There is a jigsaw puzzle in the living room of Lidwien Smit (46). 200 pieces, all with names written on the back. “I haven’t had time to make it yet… But on the box you can see what it should be.” She smiles and shows the image: a close-up of a goat. A fitting gift for her inaugural lecture at Utrecht University, last April – the names come from the guests. In the past, Smit conducted research into Q fever, the infectious disease that caused an epidemic among dairy goats in the Netherlands between 2007 and 2011, and then spread to humans.
It is precisely the interaction between animals and humans that is now also central to her current position as a professor onehealth and environmental epidemiology at the Faculty of Veterinary Medicine. She is looking for a sustainable way to balance the health of people, animals and ecosystems. “The term onehealth is defined by the World Health Organization, the World Organization for Animal Health, the Food and Agriculture Organization and the United Nations Environment Programme. They describe it as an interdisciplinary approach to threats to health and ecosystems. So in addition to good health care for humans and animals, it is also about nutrition and climate, clean water, clean energy and clean air.”
A better environment starts with ‘one health’, you say in your inaugural lecture. How do you mean?
“Yes, in my youth, in the early nineties, the slogan ‘A better environment starts with yourself’ was in vogue. At school we did projects around acid rain, and I remember being deeply impressed by that as a child – I also wanted to do something for the environment. But a sustainable, structural environmental policy requires more than individual responsibility. One health offers such a broad view, and underlines that we should not see the environment as a problem, but as the foundation of all life on earth.” The term has only been widely used since a major convention in 2004.
Janet Elizabeth Lane-Claypon stood at the cradle of modern epidemiology more than a hundred years ago
That does not mean that there were no One Health problems in the past, of course…
“Certainly. Just think of the plague. We now know that this was due to a zoonosis, an infectious disease that passed from animals to humans, in which the bacteria Yersinia pestis played a crucial role. Before people realized that hygiene was essential to prevent the disease, a huge number of people had already died. Here in Utrecht alone, an outbreak in 1636 killed about 15 percent of the population.
“But you certainly already had researchers who were in onehealththought solutions. For example, I came across Janet Elizabeth Lane-Claypon. It stood at the cradle of modern epidemiology more than a hundred years ago. I like that she underlined all the similarities between human and animal needs. For example, she emphasized the importance of mother’s milk for the young of all species. She also did biological research into goat milk, among other things.”
Those goats also played an important role in your research.
“Yes, in 2008 I obtained my PhD on exposure within the agricultural sector to particulate matter and endotoxins – these are toxins that are excreted by bacteria. After that I worked in Paris for another year and a half, but then I came back and the Q fever epidemic was in full swing, and I started doing environmental epidemiological research into goats in the area.”
After 2010, Q fever was under control, while pneumonia continues to increase around goat farms
What is Environmental Epidemiology?
“It is a field in which, just like ‘classical’ epidemiology, we look at the spread of diseases, but specifically in relation to environmental factors. So, for example, micro-organisms and chemical substances, but also social or economic influences. What I like about it is that it is very practical and socially oriented. For example, as a follow-up to the Q fever study, we used data from GPs and found that there was a much higher rate of pneumonia around goat farms than elsewhere. We looked at whether there could be other explanations, but that was not the case.”
What caused those pneumonias?
“Until 2010, the culprit was in any case the bacteria Coxiella burnetii, which is excreted in large quantities during miscarriages of infected goats and survives well in the air. You only need to inhale relatively few particles to become infected. Later, we also confirmed with blood tests that there was a very clear Q fever effect among local residents. But after 2010, Q fever was under control, while pneumonia continues to increase around goat farms. We are now investigating how this is possible.”
Is it difficult to safeguard the health interests of people, animals and the environment?
“Certainly, the conflicting interests are sometimes enormous. Think of adjusting the stables because of the ammonia reduction, which in turn has an impact on animal welfare. If you adjust the barn floor to better separate urine and faeces, it may mean that the cows get complaints about their hooves due to the different surface. Then the challenge lies in looking with one onehealth-look: how can you include all those facets?
“The Netherlands is an interesting country in that respect. We are one of the most densely populated countries in the world, living in a low-lying delta with an international infrastructure that brings us into contact with people, animals and microorganisms from all over the world. And then we also have about twelve million pigs, one hundred million broilers and laying hens, four million cows and calves, half a million goats, 850,000 sheep and 27 million pets. You can hardly get more fascinating.”
That poor air quality can mean that we live more than a year shorter
Where are still challenges?
“Including particulate matter emissions. Traffic is getting cleaner, but intensive livestock farming is also still a major source of air pollution in the Netherlands – about 30 percent of all particulate matter comes from agriculture. There is a Clean Air Agreement in the Netherlands, but it is hardly observed. Maybe because air pollution is so invisible. You don’t see it, you don’t smell it, you think: oh, what a beautiful blue sky. But that poor air quality can mean that we live more than a year shorter, according to the latest calculations.”
You have your own racing bike. Do you still dare to cycle when it comes to air pollution?
“Fortunately. Almost everywhere in the world, it is still better to choose to be outside and to exercise than to sit exclusively in the house or in the car. Exercise is also important for your health.”