|Hundreds of thousands of people around the world are waiting for kidney transplants [File: EPA]
Information on the shadowy world of of organ trafficking is difficult to come by, but international organisations believe that the trade is growing.
"The international trade in human organs is on the increase fuelled by growing demand as well as unscrupulous traffickers," the World Health Organisation said in a report in 2004.
More than 80,000 people are waiting for a kidney transplant in the United States alone, so there is a huge market for those willing to sell organs. Thousands of people die while waiting for a kidney donation from a living or deceased donor.
Organ trafficking accounts for around 10 per cent of the nearly 70,000 kidney transplants performed worldwide annually, according to the Janes' Intelligence Group.
As many as 15,000 kidneys could be trafficked each year, the group says.
Organ trafficking is largely organised by criminal networks that can connect buyer and seller as well as facilitate the hospitals or clinics where it is possible to have the transplant without questions being asked.Kidney rackets
In 2008, an Indian doctor was accused of harvesting hundreds of kidneys from poor labourers for sale to wealthy patients, some from abroad.
Victims were apparently offered up to $2,000 for the kidney, but some claimed that the organ had been forcibly removed after they had been drugged.
An earlier racket in South Africa saw wealthy recipients, mainly Israelis, brought together with donors recruited from Brazil, Israel or Romania, in Durban for a transplant.
In many countries it is difficult to ensure whether the organs have been purchased illegally as it is perfectly legal to donate organs.
The problem is exacerbated by ageing populations, hypertension and obesity as well as a reduction in the number of road deaths in developed countries, one of the principle sources of donor organs.
Demand for live donors is increased by a widespread resistance in Asia, South America and Africa - for cultural and personal reasons as well as due to the high cost - to using organs from dead bodies.
Most countries which were traditionally the centre of the trade - including China, the Philippines and Pakistan - have now effectively criminalised the sale of organs.
Iran, however, has chosen another route, officially sanctioning financial compensation for those willing to part with an organ for transplant.
Although controversial, the move has been a success in eliminating Iran's kidney transplant waiting list in just 11 years and has encouraged some medical professionals to call for it to be adopted in their own countries.
Source: Al Jazeera and agencies