After pneumonia, childhood diarrhea is the biggest killer of children under the age of five worldwide. Despite this, figuring out the exact causes of the condition that would then allow medical staff to treat it is surprisingly complicated and difficult to achieve. Now, researchers have managed to establish that the vast majority of cases of diarrhea are caused by just six pathogens, allowing doctors to radically refine their attention.
While in the Western world, a short bout of the runs is never usually seen as anything life threatening, out of the nearly 1.7 billion cases of the disease worldwide, 760,000 children under the age of five are thought to die as a result. This major public health problem is also the leading cause of malnutrition, as young children lose the water and salts that their body needs for survival, leading them to succumb to dehydration and fluid loss.
The disease is caused by an infection of the gastrointestinal tract, and thought to be caused by up to 40 different bacterial, viral, and parasitic organisms, spread through contaminated water and food. Yet traditionally, pinning down the exact cause of the infection has been a complicated undertaking, requiring a range of diagnostic approaches and varying tests. The World Health Organization simply recommends that infected children should be given oral rehydration, intravenous rehydration if they cannot keep the liquid down, and zinc supplements.
But a new review, published in The Lancet this week, has looked over a previous wide-scale study of diarrhea in the developing world and discovered something surprising: 78 percent of all cases were caused by just six pathogens. The team of scientists reanalyzed stool samples taken from over 10,000 children living in Bangladesh, The Gambia, India, Kenya, Mali, Mozambique, and Pakistan as part of the three-year Global Enterics Multi-Center Study (GEMS). The initial study found that just over 50 percent of cases were down to pathogens, while this new reanalysis reveals that the figure is much greater.
If doctors can hone in on these few key causes, it could play a vital role in how children are now treated. The most common pathogens to be implicated were the bacterium Shigella and the rotavirus, followed by adenovirus, enterotoxin-producing E. coli, cryptosporidium, and campylobacter. What is more, just under 40 percent of all cases were caused by more than one pathogen, meaning that treatment should not just focus on a single cause.
With a vaccine already available for rotavirus, and others being developed for Shigella and enterotoxin-producing E. coli, it means that doctors now have a clear idea of what infections they need to target in order to cut the number of children dying each year due to diarrhea.