Solving the infectious diseases puzzle

In the fight against infectious disease, prevention is always better than cure. But are our current prevention strategies enough, or do we need to look beyond measures such as immunisation and the use of aseptic technique?

Proponents of One Health — a framework that recognises the interlinkages between human, animal and environmental health — believe so. They argue that, while clinical measures are important, they are only one small piece of a much bigger puzzle.

“We tend to think vaccines are the gold standard when it comes to infectious disease prevention. And yes, they are very important,” said One Health expert Francette Geraghty-Dusan^*.

“But actually, if you dig deeper — and roam into other disciplines — there are other impactful things we can do alongside immunisation. Things which actually reduce the likelihood of organisms transferring to humans in the first place.”

Animal health management impacts human health

Indeed, a recent work by Australian scientists, featured in the journal Nature, revealed how dwindling bat food reservoirs, caused by deforestation and climate change, are forcing bats to disperse more widely into agricultural and urban areas in search of food. Here, when stressed, they excrete Hendra virus, infecting horses, who in turn spread it to humans.

“People often feed horses underneath the shade of fruiting trees, where they are exposed to bat urine and saliva on dropped fruit. The horses get sick, and without appropriate IPC, exposed horse owners and veterinary workers can get infected with this deadly virus.

“A One Health approach would say, ‘yes, let’s immunise, but let’s also do more to protect bat food reservoirs, so they are less susceptible to ongoing climate variation, and spend more time in areas which are less populated’. This gets to the real heart of the issue,” Geraghty-Dusan said.

Safeguarding wildlife and wilderness areas can also prevent the emergence of other infective organisms. Scientists already know that SARS had its origins in bats, and was transmitted through civet cats in wildlife markets. Similarly, a genetic sequencing study in 2023 showed that SARS-CoV-2 — the pathogen responsible for COVID-19 — likely had animal origins.

“Public health emergencies often come from the disruption of the environment and inappropriate animal use. And tackling this is far more impactful than a purely clinical approach like a human immunisation program,” Geraghty-Dusan said.

Environmental management impacts human health

The spread of antibiotic-resistant genes (ARGs) through wastewater is an example of how the environment can impact human health in the realm of infection prevention and control (IPC).

In some countries, agricultural animals are fed antibiotics for weight gain, and their ARGs can migrate to humans via water bodies in turn, fuelling antibiotic resistance.

This huge global problem was first highlighted in 2013 by the USCDC, which found at least 2 million Americans were developing antibiotic-resistant infections (ARI) every year, with more than 23,000 cases becoming fatal.

“Clearly, we need to find ways to manage wastewater to minimise the transmission of ARGs into the environment; this includes from hospitals,” Geraghty-Dusan said.

Human health management impacts the environment

Just as the environment can impact human health, so too can human health management impact the environment. In the realm of IPC, hospitals are responsible for vast volumes of material waste, consuming around 85–95% of the 150 billion pairs of disposable gloves manufactured each year.

“Reuse and recycle can only go so far. With a One Health mindset, we really need to call on engineers and manufacturers to find better options — like compostable materials — that don’t harm our environment, because we know how cyclical this harm can be,” Geraghty-Dusan said.

National framework needed

While One Health originates from First Nations’ understanding of interconnectivity, it was first used as a term in 2003. Since then, it has gained prominence in a post-pandemic world, becoming a founding principle of the new Australian Centre for Disease Control, and a feature of the National Health and Climate strategy. The United Nations quadripartite now also has a shared definition of the term.

However, as yet, there is no national One Health framework for Australia.

Geraghty-Dusan believes this is stunting progress, and that it may limit the efficacy of the pandemic agreement, currently being penned by global leaders in preparation for the next major outbreak.

“Whilst it [the agreement] does include things like financing for pandemic preparedness, equitable access to countermeasures and health works, there are concerns that it doesn’t go far enough upstream in terms of prevention,” she said.

“And with the interim Australian CDC residing in the Department of Health, we aren’t getting that transdisciplinary authority we need to execute One Health.

“A One Health-focused CDC is certainly a step in the right direction and may give us more hope than other initiatives we have seen over the years. But we ultimately need a framework that goes beyond one sector.” 17–20

*Francette Geraghty-Dusan is a passionate One Health practitioner who has spent her career addressing the complex challenges of antimicrobial resistance, pandemic prevention and food security. As an agricultural scientist and veterinarian with a Master’s in Public Heath, she has an excellent understanding of conservation, agriculture, and animal and human health systems, coupled with strong technical skills in epidemiology, disease risk reduction, capacity building and emergency disease management. She has worked for the World Health Organization on zoonotic collaboration and One Health in Beijing, Laos and Fiji, and for the World Bank in Mongolia. Most recently, she spent 5 years as Senior One Health Advisor at the Australian Department of Foreign Affairs and Trade’s Indo-Pacific Centre for Health Security.

Geraghty-Dusan is presenting at the ACIPC International Conference 2024 to be held from 17–20 November at the Melbourne Convention & Exhibition Centre. The conference — themed ‘Succession, sustainability, and the advancement of infection prevention and control’ — aims to address emerging challenges, promote innovative approaches, and create a collaborative environment where diverse perspectives are valued. To hear more of her insights and attend the conference, please visit the ACIPC Conference website: https://acipcconference.com.au/registration/.

Image credit: iStock.com/syolacan