Aflatoxin,the silent killer in Africa’s food
If I told you there was a cancer-causing poison that 4.5bn people are chronically exposed to you’d think I was making it up. But I’m deadly serious.
Most of you won’t even have heard of its name before. That needs to change and we need to eradicate it. And the incredible thing is that the very people who could do this aren’t scientists – they’re computer gamers.
The poison is called aflatoxin. It’s an invisible substance produced by fungus that contaminates staple food and cash crops, mainly in the developing world. Staple foods that billions of people need to survive – maize, tree nuts, cassava, millet, peanuts, wheat – are affected, as are animal feeds too. Billions of people around the world are eating foods contaminated by aflatoxin as you read this.
Aflatoxin B1 is the most potent naturally occurring liver carcinogen that we know. It’s considered a Class 1 carcinogen by the WHO International Agency for Research on Cancer. As a result, it is thought that aflatoxins may play a role in up to 28% of all liver cancer cases globally. Climate change will only make this worse. Rising temperatures allow the aflatoxin-causing fungi to flourish.
Worryingly, the impact doesn’t stop at increased cancer rates. Eating aflatoxin-contaminated food is also associated with stunting in children, as well as increased rates of maternal anaemia and mortality. Stunted children suffer from poor cognitive skills, leading to low educational performance and even lower wages in adulthood. There is no reason why there can’t be many more brilliant African scientists in the world, but aflatoxins make that much less likely. We have an urgent moral imperative to change this.
This burden falls primarily on the developing world. In developed countries, laws limit the parts-per-billion (ppb) of aflatoxins allowed in food for humans, livestock and pets. These laws are enforced by extensive – and expensive – monitoring processes and technology. The developing world, on the other hand, has low healthcare budgets, subsistence agriculture and small-scale, under-regulated food production businesses. And in that context limits are set, but often not enforced.
At Mars, we test raw materials for aflatoxin to ensure that our products are safe. But consistently over the past 50 years, most food and feed samples in the developing world have been found to be well above legal aflatoxin limits.
In Nigeria, aflatoxin is now the single largest cause of liver cancer. Kenya has been particularly badly affected by aflatoxins. In 2004, Kenya was beset by the largest recorded aflatoxicosis outbreak in which 319 people who had consumed aflatoxin-contaminated maize were hospitalised. Scientists have been working hard to address aflatoxin for years, but no current strategies to remove aflatoxin infestation have been successful.
The harm isn’t just to human health either. It’s also a massive trade and economic issue. In the 1960s, before the effects of aflatoxin were understood, Africa had 77% of the global peanut export market. Its current share is about 4%. African countries now find it very difficult to meet aflatoxin standards in the developed world, and this hits exports hard. This is costing it $1bn per year in lost peanut revenue alone. If you include other indigenous crops to this, the number will increase dramatically.
Computer gamers seek solution
But the solution to this growing public health crisis may come from an unlikely source: an army of global computer gamers. On World Food Day 2017, we launched a series of aflatoxin puzzles on the Foldit platform led by computer scientists from Northeastern University and the University of Washington.
Foldit is a revolutionary crowd-sourcing computer game that allows anyone in the world with a computer and imagination – but not necessarily any scientific training – to help solve scientific puzzles. Foldit has already had great success by solving a riddle involving an HIV enzyme that had troubled scientists for decades.
The gamers cracked the structure within three weeks and helped identify targets for drugs to neutralise HIV. In this case, the puzzle is to figure out how amino acids are folded together to create proteins, the workhorses of our bodies. Gamers don’t need to know how the science works, they just need to create an increasingly perfect folded form that might mimic the one that exists in nature.
At the start of the gaming session, Foldit players are provided with the form of an enzyme that has the potential to degrade aflatoxin. Gamers can then put their skills to the test to see if it can be redesigned and improved by twisting and turning the enzyme’s structure. In the month that the puzzles have been active, gamers have generated over 400,000 designs.
The important thing is this – humans have an innate skill in coming up with solutions to 3-D puzzles, more so, at the moment, than computers. Science has not been able to provide a solution to aflatoxin yet. This initiative means this challenge is now open to hundreds of thousands of gamers around the world.
The gamers’ best designs are currently in development using the latest synthetic biology techniques and materials donated by Thermo Fisher Scientific. The souped-up enzymes will then be tested in real life by the Siegel Lab at the University of California, Davis to see how they can recognise and neutralise aflatoxins. And all of the players’ discoveries will be kept in the public domain, free of patents. The Siegel Lab is optimistic that we can expect the first results later this month.
We’ve brought together a diverse set of partners to make this happen, including the Partnership for Aflatoxin Control in Africa, led by the African Union Commission. And on World Food Day 2017, we brought together some of the world’s best Foldit players to bring the search for a way to eradicate aflatoxin that bit closer.
Over my lifetime, computer technology has transformed the potential for finding solutions to complex scientific problems. I never thought that computer technology and science could work hand in hand one day to solve some of the world’s most terrible health issues. It’s a dream that will hopefully come true when we say game over to aflatoxin, the silent killer in our food.