CCID Spectrum
Volume 1, Number 2 May 2006

Botswana experiences nationwide infant diarrhea/malnutrition outbreak

MOH requests CDC support

Photo: Dr. Tracy Creek
A nationwide outbreak of diarrhea among infants in Botswana, coinciding with the heaviest rains seen in several years, has led to the deaths of more than 400 children under age 5 since January. CDC has been assisting with investigation of this outbreak since February 18, and has been conducting a detailed investigation since that time in Francistown, at the country's second largest referral hospital.

The outbreak investigation team to date has included eight CDC Atlanta staff: four from the Global AIDS Program (GAP), NCHSTP; two from Foodborne & Diarrheal Diseases, NCID; one from Refugee Health; and one from the Coordinating Office for Global Health. More than 20 GAP Botswana staff members are working to address the outbreak.

Shipment of stools sent to CDC Atlanta for testing revealed that about 50% of inpatient children with diarrhea have cryptosporidium, and 60% have enteropathogenic E. coli (EPEC). Both of these pathogens are transmitted person-to-person and in healthcare facilities via a fecal-oral route, but can be found in water or foods.

To date, water and foods have not been implicated through epidemiologic study. Mortality among inpatient African cohorts has been 12%–18% for cryptosporidium, and mortality among EPEC cohorts has been 20%–70% depending on the setting.

"No treatment is currently available for cryptosporidium in Botswana," notes Dr. Tracy Creek of the GAP Prevention of Mother to Child Transmission Team. The team is in Botswana working with the outbreak investigation team.

EPEC can be treated with antibiotics, though it is resistant to many, and the samples processed at CDC Atlanta have been sensitive to nalidixic acid and ciprofloxacin which are available in only limited quantities in Botswana, Dr. Creek adds.

CDC has been following a group of 156 children admitted to the hospital for diarrhea and enrolled in the study from February 20–March 1.

Among these children:

  • Median age is 10 months, 66% <1yr, 93% <2yrs;
  • 30% had diarrhea for more than 4 weeks at enrollment;
  • 63% have HIV-positive mothers;
  • 15% of the infants are HIV infected;
  • Feeding among children <2years oldó
    • HIV-positive mothers 1.6% breastfeeding;
    • HIV-negative mothers 29% breastfeeding;
  • 43% of the children have been hospitalized at least twice; and
  • 20% have died.

In addition to these multiple pathogens with complex medical implications, severe malnutrition has developed among many affected infants. Some of these children were malnourished before the outbreak, as evidenced from their outpatient growth curves, and have just "been tipped over the edge into severe illness," explains Creek, adding "but many have become severely malnourished in recent weeks as a result of their chronic diarrhea."

Malnutrition generally low in Botswana

The overall prevalence of malnutrition in Botswana has been low for many years, and systems for treating children with severe malnutrition are not in place. Currently, more than half of the inpatients on the pediatric ward are significantly malnourished with either proteincalorie malnutrition or kwashiorkor, which is an acute protein, high-mortality form of malnutrition. Among the cohort of inpatients, to date 17% have developed acute protein malnutrition, and, of these, 46% have died.

A case-control study by the outbreak investigation team was conducted in emergency department-enrolled children with and without diarrhea in order to determine personal and environmental risk factors for illness.

Risk factors that were significantly associated with diarrhea include:

  • Standing water around the home;
  • Overflowing latrines during rainy season;
  • Storing water in the home (usually in open bucket);
  • Caregiver not washing hands after using toilet;
  • Not breastfed;
  • HIV-positive mother.

Given the very high prevalence of malnutrition among inpatients, the Ministry of Health (MOH) and the CDC team concluded that an emergency malnutrition survey in the surrounding community was needed. A 30x20 household cluster survey is currently being conducted to determine the prevalence of malnutrition in the community and to further describe risk factors and feeding practices.

The CDC team has made significant contributions to the outbreak investigation since February.

CDC activity at the national level has included:

  • Designing Information-Education-Communication (IEC) messages for diarrhea prevention;
  • Facilitating outbreak control funding through the U.S. embassy and the USAID Office of Foreign Disaster Assistance;
  • Assisting to develop national guidelines for diarrhea treatment during the outbreak;
  • Facilitating procurement of therapeutic formula for severe malnutrition, zinc for treatment of diarrhea, nitazoxanide for treatment of cryptosporidium;
  • Assisting development of a national policy for treatment of acute malnutrition;
  • Planning with UNICEF for national training in the World Health Organization protocol for management of severe malnutrition;
  • Reporting to national water control authorities on fecal contamination of village water supplies tested by CDC and discussing improvement of water quality in villages;
  • Facilitating introduction of point-of-use water treatment for areas with unsafe water through PSI;
  • Facilitating assistance for national laboratory capacity development in detection of enteric pathogens through the Association of Public Health Laboratories.