Aameena Mohammed gives her 20-month-old daughter Daslim Banu plenty to eat. The girl’s mother supplements breast milk with eggs, soup and rice to help her grow. The extra food doesn’t help. Daslim still weighs only as much as a healthy infant half her age.
Mohammed’s home, in one of the poorest districts of the south Indian city of Vellore, is among the 65 percent of India’s homes without running water and safe sewage disposal. Feces and urine collect next to the doorway in an open drain -- the source of odor permeating the tin-roofed shack and of the microbes likely retarding the toddler’s growth.
Scientists increasingly suspect that constant exposure to bacteria, virus and parasite-laden fecal contaminants may be frustrating attempts to end malnutrition. In effect, the best diet-based measures to fight chronic hunger in the developing world are being negated by a failure to meet basic human needs: clean water and sanitation.
The problem exists not just in India. A quarter of children in developing countries are underweight, and malnutrition is the root cause of the deaths of more than 2 million children annually, according to the United Nations Children’s Fund in New York. Worldwide, 870 million people are chronically hungry, almost all of them in developing countries.
“You really can’t address stunting unless you clean up the sanitary environment,” said Clarissa Brocklehurst, Unicef’s former chief of water, sanitation and hygiene, who worked in India from 1999 to 2001. “It doesn’t matter how much extra food you try to stick into kids or how much dietary supplements you give them, it will all just go through them.”
Daslim, who runs about the home in an oversized red and green dress that hangs limply from her bony shoulders, has suffered at least five bouts of debilitating diarrhea in the past 10 months, and was hospitalized for three days with a high fever in September. In November, she weighed 7 kilograms (15 pounds) -- about two-thirds the normal weight of a girl her age.
A decade of economic growth averaging almost 8 percent a year has doubled the size of India’s middle class and produced more billionaires than the U.K. Still, almost half the nation’s children under 5 years remain stunted -- and the situation has worsened in the past 10 years. India’s response has been to distribute nutrient-fortified supplements and meals to children. The UN has called for a broader approach that includes providing safe drinking water and toilets.
About 200,000 children under 4 years die in India annually because of diarrheal diseases caused by dirty water and lack of proper sanitation, according to a study published in the Lancet medical journal in April. Waterborne diseases also hamper productivity, depriving India of 73 million working days each year, the nonprofit group WaterAid said in a 2008 report.
As evidence of the economic impact of lingering hunger mounts, scientists are widening their search into understanding the causes of malnutrition.
Mohammed’s daughter is one of more than 200 children in Vellore enrolled in an international study examining how pathogens damage children’s digestive tracts. Previous studies have shown that a gut constantly assaulted by infections is less adept at absorbing nutrients needed for growth and development.
The researchers involved in the latest study, funded by the Bill & Melinda Gates Foundation, are testing urine and stool specimens from the children each month for signs of infection and carbohydrate absorption, and checking the results against their weight and height records. Their hypothesis is that children living in unclean environments are continually ingesting germs, yet don’t show signs of being sick as often because of the defensive response by their intestinal tracts to the daily microbial pummeling. As a tradeoff though, the germs may compromise the uptake of key nutrients through the intestinal wall.
“The gut is supposed to absorb, secrete and act as a barrier, and all of these functions can be affected in people who are exposed to a lot of pathogens all the time,” said Gagandeep Kang, professor of gastrointestinal sciences at Vellore’s Christian Medical College, who is leading the study in India. “You may be getting what is considered an adequate diet, but if you don’t absorb it, it doesn’t help.”
Kang suspects Daslim’s growth is being impeded by environmental enteropathy, a condition in which the nutrient-absorbing finger-like projections lining the small intestine are transformed into broad, leaf-like flaps in response to constant exposure to pathogens. While externally there may be no obvious signs, internally the changes reduce a person’s ability to take in carbohydrates and proteins.
“We think it’s because their gut gets damaged because they are repeatedly infected with organisms that damage the intestinal lining,” said Kang, who has been studying gastrointestinal diseases for the past 25 years. “We are trying to investigate whether that damage is what stops children from being able to use the nutrients they get in the food.”
The condition can be reversed with cleaner drinking water and contaminant-free food, though a toddler with the condition can suffer lasting damage as a result of malnutrition. Children who suffer from malnutrition in the first five years of life are likely to suffer in adulthood with poorer cognition, less stamina, more chronic illness and a shorter life expectancy, according to Unicef.
There are no outward signs of the condition -- a child may suffer from environmental enteropathy for months and not have a single bout of diarrhea. More than 100 scientists and epidemiologists worldwide are studying different aspects of the condition, from identifying the underlying biochemical processes to developing a standardized diagnostic test.
Researchers have known about the link between nutrient malabsorption and environmental pathogens since at least the 1960s, when Peace Corps volunteers returning from India and Pakistan reported weight loss, diarrhea and abnormal vitamin absorption. Symptoms disappeared several months after their return to the U.S.
Similar symptoms have been noticed in severely malnourished children in other nations in Asia and in Africa. In those instances, children’s bodies didn’t grow normally after they were fed a variety of diets, including ones rich in energy and protein. Even the best dietary interventions only reduced a third of the growth deficit, according to an analysis by University of California researchers published in 2008 in the journal Maternal and Child Nutrition.
“I have worked with children with severe environmental enteropathies and it’s very difficult to get them to put on weight,” said David Nabarro, 63, who worked as a doctor in villages in Nepal and oversaw the World Health Organization’s fight against malaria before becoming special representative to the UN Secretary-General Ban Ki-Moon for food security and nutrition. “A big shift is happening, and everyone is realizing that there are a factors other than food that need to be addressed if you want to fix malnutrition.”
Clean drinking water and adequate sanitation systems are two of those factors. The squat-style outhouse in Daslim’s yard empties into an open drain that lines one side of the lane bordering her house. Entering the home requires stepping over the foul-smelling sludge where the family’s chickens forage. Neighbors typically take a seven-minute predawn stroll to a secluded spot on a hill bordering their settlement to defecate, Daslim’s mother, Aameena Mohammed, says.
Only 26 percent of the 6 billion gallons of sewage generated daily in India is treated. A shortage of toilets and proper sanitation trimmed 6.4 percent from India’s gross domestic product in 2006, or the equivalent of $53.8 billion, mostly through premature deaths and hygiene-related diseases, the World Bank’s Water and Sanitation Program found in a study published in 2010.
Mohammed says she knows boiling water for at least 10 minutes kills most pathogens. Her dilemma is that the 10 liters of government-subsidized kerosene she receives each month goes on preparing meals.
“What we get from the ration shops is just enough to cook,” Mohammed, 23, says. “It’s not possible to boil all the water.”
The family’s drinking water is stored in a row of 11 wide-necked, plastic pitchers in a bedroom. The containers are filled every 10 days, after the public supplies are turned on. A single steel cup is used to ladle out water for cooking or drinking.
“Any water that is collected, carried home and then stored in the house is very vulnerable to contamination because it gets handled so much,” said Brocklehurst, the water and sanitation consultant. While water at the pump might be fine, what’s consumed in the home might be contaminated, she said.
India has spent more than 1.56 trillion rupees ($28 billion) on water supply and sanitation projects over the past 60 years. Still, infrastructure has struggled to keep pace with the demands of a growing population, and most Indians do not have access to reliable, piped water in their homes.
In 57 percent of homes, one family member -- usually a woman or young girl-- walks at least 500 meters (0.3 miles) daily to fetch water from a communal tap or hand-pump.
Water from communal taps in even India’s biggest cities carries health risks. Eighteen percent of samples tested at more than 600 sites in New Delhi were tainted by E. coli, Salmonella, or other disease-causing bacteria found in human excreta, according to a 2011 survey by the capital’s government. Two of 50 samples contained bacteria resistant to all commonly used antibiotics, a study published in the Lancet in 2011 found.
The gastrointestinal damage caused by contaminated water could also explain why some vaccines fail to work in children in developing countries, according to Myron Levine, director of the Center for Vaccine Development at the University of Maryland. Since the 1960s, there have been more than a dozen reports of polio, rotavirus, and cholera vaccines failing in patients in India, Brazil, Peru, Bangladesh and other countries where sanitation lapses have been reported.
Vaccine failure is particularly problematic for polio, a viral scourge that continues to cripple children despite being the focus of one of the most expensive public health campaigns in history -- $9 billion to date. Children in India and the rest of South Asia need more doses of the vaccine compared with their western counterparts, and the vaccine fails in a “far higher” proportion of kids, said Nicholas Grassly, an epidemiologist at Imperial College London, who has studied the efficacy of polio vaccine for the past eight years.
“There is increasing evidence that oral polio vaccine failure is the result of exposure to other gut infections,” Grassly said in an interview. Places that have poor sanitation and environments that favor transmission of enteric pathogens are likely venues for vaccine failure, he said. Consequently, vaccines are less likely to protect children when administered in the rainy season or other times when diarrhea is rampant.
Oral vaccines, like the ones for polio and rotavirus, work in the intestine by training the body’s immune system to identify and kill their viral causes. In children with environmental enteropathy, the immune response is so well primed to fight gut infections that the live, but weakened virus is attacked before it has a chance to replicate in the gastrointestinal tract. Replication of the vaccine virus is an important step in generating protective antibodies.
Children in Uttar Pradesh and Bihar, the Indian states where sanitation deficiencies are among the country’s worst, need an average of 15 doses of polio vaccine, compared with 10 doses in the rest of India. Only three shots are usually needed in developed nations.
Back in the Aameena Mohammed’s house, Daslim has put on about 700 grams in the past six months as her mother began supplementing her diet with spinach, lentils and potatoes. Yet she is still underweight and isn’t gaining enough to claw her way out of malnutrition, according to monthly records kept by the researchers. Even after the enhanced diet, Daslim weighed 7.6 kilograms at the end of April, 3 kilograms less than what’s considered normal.
“She is maintaining her growth, but that’s not enough,” said Srujan Sharma, a physician and former project manager of the Vellore study. “She is trying to play catch-up, and repeated illnesses from the contaminated environment keep her from catching up.”