Theses and Dissertations

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Molecular Diversity of Bacteria from a Municipal Dumpsite: Implications to Public Health
(The Nelson Mandela African Institution of Science and Technology, 2016) Mwaikono, Kilaza Samson
Despite known risks of inappropriate disposal of solid wastes; most cities in developing countries dispose waste in open dumpsite where humans, animals and microbes interact. This study was done in Arusha municipal dumpsite, Tanzania to investigate the abundance and diversity of bacteria, compare the faecal microbiota of pigs scavenging on dumpsite and indoor reared pigs, and also determine the resistance profile of enteric bacteria from the dumpsite. Domestic wastes, solid biomedical wastes, sludge from the river near the dumpsite and faecal materials of pigs were sampled. Total DNA was extracted and the variable region four (v4) of the 16S rRNA gene was sequenced using high throughput Illumina MiSeq platform. The quality control of sequences and the statistical analyses was performed using Mothur platform. A total of 8,469,294 quality sequences were generated. The mean of bacterial species per sample was 8,243. Diversity was high with an average InvSimpson index of 44.2. Thirty-five bacterial phyla dominated by Firmicutes (38%), Proteobacteria (35%), Bacteroidetes (13%) and Actinobacteria (3%) were found. Overall, 76,862 operational taxonomic units (OTUs) dominated by Acinetobacter (12.1%), Clostridium sensu stricto (4.8%), Proteinclasticum and Lactobacillus (each 3.4%), Enterococcus (2.9%) and Escherichia/Shigella (1.7%) were revealed. There was a significant difference in faecal microbiota between scavenging and indoor reared pigs. Pathogenic genera like Brucella, Rickettsia and Listeria were exclusive to scavenging pigs. In solid biomedical waste, 36.2% of OTUs were related to dehalogenation, 11.6% degraders of aromatic hydrocarbons, 8.5% chlorophenol degradation and Atrazine metabolism 8.3%, and bacteria related to pathogens were 34%. Escherichia/ Shigella, Bacilli and Proteiniclasticum were predominant enteric bacteria. Some bacteria in scavenging pigs had 99% sequence similarity to pathogenic Escherichia furgosonii, Shigella sonnei, Enterococcus faecium and Escherichia coli O154:H4. Over 50% of the isolates were multidrug resistant. The study provides a comprehensive report on diversity of bacteria in Arusha municipal dumpsite. The high species richness shows the complexity of this man-made ecosystem, and calls for further research to assess for a link between human diseases and the dumpsite. This would provide insight into proper disposal of the waste, as well as, limit the risks to human health associated with the dumpsites.
Status, physiognomies and economic viability of hydroponic lettuce production in selected areas of Sothern TANZANIA and Central UGANDA
(2023-08) Gumisiriza, Margaret
There is an increasing interest and research in soilless farming due to its ability to enhance food production amidst challenges presented by urbanization. However, the adoption of this technology is still very limited in East Africa. This main objective of the research was to study the appropriateness of hydroponics as a feasible urban cropping system for improved vegetable production and accessibility in Uganda. An assessment on status of hydroponics in Northern Tanzania and Central Uganda was carried out using google questionnaires and face-face interviews which revealed limited uptake of the technology majorly due to the high initial costs required. An experiment was set up in central Uganda to evaluate the performance of red and green leafy lettuce produced using a non-greenhouse and non-circulating hydroponic system. Parameters assessed included; plant height, root length, number of leaves, leaf width, fresh weight and dry matter content. Data was analyzed using 2 sample T-test under origin software. A significant difference was noted at harvest for dry matter content (P=0.02, P=0.01), fresh weight (P=0.03, P=0.02) and root length (P=0.01, P=0.02) between red and green lettuce grown under soil and hydroponics in that order at P < 0.05. An economic analysis was done on the system to assess its profitability. Budgeting techniques results showed: Net present value (16.37$), Internal rate of return (12.57%), Profitability index (1.1) and non-discounted payback period (4,5) for annual crop production. Net present value was sensitive to changes in discount rate and unit price while revenue varied with a change in quantities sold and unit price. Regression analysis showed that a variation in the unit price of lettuce was stronger and negatively affected the quantity sold (R=0.91) than the influence the same independent variable on revenue earned (R=0.84). Based on the study results, hydroponics has the potential to act as a suitable alternative in vegetable production system and improve accessibility to vegetables across urban areas in a cost-effective manner. This will also assist in contributing to sustatinable develeopment goals; 3 (good health and wellbeing) and 11 (sustainable cities and communities). There is need to study the perfomance of other vegetables as well as various factors that can improve crop perfomance using the hydroponic system inorder to boost; crop yield, adoption of the system and hence vegetable accessibility and food security. Policy makers and governments should put more efforts in training farming communities about hydroponics.
From Field to Phamacy: Euphorbia Hirta’s Role in Treating Urinary Tract Infections in Northern Tanzania
(NM-AIST, 2024-11) Mbwale, Issaya
Urinary Tract Infections (UTIs) are among the most prevalent bacterial infections globally, occurring in both community and healthcare settings. Escherichia coli and Klebsiella pneumoniae, are the prominent pathogens responsible for UTIs. Euphorbia hirta, is traditionally used by the Maasai and Meru societies to combat pathogens causing UTIs. Despite its extensive use, significant gaps remain in understanding the population density, distribution, ethnobotanical practices, phytochemical constituents, and therapeutic effectiveness of E. hirta, especially in the Arusha region of Tanzania. This study aimed to address these gaps by investigating 1) the distribution and density of E. hirta, 2) the influence of different land use and environmental conditions on density of E. hirta, 3) the traditional knowledge related to E. hirta’s use among the Meru and Maasai societies, 4) the antimicrobial compounds in aqueous and methanolic extracts of E. hirta, and 5) the antibacterial activity of both extracts against strains of E. coli (ATCC 25922) and K. pneumoniae (ATCC 13883). Ecological data were collected from 300 plots across 60 randomly selected grids from Kisongo and Kikwe wards. Ethnobotanical interviews involved 154 households chosen via the snowball technique. Kruskal-Wallis and Wilcoxon rank-sum tests showed significant differences in E. hirta density between wards and land use types. Gas chromatography-mass spectrometry analysis revealed ten potential compounds with antibiotic activities, including dodecanal, trans-Farnesol, phytol, cis-5,8,11,14,17-Eicosapentaenoic acid, 2(4H)-Benzofuranone, 5,6,7,7a-tetrahydro-4,4,7a- trimethyl-, (R)-, Paromomycin, azelaic acid, palmitoleic acid, and 8,11,14-Eicosatrienoic acid, methyl ester (Z,Z,Z). Traditional methods of preparing E. hirta among the Maasai and Meru recorded by this study include boiling and soaking in cold water. Organic solvent extraction with methanol generally outperformed aqueous extractions. However, cold water soaking produced extracts with stronger inhibition against E. coli, while boiling was more effective against K. pneumoniae. These confirm that water-based extracts are effective and safe for treating UTIs, reinforcing traditional practices in contemporary medicine.
Seroprevalence and Genetic Resistance of Dairy Cattle To Brucellosis in Smallholder Dairy Farming System In Selected Regions of Tanzania
(NM-AIST, 2025-01) Mengele, Isaac
Brucellosis in livestock is caused by different species such as B. abortus (cattle), B. melitensis (goats), B. ovis (sheep), B. suis (pigs) and B. canis (dogs). Recent studies in different regions have reported an increasing trend in smallholder dairy cattle. Furthermore, neighboring countries have reported identification of B. melitensis in dairy cattle, this is not known in Tanzania. In addition, the use of brucellosis resistant cattle has shown promising impact in controlling the disease in other countries, however it is not known if Tanzanian dairy cattle population contains genetic markers which are associated with the resistance/susceptibility to brucellosis. To address these questions, a cross-sectional study design was conducted in two agroecological zones, the Northern zone (Arusha, Kilimanjaro and Tanga regions) and the Southern highland zone (Iringa, Njombe and Mbeya regions) to determine brucellosis seroprevalence, risk factors, Brucella species circulating in smallholder dairy cattle farming systems and conduct Genome-wide association studies on cattle genome to identify SNP markers associated with brucellosis resistance/susceptibility. Seroprevalence was calculated at different administrative scales, and spatial tests were used to detect disease hotspots. A generalized mixed-effects regression model was built to explore the relationships among Brucella serostatus, animals and farm management factors. The overall seroprevalence was 2.39% (49/2048 cattle, 95% CI 1.7-3.1) across the study area and the Njombe Region represented the highest percentage with 15.5% (95% CI 11.0-22.0). In addition, hotspots were detected in the Njombe and Kilimanjaro Regions. Mixed-effects regression models showed that having goats around (OR 3.02, 95% CI 1.22-7.46) and abortion history (OR 4.91, 95% CI 1.43-16.9) were significant risk factors for brucellosis. The GEMMA analysis results identified a SNP marker BovineHD0900011750 located in chromosome number 9 responsible for brucellosis susceptibility (odds ratio >1) in 5.6% of the 1977 study animals. The web-based Ensembl variant effect predictor showed that the marker is found in a protein-coding region called ATPase Family Gene 1 homology (AFG1L) which produces mitochondrial integral membrane protein responsible for mitochondrial protein homeostasis and its impact in gene expression has been categorized as modifier as the direction of the impact is not yet known. Education of dairy farmers about brucellosis and its control, particularly in relation to goats in this setting is advised. In addition, a One-Health approach is needed to further study the role of small ruminants in dairy cattle brucellosis and the status of brucellosis in dairy farmers in the Njombe and Kilimanjaro Regions.
Assessment of the Population Structure and Regeneration Potential of Ocotea Usambarensis in Response to Recent Selective Logging on the Southern Slopes of Mt. Kilimanjaro, Tanzania
(NM-AIST, 2025-01) Moshy, Stephen
East African Camphorwood (Ocotea usambarensis) population in montane forests of East Africa has been declining at alarming rates. The decline is attributed to the historical legal commercial harvesting of the species sanctioned by colonial governments and later on illegal selective logging due to its high timber value. O. usambarensis is a vital component of the Mt. Kilimanjaro catchment forest and plays an important role in its hydro-ecological functions, making its population worth conserving. This study assessed the population structure, relative abundance and regeneration status of O. usambarensis in its range areas with different historical logging intensity and along elevation gradient on the southern slopes of Mt. Kilimanjaro. The age structure varied along the elevation gradient and across different blocks with high and low logging intensities blocks. However, a healthy regeneration status of O. usambarensis was observed, with a higher density compared to other tree species, as indicated by a reverse J-shaped population structure. Relative abundance of O. usambarensis decreased with increased logging intensity and increased along the elevation gradient. Stem density and basal area of seedlings, saplings and adults were compared using Wilcoxon signed-rank test. The comparison between blocks with different historical logging intensity showed no significant difference; adults (W = 67, p = 0.33), saplings (W = 101.50, p = 0.72), and seedlings (W = 102, p = 0.90); however, adults stem density (stems ha-1; W = 41, p = 0.002) and basal area (m2 ha-1; W = 34, p = 0.001) varied significantly along the elevation gradient. Moreover, I computed tree species Importance Value Index (IVI) in both blocks and along the elevation gradient. The IVI in both blocks and along the elevation gradient showed O. usambarensis is still the most important tree species with higher IVI compared to other tree species found in the study plots. The findings suggests that logging targets mainly adults which are located close to the park boundary. Thus, calling for more enforcement efforts in areas adjacent to park boundaries and participatory approaches towards sustainable management of the species in range areas. Also, more efforts should be put on supporting local communities to plant O. usambarensis and other timber trees in their village lands and farms in areas with favourable climate and at the required altitudes. This will help to reduce pressure in the protected forest resources.
Development of a Field Deployable Handheld Electrochemical Biosensor for Detection of Aflatoxin B1 in Grains
(NM-AIST, 2025-01) Mtweve, David
Aflatoxins (AFs) are highly toxic compounds, with Aflatoxin B1 (AFB1) being the most harmful, necessitating rapid and reliable on-site detection to ensure food safety. This study introduces a portable electrochemical biosensor for detecting AFB1 in grains, leveraging a screen-printed electrode (SPE) pretreated with sulfuric acid and modified with bovine serum albumin (BSA). The BSA serves as a scaffold for immobilizing anti-AFB1 antibodies via terminal carboxylic groups, reducing nonspecific binding. The biosensor employs Differential Pulse Voltammetry (DPV) for detection, using a wireless portable potentiostat to transmit results to a mobile device via Bluetooth. The system achieved a Limit of Blank (LoB) of 1.67 ng/mL, a Limit of Detection (LoD) of 2.058 ng/mL, and a dynamic range of 1–20 ng/mL, demonstrating high sensitivity. Specificity and sensitivity were validated against the ELISA gold standard, with a correlation coefficient of 0.92 and a significant p-value of 0.04, indicating robust diagnostic performance. Real-sample testing in maize and peanut matrices showed recovery rates of 90–105%, confirming its accuracy in diverse food systems. The biosensor’s ability to differentiate AFB1 from fumonisin further highlights its selectivity. These findings position the developed biosensor as a cost-effective, portable, and highly reliable tool for on- site mycotoxin monitoring in food safety applications.
Anti-Aging Potential of Vitamin D: An Insilico Study
(NM-AIST, 2025-02) Tuntufye, Edna
Despite extensive studies on the impact of vitamin D in aging retardation, the detailed atomic- level binding interactions between vitamin D (D2 and D3 forms) and associated anti-aging proteins have been largely unexplored. The study investigates these interactions by using molecular docking techniques to provide deeper insights into how vitamin D affects the structural dynamics and stability of the proteins associated with anti-aging process. The docking results reveal that vitamin D interacts most favorably with Sirt1 (PDB ID: 4zzi), a crucial anti-aging protein involved in DNA repair and metabolic regulation. Docking studies, including blind, grid, and hydrated docking approaches, show that vitamin D2 binds more strongly than vitamin D3 across all receptors evaluated. Specifically, in blind docking, vitamin D2 exhibited a binding affinity of −37.99 kJ/mol, while vitamin D3 showed a binding affinity of −34.85 kJ/mol. Grid docking revealed a similar trend, with vitamin D2 demonstrating a higher binding affinity of −41.38 kJ/mol compared to −40.08 kJ/mol for vitamin D3. These interactions are primarily hydrophobic, involving key residues such as Val445, Phe273, and Ala262 which form alkyl and pi-alkyl interactions with the ligands. The introduction of water molecules in hydrated docking further enhanced binding affinity, with vitamin D2 achieving an average binding free energy of −48.33 kJ/mol and vitamin D3 −45.94 kJ/mol highlighting the stabilizing effect of water in ligand-protein interactions. The Sirt1-vitamin D complexes maintained stable structural integrity with minimal RMSD and Rg fluctuations. The free energy surface revealed two preferred conformations for vitamin D2 and one for vitamin D3 indicating greater conformational flexibility for vitamin D2. The MM-PBSA results indicated that the vitamin D3-Sirt1 complex demonstrated superior stability, with a binding free energy of −167.12 ± 16.35 kJ/mol, compared to the vitamin D2-Sirt1 complex (−144.07±19.45). This suggests that vitamin D3 might have a more stable interaction with Sirt1, potentially offering enhanced therapeutic efficacy. The structural analysis revealed that both forms of vitamin D exhibited similar binding modes with vitamin D3 interacting at a lower energy than vitamin D2. These findings offer crucial insights into the molecular mechanisms underlying the role of vitamin D in aging, revealing key differences between vitamin D2 and D3 binding to Sirt1.
Characterization Of Phenotypic Traits Linked To Anthracnose Resistance And Their Impact On Farmer Adoption Of Common Bean In Tanzania
(NM-AIST, 2025-03) Kadege, Edith
Tanzania is the top bean producer in Africa and seventh globally, exporting half of beans to neighboring nations. However, only 14% of Tanzanian farmers use improved bean varieties, leading to suboptimal productivity. Diseases, like anthracnose significantly hinder adoption. From 2021-2023, research was conducted in Tanzania to identify phenotypic traits associated with anthracnose resistance and farmers-preferred traits for adopting bean varieties. Twenty-two bean genotypes were evaluated in anthracnose hotspot fields and in screen house to validate resistance. Eighteen genotypes were further assessed under local conditions to evaluate performance and farmers-preferred traits. Phenotypic traits like anthracnose infection score, plant vigor, days to maturity, plant stands at harvest and grain yield were recorded and analyzed using R statistical software. Results revealed 75% of phenotypic traits are positively correlated with anthracnose resistance, with strong correlations (P≤0.001) on days to maturity, plant stands at harvest, plant vigor and grain yield. The NUA 48, NUA 64, Sweet Violet and VTT 923-23-10 demonstrated resistance and high yields. Significant differences (P≤0.001) were observed among genotypes, environments and their interactions, influencing disease resistance and grain yield. Advanced breeding lines outperformed commercial checks by 56%. Anthracnose incidence varied regionally, with higher rates in Northern Tanzania (22.7%) compared to Lakezone (10%) and Southern regions (5.8%). Highest incidence in Northern is due to higher soil inoculum levels sustained by two cropping seasons. In contrast, Southern highlands with single cropping season and continuous crop rotation, these practices help reduce anthracnose inoculum. The NUA 48, NUA 64, Sweet violet and VTT923-23-10 were identified as top perfoming genotypes in terms of yield and farmer preference in Tanzania. High yield, market preference, and disease resistance were key selection criteria. Cooking suitability with banana and intercropping compatibility emerged as unique farmer preferences, suggesting the importance of incorporating these traits in future variety development. Based on these findings, phenotypic traits like plant vigour, days to maturity, plant stands at harvest, and grain yield can be considered in breeding efforts. The NUA 48, NUA 64, Sweet violet and VTT 923-23-10 are proposed for release dueto their anthracnose resistance, adaption to local conditions, and preference by farmers in Tanzania.
Characterization of Alalili Systems in Rangelands of Northern Tanzania
(NM-AIST, 2025-06) Hezron, Elkana
Alalili systems in northern Tanzania face conservation threats due to lack of information regarding their key features and practices which are meant to govern their sustainable management and utilization. This study characterized the Alalili systems across land uses of northern Tanzania’s rangeland. It aimed to gather information on the structure of Alalili systems, their fodder species composition and diversity, as well as their compliance with the traditional management principles and guidelines. Furthermore, the potential socio-ecological benefits of these systems to local communities were explored. The study employed a cross- sectional stratified random sampling design and mixed methods of data collection. Data analysis deployed Microsoft Excel 11 for data organization and Q-GIS for mapping the structural distribution of Alalili systems. Sampled t-test and ANOVA analyzed the size of Alalili systems, their fodder species composition, and income gain across Alalili categories and land-use strata, respectively, through R version 4.2.3. The historical fodder plants composition in the rangelands of northern Tanzania was analyzed by a systematic literature review. Narrative and descriptive analysis evaluated the compliance attributes of the traditional principles and guidelines, as well as the community’s perception on socio-ecological roles of the Alalili systems through N-Vivo 14. The results indicated the existence of both communal and private Alalili systems, with varying sizes. Communal Alalili systems were larger and highly distributed compared to private Alalili systems recorded from each land-use category. It was observed that most of the historical fodder plants found in the rangelands of northern Tanzania commonly appeared in the Alalili systems. Instantaneously, low fodder species diversity in the private Alalili systems may increase the risk of species homogeneity, in contrast to the communal Alalili systems, which had high fodder species diversity. More than 50% of the surveyed Alalili systems are not complying with management principles and guidelines, thus increasing their risk of being degraded. The Maasai community regards Alalili practices as the system that maintains their livestock wealth, socio-cultural prestige, and moral identity. Therefore, this study has pioneered the structure and compliance of Alalili systems, thus forming the basis of the indigenous knowledge practices needed to promote sustainable rangeland management.
Population Density and Extent of Harvesting of Warburgia Ugandensis (Sprague) in Northern Tanzania: Implications for Conservation
(NM-AIST, 2025-06) Mollel, Letan
Warburgia ugandensis, commonly known as Osokonoi and Endoroniki in Maa, is highly overexploited medicinal plant for commercial purposes. Despite its significant therapeutic potential, unsustainable harvesting practices threatened its survival thereby risking local extinction in its native range areas. This study aimed to assess the population density, distribution, and extent of harvesting of Warburgia ugandensis across its native ranges, land use types, and elevation gradients in Northern Tanzania. Meanwhile, it assessed ethno- botanical uses and conservation measures of Warburgia ugandensis across its native range areas in northern Tanzania. Data were collected from 128 plots each measuring 1ha within species native range areas (Kilimanjaro, Monduli, Ketumbeine, Gelai, and Longido) while open-ended questionnaires were administered to 221 randomly chosen respondents. Data were analyzed using the Kruskal-Wallis test, post hoc (Dunn test), Generalized Linear Models (GLMs), and Descriptive Statistics. Land use types significantly influenced population density, with Forest Reserves recording the highest mean density of 6.485 stems/ha compared to grazing land with 1.833 stems/ha. Elevation also influenced density, with higher densities at 2001-2500 m compared to 1000-1500 m. A significant variation in the extent of harvesting was revealed with Ketumbeine experiencing extensive debarking and root cutting. Community knowledge of Warburgia ugandensis medicinal uses was highest around Kilimanjaro, with gastrointestinal disorders and cough being the most common ones. Respondents’ perceptions of species utilization were high in Gelai and Monduli, while Ketumbeine and, Longido revealed more variability. Community awareness of conservation measures for the species was notably high in Kilimanjaro compared to Monduli. The study underscores the need for targeted conservation efforts, in areas where the species is over-exploited, particularly Ketumbeine, and Longido while taking into consideration soil topography, climate factors, and sustainable harvesting practices.
Enhancing Banana (Musa Acuminata) Breeding Efficiency: Genotypic Pollen Performance and The Influence of Irrigation And Potassium on Seed Set and Viability
(NM-AIST, 2025-06) Bayo, Stanley
Banana (Musa spp.) is a crucial staple food for over 30 million people in Tanzania. Mchare is significant globally as it is one of the ancestors of popular dessert bananas like Cavendish and Gros Michel. However, Mchare is highly susceptible to all potential banana pathogens that cause significant yield losses and threaten food and income security. Developing resistant banana varieties through crossbreeding is essential, with researchers identifying wild banana types as potential sources of resistance. A major challenge in this process is low seed production, which this study aims to address by exploring the effects of pollen quantity, supplemental irrigation, and potassium fertilization on seed set and viability in Mchare banana breeding. The study was conducted at the Nelson Mandela African Institution of Science and Technology (NM-AIST), Tengeru campus, and the World Vegetable Centre in Arusha. Fourteen banana genotypes were analysed for pollen production and viability, selecting the best male and female candidates for crossbreeding under irrigation and rainfed conditions with varying levels of potassium fertilization 0, 150, 300 and 500 g K/mat/year (0, 375, 750 and 1250 kg K/ha/year). Data analysis was performed using the GenStat 21 st version. The results showed that Calcutta 4 and Borneo (both wild types) and Huti-White (Mcharesub-group, a landrace) exhibited high pollen production. Calcutta 4 and Borneo produced 31 000 pollen grains per anther, while Huti-White produced 8120 pollen grains per anther. Pollen viability was 74.2% for Calcutta 4 and Borneo and 59.3% for Huti-White, indicating their potential as suitable male parents for breeding programs. It was found that higher temperatures of 25 to 27°C (the temperature range was 18 to 29°C), rainfall 250 to 300 mm per month, and irrigation improved pollen quantity and viability, with the best pollination occurring between 6:00 AM and 10:00 AM. Supplemental irrigation and potassium levels of 300-500 g K/mat/year (750 and 1250 kg K/ha/year) positively influenced seed viability. The study concludes that supplemental irrigation and potassium application are critical for improving pollen and seed quality, recommending 300 g K/mat/year (705 kg K/ha/year) for optimal results as it give significant result like 500 g K/mat/year (1250 kg K/ha/year) so for proper resources immobilization 300 gK/mat/year (705 kg K/ha/year) is recommended. Further research is needed to understand factors affecting pollen viability and seed production, as well as to explore more male parent varieties with superior pollen traits for enhancing breeding success.
Determinants of Weight Gain Among Postpartum Women in Arusha-Urban, Tanzania
(NM-AIST, 2025-06) Ngowi, Restituta
Overweight and obesity among women of reproductive age are a concern of public health significance. Currently, there is minimal information on the magnitude of postpartum overweight and obesity in Tanzania. The present study sought to establish the prevalence of postpartum overweight and obesity, its association with dietary patterns and sociodemographic attributes in an urban setting of Arusha region. A longitudinal study using a multistage sampling is implemented to determine the magnitude of overweight and obesity among post- partum women. A total number of 247 women were randomly recruited while attending their routine postnatal care services from three health facilities which were: Ngarenaro, Kaloleni and Moivaro health centers between March 2022 and June 2022. The study used a quantitative approach to examine the relationship between postpartum overweight and obesity, dietary patterns and sociodemographic attributes. The study used semi structured questionnaire for data collection and food consumption was measured by using 24-hours dietary recall. The analysis used IBM SPSS Version 25, where measures of central tendency for description of some social demographic data was conducted. The Pearson chi-square test to compare weight gain (BMI) with independent and dependent variables and Ordinal logistic regression to assess association between study variables. The study shows that prevalence of overweight and obesity at both six- and twelve-weeks post-partum women was high (56% and 59% respectively). A significant relationship between age and BMI was observed at six and twelve weeks (p<0.01). Odds of being obese or overweight versus in normal BMI are 1.6 and 1.7 times greater at six and twelve weeks, respectively, than those who met their minimum dietary diversity (p < 0.01 and p < 0.05, respectively). The research results demonstrated an association between participants’ sociodemographic characteristics, postpartum dietary practices and weight gain. The study recommends that dietary diversification and participation in physical activities at all period of reproductive cycles (pre-pregnancy, during pregnancy and post-partum) is necessary.
Cashew Wastes Biomass in Tanzania Auditing and Characterization: A potential bioresource for production of value-added products
(2025-06-27) Mwema, Hadija; Kassuwi, Shaaban; Mosha, Prosper; Mshandete, Anthony
Cashew waste biomass presents a valuable resource for production of value-added products. This study evaluated potential for valorization of cashew wastes (husks, apples and leaves) generated in Mtwara, Tanzania through integrating quantitative and laboratory analysis methods. Chemical composition of cashew waste analyzed were nitrogen, phosphorus, pH, moisture content, total organic matter, ash content, crude fiber, and conductivity. Nitrogen contents of cashew waste including husks, apples and leaves ranged between 1.46 – 2.58%, phosphorus was 0.03 – 0.38%, moisture content between 5.63-23.10%, and pH ranged between 4.44 -5.91. Solid wastes were characterized by crude fiber content in the range of 0.32-0.49 g, ash content between 6.65 – 14.24% and total organic matter content between 95-97%. Results showed that the annual generation of cashew wastes was estimated at 458,874 tons. Out of these, 66% were dried cashew apples, 33% cashew nut shells and 1% cashew husks. These wastes can be transformed into food, feed, bio-energy and bio-based products using bioconversion technologies in integrated and sustainable manner. A scheme for utilization of cashew waste into value added products has been proposed which contributes to environmental preservation. This approach offers a circular economic growth and aligns with global sustainable development goals by responsible consumption and production.
Evaluation Of The Malaria Transmission-Reducing Activity Of Pfs25-Imx313/Matrix-M Vaccine And Naturally Acquired Antibodies In Tanzanian Volunteers
(NM-AIST, 2025-07) Mulamba, Charles
Malaria is still a public health challenge in Tanzania, control relies on the use of artemisinin-based combination therapies and insecticide-treated materials. The effectiveness of these interventions is threatened by drug and insecticide resistance in parasites and vectors respectively. Transmission-blocking interventions are therefore needed to supplement the current interventions. This study evaluated the ability of vaccine-induced Pfs25 antibodies, to block malaria parasite development in mosquitoes, following a Phase1 vaccine trial in Bagamoyo, Tanzania, between 2021 and 2023. The transmission reducing activity (TRA) was evaluated via Standard Membrane Feeding Assays (SMFAs), where laboratory mosquitoes were fed with a mixture of test or control antibodies and cultured Plasmodium falciparum gametocytes. The TRA was determined as the reduction in the number of oocysts by test antibodies compared to a negative control lacking blocking antibodies. In addition, a survey was conducted to determine the seroprevalence of natural antibodies to malaria antigens; Pfs25, Pfs230D1M, and Pfs48/45, as well as the malaria prevalence in 467 participants from five villages in Bagamoyo district. The malaria and natural antibody survey were conducted as a baseline for phase1 evaluation of Pfs25-IMX313/Matrix-M vaccine candidate. Trial results indicated that the Pfs25-IMX313/Matrix-M vaccine induced long-lasting antibodies, which promoted significant TRA in 18 of the 20 vaccinated participants. Survey findings showed that 23.5% (110/467) of the participants tested positive for malaria, and 24% of the malaria-positive participants had the sexual form of malaria (gametocytes) responsible for transmission. Regression analysis showed that gametocytes were more likely to be present among male participants than female participants [ORa: 2.79 (95% CI: 1.19 – 6.59) p=0.019]. The survey results further indicated that the seroprevalence of Pfs230D1M IgG was 56% (157/281), whereas that of Pfs48/45 IgG was 49% (141/291). Seroprevalence for anti-Pfs230 and anti-Pfs48/45 IgG increased significantly with participants’ age, with adults more likely to have antibodies than children; for Pfs230 [adjusted OR 3.18, (95% CI: 1.85 - 5.57), p=<0.0001], and Pfs45/48 [OR 3.11, (95% CI: 1.83 - 5.29), p = <0.0001]. When Pfs48/45 and Pfs230 seropositive serum was tested in the SMFAs, only two (2) of the 10 participants demonstrated significant TRA. We conclude that a transmission-blocking vaccine will be a great addition to the current malaria interventions, and children as well as adults should be targeted, if malaria elimination to be achieved. The Pfs25-IMX313/Matrix-M vaccine in this study should be further developed in combination with another transmission-blocking target such as Pfs230D1M or Pfs48/45.
Effects Of Adjunctive N-Acetyl Cysteine (Nac) In Tuberculosis Patients In Mbeya Region, Tanzania
(NM-AIST, 2025-07) Mapamba, Daniel
Half of the global health burden of tuberculosis (TB) is due to post-TB disability and mortality occurring despite microbiologic cure. Sustained TB infection elicits an immune response against Mycobacterium tuberculosis and overproduces TNF-α and reactive oxygen species (ROS), which help to kill or contain the pathogen. However, they cause lung injuries. Adjunctive, host-directed therapies have been proposed to address these concerns. One such candidate, N-acetylcysteine (NAC), has been in clinical use since the 1970s to prevent fatal hepatic necrosis following acetaminophen poisoning. The usefulness of NAC in replenishing glutathione (GSH) and treating various diseases, including COVID-19, has been studied. The present study investigated the effect of NAC in TB treatment, focusing on the levels of glutathione, TNF-α, IL-10, hemoglobin, and its antibacterial activity. A prospective, open label, randomized controlled trial enrolled 140 adult TB patients from health facilities in the Mbeya region, who had confirmed pulmonary TB by Gene Expert, with a cycle threshold (Ct) value ≤27 and were Rifampicin-sensitive, and had chest X-rays showing moderate or far advanced lung disease. Participants were randomized to receive standard anti-TB (2HRZE/4HR) with or without NAC 600 mg BID on days 1–112. Whole blood samples were collected for measurement of hemoglobin, bactericidal activity, glutathione, TNF-α, and IL-10 expression by the ELISA method from Calorimetric Arbor Assays and R&D Systems, and sputum samples were used to assess M. tuberculosis burden. NAC treatment rapidly increased total glutathione (P<0.0001), but levels did not reach those of healthy volunteers (P<0.001). NAC reduced TNF-α expression levels (P = 0.011) without affecting IL-10 and accelerated hemoglobin recovery in participants with low values at baseline. The NAC did not affect the killing of MTB in ex vivo whole blood culture but slowed the clearance of MTB from sputum (P = 0.003). In summary, oral NAC restored GSH and resolved anemic TB patients more rapidly; it also reduced TNF-α without affecting IL-10 and antimycobacterial host defenses or treatment activity. The decline in GSH after stopping NAC may indicate sustained inflammation and oxidative stress despite apparently successful TB treatment. The reduction of the markers of oxidative stress and inflammation by NAC may account for its effects on the recovery of lung function in TB. Thus, before its use is approved, more research on various dosages and extended follow-up in various group demographics is warranted.
Analysis of the Maasai Traditional Food System and Ethnomedicine for Health Benefits and Bioactive Potential Against Gout and Metabolic Disorders
(NM-AIST, 2025-07) Clement, Richard
Maasai’s traditional food system (TFS) and Traditional Medicine (TM) are claimed to keep a low prevalence of diseases, including gout (hyperuricemia with uric-acid crystals in tissues) and predisposed/predisposing conditions thereof (GACs); however, anti-oxidants and anti- hyperuricemics (AHAs) are not well-established in the TFS and TM. This calls to establish the link between TFS qualities and health benefits; floral species against diseases: Gout, GACs, and risk factors thereof; and floral anti-oxidants and AHAs contents. Ethnobiological and ethnobotanical surveys with 21 Maasai TFS and TM practitioners (MTPs) in Monduli, Arusha, Tanzania revealed that TFS and TM had a diversity of 101 flora species distributed in 84 genera and 42 families. The TFS had 19 dishes and a diversity of 78 flora species with potential nutrition, therapeutic and protective roles against gout and GACs. Food processing technologies (FPT), nixtamalization, and meat roasting have potential protection against GACs. Cultural preferences and restrictions (CPR) ensure individual nutritional and health needs are met, and reinforce Maasai socio-structure and cohesion. About 79% of the flora species were used as medicine; some as food, and for food processing. The medicinal plants (MPs) managed 69 health conditions, including gout, “Olgila,” and GACs. The root parts (54% species) were exploited the most; most flora (94%), sourced from the wild. Spectrophotometric analyses of 43 flora parts from 35 species commonly used in the TFS and TM showed total phenolic content (TPC) in mg GAE/g ranged between 0.02 ± 0.01 (Zathoxylum chalybeum fruit) and 231.39 ± 10.40 (Rhus vulgaris root). Total flavonoid content (TFC) in mg QE/g ranged between 1.24 ± 0.00 (Lepidotrichilia volkensii root) and 66.94 ± 0.03 (Dalbergia melanoxylon root-heartwood). Potassium content in mg K 100g-1 ranged between 97.68 (Rhamnus prinoides root) and 1392.01 (Piper capense root). Croton megalocarpus, Piper capense, Tetradenia riparia, and Vachellia nilotica had the highest content of calcium, iron, magnesium, manganese, and zinc, varying between 263.85 and 9117 μg/g dry weight (DW). The FPT and flora species with high TPC, TFC, and minerals content are potential antioxidants and AHAs against “Olgila” and GACs. Integrated conservation and promotion measures are needed to prevent the loss of TFS and TM.
Risks of Exposure to Contaminant Fluoride among Lactating Mothers and Children (0-24 Months) in Ngarenanyuki Communities in Northern Tanzania
(NM-AIST, 2025-07) Memba, Lucia
This study revealed important information on fluoride contamination of agricultural produce, water, cow and human breast milk, and excretion through urine. Risks of exposure to contaminant fluoride among children and lactating mothers were investigated. Structured questionnaires and 24-hour dietary recall was used to estimate dietary intake. Samples were collected and analyzed for fluoride contents. In all samples, fluoride concentration was determined by using a fluoride ion-selective electrode. Univariate logistic regression analysis was used to correlate dietary fluoride exposure and urinary fluoride excretions in children and breast milk fluoride excretion in lactating mothers. Results identified maize (21.7%), African nightshade (18.4%), and East African highland banana (15.2%) as the most consumed food crops among lactating mothers; cow’s milk (2.7%) for children aged 6 months, and maize for children aged 7-24 months (9.2%-22.5%). Fluoride mean concentration levels in maize were (0.03±0.01 mg/kg), nightshade (0.081±0.004 mg/kg), East African highland banana (0.025±0.002 mg/kg), domestic water (4.57±0.21 mg/L), public tap water (4.74±0.6 mg/L), cow’s milk (0.34±0.18 mg/L), and human breast milk (0.077±0.03 mg/L). Both domestic water and human milk fluoride levels exceeded WHO safe standards of 1.5 mg/L and 0.002 mg/L, respectively. Dietary exposure among children was found ranged from 0.7±0.02 to 15.60±6.53 mg/kg bw/day, with food crops contributing 62.16%. Lactating mothers’ exposure ranged from 0.621±0.09 to 88.12±25.2 mg/kg bw/day, with food crops contributing 60.3%. The studied population was exposed to dietary fluoride above the safe levels of 0.01 and 0.05 to 0.07 mg/kg/day by WHO for infants and adults, respectively. Biomarkers of fluoride exposure showed urinary fluoride excretion in children averaged 8.82±1.25 mg/L, with exposure increasing with age (p=0.003), and no significant gender differences (p=0.97). Positive correlations were observed between urinary fluoride excretion and consumption of cow's milk (ρ= 2.3, p<0.0000) and East African highland banana (ρ=-2.5, p<0.0001) in children, and between breast milk fluoride excretion and consumption of cow’s milk (ρ=0.027, p=0.0001), maize (ρ=0.00022, p=0.02), and tap water (ρ=-0.0002, p=0.001) in lactating mothers. The study concludes with recommendations for comprehensive research across seasons, diverse food crops, other exposure routes, and detailed biomarker assessments to fully understand the risks associated with fluoride exposure.
Development of Biopesticides for Managing Early Blight and Leaf Miner in Tomato (Solanum Lycopersicum) Production in Tanzania
(NM-AIST, 2025-07) Abel, Fikiri
Early blight disease (Alternaria solani) and leaf miners (Tuta absoluta) are major pests of tomato that can cause 80 -100% loss in fruit yield. A study was conducted at the Nelson Mandela Institution of Science and Technology (NM-AIST) laboratory, screen house and field trials in Kilimanjaro and Arusha regions of Tanzania in 2023; to evaluate the in vitro efficacy of various botanical extracts (Azaradirachta indica, Lantana camara, Capsicum frutescens, Zingiber officinale) as biopesticides against A. solani. Results showed significant inhibition of fungal mycelial radial growth in the range of 23.3 (5% fresh lemon grass) to 98.26% (10% hot pepper). The screen house trial showed the positive results on leaf miner reduction by 80%, 76.6% and 72.6% for 10% lantana, 10% hot pepper and 10% ginger respectively. The best four extracts in both laboratory and screen house experiments (10% hot pepper, 5% hot pepper, 10% ginger and 10% lantana) were used in field trials, resulting in an average 50% and 70% reduction in disease severity and incidence, and tomato leaf damage respectively as compared to the negative control. The highest number tomato fruits and weight per plant were observed at Mailisita in 10% lantana (16.56) and 10% hot pepper (2.29 kg). Most of biopesticides with 10% concentration had good performance. Water-extracted biopesticides were found to be more effective than ethanol-extracted ones in inhibiting fungal growth and leaf miners. The 5% hot pepper treatment had the highest treatment advantage revenue (2818.48 USD) and cost benefit ratio (1: 3.5) compared to the negative control.
Prevalence of Antibiotic-Resistant Escherichia Coli from Groundwater Sources and Sanitary Inspection for Contamination Risk in Bagamoyo District, Tanzania
(NM-AIST, 2025-07) Mduda, Joram
In Low and Middle-income Countries (LMICs), people have access to water but have no access to safe, clean, and protected water sources. Globally, two billion people consume water contaminated with faeces, with Escherichia coli being the most prevalent pathogen in polluted water, posing significant health risks. This underscores the urgent need to investigate resistant E. coli from groundwater sources and to conduct sanitary inspections. In the Bagamoyo District, a cross-sectional study was undertaken, examining 60 boreholes, 39 dug wells and 64 tube wells with hand-pumps. Escherichia coli was isolated through a membrane-filtration method, and the disc diffusion method was used in susceptibility testing according to Clinical and Laboratory Standards Institute (CLSI) standards. The study found E. coli contaminated 44.8% of groundwater samples and 83.6% of E. coli isolates were resistant to at least one antibiotic. Resistance was highly observed to cefazolin (56.16%) and nitrofurantoin (54.79%), Moreover, 70% of the E. coli isolates were multidrug-resistant, with an overall MAR-index of 0.28. Sanitary inspections revealed that dug-wells (46.2%) were at high contamination risk, and tube wells with hand pumps (32.8%) were at high and low contamination risk levels. Also, boreholes (73.3%) were at low contamination risk. High E. coli contamination was observed in boreholes despite of being at low contamination risk. Furthermore, groundwater sources across contamination risk categories indicated high-rate-resistant E. coli contamination. Therefore, these findings highlight the presence of resistant E. coli from groundwater in Bagamoyo district and emphasize the necessity to promote proper antibiotic use to prevent contamination by resistant bacteria.
Marker Assisted Breeding for Aflatoxin Contamination Resistance in Maize Varieties of Tanzania
(NM-AIST, 2025-07) Mwendo, Marco
Sources of resistance to Aspergillus flavus and aflatoxin accumulation in maize have been identified in several places but no such materials are currently available for use in Tanzania. This study aimed to contribute towards increased maize yield in Tanzania by reducing aflatoxin contamination, which is caused by A. flavus. The focus was on developing resistant maize genotypes through marker-assisted breeding. The objective was to reduce aflatoxin contamination in maize through genetic improvement by identification of stable and high yielding maize genotypes, identification of resistant genotypes, validation of molecular markers, and creation of F2 populations to support the long-term development of resistant, farmer-preferred varieties. Four maize crosses were used to produce F1 hybrids, which were advanced to the F2 generation between 2022 and 2024. The research included laboratory validation of SSR markers, screen-house testing for resistance following Complete Randomized Design, and field trials following Randomized Complete Block Design for assessing yield and yield component, and F2 population development. Results indicated that maize genotype traits were significantly influenced by genetic makeup, environmental conditions, and their interactions. Using AMMI and GGE models, high and stable yielding genotypes (G5, G17, and G19) were identified. The SSR marker AHGA195527 confirmed the presence of resistance genes to Aspergillus flavus infection and aflatoxin accumulation in tested maize genotypes used in this study. Nine genotypes (G3, G10, G11, G12, G14, G15, G17, G18, and G20) were resistant with G17 being highly tolerant, showing contamination levels below the tolerable limit. F2 population, developed by crossing resistant G17 with widely cultivated maize genotypes G2, G4, G19, and G20, successfully transferred resistance traits. However, stability of these traits requires further evaluation through multi-season and multi-location trials to enhance the reliability of the results.

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