Human, animal, and environmental health are not three different or independent forms of health. Instead, they need to be considered as ‘One Health’.
By One Health, this refers to the overarching concept that human, animal, and environmental health are inextricably linked and that professionals within the three realms should work together toward research findings and clinical applications that can improve the health in all three areas. Due to a shared environment and highly conserved physiology, animals and humans not only suffer from the same zoonotic diseases, but can also be treated by either structurally related or identical drugs.
According to the World Health Organisation: “One Health is an integrated, unifying approach that aims to sustainably balance and optimize the health of people, animals and ecosystems. It recognizes that the health of humans, domestic and wild animals, plants, and the wider environment (including ecosystems) are closely linked and interdependent.”
This is something that the Virginia-Maryland College of Veterinary Medicine has been attempting, both throughout its public health program and more traditional veterinary medicine.
One Health finds its most direct expression in the Center for One Health Research, a collaborative effort between the veterinary college and the Edward Via College of Osteopathic Medicine, which is a private, non-profit medical school in Blacksburg.
“I’m a veterinarian, but I study human diseases,” explains Mohamed Seleem, the centre’s director. He adds: “Neisseria gonorrhoea, for instance, does not infect animals at all, it just infects humans.”
Seleem, the Tyler J. and Francis F. Young Chair in Bacteriology. Much of his lab’s research has focused on repurposing existing drugs for treatment of diseases, such as gonorrhoea and Candida auris, that either lack vaccines or have had prior pharmaceutical treatments be rendered less effective over time.
Seleem observes that veterinarians by training enter their careers with a philosophy that aligns with the goals of One Health. The veterinarians’ oath already includes “the promotion of public health” and “the advancement of medical knowledge” as chief planks, in addition to animal welfare.
In relation to this, Seleem offers the following insight: “So when we work with animals and we want to really address the animal health, we already have in mind human health.”
The COVID-19 pandemic has highlighted how diseases originating in animals can cross over to humans through the environment and lead to dire impacts on society.
This leads Seleem to mention: “A microorganism that’s causing a problem in humans, it didn’t necessarily start in humans. It could have started in the environment or started in the animal and gone through the environment and then to humans. So to address this and to prevent the illness or find a cure, we cannot just focus on one aspect of the problem, which is the human, and leave behind the environment and the animal.”
Global climate change is already proving to be an environmental factor that is exacerbating some diseases. An example is with the rise in Candida auris, a fungal infection first discovered in humans in 2009. Climate change has likely enabled the pathogen, which has adapted to warmer, more humid conditions, to proliferate and infect humans more often.
