Mapping Disease Across the Globe

Sometimes a misunderstanding contains a kernel of truth. When Thomas Van Boeckel talks about what he does for a living, he calls his field spatial epidemiology. This sometimes raises the question: what’s this epidemiology in space all about? Contrary to what some assume, Van Boeckel’s work has nothing to do with ailing astronauts. In this his research, “spatial” refers to the geographical aspect of epidemiology. His field of expertise is also known as health geography. Van Boeckel is interested in how diseases differ in humans and animals around the world – and how they are related.

This is one of the key questions posed by One Health. The disciplines of medicine, veterinary medicine and environmental science collaborate on this still-nascent approach, because human, animal and environmental health are all closely linked. Many infectious diseases that occur in humans have a zoological origin – take, for example, the current outbreak of bird flu, which has already been transmitted to farm workers via cows in the US.

The University of Zurich founded its One Health Institute in 2023 (see box). In August 2024, Thomas Van Boeckel became its first chair. And as it turns out, spatial epidemiology does have something to do with space after all: satellites are one of the most important tools for data acquisition in the field. “Satellite technology is a revolution in our area of study,” says Van Boeckel. These images make it easy to obtain important epidemiological data across national borders, including information on temperature, air quality or the extent of deforestation. Thanks to satellites, livestock numbers can also be estimated based on the size of agricultural buildings or the acreage of forage crops for animals.

Spatial epidemiology can thus make an important contribution to One Health research. In addition, other avenues such as genetic testing, to take one example, are just as important as conducting surveys and analyzing cellphone data to record people’s health and travel behavior.

Founded jointly by the Vetsuisse Faculty, the Faculty of Medicine and the Faculty of Science, the One Health Institute (OHI) has been established as a new institute at the University of Zurich in May 2023. The institute has a correspondingly interdisciplinary approach. Following the appointment of Thomas Van Boeckel in 2024, two further professorships are to be filled this year, in the fields of evolutionary medicine and Digital One Health. The current focus is on research. There are also plans to set up a minor degree program.
 

One Health Institute

Spatial data have been central to epidemiology since its inception. In 1845, the physician John Snow tried to find out what triggered the outbreak of a cholera epidemic in London. He took a map of the city and marked each house with a case of the disease. This allowed him to recognize a pattern in the disease’s distribution, and to identify contaminated water from a particular pump as the cause.

Recognizing such geographical patterns is Thomas Van Boeckel’s daily work. His focus is on infectious disease and antibiotic resistance. His interest in geography started at a young age. Even as a child, he was fascinated by maps, which led his grandparents to gift him a globe. Despite this fascination, Van Boeckel went on to study bioengineering. However, he found lab work didn’t captivate him as he had imagined. Then, after a lecture on biostatistics had caught his interest, he went on to write several papers and his dissertation on the spread of a variant of bird flu in Asia. He increasingly realized that, “by helping to explain the risk factors and patterns of disease spread, I can contribute to prevention and health promotion.”

Thomas Van Boeckel works alone in his office on the grounds of the University Animal Hospital. Soon, however, a PhD student will join him. He has already raised additional funding and will soon be able to hire more employees. The UZH Digital Society Initiative is supporting him with a project. The aim is to use artificial intelligence to automate data collection. This is important, as satellite images aren’t always available. Until now, obtaining information from the internet and other sources often required great time and effort.

Van Boeckel is working with other researchers to create a world map of veterinary medicine: where are veterinarians located in the world, and how many of them are there? To do this, he examines a wide variety of sources, from electronic telephone directories to lists of members of veterinary societies. “The idea behind the project came about at a conference. We compared maps showing how widespread malaria and antibiotic resistance are worldwide,” explains Van Boeckel.

The maps for malaria are much more precise because the risk factors are known – it is mainly humidity and temperature that determine the presence of malaria-transmitting mosquitoes. In the case of antibiotic resistance, the risk factors are not as well known. “Access to veterinarians could play a role,” says Van Boeckel. In regions with limited access to veterinary medicine, animal owners may be more likely to resort to using antibiotics on their own, without professional guidance. A lack of vaccinations and hygiene information can also lead to higher antibiotic use.

A map of the worldwide distribution of veterinary practices (Image: Criscuolo, N.G., Wang, Y. & Van Boeckel, T.P.)

Many food animals live more than an hour away from veterinary care. Nearly 94% of these cases are in low- and middle-income regions. The study led by Thomas Von Boeckel suggests that increasing the number of veterinary personnel by 5% in specific geographic areas could reduce the number of isolated animals by 32.9%. This finding provides valuable guidance for allocating resources to improve access to veterinary care and disease surveillance worldwide.

Literature

Criscuolo, N.G., Wang, Y. & Van Boeckel, T.P. A global map of travel time to access veterinarians. Nat Commun 16, 5849 (2025). DOI: 10.1038/s41467-025-60102-y

Clear data are not available on how often antibiotics are used in livestock by country. Thomas Van Boeckel was the first to collect the available data on a global level. In a study for the Food and Agriculture Organization of the United Nations (FAO), he and other researchers turned their attention towards the future. The numbers are alarming: if measures are not taken, the use of antibiotics in livestock is set to rise by almost 30% by 2040 compared to 2019, especially in Asia and Africa. This is due to population growth and increasing incomes, as these factors also lead to higher rates of meat consumption, and therefore more farm animals.

The outlook is even more concerning when it comes to the use of antibiotics in humans. In a study in which Van Boeckel was involved, the researchers predicted a global increase of more than 52% between 2023 and 2030 if the rising rate cannot be stopped, especially in rapidly developing countries. The hotspots are mainly in Asia and southern Africa. On the one hand, this has to do with lower hygiene standards, according to Van Boeckel. On the other hand, in countries such as India and China, although there can be hurdles to accessing medical care, buying antibiotics is much easier than in Europe. “In order to counteract the increasing use of antibiotics, we need above all better water and sewage infrastructure. and improved access to vaccinations,” he says.

High consumption of antibiotics is in and of itself not the biggest problem – the question is whether the drugs are being used properly. Van Boeckel is involved in an ongoing study that attempts to estimate what proportion of antibiotics use is actually necessary. “We are working on the assumption that about a third is unnecessary,” he says. With this in mind, it’s little wonder that antibiotic resistance is on the rise. Today, an estimated 1.3 million people worldwide die each year from infectious diseases that can no longer be treated. According to estimates, this number could be almost twice as high by 2050.

“The best way to prevent resistance is to reduce the need for antibiotics in the first place. This is primarily done by preventing disease,” says Van Boeckel. In animal husbandry, this can be achieved in particular with better hygiene. Specifically, the animals should have less contact with the outside world and its germs (the extent to which more sterile stables are animal-friendly is a different matter). According to Van Boeckel, the Netherlands and Denmark have made great efforts here. Not only have they been able to reduce the consumption of antibiotics, they have also shown that profitable livestock farming is possible under these conditions.

What does Thomas Van Boeckel think about the future development of antibiotic resistance? “Until a few months ago, I was confident,” he says. However, this has changed due to the current political situation. Above all, the cuts in budgets for development cooperation, the gutting of the world’s largest donor to health projects, USAID, and the withdrawal of several countries from the WHO, including the US, have cast a shadow over his optimism: “All of this has a negative impact on infrastructure and health outcomes in particularly vulnerable countries – for example, in terms of access to clean water and medical care.” At the same time, there will also be less money available for health research projects.

Van Boeckel is more optimistic about the still young One Health approach. Taking the interrelation between humans, animals and the environment into consideration will hopefully start to become the standard in health research. Van Boeckel notes a great interest in interdisciplinary cooperation at UZH: “Great opportunities arise from this.” For example, it allows joint early warning systems for diseases and combined vaccination campaigns for humans and animals to be set up. “Joint prevention and treatment also make economic sense and is more resource-efficient,” says Van Boeckel. He is certainly well-prepared for further progress and success in connection with One Health. Even today, Van Boeckel has a globe in his office. There’s a bottle of Scotch hidden inside it – which comes out whenever he has a publication accepted.