Questions and AnswersProf. Dr. Mark E.J. Woolhouse

How or why did you become involved in infection research, what fascinates you about this subject?
Two things. I was always interested in population dynamics (how population sizes change through time and across space). Infectious diseases (in contrast to non-communicable diseases) have a property termed positive feedback: the more infection there is, the more risk there is of further infections. This makes things complicated, but mathematically interesting too. It also makes it hard to be intuitive about infectious disease dynamics, especially if the aim is to interfere in the process by introducing control measures. You need good theory to guide you.
The second aspect is that, challenging though they are, most epidemiological systems are considerably simpler than the kinds of ecological systems I worked on as a graduate student. There is often more and better data available as well. So there is a lot of potential to make meaningful scientific progress, as the huge advances in infectious disease modelling over the last two decades attest to. 

What are you working on at the moment?
We usually have a number of different projects on the go at any one time. Often ideas or techniques developed while working on one system turn out to useful in other contexts too. But the project I’ve been spending most time on recently is a study of the population biology underlying the emergence of novel pathogens: what kinds of pathogen are involved, where they come from, what drives their spread into new populations, can we make any useful predictions about future trends?

What was a single most important moment of your career?
The pivotal decision was to apply for a research fellowship advertised by the University of Zimbabwe in 1985. This was a pre-meditated switch from ecology to infectious disease epidemiology, but as well as being a change in career path it was also an introduction to science and scientists in developing countries. I kept that link ever since; much of my research has been based in Africa.

What was your most important scientific discovery?
The work that’s given me the most intellectual satisfaction was written up as the “20-80” rule: 20% of the population account for (at least) 80% of the transmission potential. This works for a very wide range of infections. It’s important for understanding epidemiological patterns and how best to target interventions.

What drives you and carries you on? What do you love about your work?
These days my main task is to provide opportunities for the next generation of scientists. Their successes make the job worthwhile. More generally, there is a strong sense of real progress in my field: infectious disease epidemiology is a 21st century success story and it’s nice to be playing a modest part in that.

What influenced and impressed you and your life and therefore science?
The direction that my research career has taken owes a great deal to the influence of Roy Anderson and Bob May, who I worked with at Imperial College, London and later in Oxford. They have made a massive contribution to the development of mathematical epidemiology as a discipline.

Idols?
This is a far from original choice, but I’d opt for Charles Darwin. His life’s work is an utterly compelling combination of grand vision (perhaps the grandest of all), a deep knowledge of his subject and meticulous attention to detail.  

What would you recommend to someone starting out in science? What would be your advice for young scientists?
Scientific research is extraordinarily rewarding because it’s cumulative. We really can see farther than those giants on whose shoulders we stand. That’s quite something. And when we publish our work we are helping the next generation to do the same. No other creative activity (and science is creative) offers that kind of opportunity.

What would have been your alternative plan (plan B) if science /your job
had not worked out?
I never had a “Plan B”. It’s hard to imagine doing anything else.

What are your dreams for the future?
I’ll mention just the one. I hope that in the future decisions about how best to control and prevent infectious diseases will be based on sound scientific evidence and a good understanding of epidemiological principles. Sadly, this isn’t always the case even now, but the issue was highlighted for me by the epidemic of foot-and-mouth disease in Britain back in 2001. I was very much involved with the real time research effort that informed government policy during that emergency. Mathematical models were used very successfully to demonstrate the potentially massive scale of the epidemic and to help decide how best to control it. The pity is that this kind of rigorous input wasn’t sought earlier, before the outbreak got out of hand, instead of relying on so-called “expert opinion”.

What do you think is important and should be worked on in the future?
There is a whole series of unanswered problems in epidemiology. Why are most infections rare? Why do different pathogen strains come and go? How important is it that most hosts experience multiple infections in their lifetime? Why do novel infectious diseases ‘emerge’? These are all interesting questions in their own right but, to me, they also point towards a deeper issue. We like to simplify and make abstractions, modellers as much as (if not more than) anybody. But the interaction between a host and a pathogen is often part of a larger system, encompassing other pathogens, other hosts and wider environmental factors. In the future, I hope we will have the skills, data and confidence to study the bigger picture. This is a key lesson from my own work on emerging diseases and it appeals to me because it requires the kind of interdisciplinary approach that comes naturally to ecologists, taking me back to my scientific roots.

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