught everyone by surprise.”  In his role as a former Chief Veterinary Officer of Queensland Dr. Glanville had previously only encountered the disease in the far north of the country, in Cape York and the Torres Strait, but last year’s outbreak made it as far south as Victoria.   “We don’t fully understand the reasons for this but I’m sure climate change is one of the factors we need to consider,”  Dr Glanville suggested.   

You can read more about the links between climate change and vector borne diseases in VfCA’s factsheet “The Risk of Arthropods to Animals in a Changing Climate”.

Insects aren’t the only vectors of concern, however.  Dr. Glanville also spoke about Hendra virus, a disease which first emerged from fruit bats in Queensland in 1994, jumping initially to horses and then to humans, with devastating consequences.  “There’s a couple of vets that I know have died from Hendra virus,” Dr Glanville said.  The reasons for these inter-species infections are complex, and in the case of Hendra virus there were many factors involved, not least of which being the destruction of the bats’ natural habitat, bringing colonies into closer contact with both horses and humans.  Dr Glanville explains further that climate change and its associated extreme weather events can put the bats under stress, exacerbating risk of disease.   “When populations of animals are under stress they express viruses more, and are more likely to pass those viruses to animals and then on to people.”

Unfortunately, Hendra is not an isolated example.  According to Dr Glanville “if we look at new and emerging diseases worldwide, over the last 50 years probably 70-80% of new diseases have come out of wild animal populations…It’s a complex picture and needs to be looked at in a holistic way.”  One Health, he believes, is one way to address these issues going forward.

Professor Jeggo agrees and also suggests that a One Health approach must consider the reverse angle; the impact that humans and animals are having on the health of the environment, as drivers of climate change.  “Anthropomorphic impacts on climate have been extensively documented over the past few years. For example, in livestock the impact of overgrazing of livestock on environmental degradation and deforestation are critical areas to consider.”

Historically, Professor Jeggo tells us, those engaged in agriculture, human medicine and environmental management have worked separately, and embracing the One Health paradigm requires a change in culture and resourcing.  Hopefully, however, Professor Jeggo says that “taking this more systems thinking approach to health research is gaining considerable traction across Governments and academia, and providing seriously important insights into some of our most intractable problems, such as antimicrobial resistance.”

One Health is an approach that Vets for Climate Action is actively embracing, collaborating with colleagues in the world of human health to advocate on climate change related issues that will impact on people, animals and the environment.  Earlier this year we joined other health professionals in Canberra, to call on the government to withdraw support for a proposed massive gas project in the Beetaloo Basin of the Northern Territory, which will have devastating implications for the environment, the climate and health.

We are also proud to endorse the COP28 Open Letter on fossil fuels from the Global Medical and Health Community.  Organisations representing 46.3 million health professionals worldwide have signed the letter, calling on the COP28 President and all national leaders to commit to an accelerated, just, and equitable phase-out of fossil fuels as the decisive path to health for all.

Biographies
	Professor Martyn Jeggo
	Professor Jeggo has worked in research and research management of infectious diseases. This included spells in a number of developing countries, at the UK high containment laboratory and within the United Nations (UN). During this period of 18 years at the UN, he managed programs of support for animal health in the developing world with research related projects in some 150 countries. One such program involved support to laboratories in 40 countries assisting the global eradication of rinderpest for which he received the UN Medal. In 2002 he became Director of the Australian Animal Health Laboratory, one of the largest high containment facilities in the world. He was heavily involved in the global development of One Health and chaired both the first and third International Congress on One Health. He currently works on a part time basis within the framework of the Geelong Centre for Emerging Infectious Diseases – a One Health consortium.
	You can read Professor Jeggo’s contribution to this article in full here
	Dr Ron Glanville
	Dr. Glanville has over 40 years of experience  as former Chief Veterinary Officer with Biosecurity Queensland. In this and other roles he led the Queensland (QLD) response to the incursion of equine influenza (EI) in Australia and the introduction of the national livestock identification system in QLD. Ron has held significant leadership roles in over 30 biosecurity emergencies and in the finalisation of QLD’s part of the $1 billion Australian brucellosis and tuberculosis eradication program. Ron works as a consultant providing strategic advice and conducting reviews on animal health and biosecurity issues.
	You can listen to Dr. Glanville’s full interview on the Climate Action Radio Show on Community Radio 3CR Melbourne here