|Malnutrition and Infection - A review - Nutrition policy discussion paper No. 5 (UNSSCN, 1989, 144 p.)|
|INTRODUCTION AND OPERATIONAL IMPLICATIONS1|
Measles is estimated to kill 2,000,000 children a year, almost all in developing countries. Measles is known to interact particularly with deficiencies of protein-energy and of vitamin A. It is a common precipitating cause of potentially blinding eye lesions (especially due to xerophthalmia) in young children, and of severe growth faltering and protein-energy malnutrition. Measles occurring in poor environments is thus associated with growth faltering, vitamin A deficiency and immune suppression. The immune suppression can persist for up to four months after infection, and goes some way to explaining both the particular risk of respiratory and diarrhoeal complications of measles, and the relatively greater severity of the disease, in poor communities. The increased risk of other infections contributes to the cycle of further malnutrition and further infection. Post-measles diarrhoea is particularly difficult to treat and has a very high mortality risk. Prevention of measles, through immunization, is thus an important means of reducing severe protein-energy malnutrition and vitamin A deficiency.
Preventive nutritional measures for reducing the severity of measles and its consequences relate to both vitamin A deficiency, and to protein-energy malnutrition. The provision of vitamin A supplements to populations at high risk from measles is recommended in all communities where vitamin A deficiency exists. In this context, distribution of vitamin A capsules with immunization programmes is particularly relevant, and is beginning in a number of countries. Protein-energy malnutrition is an established risk factor in measles, thus programmes that improve nutrition in general can also be expected to contribute to reducing the severity of measles.
Renewed emphasis on nutritional management during and after measles is of high priority, to prevent the severe growth faltering and high mortality often associated with measles. This again refers to deficiencies of both vitamin A and protein-energy.
Measles causes vitamin A deficiency, and measles is more severe in vitamin A deficient children. In all communities exposed to vitamin A deficiency, morbidity and mortality from measles would probably be reduced, not only by regular vitamin A supplementation for that population, but by ensuring that all children with measles receive vitamin A. In particular, when the case fatality rate for measles exceeds 1% in communities where vitamin A deficiency exists, all children with measles should without fail get vitamin A capsules(15). Studies in Tanzania have shown reduced case fatality rates from measles when children were given vitamin A during the disease(16). Measles infection substantially increases vitamin A utilization, thus vitamin A administration during the disease helps prevent deficiency when body stores are marginal prior to infection, in turn providing protection against xerophthalmia and probably immune suppression.
Ensuring adequate intakes of protein and energy during the management of measles, and, especially important, during the immediate post-measles period, requires fresh emphasis. As for diarrhoea, this is particularly important for young children after the age of exclusive breast feeding. Continued feeding with suitable weaning foods can help to counter the anorexia, malabsorption, and increased protein breakdown that adversely affects the nutritional status of children with measles. Practices in some cultures of withholding food during measles in young children is particularly to be discouraged. At the same time, continued breastfeeding at all ages of children who are breastfed should be supported.
Maintenance of adequate vitamin A nutrition may also reduce non-measles morbidity and mortality. There is some evidence that vitamin A deficiency increases the risk of respiratory infection and possibly diarrhoea, perhaps through its effects on cellular and non-specific immunity. In addition, mortality from these and other causes may be elevated in vitamin A deficient children.