KATHMANDU, Nepal (CNN) -

On the streets of Kathmandu, the sight of people begging for kidney treatment has become common.

The capital of Nepal is no different from many places in the world where aging populations, poor diets and no health insurance systems mean increased organ disease.

The organ in highest demand is the kidney and black market traffickers are meeting that demand. Up to 7,000 kidneys are obtained illegally every year, according to a report by Global Financial Integrity.

Organ trafficking is an illegal, yet thriving trade around the globe.

That same report shows the illegal organ trade generates profits between $514 million to $1 billion a year.

In Kathmandu, we spotted a couple begging on the street for their son's kidney treatment.

Jeet Bahadur Magar and his wife spent their entire savings to treat their son's kidney disease.

Out of money and options, they are now out on the street hoping to raise enough funds to cover the medical bills.

"I pray to God that no one has to ever go through kidney failure problems," Jeet Bahadur said.

But many Nepalis do.

During our visit, Nepal Kidney Center in Kathmandu was packed with patients having dialysis -- a grueling four-hour process of purifying blood through a machine.

A patient can avoid the kidney transplant by having dialysis at least three times a week.

Those lucky enough to afford a transplant still face obstacles: the donor must match the blood group of the recipients and Nepali law requires the organ donor to be a family member.

Nepal's 'kidney bank'

We traveled to Kavre, a tiny district close to Kathmandu, and what activists and authorities say is a ground zero for the black market organ trade in Nepal.

Here, kidney trafficking rackets -- well organized and well funded -- dupe the poor and uneducated into giving away a piece of themselves.

The district has developed an unfortunate reputation as the "kidney bank of Nepal."

For more than 20 years, activists say, people from villages in Kavre have been the primary source of kidneys for sick and desperate patients throughout Nepal. But now the numbers are being tracked.

In the last five years more than 300 people have been reported to be victims of kidney traffickers in this district alone, according to Forum for Protection of People's Rights, a Kathmandu-based non-profit human rights organization. Some activists say the number is much higher.

"Social stigma and threats from traffickers keep many victims from coming forward," said Rajendra Ghimire, a human rights lawyer, and director of Forum for Protection of People's Rights.

'The meat will grow back'

Nawaraj Pariyar is one of the many victims of kidney traffickers.

Like many in Kavre, Pariyar makes a living from selling cattle milk and doing seasonal labor jobs on nearby farms. Poor and uneducated, all he has is two cows, a house and a tiny plot of land.

Pariyar used to visit Kathmandu to find construction work. He was on a site in 2000 when the foreman approached him with a dubious offer: if he let doctors cut out a "hunk of meat" from his body, he would be given 30 lakhs -- about $30,000.

What he wasn't told: the piece of "meat" was actually his kidney.