Over the course of my career I’ve spent over thirty years working in various developing countries trying to better understand and fight infectious diseases. One of the things that alarmed me most was that in many places, parents and caretakers didn’t even have a word for diarrhea. Sadly, this wasn’t because diarrhea was rare. On the contrary, diarrhea was so common that it was seen as a normal part of early childhood, and thus didn’t need a name.
There were of course exceptions, particularly during major diarrhea outbreaks. I remember a visit to Beira, Mozambique, where the International Vaccine Institute was carrying out a vaccination campaign to control a rainy season cholera outbreak. Everyone was relieved when “the cholera” was finally gone, but with it disappeared recognition of diarrhea as a continuing health problem. Cholera was the only form of diarrhea with a name. Unfortunately, the vast majority of cases in Beira were not caused by cholera, and the problem was not limited to just the rainy season.
In Beira and elsewhere, a lack of any local epidemiological evidence about what actually causes diarrheal diseases and the impact they have on young children limited the ability of public health officials, researchers, caretakers and parents to protect children from this devastating scourge.
Fortunately, we now have a better understanding thanks to the Global Enteric Multicenter Study (GEMS), which published data on the impact and leading causes of moderate-to-severe diarrhea in The Lancet last month.
GEMS was conducted at sites in seven countries across Africa and Asia, ranging from a rural village to an urban slum, to account for the various contexts where diarrhea occurs. We were surprised, and encouraged, to learn that of the nearly 40 possible causes GEMS tested for, just four pathogens – rotavirus, Cryptosporidium, Shigella and ST-ETEC – were responsible for the majority of diarrheal disease cases across all sites. More troubling, GEMS found that a single diarrheal disease episode stunted children’s growth and increased their risk of death over a two month period. What concerns us the most is that the majority of these deaths occurred after children returned home from a healthcare facility.
To fully appreciate the importance of the GEMS data, however, we must look at the impact it can have in individual study countries.
In Mali, like Biera and other regions, local data on the causes of diarrheal diseases was utterly nonexistent prior to GEMS. My friend Dr. Samba Sow, principal investigator of the GEMS trial site in Mali, tells a story about a child who arrived at the hospital a few years ago with severe diarrhea. Ten doctors worked to save his life in the intensive care unit, but could not. When lab results later confirmed the boy died of rotavirus, the nurses and parents all asked: “What is rotavirus?”
Thanks to GEMS, healthcare providers, researchers and policymakers in Mali will know which causes of diarrheal diseases they need to target. Fortunately, Mali is preparing to introduce rotavirus vaccines later this year or early next. GEMS also helped us to identify other steps that need to be taken to combat diarrheal diseases. For instance, when children survive the initial diarrheal episode, doctors and nurses should continue to monitor them to make sure they do not die at home.
In contrast to Mali, we knew comparatively more about what caused diarrhea in India. But, in a country where the population and burden of diarrheal diseases is so high, a clear understanding of what interventions would have the greatest impact is essential. By establishing a baseline measurement on diarrheal disease, we will be able to track the impact of introducing new interventions, such as vaccines, and adjust our strategy accordingly to focus on the most effective interventions.
Fittingly, the same day that the GEMS study results were published, an Indian company, Bharat Biotech, announced promising results from the first Phase III trials of its rotavirus vaccine, ROTAVAC. It is my hope that with a clear understanding of the need, and with a vaccine almost in hand, India will strengthen its commitment to delivering rotavirus vaccines to children who urgently need them.
Regardless of context – whether in a country where the causes of diarrhea are a relative mystery or one in the final stages of developing its own rotavirus vaccine – fully understanding the problem is what enables us to act in the most effective way possible. By building on the GEMS findings, we can accelerate progress toward our goal of a world where children are no longer dying of diarrheal diseases.
To learn more about how you can get involved in combating diarrheal disease, visit the DefeatDD campaign.