On global stability of the intra-host dynamics of malaria and the immune system

AbstractIn this paper we consider an intra-host model for the dynamics of malaria. The model describes the dynamics of the blood stage malaria parasites and their interaction with host cells, in particular red blood cells (RBC) and immune effectors. We establish the equilibrium points of the system and analyze their stability using the theory of competitive systems, compound matrices and stability of periodic orbits. We established that the disease-free equilibrium is globally stable if and only if the basic reproduction number satisfies R0⩽1 and the parasite will be cleared out of the host. If R0>1, a unique endemic equilibrium is globally stable and the parasites persist at the endemic steady state. In the presence of the immune response, the numerical analysis of the model shows that the endemic equilibrium is unstable

Risk of major depressive disorder among older persons living in HIV-endemic central and southwestern Uganda.

: Major depressive disorder (MDD) is projected to become the second most common cause of disability by 2020 calling for a better understanding its antecedents across the lifespan and in diverse socio-cultural settings. In this paper we describe the risk factors of MDD among older people (50 years +) living in HIV-endemic central and southwestern Uganda. A cross-sectional study was undertaken among 471 respondents (50 years +) participating in the Wellbeing of Older People's Study cohort of the MRC/UVRI Uganda research Unit on AIDS in Uganda. Participants were from five strata: HIV negative, HIV positive on ART, HIV positive not on ART, having an adult child on ART, and having an adult child who died of HIV. Overall MDD prevalence was 9.2% (95% CI 6.7-12.2%) with a prevalence among males of 7.4% (95% CI 4.0-12.3%) and females of 10.3% (95% CI 7.0-14.3%). Factors significantly associated with MDD included: declining socio-economic status, increasing disability scores, decreasing mean grip strength, reported back pain, and not having hypertension. Marginally associated with MDD was being HIV infected and not on ART.<br/

Tracing Uganda’s global primary organic pineapple value chain

The organic sector is one of the fastest growing sectors globally. The sector provides an opportunity for developing countries to export high value products in the global market. One such opportunity for Uganda is the export of organic pineapples. The organic pineapple enterprise is relatively new, having existed for approximately 10 years. This paper traces the organic pineapple value chain, characterises and explains the functions of the actors in the chain. The study used the Global Value Chain Analysis Framework, using data obtained from 140 organic farmers, 10 exporters and 3 support institutions in Uganda. It is clear from the study that the chain is private- sector-driven, has relatively young smallholder farmers, and comprises of 10 small scale export companies. Only 45% of the organic pineapples produced by farmers reach the organic consumers. Reasons for this included limited processing capacity of exporters, competition from conventional buyers and the few local organic consumers. Other reasons were declining soil fertility, limited regulative institutional support and poor infrastructure. We recommend increased use of soil amendments, favourable legislations and investment environment, increased horizontal coordination among exporters and increasing the range of the organic export products in order to increase organic pineapple sales.Keywords: Certification, organic consumer value strea

Women’s production capacities enhancement and gender yield gap reduction in groundnuts in Uganda

Literature shows that women in many African farming communities are more involved in agricultural production activities than men, but their capacities, including access to key farm resources and markets are lower, leading to gender differentials in productivity or yield gaps. In Uganda, women make up 53% of the agricultural labor force, but reportedly manage plots that are 20-30% less productive than plots managed by the men. This study analyses groundnut production differences among female and male farmers in Uganda. Yield gaps between the male and female farmers are considered at two levels; differences between actual and potential yields, and differences between expected and actual yields. A total of 240 randomly selected farmers (58% females) were interviewed using a pre-tested questionnaire. Using regression analysis, factors that contributed to groundnut yield gaps among and between female and male farmers were determined. Results show that both female and male farmers experience a yield gap ranging from about 20% to 37%. The results further indicate that more men than women use improved seed, fungicides, and carry out timely weeding; the crucial factors that affect groundnut output and yield. Majority of farmers, especially women, use home saved seeds and fewer improved technologies due to high cost, leading to low production. Other factors contributing to the yield gap are socio-demographic, economic and institutional factors including less access to extension services by women, less access to and/or control over land, lower affordability of labor and other key inputs

Comparison of Single-Stage and Staged Progression Models for HIV/AIDS Transmission

A single-staged (SS) model and a staged progression (SP) model for HIV/AIDS with the same variable contact rate over time were formulated. In both models, analytical expressions for the HIV prevalence were obtained. A comparison of the two models was undertaken. It is shown that prevalence projections from the SS model are lower than projections from the SP model up to and beyond the peak prevalence, although the SS model prevalence may be higher than that of the SP model much later in the epidemic. A switch from faster SP model prevalence changes to faster SS prevalence changes occurs beyond the SP model peak prevalence. Hence using the SS model underestimates HIV prevalence in the early stages of the epidemic but may overestimate prevalence in the declining HIV prevalence phase. Our comparison suggests that the SP model provides better prevalence projections than the SS model. Moreover, the extra parameters that would make the SP model appear difficult to implement may not be sought from national survey data but from existing HIV/AIDS literature

SOCIO-ECONOMIC FACTORS AFFECTING APPLE PRODUCTION IN SOUTH-WESTERN UGANDA

Apple ( Malus domestica ) accounts for 50% of the world\u2019s deciduous fruit tree production. Apple, commonly known as a temperate crop, has become a gainful cash crop for the people in south-western Uganda. The objective of the study was to determine the various costs involved and how different socio-economic factors influence production in south-western Uganda. The analysis was based on data from a research institute orchard and a survey of 136 farm households. There was positive net cash flow (US 2,398.5) after the fourth year. Labour was the highest cost accounting for 41.8 percent of total production costs. Organic fertiliser, farmers experience and labour were the most critical factors of production. They had a positive and significant effect, explaining 63.6 percent of the variation in apple production. Organic fertiliser had the highest elasticity (0.77), followed by labour and land with 0.28 and 0.01, respectively.La pomme ( Malus domestica ) compte pour 50% d\u2019arbres de production mondiale de fruits caduques. Commun\ue9ment connu comme \ue9tant une culture \ue0 regions temp\ue9r\ue9es, la pommee est devenue une culture de rente b\ue9n\ue9fique pour le people du sud ouest de l\u2019Uganda. L\u2019objectif de cette \ue9tude\ue9tait de d\ue9terminer divers co\ufbts impliqu\ue9s et la mani\ue8re dont diff\ue9rents facteurs socio\ue9conomiques influencent sa production au Sud Ouest de l\u2019Uganda. L\u2019analyse \ue9tait bas\ue9e sur des donn\ue9es d\u2019un institut de recherche sur le verger et des donn\ue9es d\u2019enqu\ueate sur 136 m\ue9nages des fermiers. Apr\ue8s la quatri\ue8me ann\ue9e, il n\u2019y avait pas de cash flow positif (US 2,398.5). La main d\u2019oeuvre faisait le co\ufbt le plus \ue9lev\ue9 avec 41.8 % du co\ufbt total de production. La fumure organique, l\u2019exp\ue9rience de fermiers et la main d\u2019oeuvre des facteurs critiques de production. Ils ont manifest\ue9 un effet positif et significatif, explicant 63.6 % de la variation dans la production de la pommee. La fumure organique avait l\u2019\ue9lasticit\ue9 la plus \ue9lev\ue9e (0.77), suivi de la main d\u2019oeuvre et la terre avec 0.28 et 0.01, respectivemen

Value chain analysis and mapping for groundnuts in Uganda, Socioeconomics Discussion Paper Series Number 14

Groundnut is grown on about 23.95 million ha worldwide with the total production of 36.45 million tons and an average yield of 1520 kg/ha in 2009 Developing countries in Asia, Africa and South America account for about 97% of world groundnut area and 95% of total production. It is one of the important legumes grown in Uganda, ranking second after beans. Its production is most common in Northern, Eastern and Southern parts of the country with higher volumes being produced in the Eastern part compared to the other two. The value chain for groundnuts in Uganda consist of many actors (individuals and institutions) including input suppliers and seed dealers, producers, market sellers, rural traders, urban traders, processors, exporters and consumers. The general objective of this study was to map the value chain for groundnuts, indicating the opportunities that value chain actors can benefit from and strategies that can be used to upgrade the chain. The specific objectives were to characterize the key actors along the groundnut value chain; determine the costs and value added along the groundnut value chain; determine the level of awareness of health problems associated with groundnuts; and determine the constraints and opportunities in the value chain and suggest ways to upgrade the chain. A cross sectional survey was conducted among the key actors in the value chain in 16 purposively selected districts in Uganda where groundnuts are predominantly produced marketed and/or consumed. The districts are Arua in North western Uganda, Lira in the North, Bugiri, Bukedea, Busia, Iganga, Jinja Kaberamaido, Mbale, Pallisa, Kumi and Tororo in Eastern Uganda; Soroti and Katakwi in the North east, Kampala and Wakiso in Central where a total of 145 wholesale traders, 209 retail traders wand 51 processors were randomly selected and interviewed. In addition, data collected by NARO from a total of 314 randomly selected groundnut farmers were used in this study.The data collected included socio-economic characteristics of the value chain actors, type and varieties of groundnuts handled, sales volumes and prices, trends in demand and supply, aflatoxins awareness and control, challenges, constraints and opportunities in groundnuts and trade policy related issues

Identification of upgrading options for legume value chains using a comparison across countries and crops – Tanzania pigeonpea and Uganda groundnut. Socioeconomics Discussion Paper Series 24

The International Crops Research Institute for the Semi-Arid Tropics (lCRISAT) is a non-profit, non-political organization that conducts agricultural research for development in Asia and sub-Saharan Africa with a wide array of partners throughout the world. Covering 6.5 million square kilometers of land in 55 countries, the semi-arid tropics have over 2 billion people, of whom 644 million are the poorest of the poor. ICRISAT innovations help the dryland poor move from poverty to prosperity by harnessing markets while managing risks – a strategy called Inclusive Market- Oriented development (lMOD). ICRISAT is headquartered in Patancheru near Hyderabad, Andhra Pradesh, India, with two regional hubs and five country offices in sub-Saharan Africa. It is a member of the CGIAR Consortium

Chronic disease, risk factors and disability in adults aged 50 and above living with and without HIV: findings from the Wellbeing of Older People Study in Uganda.

BACKGROUND: Data on the prevalence of chronic conditions, their risk factors, and their associations with disability in older people living with and without HIV are scarce in sub-Saharan Africa. OBJECTIVES: In older people living with and without HIV in sub-Saharan Africa: 1) to describe the prevalence of chronic conditions and their risk factors and 2) to draw attention to associations between chronic conditions and disability. METHODS: Cross-sectional individual-level survey data from people aged 50 years and over living with and without HIV were analyzed from three study sites in Uganda. Diagnoses of chronic conditions were made through self-report, and disability was determined using the WHO Disability Assessment Schedule (WHODAS). We used ordered logistic regression and calculated predicted probabilities to show differences in the prevalence of multiple chronic conditions across HIV status, age groups, and locality. We used linear regression to determine associations between chronic conditions and the WHODAS. RESULTS: In total, 471 participants were surveyed; about half the respondents were living with HIV. The prevalence of chronic obstructive pulmonary disease and eye problems (except for those aged 60-69 years) was higher in the HIV-positive participants and increased with age. The prevalence of diabetes and angina was higher in HIV-negative participants. The odds of having one or more compared with no chronic conditions were higher in women (OR 1.6, 95% CI 1.1-2.3) and in those aged 70 years and above (OR 2.1, 95% CI 1.2-3.6). Sleep problems (coefficient 14.2, 95% CI 7.3-21.0) and depression (coefficient 9.4, 95% CI 1.2-17.0) were strongly associated with higher disability scores. CONCLUSION: Chronic conditions are common in older adults and affect their functioning. Many of these conditions are not currently addressed by health services in Uganda. There is a need to revise health care policy and practice in Uganda to consider the health needs of older people, particularly as the numbers of people living into older age with HIV and other chronic conditions are increasing