BATTLE A DEADLY PARASITE

WHAT makes a successful parasite? That’s the question I’m trying to answer through my work as Professor of Evolutionary Parasitology at the University of Edinburgh. My research focuses on malaria parasites and uses evolutionary biology to understand the strategies that the parasites have evolved to survive and spread.

I head up a 10-strong team and one of the things we look at is the challenges that being a parasite brings. The host they are inside is constantly trying to get rid of them. That can be a brutal environment. We use knowledge of the strategies that animals, birds, plants and insects have evolved to ask how sophisticated parasites are. Parasites have been rather underestimated. While they don’t have brains or neurological processing powers, they do behave in similar ways to these other creatures. Our work involves assessing how parasites interact with each other and cope with the changing environments they experience inside hosts and the vectors, such as mosquitoes, that transmit them.

We know that parasites can work together to overcome their host and organise themselves according to the time of day. They have quite a lot of different tactics to help themselves when their hosts are treated with antimalarial drugs. We are uncovering how good they are at moving the goalposts when medicine attacks them.

Malaria parasites and their relatives are responsible for some of the most serious diseases of humans, livestock, companion animals and wildlife.

For example, almost half the world’s population are at risk from malaria; it kills approximately half a million people each year, mostly children under five, and several hundred million cases occur annually. It is a complex disease and a sophisticated parasite. Over the past decade, there has been a very promising reduction in the number of malaria cases. However, progress in reducing malaria has slowed dramatically over the last two years. It looked like everything was going well but now eradication of the parasite is looking further away.

Malaria parasites are famous for their ability to resist anti-malarial drugs. We know that if we attack the parasites, they are going to move the goalposts. The questions are how far are they

moving them, how quickly and where do they end up? We aim to couple this knowledge with information on how parasites make decisions to improve our armoury against parasites.

There is still an ambition to eliminate malaria by 2050 but that depends on how the parasites respond to what we do to them. Every time we experiment to ask a particular question, the insight we gain throws up at least 10 new questions. It is a bit like travelling up a tree. You start at the trunk and need to find your way through the branches and twigs towards the top. It is exciting getting results because you have learned something that no one knew before. Parasites: Battle for Survival is at the National Museum of Scotland in Edinburgh until April 19. Visit nms.ac.uk/parasites

PICTURE: GORDON TERRIS