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It is only recently that serious attention has been given to documenting the situation of vitamin A status in most countries. Information therefore remains incomplete around the world. Currently, Vitamin A deficiency (VAD) is a moderate to serious public health problem in 76 countries, particularly in Africa, South-East Asia and the Western Pacific.
    When vitamin A deficiency occurs, the integrity of epithelial barriers and the immune system are compromised before the visual system is impaired. This leads to increased severity of some infections and risk of death, especially among children. When vitamin A depletion is sufficient to affect the visual system, nightblindness occurs first, followed by xerophtalmia which can affect both the conjunctiva and cornea, and may lead to irrreversible partial or total blindness (see: WHO. Global Prevalence of Vitamin A Deficiency. MDIS Working Paper no. 2. 1995 (WHO/NUT/95.3)).
    Interestingly, in most populations where VAD is now prevalent, a word exists in their language or dialect to depict, for example nightblindness!

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