M.G.M. Rowland

BACTERIAL CONTAMINATION IN TRADITIONAL GAMBIAN WEANING FOODS

Although emphasis on infant feeding is rightly being placed on breast-feeding, the need for safe weaning foods for the developing world must also receive its due attention. Traditional weaning foods used for young infants in a typical West African village can be as hazardous, bacteriologically, as commercial milk products, and providing a breast-fed child with supplements under the conditions which prevail in much of the developing world is potentially dangerous, whatever the source of the food.

Infant foods as a potential source of diarrhoeal illness in rural West Africa

It is common practice in rural areas of The Gambia to prepare infant foods in quantities which are sufficient to meet the needs of the day rather than one meal. These are then stored at ambient temperatures for periods up to 12 hours for feeding to the child on demand. The total viable counts and levels of Bacillus cereus, Clostridium welchii, Staphylococcus aureus and Escherichia coli were determined in 294 infant foods samples from nought to eight hours after preparation. The presence of Salmonella was determined in 10 g samples of food. In the first hour after preparation the proportion of foods dangerously contaminated was high during the rainsy season, significantly more so than during the dry season. Foods not consumed fresh were very often hazardous and almost always so after 8 hours. This problem may be a causal factor in weanling diarrhoea which also shows marked seasonal variation in prevalence.

FACTORS INFLUENCING LACTATION PERFORMANCE IN RURAL GAMBIAN MOTHERS

Breast-milk consumption has been measured in a rural African community in which breast-feeding on demand is universally practised until the baby is 18 mos old. The mothers long-term capacity for breast-milk production is determined by the end of the second month of lactation, yield being closely correlated with the infants birth-weight. Other factors significantly influencing output were parity, month of lactation, babys weight-for-age, season, and maternal diet. Daily milk consumption was limited primarily by the amount delivered per feed, not the frequency of feeding.

IMMUNISATION OF 4-6 MONTH OLD GAMBIAN INFANTS WITH EDMONSTON-ZAGREB MEASLES VACCINE

Five different vaccination schedules were used to immunise Gambian infants aged 4-6 months against measles with the attenuated Edmonston-Zagreb strain of virus, which has a history of passage in human diploid cells. Vaccine aerosol given either by mask in a dose of 3500 or 7000 plaque-forming units (PFU) or from a plastic bag at a dose of 7000 PFU raised haemagglutinin-inhibiting or plaque-inhibiting measles antibody 16-24 weeks after vaccination to a titre of 1 in 8 or greater in all but 3 of the 51 children so vaccinated. All 21 infants given 11 400 PFU of vaccine intradermally in two divided doses and the 21 given 39 000 PFU of the virus subcutaneously also had satisfactory levels of measles antibody 16 weeks after vaccination. None of the vaccinated children had clinical evidence of measles in the 12 to 17 months after vaccination. The Edmonston-Zagreb vaccine, given subcutaneously or by other routes at 4-6 months, may be useful in preventing measles in infants in African cities, where 15-30% of children have measles before they are 9 months old, which is the recommended age for immunisation with the chick-cell-adapted strains of measles virus.

Malnutrition and gastroenteritis in The Gambia.

Abstract There is a strong association between failure to thrive and diarrhoeal disease in young Gambian children. The high prevalence of diarrhoeal disease seen is not due to frequent attacks of “acute infantile diarrhoea” of viral origin. The picture of protracted diarrhoea is almost certainly due to colonization of the upper bowel and the high prevalence demonstrated to be at least partly due to the environment to which the children are exposed, particularly in terms of food and water hygiene. Until this cycle of upper bowel colonization and protracted diarrhoea is broken, a diet-based nutrition programme cannot be expected to function effectively.

The relationship between rainfall and well water pollution in a West African (Gambian) village.

Water pollution was monitored in six Gambian village wells over a period of 8 months spanning the 5-month monomodal rains and the pre- and post-rains dry periods. Faecal coliform (FC) and faecal streptococci (FS) counts were high throughout and there was a massive increase associated with the onset of the rains, maximum counts exceeding 5 x 10(5)/100 ml. This pattern was largely sustained throughout the rainy season. Some individual variations in patterns of pollution could be ascribed to well design, in particular lining of the shaft, but no well was protected from the seasonal increase in faecal pollution. The source of the increased pollution appeared to be a flushing in of faecal material of indeterminate or mixed human and animal origin, probably over considerable distances. Peaks of pollution not associated with rainfall episodes could have resulted from the practice of communal laundering in the near vicinity of the wells. Specific pathogens including Salmonella spp. were isolated only intermittently. Attention has been drawn to a problem complicating the standard method for assessing FC counts.

Food and water hygiene and diarrhoea in young Gambian children: a limited case control study

During the annual rainy season epidemic of diarrhoea in The Gambia, two groups of urban children were identified, one of which remained completely free of diarrhoea and another in which diarrhoeal prevalence exceed 30% over a period of three months. Microbiological studies on the food and water consumed by these children during one day showed widely varying degrees of contamination in both groups. No difference was observed in levels of contamination, faecal or otherwise, between the two groups. The real problem seemed to lie in accounting for the freedom from diarrhoea of some children rather than explaining possible causes of morbidity in others.

Weanling diarrhoea in The Gambia: implications of a jejunal intubation study

Abnormalities in jejunal flora and bile salt metabolism were most marked in the youngest members of a group of Gambian village children in the weanling age group. These may be linked with the profound change in diarrhoeal morbidity, particularly diarrhoea-induced growth impairment, which occurs as soon as breast-fed infants are regularly supplemented. The pathogenesis of these changes is not understand. The presence of small bowel colonization did not appear to be a causal factor but, it is speculated, its appearance may mark the development of a post-enteritis enteropathy which is responsible for the weanling diarrhoea syndrome and which is caused and perpetuated by traditional weaning foods.

The effect of early glucose-electrolyte therapy on diarrhoea and growth in rural Gambian village children.

Although breastfeeding is universally practiced in Gambia until 18 months of age diarrhea is still the most important nondietary cause of failure to thrive among children. This paper reports the results of a controlled study conducted to determine the effect of the domiciliary use of an oral glucose-electrolyte mixture administered by mothers to a group of young children (n=21) in a Gambian village within 24 hours of onset of diarrhea. Average number of days of diarrhea complained of by subjects (n=10) and controls (n=11) at time of visits were 4.5 (range 2 to 11) days and 8.6 (range 0 to 21) days respectively with the difference approaching significance at t=1.77 p < 0.0. The study concentrated on the age group in which diarrhea had maximum prevalence and greatest impact on growth. Mean age of subjects at start of study was 10.8 months and of controls 16.9 months; t=2.39 p < 0.05. The glucose-electrolyte mixture (Choloral) was well accepted by both mothers and children. Average gain in length in subjects was 34 mm. and in controls was 21 mm. This was significant at t=2.55 p approximately 0.02. Average weight gain in the 2 groups was not significant. There was a marked reduction of prevalence of diarrhea during the study period as a result of oral administration of the mixture within 24 hours of onset of diarrhea. It was suggested that in the weanling diarrhea syndrome early use of glucose electrolyte mixture may have little effect on growth unless accompanied by specific nutritional measures.

Bacteriostasis of Escherichia coli by milk. VI. The in-vitro bacteriostatic property of Gambian mothers' breast milk in relation to the in-vivo protection of their infants against diarrhoeal disease

A one-year field-study has been carried out in a diarrhoea-endemic area in West Africa to determine the relationship between the bacteriostatic activity of fresh human milk for Escherichia coli in vitro and freedom from diarrhoea of the infant recipients of the milk. The specific contribution of E. coli gastroenteritis to gastrointestinal diseases of infants in general is not known, nor is its particular role in the Gambian infants studied. During the study period, however, both enteropathogenic and toxigenic strains of E. coli were isolated. The incidence of diarrhoea in Gambian infants of seven age-groups from 2 days to 12 months was not significantly correlated with the bacteriostatic activity of milk. This was due rather to absence of diarrhoea in babies fed on low-activity milk than illness in those receiving highly bacteriostatic milk. Indeed, very active milk appeared to protect recipients almost completely, including seven babies of over 3 months of age, five of them during the rainy season, when the risk was high. Babies receiving lower-activity milk experienced more diarrhoea. In a situation where diarrhoeal disease is multifactorial, field evaluation of the protective action by one antibacterial property of milk is difficult. A better understanding of in vivo protection is important, and the factors which have to be taken into account are discussed.