LCIRAH Seminar Series: Mycotoxins as factors in Africa's Health, Trade and Development
Thursday, November 29, 2012 - 10:00 to 11:00
Africa experiences largely uncontrolled contamination of staple foods by two mycotoxins - Aflatoxin (AF) and Fumonisin (FN). Maize is the predominant source of both these toxins. Aflatoxin from groundnuts, rice and dried cassava also have a risk of contamination, with peanut having the highest levels and contamination frequencies.
The vast majority of Africa's foods are consumed close to the site of production, and most of it is traded in the informal market making management of mycotoxins problematic, and the predominant management approach (regulation) ineffective; particularly where food insecurity ensures that even what is known to be contaminated will get eaten. The trade cost of EU regulations is >$700M, which is probably much less than the cost of infrastructure to manage the problem, and the higher cost of food in Africa that management will require.
Where the mycotoxins are most important is the hidden health costs; aflatoxin alone modulates >40% of the burden of disease in developing countries. FN is associated with esophageal cancer, spina-bifida, and infant stunting. Although not yet proven causal there is a very strong correlation between HIV transmission and maize consumption that may be due to the effect of FN on membrane integrity.
AF exposure of Sub-Saharan Africans is almost universal with >90% having biomarkers of chronic exposure and 30-90% having been exposed in the preceding 24h. AF promotes liver cancers, particularly in conjunction with HVB. Although not well documented it is probably that the immune suppress and nutritional interference of AF is much more important than the cancer burden. Chronic AF exposure is associated with suppressed immunity, this effect being synergistic with HIV infection resulting in accelerated progression, more opportunistic infections (TB RR >3), adverse pregnancy and childhood growth faltering. Both protein nutrition and micro-nutrient status are compromised by AF exposure.
Solutions to both mycotoxins exist and can be deployed reactively rapidly. The completive exclusion of toxigenic fungi can address the trade aspects and promote development where scale and profit margins are adequate. It is likely that this technology will not be economic for small farmers without subsidy. Food additives the bind both toxins are also a viable option and perhaps more affordable by the general population ($0.7 per year) to protect and adult.
The case to manage the mycotoxins of Africa is strongest from a public health cost perspective and should be considered as a development investment.