Focus on One Health

“We’re all in the same boat,” says Liza Rosenbaum Nielsen. “The health of wildlife, livestock, humans and plants is more intertwined than most of us realize.” Rosenbaum Nielsen is professor of preventive veterinary medicine at the University of Copenhagen and a member of the advisory board of UZH’s One Health Institute.

She is one of the experts who will speak at the institute’s inaugural symposium on 21 September and explain why One Health research is necessary: “Humans tend to dominate everything without regard for other species and ecosystems,” she says. This dominance leads to many problems for the environment and for health – of both humans and animals. “The holistic approach of One Health can address these issues.”

The Danish professor welcomes UZH’s initiative and believes the emerging institute will become a well-regarded pioneer in the field. As we reported earlier this year, in summer 2023, UZH became the first European university to establish a One Health Institute.

The comprehensive goals of One Health as described by Rosenbaum Nielsen constitute long-term tasks. The job at hand for now is to develop and expand the institute. Specifically, the 21 September inaugural symposium will highlight and promote two key areas: evolution and epidemiology. As Thomas Lutz, professor of veterinary physiology and head of the One Health Institute steering committee, explains, these two broad areas encompass cross-cutting themes relevant to the entire field of One Health.

In terms of content, the institute will initially focus on the three main topics of zoonoses, drug resistance and metabolic diseases. These topics reflect the expertise of the three host faculties (Vetsuisse, the Faculty of Medicine and the Faculty of Science). The institute’s leadership team has advertised two assistant professorships in the core fields of evolution and epidemiology. At next week’s symposium (which is open to the public), selected candidates will outline their research in these areas.

Paleogenetics, a branch of genetics in which centuries-old tissue samples are analyzed to open a window into the past, provides a prime example of why evolution is an important topic in One Health. The Nobel Prize awarded to Svante Pääbo in 2022 for decoding the Neanderthal genome brought the discipline to the attention of a wider audience. “We can use paleogenetics to reconstruct the evolutionary trajectories of zoonotic diseases and identify old pathogen reservoirs,” says Verena Schünemann, professor of paleogenetics at the UZH Institute of Evolutionary Medicine.

Schünemann has researched a whole series of significant pathogens that are transmitted from animals to humans and have caused millions of deaths. For example, Yersinia pestis, the pathogen that causes the plague. Studies of old samples from the Middle Ages revealed where the dangerous pathogen originally jumped to humans and led to deadly epidemics. “Looking at the major pandemics of the past as well as local epidemics and their causes helps us better understand how epidemics develop,” says Schünemann.

By analyzing the genetic differences of the various strains, scientists can assess the potential for evolutionary changes in the pathogen and thus draw conclusions about the hazard potential. The plague pathogen is still far from being eradicated and continues to cause outbreaks, especially in Africa.

Paleogenetics can also shed light on the underlying causes of ecological disasters. The potato blight Phytophtora infestans, which led to the great Irish potato famine and mass emigration in the 19th century, is a case in point. On the basis of samples from herbaria, Schünemann and her colleagues were able to show that the blight must have been caused by a unique strain which had probably disappeared in the meantime. This raises the question of what environmental or other changes produced this lineage of the organism and how it was displaced by other lines.

Other uses for paleogenetics are to examine the development of resistances to agents or to investigate the emergence and formation of pathogen reservoirs in animals. For example, the tuberculosis pathogen easily jumps between animal and human populations. So do influenza pathogens, which move back and forth between birds, pigs and humans in a complicated cycle of change and adaptation that regularly leads to dangerous pandemics.

An example is the Spanish flu outbreak at the end of the First World War in 1918. Here too, paleogenetics provided the crucial pieces of the puzzle to understand the factors leading to the formation of the pandemic strain, explains Verena Schünemann, who has worked with these lineages.

As the Sars-CoV2 pandemic showed, epidemiologists are the line of first defense when it comes to fighting a pathogen, and this holds true in both human and veterinary medicine. “Epidemiologists are often the first to identify the spread of a pathogen, and they provide vital information with which to develop interventions,” says Adrian Hehl, professor of parasitology and a member of the One Health Institute steering committee. He mentions the African swine fever currently rampant in Eastern Europe. At the moment, mainly wild boars are affected, but the virus can be transmitted from them to farm pigs. Animals usually die from the contagious disease, but for humans it poses no danger. In this situation, epidemiologists who can model the spread of the disease play a vital role.

“The field of epidemiology is very broad,” says Hehl. It ranges from identifying and monitoring the spread of diseases and germs to examining how resistance develops and analyzing agricultural practices that may be causing new diseases or germs to emerge. Ultimately, epidemiology should be used to help get zoonoses and diseases under control, says Hehl, and that requires particularly close cooperation between experts in veterinary and in human medicine.

While the two professorships on evolution and epidemiology are funded through the TRANSFORM funding line, a third professorship is planned in the area of Digital One Health, which will be funded by the Vetsuisse Faculty. “Large amounts of data are also increasingly common in One Health,” says Thomas Lutz. The introduction of a professorship in Digital One Health at this early stage will help the initiative compete on the international stage. The content of the role will be focused on designing new research approaches through intelligent analysis of large volumes of data.

At its core, One Health takes an interdisciplinary approach to research, and the new institute will intensify and expand on the university’s existing transdisciplinary networks. This is where UZH can play to one of its strengths, notes Liza Rosenbaum Nielsen. “The interdisciplinarity and worldwide recognition of its research mean UZH is perfectly placed to implement the One Health initiative and are prerequisites for a successful institute.”