One Health Approach SNAP Zoonotic Transmission to Prevent Next Pandemic

COVID-19 is one of the worst zoonotic diseases, but it’s not the first. Health of Humanity is at stake. One Health is a trans-disciplinary, collaborative approach in understanding zoonotic diseases risks. - Gopal Krishna Anand

The pandemic which saw its first outbreak in a wet market in Wuhan, China last year, has spread all across the world. United Nations General Assembly called on its member states and global organizations, to mark December 27 every year as ‘International Day of Epidemic Preparedness’ to advocate the importance of global partnership against epidemics.

The zoonosis diseases are emerging because of unsustainable agricultural practices aimed at meeting the demand for animal protein from growing populations, say epidemiologists, ecologists and veterinarians. Most Zoonosis – the diseases which can be transmitted to humans from animals- happen indirectly through insects, such as mosquitoes or, more commonly, through food systems. Sixty percent of known infectious diseases and 75 percent of emerging infectious diseases are zoonotic. Scientists say, stronger bio-security measures in the global food system could help prevent future pandemics, as the rate at which diseases jump from animals to humans is increasing. Sustainable agriculture and better health monitoring needed to break chain of disease transmission in food systems. In the global South, meat production increased 260% in the past 50 years, with milk production up 90% and egg output up 340%.

Delia Grace Randolph, a professor of food safety systems at the University of Greenwich and a contributing scientist at International Livestock Research Institute says, “Most emerging diseases over the last century have come from intensive agriculture, not wet markets. Wet markets sell fresh foods, as opposed to dry, packaged goods, and some sell live fish and animals. The lead author of a new report published jointly by ILRI and the UN Environment Programme (UNEP), notes that about 60% of human infections are estimated to have an animal origin. Among the new and emerging human infectious diseases, about 75% do “jump species” from animals to people.

One Health approach
Image credit: UNEP

Protein hungry people

Randolph and co-authors say, the vast majority of animals involved in zoonotic outbreaks are domestic livestock or pets. The domesticated animal species share an average of 19 zoonotic viruses with people, while the average for wild animals is just 0.23 viruses, they say. Source:’ by Fatima Arkin . As the global human population continues to surge, the number of domesticated animals that provide protein-hungry societies with food and the number of animals, such as rats, that thrive in such environments have also increased.

The science is clear that if we keep exploiting wildlife and destroying our ecosystems, then we can expect to see a steady stream of these diseases jumping from animals to humans in the years ahead. Wild habitats have become settled by human populations, bringing people and livestock into closer proximity with wildlife, notes UNEP executive director Inger Andersen, and he remarks, once established in humans, these diseases quickly spread across our interconnected world, as we have seen with COVID-19.

Low- and middle-income countries’ food supply chains are lengthening and diversifying. There is increased demand for animal protein and agricultural intensification is poorly regulated, all of which creates additional opportunities for disease transmission, notes the report. “The best chance we have of effectively dealing with another coronavirus or similar infectious pathogen is at the beginning — when spillover occurs — and by ensuring global coordination.” – Sophie Von Dobschuetz, global surveillance coordinator, Food and Agriculture Organization.

Pathogen flow at the wildlife-livestock-human interface
Image credit: UNEP

Food systems

The burden of neglected zoonotic diseases falls heaviest on the world’s poor, vulnerable and marginalised people, the report says.  Food systems must be transformed by improving policy, regulation and the monitoring of traditional food markets, because while some recent zoonotic pandemics originated from wildlife, many also came from livestock. Randolph remarks, “Our food system is good at delivering large amounts of calories to ever-increasing populations, if we continue with our current food systems we will inevitably have more emerging disease.”

World Health Organizations chief, Tedros Adhanom Ghebreyesus, on December 26, 2020 said that the COVID-19 crisis will not be the last pandemic and all steps taken to improve human health will be “doomed”, if the global community fails to tackle climate change and animal welfare. In a video message marking first International Day of Epidemic Preparedness on Sunday, the WHO chief said that people are following “dangerously short-sighted” method of using money to control outbreaks but are not doing anything to prepare for the next one.

Climate change and diseases

The rising trend in zoonotic diseases is driven by the degradation of our natural environment – through land degradation, wildlife exploitation, resource extraction, climate change, and other stresses. Agriculture and meat production are significant contributors of greenhouse gases, both directly and through land-use change. The drivers of pandemics are often the same drivers of climate change and biodiversity loss.  Accelerating climate change has made conditions more conducive to the spread of infectious and mosquito-borne diseases that plague poor communities, such as malaria and dengue fever, and trypanosomiasis – sleeping sickness spread by tsetse flies.

Dirk Pfeiffer, a professor of veterinary epidemiology at City University of Hong Kong and the Royal Veterinary College in London remarks, “Climate change results in changing environmental conditions, which impacts on the ecosystem characteristics and as a result, it changes the distribution of animal species, and therefore also of any microorganisms which they carry,”

Mapping global hotspots for zoonotic spillover, focusing on wildlife as the origin was a pivotal 2017 study, published in Nature Communications. It argues that the risk of emerging zoonotic diseases is greatest in forested tropical regions experiencing land-use changes related to agriculture, logging, mining and infrastructure development. The study also found that the risk of zoonotic disease outbreak is high in areas rich in mammal species diversity and notes that “that the relationship between biodiversity and disease risk is complex, context-specific and idiosyncratic”.

Veterinary epidemiologists hesitate to say where the next zoonotic pandemic will originate. Experts are still working to determine how COVID-19 and other coronaviruses, such as the 2003 Severe Acute Respiratory Syndrome (SARS) virus, emerged. The possibilities of genetic mutations, or the viral recombination of genetically unrelated virus strains, are also alarming scientists. The best chance we have of effectively dealing with another coronavirus or similar infectious pathogen is at the beginning – when spillover occurs – and by ensuring global coordination.

One Health approach

Every year, some two million people, mostly in low- and middle-income countries, die from neglected zoonotic diseases. The outbreaks can cause severe illness, deaths, and productivity losses among livestock populations in the developing world. In the last two decades alone, zoonotic diseases have caused economic losses of more than $100 billion, not including the cost of the COVID-19 pandemic, which is expected to reach $9 trillion over the next few years.

Global efforts to reduce the impacts of emerging diseases are largely focussed on post-emergence outbreak control, quarantine, treatment and vaccine development. But, in the past decade a range of projects have been launched to identify existing viruses in animals and better understand the interface between wildlife, livestock and human interactions.

The University of California’s Davis ‘Predict’ project, part of USAID’s Emerging Pandemic Threats programme, aims to strengthen and support global surveillance and diagnostic capabilities, primarily in Africa and Asia. Predict has trained almost 7000 people in more than 30 countries in One Health — a trans-disciplinary, collaborative approach to understanding zoonotic diseases risks.

Still, more investment in early warning and preparedness is a priority, to include the animal and wildlife health sectors in the One Health approach.  FAO and the WHO, along with the World Organisation for Animal Health are adopting the approach. Improved and sustained collaboration between medical, veterinary and wildlife authorities is key and partnerships need to be institutionalized to ensure collaboration beyond crisis periods. Randolph emphasises the need for evidence-informed policy to better understand the complex risks between humans and livestock, as well as the possibilities for action to reduce diseases.

Inger Andersen, UN Under Secretary General and ED, UN Environment Programme recognizes that human health, animal health and planetary health cannot be separated, and we are planning our responses accordingly. We have intensified agriculture, expanded infrastructure and extracted resources at the expense of our wild spaces. Dams, irrigation and factory farms are linked to 25% of infectious diseases in humans. Travel, transport and food supply chains have erased borders and distances. Climate change has contributed to the spread of pathogens. The end result is that people and animals, with the diseases they carry, are closer than ever.

Concluding to say, there are many solutions, which will also help to fight climate change and biodiversity loss. We need to invest in ending the other natural resources, farming sustainably, reversing land degradation and protecting ecosystem health. Part of this process is the urgent adoption of integrated human, animal and environmental health expertise and policy – a One Health approach. One Health is not new, but uneven uptake and institutional support means it hasn’t hit its potential. The weakest link in the chain is environmental health. We have to fix this.

Global Pandemic requires a Global Response: connect all nations. We were warned that the current pandemic was a matter of if – not when. It is a human failing that we predict but not prepared. Now, we must become more proactive to avoid another pandemic and address endemic zoonotic diseases.

By Gopal Krishna Anand

Leave a Reply