Review of past and present research on aflatoxin in Uganda

Uganda is a landlocked country located in Eastern Africa covering an area of about 241,000 km2. Its climate is tropical, with  most parts of it receiving bimodal rainfall of 500 to 2000 mm per annum, and an average temperature of 25 oC. These  temperatures and the humid environment are optimum for growth of Aspergillus flavus/parasiticus and subsequent production of aflatoxins in the produce. The country was among those in the world where aflatoxin studies were first conducted following their discovery, in the 1960s and, during that time, hepatoma frequency was related to aflatoxin content of food. The objective of this paper is to review the past and present status of aflatoxin research in Uganda by considering the epidemiology, measurement, research, promoting factors, control strategies and problems associated with this toxin in the country. It is  revealed that aflatoxin contamination has been studied mainly in maize and groundnuts, and aflatoxin B1 is the most prevalent in the country. More studies have been done on foods sampled at the market level than on-farm level. There is more aflatoxin contamination of  foods in markets, than those stored by farmers, with some having levels above the FDA/WHO recommended limits of 20 ppb. However, no strategies for controlling aflatoxin contamination of food and food products in Uganda have been reported. It is concluded that aflatoxin contamination of agricultural produce is a big problem in the country, and this is  attributed to inadequate research, lack of proper sampling and analytical procedures; poor legislation and lack of awareness of the problem by farmers, traders, processors and consumers. Therefore in order to reduce the  potential hazard of aflatoxins,  government of Uganda through the Ministries of  Health, and Agriculture, Animal Industry and Fisheries; together with the  Uganda National Bureau of Standards, should put into place information dissemination and training programs for farmers,  traders and consumers on proper pre- and  post-harvest aflatoxin management strategies. To reduce further this potential   hazard, regulations for monitoring susceptible produce from buying points to retail markets should be put in place and strict measures on the quality of food at both household and market levels be enforced by all policy makers.Key words: Uganda, aflatoxin, contamination, maize, groundnutsL’Ouganda est un pays enclavé situé en Afrique orientale, qui couvre une superficie de près de 241.000 km2. Son climat est tropical, la plupart de ses régions  reçoivent des pluies bimodales de 500 à 2000 mm par an, et la température moyenne est de 25 oC. Ces températures et l’environnement humide sont optimaux pour la culture et la croissance d’Aspergillus  flavus/parasiticus et la production subséquente d’aflatoxines dans ses produits. L’Ouganda compte parmi les premiers pays du monde où des études sur les aflatoxines ont été menées aussitôt après la découverte de ces dernières dans les années  1960. A cette époque, la fréquence de l’hépatome a été associée à la teneur en aflatoxine dans les aliments. L’objectif du présent document est d’évaluer l’état des recherches passées et actuelles sur l’aflatoxine en Ouganda en considérant  l’épidémiologie, les mesures, les  recherches, les facteurs de promotion, les stratégies de contrôle et les problèmes associés  à cette toxine dans le pays. Il a été révélé que la contamination par aflatoxine a été étudiée principalement dans le maïs et l’arachide, et l’aflatoxine B1 est la plus prévalente dans le pays. Des études ont été effectuées sur les aliments pris comme échantillons plus au niveau du marché qu’au niveau des champs. Il y a plus de contamination par aflatoxine dans les aliments exposés au marché que dans les aliments conservés par les cultivateurs, certains aliments ayant des niveaux supérieurs aux limites de 20 ppb recommandées par l’OMS/FDA (organisme gouvernemental de contrôle pharmaceutique et alimentaire). Cependant, aucune  stratégie de contrôle de la contamination par aflatoxine d’aliments et de produits alimentaires en  Ouganda n’a été rapportée. La conclusion est que la contamination des produits agricoles par aflatoxine est un grand  problème qui se pose dans le  pays, et ceci est dû à des facteurs tels que des recherches inadéquates, le manque  d’échantillonnage approprié et de procédures analytiques; une mauvaise législation et aussi parce que les agriculteurs, les  commerçants, les agents de la   transformation industrielle et les consommateurs ne sont pas au courant du  problème. Par  conséquent, pour réduire les possibilités des dangers présentés par les aflatoxines, le Gouvernement de l’Ouganda, par le  biais des Ministères de la santé, de l’agriculture, de l’industrie animale et de la pêche, conjointement avec le Bureau National de vérification des Normes en Ouganda (Uganda National Bureau of Standards), devrait mettre en place des programmes de diffusion d’informations et de formation à l’intention des cultivateurs, des commerçants et des consommateurs sur des  stratégies de gestion de l’aflatoxine avant et après la récolte. Dans le souci de réduire davantage ce danger éventuel, des  règlements visant à contrôler des  produits sensibles depuis les points d’achat jusqu’aux marchés de vente en détail   devraient être mis en place et des mesures strictes relatives à la qualité des  aliments aussi bien au niveau des ménages qu’au marché devraient être mises en application par tous les décideurs.Mots-clés: Ouganda, aflatoxine, contamination, maïs, arachides

Seasonal variability in food and nutrition security among children 0-3 years in Karamoja sub-region of Uganda

Optimal nutrition and good feeding of infants and young children are among the most important determinants of their health, growth and development. Due to unimodal climate in Karamoja sub-region, north eastern Uganda, achieving food security remains a development challenge in the area impacting negatively on the nutrition and health status of infants and young children. The current study, therefore, is important in providing the basis for season-based interventions to improve food and nutrition security in Karamoja sub-region. A longitudinal study involving 267 lactating mothers during harvesting season and 380 during planting season was conducted. Data were collected using Individual level Dietary Diversity questionnaire, 24-Hour Dietary Recall, and Anthropometry and were analyzed statistically. The findings indicated that except Abim district, 77.8-97.8%of the lactating mothers never attended school; 75- 100% depend on subsistence farming. Lactating mothers (29.9-41.9%) introduced complementary foods to their infants at 6 months, while the age at first introduction of any food to the infant was mostly between 4-6 months. Dietary quality of complementary foods was low across all the districts; 6.7-38.9% of the children ate foods from four or more of the seven food groups in the previous day (Minimum Dietary Diversity) in both seasons. Complementary foods were characterized by plant food sources. With exception of milk and milk products, proportion of children who consumed animal-sourced foods was low, ranging from 0% in meats to 8.9% in fish and sea foods. Energy and nutrient intakes varied according to age groups of the children across districts and season. The proportion of children below -2 Z-score also varied according to districts and it is generally higher during the planting season than the harvesting season. The median of the z-scores for height-for age and Mid Upper Arm Circumference for age ranged from -1 to -2.5. In conclusion, there were variations and disparities in dietary diversity, energy and nutrient intake as well as nutrition status of infants and young children across season and districts in Karamoja sub-region of Uganda. Therefore, interventions to combat malnutrition among children 0-3 years need to take into account seasonal variations for each of the geographical locations in Karamoja sub-region

Metalloproteases in Trypanosoma rangeli-infected Rhodnius prolixus

Protease activities in the haemolymph and fat body in a bloodsucking insect, Rhodnius prolixus, infected with Trypanosoma rangeli, were investigated. After SDS-polyacrylamide gel electrophoresis containing gelatin as substrate, analysis of zymograms performed on samples of different tissues of controls and insects inoculated or orally infected with short or long epimastigotes of T. rangeli, demonstrated distinct patterns of protease activities: (i) proteases were detected in the haemolymph of insects which were fed on, or inoculated with, short epimastigotes of T. rangeli (39 kDa and 33 kDa, respectively), but they were not observed in the fat body taken from these insects; (ii) protease was also presented in the fat bodies derived from naive insects or controls inoculated with sterile phosphate-saline buffer (49 kDa), but it was not detected in the haemolymph of these insects; (iii) no protease activity was observed in both haemolymph and fat bodies taken from insects inoculated with, or fed on, long epimastigotes of T. rangeli. Furthermore, in short epimastigotes of T. rangeli extracts, three bands of the protease activities with apparent molecular weights of 297, 198 and 95 kDa were detected while long epimastigotes preparation presented only two bands of protease activities with molecular weights of 297 and 198 kDa. The proteases from the insect infected with T. rangeli and controls belong to the class of either metalloproteases or metal-activated enzymes since they are inhibited by 1,10-phenanthroline. The significance of these proteases in the insects infected with short epimastigotes of T. rangeli is discussed in relation to the success of the establishment of infection of these parasites in its vector, R. prolixus