Mosha was just seven months old when she stepped on a landmine. The baby elephant - trailing behind her mother, who was transporting logs across the Thai-Myanmar border - lost the lower part of her right leg in the explosion. Crippled and in agony, she would have died if Soraida Salwala, founder of the Friends of the Asian Elephant (FAE; hospital in Lampang, northern Thailand, had not heard of her injury.

"We were called by her mahout, and Mosha and her mother were brought here. We almost lost her during the treatment, because her wound became infected. But we treated her with fresh medicinal herbs and then she got up and the wound healed beautifully," says Bangkok-born Soraida, who established the FAE hospital, the world's first dedicated to elephants, in 1993.

I see myself as my elephants' mother. If I'm away, I'll call them every day.

Now, Mosha is eight and taking her first, tentative steps on the most sophisticated prosthetic leg ever created for an animal of her size. The newly fitted artificial limb means the difference between life and death for her.

"If she didn't have it, she would die in the next five to 10 years," says Dr Preecha Phuangkum, chief vet at the FAE hospital.

Elephants can walk on three legs but doing so shortens their lifespan dramatically, as Mosha's curved spine and bent front leg reveal.

"An elephant's front legs carry two-thirds of their body weight. So when she bends down, it puts a huge strain on her good leg. Without the artificial limb, her good leg would go and then her other joints, too," says Preecha.

Ears flapping, her trunk waving and sniffing for the bananas she scoffs by the bunch, Mosha lumbers around her enclosure on her new leg. She moves slowly but is already accustomed to the prosthetic limb and clearly delighted to be on four legs again.

"She really likes it. If we're late putting it on in the morning, she gets restless and starts roaring," says her keeper, Palahdee Sujaritsuchada.

Mosha's is no ordinary artificial leg. Having to bear an animal that is almost seven feet tall and more than 1,300kg, it weighs 10kg and employs the type of rubber used in car shock absorbers. Just putting it on takes three people. Her stump is first smothered in baby powder, before a giant nylon tight is put over it to stop the artificial limb rubbing Mosha's skin. Then, the leg is slipped on.

"It's like fitting a shoe. It feels like a boot for her," says Preecha.

The life-saving leg is the brainchild of Dr Therdchai Jivacate, secretary general of the Prostheses Foundation, in the nearby city of Chiang Mai. Over the past 21 years, the foundation has supplied more than 27,000 free prosthetic legs to amputees across Thailand, Myanmar and Laos.

"Our objective is to make free artificial legs for the poor and underprivileged regardless of their race, religion or nationality," says Therdchai. But with 1,000 elephants working in the timber trade along the Thai-Myanmar border, more and more pachyderms are losing limbs. The ongoing conflict between the Myanmese army and ethnic Karen rebels fighting for their own homeland has resulted in the border regions that supply much of Thailand's imported wood being heavily mined. At least 100 elephants have taken catastrophic steps similar to Mosha's in recent years.

The casualty rate prompted Therdchai to offer his services to the FAE hospital, located in the jungle outside Lampang. "At first, it was curiosity and the challenge. I'd made a lot of prosthetic legs for humans, as well as a few for dogs, so I wondered, 'Can I make one for an elephant?'," he says. Now, the doctor sees assisting these giant but sensitive beasts as a matter of honour. "Elephants are Thailand's national animal. They've done a lot for us in the past, so I am proud to help them."

Creating a prosthetic leg for an elephant is "very different from making an artificial leg for a human. You'd think it would be easier, because an elephant has four legs, so if they lose one they still have three and better balance than a human who is left with just one. But you can't tell an elephant what to do", says Therdchai.

Getting an animal to stay still while the mould is being made for an artificial limb is the hardest part. If they move while it is being made, the leg won't fit correctly. And as a doctor, rather than a vet, Therdchai was further hampered by his lack of knowledge about the mechanics of how an elephant walks.

"I just relied on my common sense," he says.

Almost as crucial as fitting the leg is the need to ensure that the elephant is ready.

"The first time you put an artificial leg on an elephant it's very difficult. They're like children; they are very scared," says Preecha. "And if they reject a prosthetic leg the first time, then they'll never accept it. So we really have to prepare them by first showing them the limb and slipping it on and off. It can take a couple of years to get an elephant ready to wear one."

With Mosha growing all the time - elephants can live to be 70 and continue to grow until they are 20 - she needs a new leg every six months. Now, Therdchai believes he has created the most sophisticated yet, first fitted to Mosha just two days before Post Magazine visits. A polyester resin has been used to create the outer shell of the leg and the inside is cushioned foam. Steel supports give it the appearance of a human prosthetic limb.

"The leg has a joint and it can bend, so she can walk on uneven terrain," says Therdchai. "I think that has achieved our main objective: giving her as much freedom of movement as possible. I'm not sure we can do much more for an animal of Mosha's size."

Mosha may have the most advanced prosthetic, but it is another patient at the hospital who became the world's first elephant to walk on a false leg. At 52, Motala is fully grown, weighing in at 2,600kg. She has been at the facility since 1999, when she lost the lower part of a leg to a landmine. Her latest prosthetic employs the same materials as Mosha's but is much larger and weighs 18kg. It is a far cry from Motala's first fake leg, which had to be held on by straps over her body.

Boomee, a 10-year-old female, is another of the hospital's landmine victims. Two of her toes were blown off in the blast three years ago and her foot has yet to heal fully, although she does not require a prosthetic leg.

Soraida is now appealing for international help to clear not just the Thai-Myanmar frontier of the landmines that litter it, but the entire region.

"I want all of Southeast Asia de-mined," she says. "I want the money spent on buying mines to be used to get rid of these evil weapons. Mines don't kill outright, they maim. Elephants who step on landmines and can't get up die slow, horrible deaths. And for the ones who are rescued and treated, it is a huge psychological injury for them."

Soraida has been obsessed by elephants ever since she saw the Disney movie Dumbo as a child. "I felt so sad for him," she says.

Suffering from lupus, an incurable disease that affects the auto-im-mune system, the 56-year-old spends a lot of time in hospital herself.

"Maybe it's because I have been ill all my life and so I know what pain is, but when the elephants see me and hear the tone of my voice they know there will be no harm from me or my staff. Maybe they don't understand what I am saying, but they do understand the tone of my voice and get the message," she says.

Along with her staff, Soraida has become hugely attached to the elephants at the hospital, especially those, like Mosha and Motala, who will spend their entire lives here: "I see myself as my elephants' mother. If I'm away, I'll call them every day. One of the keepers will hold the phone a few metres away. They'll flap their ears, or wave their trunk, or sometimes roar when they hear my voice."

Her struggle to conserve Thailand's national animal is an increasingly urgent task. Deforestation of their natural habitats and poaching, as well as landmines, have reduced the elephant population to about 5,000, a huge decline from the 40,000 that roamed the country 40 years ago. Just 2,000 of them live in the wild.

Many have been kidnapped by gangs who take them to the cities and use them to beg, or are confined to poorly run elephant camps set up to attract tourists - there are now about 100 such facilities in Thailand. Elephants prove more profitable in those endeavours than when they are put to work in the logging industry. A working elephant sells for 600,000 baht (HK$150,000) in Thailand but a baby one that can be used to panhandle will sell for a million baht.

Poaching poses perhaps the biggest danger to Thailand's elephants, whose numbers are dropping by about 200 a year. The sawn-off tusks of Kammee, a 56-year-old male patient at the hospital, are sad testimony to the continued illegal trade in ivory. But there is rising demand, too, for other parts of their bodies, with elephant penises, trunks and teats all used in so-called traditional medicine or as good-luck charms. Both China and Vietnam are major markets for ivory and other elephant body parts.

A large proportion of Thailand's remaining elephant population has passed through the FAE hospital or been seen at one of its mobile clinics. Since 1993, more than 3,800 pachyderms have been treated for everything from amphetamine addiction (some mahouts give their elephants speed pills to make them work harder) to cataracts and broken legs, as well as injuries caused by physical abuse from their handlers.

"To a lot of Thai people, elephants are just working animals," says Preecha. "Some mahouts love their elephants and treat them well. Others don't. We see many cases where the animals have been left chained up in the jungle for long periods, or made to work while injured. We think we have raised awareness among the villagers who use working elephants about the need to look after them. But how an elephant lives really depends on their handler."

Being a vet around an elephant is risky; Preecha has been kicked and hit by flying trunks many times.

"Other animals are easier to treat," he says. "Elephants are big and can be very bad-tempered. We've had patients who have killed their mahouts in the jungle before they come here. So when I treat them, I go into the enclosure surrounded by people with sticks and spears. It's a precaution. I could get killed giving an injection."

Entirely reliant on donations from the public, the hospital costs one million baht a month to run, according to Soraida. "We get no money or encouragement from the government. It makes me very upset." With an elephant eating up to 150kg each day, she says much of the budget is spent on food. "When we have a lot of patients, we'll go through four tonnes of grass and bananas a day."

About 80 per cent of donations come from the Thai public, while French actress and animal-rights activist Brigitte Bardot makes an annual contribution.

"We've never met because she doesn't fly anymore. But she's been donating since 2007 and we text each other. I named one of our elephants 'BB' in her honour," says Soraida.

Yet while she stays in close contact with elephant conservation campaigners around the world, and hosts students from schools and universities, as well as overseas vets, at the hospital, Soraida is happiest when she is with her patients.

"Sad as it is, it is easier for me to get on with elephants than humans. It's so hard to get humans to understand what I am doing, sometimes," she says. "Some people say I am too emotional about elephants, but when you see their pain every day, it is natural."