If you’re looking for evidence of human shortsightedness, you might start with landmines. Popular as an inexpensive tool of warfare, landmines now render land uninhabitable and unusable in 45 countries. They’re hard to remove: there’s an estimated 110 million unexploded mines waiting to kill, injure and maim, and at current demining rates, it will take $33 billion and 1,100 years to do the job.
(The US has been unwilling to sign the Ottawa treaty agreed to by 154 countries banning anti-personnel mines. The Bush administration has offered an “alternative” policy that’s gained little international traction. One of the sticking points is a possible exception for the Korean DMZ, where the US relies heavily on mines to maintain a large land border.)
Mine removal is a topic that’s generated a great deal of innovative thinking in the engineering and social change communities. One of the favorite projects of green innovation folks like my friends at Worldchanging.com has been the Arsena project to genetically engineer a flowering weed that can detect landmines. The plant – a modified thales cress – turns red in the presence of nitrogen dioxide, a product of the degredation of the explosives in landmines.
Unfortunately, the thales cress project never really achieved its goals – the flower was too sensitive, leading to a large number of false positives. In March, the Arsena team transfered the genes from the thales cress to tobacco, looking for a hardier organism. Now they’ve given up on the project entirely, focusing instead on investment in mined land, rather than on new detection technologies and, unintentionally I’m sure, robbing the green engineering community of one of their (our?) favorite examples.
Fortunately, Bart Weetjens is here to help, and he’s got lots of backup: cages filled with African giant pouched rats. The rats have an amazing sense of smell, and Weetjens has trained rats to detect landmines by scent. The rats are too light to trigger the mines (though they look roughly as large as my cat), but they stand on the mine and dig until a handler picks them up, rewards them with food and removes the ordnance. The rats have already cleared 416,500 square meters of minefield, and can detect more mines in an hour than a professional human deminer can in a day.
I met Weetjens in Dubai at an absurdly lavish banquet put on by an Emirati real estate firm for WEF attendees. More to the point, since the banquet was far off in the desert, I met him on the 90 minute bus ride, when a group of us in the back of the bus started talking about Africa-focused projects. My first question to Weetjens: “So you’re a bioengineer?” “Nope. I’m a mechanical engineer who really likes rats.” According to his biography on the Ashoka website, Weetjens was fascinated both by weaponry and rodents as a child, so his current interest seem perfectly logical given his history. He now runs a social venture called Apopo that tries to harness rats’ talents for the benefit of humanity.
Why rats? He was hoping you’d ask. The Apopo site features a wonderful section called “Hero Rats“, which outlines the abilities of the robust rodents. As well as being light, and blessed with an amazing sense of smell, rats are easy to breed, relatively easy to train, easier to house and feed than dogs, willing to work with different handlers (a problem for dogs, evidently), and surprisingly cute. (You’ll be unsurprised to discover that you can adopt a rat for 5€ a month. And yes, you can send them email and they’ll mail you back. Or their handlers will. I’m not really sure.)
So here’s the truly amazing thing – Apopo is now looking at other applications for rodent-based sensing. Weetjens and crew are training rats to smell tuberculosis in sputum samples. Early tests suggest that rats can perform this task far more efficiently than lab technicians – rats evaluate several hundred samples in the time a human technician with a microscope can evaluate twenty samples. Weetjens admitted to me that he and his team don’t know what the rats are smelling – they’re now doing gas chromatography to compare samples and see if they can figure out the chemical mechanism for TB detection.
What would be truly amazing is if rats are able to detect between TB strains. One of the most serious problems associated with XDR TB is the difficulty of culturing the bacteria and distinguishing between “ordinary”, drug resistant, multiply drug-resistant and extremely drug resistant TB – I have no idea whether the strains are sufficiently different to make rat-based testing realistic, but it would be a fascinating research project…
My favorite thing about Apopo is not the rats… though I would confess to having falled in love with Kim, pictured above with her handler, Saidi. It’s the location of the project – Morogoro, Tanzania, based at the Sokoine University of Agriculture. (Morogoro is roughly halfway between Dar and Dodoma, for those of you who know Tanzania.) It would be possible to do his research in his native Belgium, but Weetjens is trying to bring research opportunities and jobs to this community as well as developing an innovative new strategy. I think that’s phenomenally cool, and wonder what Apopo will figure out what to teach rats next.