Evolutionary biologist sets sail in Darwin’s tracks

 

Reiner Van Hove

As part of a large-scale television programme, evolutionary biologist Tine Huyse boarded a beautiful three-master in Brazil at the beginning of October, which is sailing the same course as Darwin did between 1831 and 1836. In the programme, Huyse illustrated how an African parasite spread across South America as a result of the slave trade.

In 35 episodes, the programme, which is entitled Beagle, in het kielzog van Darwin (in Darwin’s Wake) – a co-production by the Belgian Canvas and the Dutch VPRO – is reconstructing the legendary voyage of discovery that resulted in the theory of evolution through natural selection. Over the course of the expedition, a whole series of scientists, artists and philosophers will be travelling on the ship, including the biologist Sarah Darwin, Charles’ great-great-granddaughter and our very own Tine Huyse, who conducts research at the Laboratory of Animal Diversity and Systematics at K.U.Leuven. She also works part-time at the Institute of Tropical Medicine in Antwerp. Along with Bruno Gryseels, the director of the institute, she submitted a proposal that was selected from the many applications and resulted in a stay in one of the coveted cabins aboard the three-master.

Huyse researches the Schistosoma-worm, a parasite that enters the human body via the skin after passing through a ‘snail intermediate host’ and can cause damage to the liver, intestines, bladder and kidneys. 200 million people are infected with the parasite worldwide. The rise of the slave trade between Africa and South America in the sixteenth century contributed substantially to the spreading of the worm, which originated in Africa.

Huyse: “Various parasites travelled across the Atlantic with their human hosts, including the Schistosoma mansoni, one of the two most important species that occur in Africa. The worm adapted to the new, local snail host, and very soon, an epidemic erupted. The enormous sugarcane plantations in South America ensured the further spread of the parasite, just as they had done in Africa – irrigation canals are an ideal habitat for the snails.”

Huyse, who has previously done fieldwork in Africa, was given a unique opportunity to conduct further research on the South American variant thanks to the Darwin project: “We went to a small plantation in the centre of Salvador de Bahia in Brazil with the camera crew and found huge numbers of snails. All the sewage from the surrounding houses drains into the plantation, including the parasite’s eggs in human faeces, so that the parasite’s life cycle is closed and infections can easily occur. We also went to film in the favelas, where the local children helped us to hunt the snails. In some slum areas, the infection rate amongst children reaches as high as sixty to seventy percent.”

“We set up a primitive lab at the reception desk on the ship. I used a small field microscope to examine the snails we had caught, and the very first snail I looked at was a ‘winner’: I saw hundreds of Schistosoma-larvae swimming to and fro, to the rocking of the sea.”

“We are now going to investigate the relationship between the African parasite and its South American ancestor in the lab, using the very latest genetic tools. Our research has already yielded some conclusions, for example that the bottleneck hypothesis is correct. During the crossing from Africa to Brazil, the parasite population decreased so significantly that as a result, there is far less genetic diversity in Brazil; there are more genetic variations in one village in Senegal than in the whole of Brazil. This information may be very useful in optimising control campaigns.”

The locality in which Huyse collected the snails has great symbolic value; it is the place Darwin first encountered slavery. Huyse: “In his journals, he describes how horrified he was when he heard the groaning of the slaves. His grandfather, Josiah Wedgwood, who ran a ceramics factory, was a famous slavery abolitionist. He even designed a medallion with the iconic emblem of a chained slave and the inscription ‘Am I not a man and a brother?’. In homage to Wedgwood, we used his crockery in our lab onboard and we wore replicas of his medallion.”

Huyse is very excited about having participated in the project: “It brings you out of your ivory tower, at least temporarily: you come into contact with other scientists, but also with artists and philosophers, which is very inspiring. The ship itself was magnificent — the masts alone were very impressive.”

“I did suffer quite badly from sea sickness, apparently because my vestibular system works too well. But in all honesty, it was also because I stopped taking my medication too soon. (laughs) Worse still, my cabin was right at the front of the ship, where you feel the choppy heaving of the sea the most. The ship didn’t only move up and down, it bounced in every direction, like a fairground attraction that never ends. This made me admire Darwin all the more; apparently he suffered from seasickness constantly, and of course he did not have the medications we have access to today.”

“I had only really developed sea legs once we reached Rio de Janeiro, my final destination. Our arrival at the harbour was actually a very impressive and memorable moment: we could see the statue of Christ on the Corcovado and Sugarloaf Mountain looming above us as the frigate-birds flew on ahead of the ship…”