Rats sniff out unexploded mines

BAKEND Temple, on a hill west of Angkor, offers spectacular views of the setting sun.

Elephants are on hand to transport visitors to the summit. They’re not really needed. The walk up to the temple is pleasant: cicada choruses and jungle birdsong fill the balmy evening air. Just off the path, last week, a band played: squeaky traditional instruments producing a wistful haunting refrain. But this was no ordinary band: every member of it had been disabled by a landmine or a bomb. Some were blind, all had lost limbs.

In 1969, the United States began carpet-bombing Cambodia. In the civil war which followed, the notorious Kymer Rouge killed two million people. They thought that blowing up innocent children and farmers would demoralise the population into submission, so landmines were laid all over the countryside. Pol Pot, aka Blood Brother No 1, and his thugs were defeated by the Vietnamese but the civil war continued. It would be the late 90’s before hostilities ceased.

Landmines don’t recognise peace treaties. As recently as 2004, there were 898 fatalities and injuries from bombs and mines. One Cambodian in 2,000 is an amputee and visitors are warned not to venture off well-worn paths in the countryside. According to the March 23 edition of the Phnom Penh Post, five people were killed by landmines in January this year. Nine were injured, two of them requiring amputations. This was presented as a ‘good news’ story; the number of casualties in January 2009 was 34.

It’s thought that there are still about three million mines and unexploded bombs in the ground. They can be defused or detonated; the problem is to locate them. Screening with hand-held metal detectors is dangerous; one searcher is killed for every 5,000 mines found. The faint odour given off by explosives can be detected by sniffer dogs, but dogs are heavy enough to set off mines, killing them and endangering their handlers. Dogs are expensive to train, work with only one handler and, like humans, are prone to illness when taken to tropics.

But thanks to the work of a Belgian ‘social entrepreneur’ and Buddhist monk, working in Mozambique, help has come from an unlikely source; rats. Apopo is a non-profit-making organisation founded by Bart Weejens who kept pet rats as a boy. He discovered then that the rodents have extremely sensitive noses. These scavengers are constantly at risk of poisoning so they have developed extraordinary powers of smell. Weejens also found that rats are easy to train. Apopo has training centres in Mozambique and Tanzania where African giant-pouched rats, with leashes attached, are led by trainers over plots in which mines are buried. A rat finding a mine will scratch at the surface and is rewarded with food. Training can take as little as three weeks, whereas a dog needs at least a year. Rats have longer concentration spans than dogs, are immune to local diseases and can be taken anywhere. Nor do they become attached to one handler but will work with anybody. Easy to maintain and support, they are too light to set off the mines they detect. Their only disadvantage is a shorter life span; a rat won’t live beyond the age of eight.

Finding mines, it turns out, is not the rats’ only useful skill. With training from Apopo they are helping to fight one of the world’s most lethal diseases. Tuberculosis is a major health problem world-wide. According to the World Health Organisation, deaths from the disease will reach eight million annually by 2015. Testing for the presence of TB is time-consuming. Samples of sputum taken from the lungs are examined under microscopes. The process is unreliable, however, the disease being correctly diagnosed in about 60% of cases.

Apopo’s rats are trained to sniff at holes in Perspex sheets, behind which samples of sputum are placed. When a rat identifies TB in a sample, it is given a piece of banana as a reward. The success rate recorded in clinical trials is 67%, better than that achieved by laboratory technicians. The most important pay-off is its speed. A rat can get through 2,000 samples in a day, whereas the technician can manage only 20.

Come back rats, all is forgiven!