The disease, now a humanitarian emergency, is forcing scientists, policy makers and activists in South Asia to think outside their usual boxes and silos.
Containing the disease needs a well-coordinated response from public health, agriculture and water supply sectors. Typically, these fall under separate ministries and government agencies.
Concerned scientists realise that they must carry out multidisciplinary studies to better understand the causes and dynamics of this non-communicable disease. Social scientists form an integral part of this approach.
The disease was first reported from Sri Lanka’s dry zone (north, east and south of the island) in the early 1990s. Hundreds were diagnosed with kidney failure — but none had the common causative factor of diabetes or high blood pressure. Most were male farmers between 30 and 60 years. 
Building up stealthily in the body, the disease manifests only in advanced stages. By then, regular dialysis or transplants are the only treatment options.
Similarly, unexplained kidney failures started being reported in India a decade ago.  The Indian Council of Medical Research (ICMR) has identified the states of Odisha and Andhra Pradesh as hotspots.
In both countries, a definitive link to a specific factor has yet to be found. Hence, the name Chronic Kidney Disease of uncertain aetiology, or CKDu.
Over the years, researchers in Sri Lanka have probed various environmental, geochemical and lifestyle-related factors. They have produced a dozen hypotheses, none proven.
The most comprehensive study to date, the National CKDu Research Project from 2009—2011, concluded that CKDu results from not one but multiple factors. 
The multidisciplinary study, led by Sri Lanka’s ministry of health, with support from the WHO, highlighted several risk factors. These include long-term exposure to low levels of cadmium and arsenic through the food chain, which are linked to the wide use of chemical fertilisers and pesticides. Selenium deficiency in the diet and genetic susceptibility might also play a part.
The findings, released in mid-2013, were also published in BMC Nephrology in August 2013. Researchers agreed that more studies are needed to understand how certain plants accumulate heavy metals from their surroundings. 
Studies in India are less advanced, but heavy metals like mercury, cadmium and arsenic are among the suspects. India's ICMR is planning a major study to look at CKDu’s links to environment, genetics and maternal nutrition.
Scientific rigour crucial
Indian officials and researchers can draw some useful lessons from Sri Lanka where CKDu has sparked heated controversy and created policy dilemmas.
One thing is certain. Neither country can delay remedial or precautionary measures until full understanding of the disease emerges. Indeed, WHO has recommended taking care of the affected while science takes its own course.
As Shanthi Mendis, WHO director for managing non-communicable diseases, based in Geneva, says: “CKDu is a major public health issue placing a heavy burden on government health expenditure and is a cause of catastrophic expenditure for families, leading to poverty and stigma in the community.”
A priority is providing clean drinking water to all people living in the endemic areas. Sri Lanka’s 2014 budget has allocated 900 million Sri Lankan rupees (US$ 6.9 million) for setting up reverse osmosis treatment plants to purify groundwater locally. Rainwater harvesting systems are also being promoted.
Accurate diagnosis and data integrity are also needed. In early 2013, Sri Lanka’s ministry of health estimated that some 450,000 persons were affected. The cumulative death toll is estimated to be between 20,000 and 22,000, but these numbers are not verified.
The kidney specialist who first detected the disease worries that some activists are exaggerating the numbers. Tilak Abeysekera, who heads the department of nephrology and transplantation at the Teaching Hospital, Kandy, underlines the critical need for correct diagnosis. CKDu should not be confused with other types of kidney disease.
Abeysekera told a national symposium organised by the National Academy of Sciences of Sri Lanka, Colombo, in December 2013 that only 16 per cent of kidney patients in the Anuradhapura district — ‘ground zero’ of the mystery disease — can be classified as having CKDu.
At the same event, Tissa Vitharana, Sri Lanka's senior minister of scientific affairs, urged researchers to keep an open mind in their investigations, ensure rigour of testing and analysis, and discuss findings widely.
Such adherence to the scientific process is vital, especially in view of activists demanding drastic policy measures based on current, partial evidence. Some want a complete ban on all imported agrochemicals, whereas WHO has recommended their stricter regulation.
For sure, the double-edged legacy of the Green Revolution which promoted high external inputs in agriculture must be critiqued. Past mistakes can be rectified at least now.
However, corrections have to begin upstream by questioning macro-level policies. For example, for half a century, Lankan farmers have had a huge — 90 per cent — state subsidy on chemical fertilisers. This does not encourage thrifty use, yet successive governments have hesitated to fix the massive drain of taxpayer funds.
Thus, mass kidney failure is more than just a public health emergency or environmental crisis. It is symptomatic of cascading policy failures in land care, water management and farming over decades.  There are no quick fixes. In searching for solutions, health and environmental activists must rise above their single-issue advocacy positions. They can bring grassroots concerns to national debates. Collaboration – not confrontation or conspiracy theories – is the need of the hour.
Hijacking a human tragedy for scoring some debating points is not worthy of any true follower of Rachel Carson.
Nalaka Gunawardene is a Colombo-based science writer, blogger and development communication consultant. He is also a trustee of SciDev.Net. The views in this column are his own.
References Nalaka Gunawardene. Science and Politics of Mass Kidney Failure in Sri Lanka. Groundviews.org, 19 August 2012.
 Kidney Conundrum. Down to Earth, India. 15 December 2013.
 Investigation and evaluation of chronic kidney disease of uncertain aetiology in Sri Lanka: final report. WHO, 2013.
 Nihal Jayatilake, Shanthi Mendis, Palitha Maheepala, Firdosi R Mehta and CKDu National Research Project Team. Chronic kidney disease of uncertain aetiology: prevalence and causative factors in a developing country. BMC Nephrology 2013, 14:180
 Nalaka Gunawardene. Mass Kidney Failure & Mass Media Failure: Communicating Risk in Times of Crisis. Conference paper. October 2012.