Sampath Kumarasinghe's aunt sweeps dirt outside their home near Kebithigollewa, Sri Lanka.

A farmer tills his rice paddy in Padaviya, Sri Lanka.

21-year-old Sampath Kumarasinghe relaxes with family outside his home near Kebitigollewa, Sri Lanka. Sampath has the most advanced form of CKDu, end-stage renal disease. He is slated to have a kidney transplant in the next few weeks, one of the first transplants to take place at Anuradhapura General Hospital.

Nurses talk in the dialysis ward of Anuradhapura General Hospital.

Sampath Kumarasinghe discusses the next steps towards getting a kidney transplant with nephrologist Rajeewa Dissanayake at Anuradhapura General Hospital, Sri Lanka. The 21-year-old rice farmer has end-stage renal disease.

Sampath Kumarasinghe talks to Ajantha, a potential kidney donor, while undergoing dialysis treatment at Anuradhapura General Hospital, Sri Lanka.

Mihintale Dhammarakkita Thero, a Buddhist monk, and high school principal G Gunasena sit outside the educator's home near Kebithigollewa, Sri Lanka. The monk donated a kidney to the principal, who suffers from CKDu.

Mihintale Dhammarakkita Thero, a monk in Sri Lanka, donated his kidney to a high school principal with kidney disease. Mystery in the Fields is a three-part series that explores in text, photos and video how a rare form of kidney disease is killing laborers and crippling communities in three different regions, from Central America to Sri Lanka to India. As the death tolls mount, researchers remain puzzled, unable to definitively uncover the disease’s causes.

Mihintale Dhammarakkita Thero (center), a monk in one of the regions of Sri Lanka most affected by CKD, donated his kidney to a high school principal with the disease.

Buddhists visit the Temple of the Tooth in Kandy, Sri Lanka on Vesak, the anniversary of the day the Buddha attained enlightenment, one of the most auspicious days for Buddhists.

Doctors replace a catheter inserted into the neck of Sampath Kumarasinghe. The tube facilitates his twice-weekly dialysis

A rice farmer and his daughter outside their paddy fields in Anuradhapura, Sri Lanka.

Sampath Kumarasinghe's grandmother cooks by candlelight in their home near Kebitigollewa, Sri Lanka.