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Member Research and Reports

Member Research and Reports

Washington Researchers Say Health Systems May be Missing Critical Window for Shigella Prevention

Death from diarrheal disease is entirely preventable, yet it remains the second leading cause of death worldwide in children under five. When a child arrives at a clinic with severe diarrhea in a low-income country, what dictates the treatment they get? How do we define the severity of their condition and when do we assume it could be life threatening?

[Photo: Dr. Kirk Tickell]

The answer is more complex than you might think. Diarrhea doesn’t have just one cause – there are many – and the diagnostics to identify the different pathogens at the root of the problem are unreliable and rarely available in low-income countries. Symptoms, such as dehydration or dysentery, are used instead to guide treatment decisions.

In a new study, published in The Lancet Global Health, researchers from the department of global health at the University of Washington School of Public Health found that many Shigella-infected children do not have dysentery when they arrive at the hospital and health systems may be missing a critical window for treating this potentially lethal bacteria.

Shigellosis – a bacterial infection characterized by loose and watery stool, dysentery, fever and stomach cramps – is one of the leading causes of diarrheal deaths in children in low- and middle-income countries. International guidelines from the World Health Organization (WHO) currently rely on patients to show signs of dysentery, or blood in their stool, before recommending treatment with antibiotics for diarrhea.

Given the limitations of diagnostics and the danger of developing antibiotic resistance by over treating children without bacterial causes of diarrhea, “the pragmatic solution that people came up with 20 years ago was to assume that children who had Shigella would get dysentery, and to treat kids with dysentery with antibiotics,” said Dr. Kirk Tickell, senior research fellow and lead author of the study. “What we aimed to do is determine whether this logic still holds true, and we conclude that it does not.”

Researchers from the Global Center for the Integrated Health of Women, Adolescents, and Children, or “Global WACh”, at the University of Washington, conducted a series of systematic reviews to determine whether dysentery appropriately identifies children most likely to benefit from antibiotic therapy. They explored the efficacy of antibiotic therapy for treating both the symptom (dysentery) and the infection (Shigella).

In their review, the authors found that Shigella-infection itself, not dysentery, is associated with mortality. “Our global goal is to prevent children from dying from diarrhea, so we must think critically about how to identify and intervene upon children with Shigella infections, before the infection leads to dysentery,” said Dr. Patricia Pavlinac, assistant professor of global health and senior author of the study, emphasized.

Antibiotics are powerful tools for treating severe diarrhea, but rising concerns about antibiotic resistance have many in the diarrhea community concerned about overprescribing these medicines to treat the disease.

Dr. Tickell says his team shares these concerns and that scientists and policy makers must “walk the fine line of using an incredibly powerful treatment today, but not creating problems tomorrow.” In real world settings, antibiotics are already widely prescribed to children with diarrhea. All antibiotics, however, are not created equal when it comes to treating Shigella and Dr. Tickell and Dr. Pavlinac are concerned that children may not be getting the right antibiotics. Currently, there is no guidance for clinicians on what antibiotic to use in treating non-dysenteric bacterial diarrhea.

In their paper, Dr. Tickell and Dr. Pavlinac call for evidence-based approaches for managing Shigella cases where dysentery is not present and for continuing to aggressively manage dysentery to safe guard against future epidemics of Shigella dysenteriae type 1.

Their paper also underscores the importance of continual re-assessment of international guidelines for pediatric illnesses like diarrhea. These critical assessments should be used to inform future research to address evidence gaps. Future directions might include moving towards a risk scoring tool that prioritizes antibiotic treatment for vulnerable children with diarrhea.

“We’re not proposing more antibiotics, we’re proposing more data driven approaches to determine which child should receive an antibiotic,” Dr. Pavlinac said. “We have made substantial progress in reducing under-five mortality, particularly those due to diarrheal disease. To continue progress to end diarrheal deaths we will need to identify and capture critically ill children slipping through the cracks in health systems around the world and, when necessary, consider altering our approach to their treatment.”

Full article: “Identification and management of Shigella infection in children with diarrhoea: a systematic review and meta-analysis