Complex agricultural livelihoods and aflatoxin exposure in rural Uganda

Abstract

Aflatoxins are secondary metabolites produced by Aspergillus flavus and A. parasiticus species of fungi. They are highly toxic and have been designated by the International Agency for Research on Cancer (IARC) as human carcinogens (Class 1: definitely carcinogenic to humans). High levels of exposure can cause acute hepatic necrosis and death while chronic exposure can cause carcinoma of the liver and possibly also growth impairment in children and compromised immunity. Contamination of crops most often occurs during harvest and storage, when damp, warm conditions allow the fungi to proliferate. Possible barriers to effective local interventions to reduce exposure were explored, by examining agricultural livelihoods and patterns of household food consumption within a population cohort in rural south west Uganda. Previous work in this cohort and elsewhere in Uganda showed that aflatoxin exposure was ubiquitous and that there are multiple sources of exposure. Data on agricultural practices were collected through a survey of 200 households; 22 of those were randomly selected for in-depth interviews. While crops such as maize, cassava, beans and groundnuts - all potential sources of aflatoxin - are grown, stored and consumed locally, the sale of home-grown foods, unfavourable climate, pests and diseases and limited labour, all facilitate food scarcities and subsequent insecurities leading to purchase of poorly stored foods which may also contain aflatoxins. Processed foods are easily accessible by many households, from the numerous trading centres established within villages. This paper gives background information on heterogeneity of household diets and seasonal trends in food consumption in rural Uganda and by so doing, identifies potential risk factors for aflatoxin contamination in the study area. Risks of aflatoxin contamination are multifaceted and this complexity makes it challenging to design and implement risk control measures and advocacy strategies. The argument of the paper is that the complexity of agricultural livelihoods and patterns of household food consumption in rural Uganda may mitigate the impact of simple, local interventions to reduce aflatoxin exposure. Therefore, intervention approaches need to take into account this complexity in order to minimize risk factors, especially amongst poor populations in rural areas.