Diarrhoea risk associated with not breastfeeding in Botswana

Summary of report and presentation¹

Between November 2005 and February 2006, there were unusually heavy rains and flooding in Botswana, and by January 2006, there was an increase in infant diarrhoea and mortality. By February, the number of cases and deaths were overwhelming hospitals throughout the country. In the first quarter of 2006, in just twelve health districts, there were 22,500 cases of diarrhoea, with 470 deaths in children under five (compared to 9,166 cases and 21 deaths for the entire country in the first quarter of 2005).

The Ministry of Health (MOH) had difficulties attributing the outbreak to any one pathogen, but most of the cases appeared to be associated with bottle feeding, Assistance from the US Centres for Disease Control (CDC) was sought and the results of the CDC/MOH investigation were presented at the PEPFAR (President's Emergency Plan for AIDS Relief) meeting in Durban, 2006. The main findings and recommendations are shared here.

In Botswana, the HIV prevalence in pregnant women is 33.4% (2005), The national Prevention of Mother to Child Transmission (PMTCT) programme started in 1999 providing:

• Anti-retroviral therapy for women with CD4<200
• Azothioprine (AZT) for 12 weeks to mothers, 4 weeks to infants
• Standard dose Nevarapine for mothers and infants
• Free infant formula for 12 months. Since 2004 there has been a high uptake, with 80% receiving AZT. According to recent data HIV transmission to infants is 7%². All HIV-positive women are advised to formula feed, and 63% of HIV-positive women used formula in 2005.

Main Findings

The CDC found widespread water contamination in four northern districts of the country. The public water supply, which has long been considered safe, was contaminated in 26 villages tested. A variety of pathogens causing the outbreak were identified, including cryptosporidium, enteropathogenic e coli (classic 'bottle diarrhoea') and salmonella, amongst others.

Amongst HIV negative mothers or mothers of unknown HIV status, a CDC survey found that 20% of infants had been weaned from the breast before the age of six 6 months. Amongst HIV positive mothers, 63% of infants were formula fed from birth. Overall 35% of infants under 6 months old were not breastfeeding.

The CDC investigators identified a variety of risk factors (adjusted for socio-economic status, age, and mother's HIV status) that were associated with children with diarrhoea presenting for acute hospital care, such as caregivers not washing their hands (2.5 Adjusted Odd Ratio (AOR) (95% CI 1.1-5.0), standing water near home (AOR 2.6 (1.1-6.3), overflowing latrines (AOR 3.0 (1.1- 8.6), storing drinking water (AOR 3.7 (1.5-9.1). However, the most significant risk factor was not breastfeeding (AOR 50 (95% CI 4.5-100).

The CDC conducted a closer evaluation of 154 children hospitalised for diarrhoea. Most (96%) of the children were under 2 years of age, median age 9 months. They found that:

• The majority (93%) were not breastfeeding and more than half (51%) of the infants were growing poorly before this illness.
• Among the hospitalised children, 18% were HIVinfected. Among infants of HIV positive mothers (65%, where 94% tested), 27% were HIV infected (85% tested).
• Thirty-five per cent of children had suffered from diarrhoea for >= 2 weeks, and 43% had been discharged and then readmitted at least once.
• Many developed severe acute malnutrition during or after diarrhoea; 42% developed marasmus and 20% developed kwashiorkor. Most had been growing poorly before the diarrhoea outbreak but had not been adequately managed despite monthly weighing at clinics.
• Twenty-one per cent of the children admitted died (32/154). Risk factors for death included not being breastfed (OR 8.5, p=0.04) and kwashiorkor (OR 2.6, p=0.03).
• HIV status (maternal or infant), socio-economic status, water source, urban versus rural residence and pathogen were not associated with the risk of death.

Among the HIV-positive mothers, problems were reported with adequate and consistent formula supply. Although most were given the appropriate amount of formula at birth, only 51% received the amount of formula they should have received before their illness. Mothers reported returning to clinic on many occasions each month but were still not given adequate formula.

The CDC investigators consider the true extent of the mortality from this outbreak remains unknown but may exceed the figures reported above, since many infants died outside of the health facilities. In three districts alone, there were 547 excess deaths reported (four times the historical under fives mortality rate). In one village visited, 30% of their formula-fed babies (and no other babies) died during the outbreak. Among formula-fed newborns CDC started following in January before the outbreak, preliminary data indicate 10% dead when re-visited at age 3-4 months.

Conclusions

On the strength of these findings, CDC has recommended a formula policy review and external consultation in Botswana. Other feeding strategies may promote higher child survival, for example women who are exclusively breastfeeding, have high CD4, or take ARV therapy have low risk of HIV transmission. Early weaning among HIV-negative women was common and breastfeeding promotion needs strengthening. The investigators reiterate that it is essential to ensure formula-fed infants have enough formula and safe water, and there needs to be improved training for health staff and mothers in nutrition and management of diarrhoea. They also call for a study of the impact of point-of-use water treatment, safe water vessels, soap and handwashing promotion.

The investigators also flag the implications for other programmes. Programmes offering formula should ensure clean water, uninterrupted supply of formula, growth monitoring, and nutrition counselling. Health staff should be taught that formula fed infants are at risk, what to look for, and how to intervene.

The outbreak reinforces the use of the WHO criteria for replacement feeding (acceptable, feasible, affordable, sustainable, and safe). However it has highlighted that 'safe' cannot be assumed. The investigators strongly recommend that new programmes should verify that formula saves lives in their context before widespread implementation.

¹See http://www.blsmeetings.net/implementhiv2006/ TracyCreek_files/frame.htm. Also included in HATIP #74, 12 Sept 2006, http://www.aidsmap.com/cms1177384.asp

²Mashi study. See summary this issue of Field Exchange.