By Philip R. Fischer, MD, DTM&H

Professor of Pediatrics, Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, MN

Dr. Fischer reports no financial relationships relevant to this field of study.

SYNOPSIS: Each year, 30 million preschool-aged children still get sick with diarrhea and 330,000 die. Most diarrheal illness and death is concentrated in a few high-risk areas, including parts of Benin, Lesotho, Mali, Nigeria, and Sierra Leone. Targeting preventive and therapeutic interventions in areas of risk could markedly reduce morbidity and mortality.

SOURCE: Reiner RC Jr, Graetz N, Casey DC, et al. Variation in childhood diarrheal morbidity and mortality in Africa, 2000-2015. N Engl J Med 2018;379:1128-1138.

Childhood diarrheal illnesses often can be prevented through rotavirus vaccination, sanitation, and food and water hygiene. For children who become sick with diarrhea, appropriate use of oral rehydration and zinc supplementation can prevent death. Nonetheless, recent estimates suggest that 30 million cases of severe diarrhea occur each year and that 330,000 preschoolers die of diarrhea annually.

Even in Africa, there are variations in the incidences of diarrheal illness and diarrhea-related deaths from place to place. To provide geographically accurate data to identify high-risk areas (where interventions could be targeted), Reiner and his colleagues at the University of Washington performed a systematic analysis of local variations in the morbidity and mortality of diarrhea across Africa during the years of the Millennium Development Goals (2000-2015). They estimated the incidence of diarrhea and the frequency of diarrhea-associated deaths with detailed geographic accuracy (to 5 km2 areas).

The distribution of the burden of diarrhea among young children was unequal. There were specific pockets or regions of frequent diarrhea in Nigeria, Ethiopia, and the Democratic Republic of the Congo. In some regions of Nigeria, 35-42% of children get diarrhea each year.

Diarrhea-related mortality decreased significantly during the first 15 years of this century in nearly all areas of Africa. In fact, case fatality rates dropped by 51% from 2000 to 2015. However, death rates due to diarrhea still vary geographically. The highest case fatality rates of diarrhea were in Lesotho (1.8 deaths per 1,000 children in 2015). Mali, Sierra Leone, Benin, and Nigeria had similarly high rates of death (1.6-1.7 per 1,000).

The median country-level case fatality rate was 0.5 per 1,000 preschool children per year. If all the countries with higher rates could reduce their rates to that median (a target already attained by half the countries of Africa), 137,000 deaths would be averted. More than half of those “saved” lives would be in Nigeria (and one-fourth of those lives “saved” in just three Nigerian states — Bauchi, Kano, and Jigawa).

There are some success stories. For instance, in Ethiopia, diarrhea case fatality rates declined by more than 60% during the first 15 years of the current millennium. This decline was linked to improved childhood nutrition and, it seems, enhanced use of oral rehydration therapy. Expanded use of rotavirus vaccination presumably could further decrease the risk of becoming ill with, and dying from, diarrhea.

COMMENTARY

Location, location, location is important not only for real estate but also for diarrhea. Frequent and fatal childhood diarrhea is becoming less common in children in Africa, but there still are some localized high-risk areas. Using a combination of disease surveys and mapping techniques, Reiner and his colleagues provided helpful new information. High risk for diarrhea is not only a national situation, but it also can be a local phenomenon.

It is encouraging that case fatality rates for diarrhea in children younger than 5 years of age have declined by more than 50% since the dawn of this century. Nonetheless, there are local areas, such as parts of Nigeria and the Democratic Republic of the Congo, where preventable gastroenteritis still is not prevented. In local areas, such as parts of Lesotho and Mali, treatable diarrheal illnesses still are not treated successfully. Some countries carry greater risk than others, and some parts of individual countries, such as Nigeria, carry excessive risk compared to other areas.

In some places, the successes in achieving lower rates of acute diarrheal illnesses serve as encouraging reminders to people living and working in other areas where diarrhea remains all too common. Sanitation and hygiene should continue to advance; indeed, the reduction of enteric infections in North America a century ago was linked more to indoor plumbing than to specific medical advances. However, medical advances still can help prevent diarrhea.

Rotavirus is thought to cause about 29% of all cases of childhood diarrhea,1 and an effective vaccine now is available. The vaccine is effective in infants, but it is not administered uniformly in at-risk areas. It is estimated that the rotavirus vaccine prevented 28,000 deaths in 2016, but an additional 83,000 children’s lives could have been saved if the vaccine was used uniformly.1

Once a child is sick with acute diarrhea, maintenance of hydration is vital. The use of oral rehydration for children who become dehydrated is referred to appropriately as “essential,” “the most effective intervention to reduce mortality,” and “the key intervention.”2 The new data from Reiner and his colleagues identified areas of excessively high case fatality rates for childhood diarrhea; efforts to increase the appropriate use of oral rehydration for dehydrated children probably would be effective in greatly reducing mortality.

In parts of sub-Saharan Africa where zinc deficiency is common, treating children who have acute gastroenteritis with zinc facilitates recovery and seems to reduce the future risk of diarrhea.3 Prophylactic zinc supplementation for non-ill children also has some effectiveness.3

What about antibiotics? In resource-limited areas of the world, some childhood diarrhea is due to enterotoxigenic Escherichia coli infection. Aware of this bacterial cause of childhood diarrhea, some clinicians could be prompted toward the early use of antibiotics in ill children. However, researchers who conducted a study in India found that children who were treated with antibiotics when they had diarrhea were more likely to have a repeat bout of diarrhea sooner than their peers whose diarrhea was not treated with antibiotics.4 Treating infantile diarrhea with antibiotics not only risks altered microbiomes that have implications for population health, but it also risks the personal health of the sick child.

Thus, we now know much of the “what” of diarrheal illness and some of the “how” for preventing diarrheal illness and death. Reiner’s new data help with the “where” of diarrhea in Africa so policy-makers and program-implementers can target future interventions appropriately in the most life-saving and cost-effective ways.

REFERENCES

  1. Troeger C, Khalil IA, Rao PC, et al. Rotavirus vaccination and the global burden of rotavirus diarrhea among children younger than 5 years. JAMA Pediatr 2018;172:958-965.
  2. Guarino A, Bruzzese E, Lo Vecchio A. Oral rehydration solution — an essential therapy for childhood gastroenteritis. JAMA Pediatr 2018;172:991.
  3. Liberato SC, Singh G, Mulholland K. Zinc supplementation in young children: A review of the literature focusing on diarrhoea prevention and treatment. Clin Nutr 2015;34:181-188.
  4. Rogawski ET, Westreich DJ, Becker-Dreps S, et al. Antibiotic treatment of diarrhea is associated with decreased time to the next diarrhoea episode among young children in Vellore, India. Int J Epidemiol 2015;44:978-987.