Doctors and researchers are puzzled by a sharp rise in chronic kidney disease among farming communities in the North Central province of Sri Lanka.
The number of cases has been steadily rising since the disease first came to light around eight years ago. Over 18,000 cases have now been reported, with cases in Eastern and Uva provinces as well as North Central.
In 2003, almost 200 hundred patients died from renal failure in the North Central province and the figure is increasing every year. Over half the population there is engaged in agriculture.
Almost all those affected are men from farming families without pre-existing conditions than can lead to renal disease, such as hypertension or diabetes.
The absence of clinical symptoms until the late stages of renal failure is also puzzling researchers and making early diagnosis difficult, leading to many deaths.
Local researchers have come up with several possible risk factors for the disease, including high groundwater fluoride content in some affected areas, leaching of heavy metals such as cadmium from agricultural chemicals into water sources, exposure to inorganic pesticides and fertilisers, and usage of aluminium vessels to store drinking water.
Several studies conducted by local researchers have found a strong link between high cadmium concentrations in water sources and high disease prevalence.
A team of medical experts from the WHO visited Sri Lanka to assess the situation in May this year. They recommended that non-affected agricultural regions be used as control areas in studies to find the disease's cause, and preventative measures such as using clay pots to store water are used.
A long-term clinical study was also proposed by the WHO but has yet to be implemented, Rohana Dayaratne, a geneticist and physician attached to the National Hospital of Sri Lanka in Colombo, told SciDev.Net.
He says local and international researchers should lead a combined effort to identify the causes and preventive measures, and that local researchers have a good knowledge about ground realities that should be combined with the financial and other resources of the international community.
The majority of the affected farming communities were settlers from different parts of the country, he says, meaning that there could be a genetic component to the disease.
The growing number of patients suffering from chronic renal disease is becoming a heavy burden on the health sector, as the treatments — dialysis and organ transplants — are costly procedures.
Efforts are underway to educate the public about risk factors, maximise early diagnosis with weekly clinics and field visits to vulnerable areas, and introduce preventive measures.