Theses and Dissertations

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Prevalence of Zoonotic Bacterial Pathogens and Associated Risk Factors among Cage-Cultured Nile Tilapia (Oreochromis Niloticus) in Mwanza Gulf of Lake Victoria, Tanzania
(NM-AIST, 2025-08) Komba, Richard
Aquaculture has the potential to improve global food and nutrition security, but climate change and poor practices can lead to chemical accumulation and zoonotic bacterial pathogens. This study aimed to identify the prevalence of zoonotic bacterial pathogens and associated risk factors in cage-cultured Nile tilapia in Mwanza Gulf, Lake Victoria, Tanzania. A total of 210 Nile tilapia (Oreochromis niloticus) samples were collected from cages distributed in three districts: Nyamagana (60), Ilemela (70) and Misungwi (80). Tissue samples from the gills, skin, kidney and liver were examined for zoonotic pathogenic bacterial infections. Bacterial isolation and identification were performed using standard conventional bacteriological methods. Additionally, a structured questionnaire was administered to 120 fish farmers to gather information on aquaculture practices, fish health status, and disease management. Water and sediment quality in cage-cultured and control sites were assessed using established physicochemical and sediment analysis procedures. Nine genera of bacteria were identified, including Salmonella spp. (12.5%), Klebsiella spp., Pseudomonas spp. (23.5%), Lactococcus spp. (16.9%), Bacillus spp. (14.7%), Shigella spp., E. coli, Streptococcus spp., and Staphylococcus spp. (16.7%). The gills had the highest bacterial prevalence (28.6%), followed by the liver (16.7%), skin (12.9%) and kidney (6.7%). Bacterial isolates were most prevalent in cages in Ilemela (44.1%), followed by Misungwi (34.6%) and Nyamagana (21.3%), and with significant differences noted (p < 0.001). Additionally, analysis showed that most farms had high stocking densities (> 8 fish/m², 44.4%) and reared Nile tilapia (Oreochromis niloticus) (67.7%). Few farmers regularly measured water quality (16.7%) or removed dead fish daily (20.8%). Key factors influencing total mortality included stocking density (p = 0.013), fish species (p = 0.031), dead fish disposal methods (p = 0.023), and predator bird control (p = 0.016). Water samples from both cage-cultured and control sites showed no significant differences in quality (p > 0.05). Farmed fish and their aquatic environments harbor potentially pathogenic and zoonotic bacteria, posing significant risks to public health and leading to considerable economic losses. Therefore, the implementation of optimal management practices, along with strict biosafety and biosecurity measures, is essential.
Detection of Rift Valley Fever Virus Interepidemic Activity in Lower Moshi Area of Kilimanjaro Region, Northeastern Tanzania: A Community Survey
(NM-AIST, 2025-08) Kumalija, Medard
Rift Valley fever virus (RVFV) is a zoonotic viral disease of public health importance that affects livestock, wildlife and humans, mainly in sub-Saharan Africa. Despite its public health importance, the ways in which RVFVs circulate during the inter-epidemics (IEPs) stages and potentially spread to new areas remain unclear. The IEPs are the period during which transmissions pass without being detected, whereas surveillance is not performed. This study aimed to compare the rates of exposure to RVFV and RVFV infection among humans, goats and mosquito vectors in an agricultural and pastoral community in the lower Moshi area of the Moshi rural district. The area is located along the Great Rift Valley and is characterized by animal maintenance and heavy seasonal rains, making it swampy and favoring mosquito reproduction throughout. Although the spread of RVFV by mosquito vectors to animals and humans during interepidemic periods has been established, less is known about the roles that animals, humans, and vector mosquitoes play in maintaining the virus during IEPs. The reservoirs in the IEPs have become an area of interest for research. Therefore, a cross-sectional study survey was conducted in Lower Moshi in the Kilimanjaro region from June to December 2020. The RVFV exposure was determined via the detection of IgG/IgM to RVFV via a competitive enzyme-linked immunosorbent assay (cELISA), whereas infection was determined via real-time quantitative polymerase chain reaction (RT‒qPCR). In humans, male sex was more related to RVFV seropositivity than female sex was (χ² = 5.351; p=0.030). People aged 50 years and above were seropositive (χ² =14.430; p=0.006). The RVFV seropositivity in goats was related to increased seropositivity in humans (χ² =6.003; p=0.021, χ² =23.213; p=0.000 and 27.053; p=0.000). The RVFV antibody concentrations were only marginally higher in humans than in goats [t (112) =0.526; p=0.60)]. The RT‒qPCR revealed that goats presented the highest RVFV infection rate (4.1%), followed by humans (2.6%), Aedes aegypti (2.3%), and the Culex pipiens complex (1.5%). Similarly, a greater proportion of goats (23.3%) were RVFV seropositive than were humans (13.2%). These findings suggest that northeastern Tanzania may serve as a persistent hotspot for RVF transmission and call for the implementation of integrated, health-based active surveillance strategies targeting livestock, humans and vectors. Enhanced diagnostics, targeted vaccination and climate-informed risk mapping are recommended to enable timely interventions and reduce the likelihood of future RVF outbreaks.
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.
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.
Optimization of Soil Fertility Under Banana-Coffee- Livestock and Maize-Legume Residues Transfer Farming Systems on the Slopes of Mount Kilimanjaro, Tanzania
(NM-AIST, 2025-08) Mhoro, Lydia
Arable land is under more pressure due to consequences of climate change and the growing global human population. Among other things, soil fertility has been most negatively impacted. This study aimed at optimizing nutrient management on the slopes of Mount Kilimanjaro for optimal crop production. The area is distinguished by two major farming systems: the banana- coffee-livestock on the highlands [> 1000 meters above sea level (m.a.s.l.)] and maize-legumes on the lowlands (< 1000 m.a.s.l.) of the slope. Data on soil nutrient management was gathered through a household survey. Soil nutrient quantification was done to assess nutrient balance highland-lowland farming systems. A field experiment was conducted in maize-legume farming to optimize soil nitrogen through inorganic fertilizer and cattle manure. The cost benefit of the existing farming systems by smallholders were assessed. The demographic results showed that most of agricultural practitioners are adults (> 40 years). The findings showed that the levels of organic carbon (1.22%) and nitrogen (0.14%) were significantly lower (p<0.01) in the lowlands. Additionally, both the highlands and lowlands had considerably reduced extractable phosphorus (P) levels, measuring 9.3 mg kg-1 and 8.2 mg kg-1, respectively. The highland had significantly (p<0.01) less potassium (K+) [0.34 cmol (+) kg-1] than the lowland [0.93 cmol (+) kg-1]. The highlands had a negative balance of N and K, while the lowlands had negative balances of all three nutrients (N, P, and K). The field experiment results showed a significant increase in maize crop yields upon N fertilization, with the highest application rate of urea (75 kg N ha-1) producing the highest grain yields of up to 4.21 and 4.32 t ha-1 in the 2021 and 2023 seasons, respectively. In the lowlands, applying manure resulted in increases in soil total N, OC, extractable P, and exchangeable K of 16.67%, 18.13%, 20.95%, and 6.76%, respectively. The highland farming systems have shown high benefit cost ratio (3.79) compared to lowland (1.20) farming systems. Apart from the efforts of the smallholder farmers on soil fertility management, the study concludes that the sustainability of farming systems on the slope of Mt. Kilimanjaro is at stake, which eventually threatens food security. Therefore, integrating organic and inorganic inputs can significantly improve crop yields and soil health sustainably.
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.
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.
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.
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.
Epidemiology of Neospora Caninum Infection and the Economic impact of Abortions In Livestock: A case Study from Northern Tanzania
(NM-AIST, 2025-08) Semango, George
Livestock abortions pose a significant challenge to animal health, food security and rural livelihoods, particularly in low- and middle-income countries such as Tanzania. This study aimed to: (a) Assess the status of surveillance and sero-epidemiology of abortigenic agents in ruminants across Africa and Asia through a systematic review; (b) Estimate the seroprevalence, risk factors, and reproductive impact of Neospora caninum in northern Tanzania; and (c) Quantify the economic burden of ruminant abortions in this region. A systematic review of the literature was conducted to evaluate surveillance and sero-epidemiological data on abortigenic pathogens. Additionally, a cross-sectional seroprevalence survey targeting N. caninum in northern Tanzania was carried out. Questionnaire data for variables on individual-level seropositivity were collected from 360 households and assessed using logistic regression, geo- coordinates were used to extract satellite-derived environmental variables. Association between herd-level seroprevalence and abortion rates was explored using negative binomial regression. Serum samples were tested using an indirect ELISA. Furthermore, a mobile phone- based surveillance platform was deployed to capture real-time abortion reports. Data from these cases, along with control households and national ministry sources, were used to estimate the direct economic losses associated with abortion event The review revealed widespread endemicity of bacterial, viral, fungal, and parasitic abortigenic agents in Africa and Asia, with limited structured surveillance. In Tanzania, the adjusted N. caninum seroprevalence was 21.5% (95% CrI: 17.9–25.4). The Body mass index identified age >18 months (OR = 2.17), restricted grazing (OR = 0.72), high cattle density (OR = 0.69), and surrounding shrub or forest cover (OR = 1.37) as significant risk factors. A strong positive association was found between N. caninum seroprevalence and abortion rates (IRR = 1.03, 95% CrI: 1.00–1.06). Economically, annual losses from abortions were estimated at TZS 300 billion. These findings highlight the urgent need for improved diagnostic capacity, integrated surveillance systems and targeted control strategies for livestock abortions. The study provides vital evidence to inform policy and intervention planning for reproductive diseases control in Tanzanian livestock systems.
Population Status and Threats of the Endangered African wild dog in the Selous-Nyerere Landscape, Southern Tanzania
(NM-AIST, 2025-07) Parsais, Singira
African wild dogs (Lycaon pictus) are one of the world’s most endangered carnivore. Despites their conservation status, there is limited information on population status and threats of African wild dogs in Selous-Nyerere landscape where viable populations are thought to still occur. Furthermore, as part of the threat assessment, communitity attitude towards the endangered African wild dog has never been studied in the landscape. This study has addressed this gap by providing an updated assessment of wild dog population status and threats of African wild dogs within the Selous-Nyerere landscape of southern Tanzania. The community attitude towards wild dogs has also being addressed to ascertain the influence of the attitudes to the conservation of the species in the landscape. Data from seven camera trap surveys deployed over 4,674 km 2 in Selous GR and Nyerere NP from 2020-2022 were used to provide an update on wild dog population status in the landscape. Camera trap data were also used to gain valuable insights on pack size and demographic structure, which were compared with direct observation data to test the method applicability for wild dog population assessment in a data-limited settings. Data from satellite imagery was used to capture human threats in terms of land cover conversion over time. Data from household surveys and focus group discussions were used to explore community attitudes towards wild dogs. Based on camera trap data a total of 222 wild dogs were identified. Of these, 38% were male, 38% were female, and 24% were of unknown sex. The population density stands at approximately 2.14 ± 0.45 adult and yearling wild dogs per 100km². Remote sensing analysis revealed a significant increase of cropland from 11.83% in 2013 to 26.49% in 2023. Distribution of attitudes among the respondents revealed that the largest group (108 individuals; 36%) expressed a neutral attitude (p <0.001) towards the species. A positive attitude was the second most common response, with 100 individuals (33.3%) expressing favourable views toward wild dogs. This research study concludes that Selous-Nyerere remains a stronghold for wild dogs. The study recommends the need for establishing long term wild dogs population changes monitoring programmes to inform management actions.
The Interspecific Competition between Larval of Aedesand Major African Malaria Vectors under Semi- Field settings in Tanzania
(NM-AIST, 2025-08) Coelestine, Sperancia
Interspecific competition between mosquito larvae may affect adult traits, potentially reducing or increasing disease transmission. It also influences population dynamics, cannibalistic, and predatory behaviors. However, knowledge of interspecific competition between Ae. aegypti and Anopheles species is limited. This study examined interspecific competition of Ae. aegypti larvae cohabiting with either An. arabiensis, An. gambiae, or An. funestus on individual fitness and population level in semi- field settings. Experiments involved density combinations of 100:100, 200:0, and 0:200 (Ae. aegypti:Anopheles), reared with and without food, in small habitats (8.5 cm × 15 cm) with 0.5 liters of water and large habitats (15 cm × 35 cm) with 1 liter of water. The first group received Tetramin® fish food (0.02 g), while the second was unfed to assess cannibalism and predation. At population level, self- sustaining colonies of Ae. aegypti and An. arabiensis were established in three separate chambers. While interspecific competition affected both genera, Anopheles species experienced greater effects, with reduced survival and delayed development compared to Ae. aegypti. Mean wing lengths of all species were significantly smaller in small habitats in a mixed population (p < 0.001). The presence of food reduced cannibalism and predation. At population level, Ae. aegypti exhibited higher numbers than An. arabiensis in mixed populations, with risk ratios (RR = 0.74, 95% CI: (0.68, 0.80), p < 0.001) and (RR = 0.29, 95% CI: (0.26, 0.30), p < 0.001) respectively, significantly lower than single populations. These interactions have implications for disease transmission dynamics and inform ecologically-based vector control strategies.
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.
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.
Effect of Increased Albendazole Coverage on Control of Human and Porcine Taenia Solium Cysticercosis In Mbulu District-Tanzania
(NM-AIST, 2025-08) Bandi, Vedasto
Taeniosis and cysticercosis are infections caused by cestodes including Taenia solium (pork tapeworm). The cysticercosis in central nervous system accounts for 30% of acquired epilepsy in endemic developing countries. The school deworming program in Tanzania targeting intestinal and tissue worms does not seem to have an effect on reducing pork tapeworm in entire communities. One of the reasons may be that the adults may re infect the dewormed children. A quasi experimental intervention was conducted to evaluate the effect of increased albendazole coverage and rounds on controlling human and porcine cysticercosis among rural communities in the Mbulu district. The study involved community meetings with the heads of households before community deworming with 400 mg of albendazole. The Ag ELISA was used to determine human cysticercosis while pigs were examined by the lingual examination method. A total of 600 human participants were recruited, whereby 300 individuals were recruited before intervention and 300 after intervention. Furthermore, a total of 510 pigs were conveniently sampled, where 267 were sampled before intervention and 243 were sampled after intervention. The study has shown decrease in human cysticercosis by 6% in all study communities and a rise for porcine cysticercosis in control and one round intervention has been recorded. The younger age group had low infection 5% compared to the adults 11% in the population which may be attributed by school deworming program. It is therefore, recommended to increase anthelmintic coverage and rounds in communities’ endemic with pork tapeworm to cover adults for some years consecutively for control of pork tapeworm and involve other sectors involved in life cycle of parasite for transmission interruption.
Assessment of twenty-four Hours Biting Patterns and Human Exposure Risk to Bites of Anopheles Mosquitoes in South-Eastern, Tanzania
(NM-AIST, 2025-08) Mukisa, Muwonge
Afrotropical malaria vectors are believed to bite nocturnally, leading to the predominant use of Insecticide-Treated Nets (ITNS), which primarily target indoor, nighttime-biting mosquitoes. However, recent evidence challenges this paradigm, showing that Anopheles biting can extend into the daytime when humans are active and beyond the reach of ITNS. This study investigated the diurnal and nocturnal biting patterns of the main malaria vectors, Anopheles arabiensis, and Anopheles funestus in rural south-eastern Tanzania, informing strategies for improved control and elimination. Host-seeking mosquitoes were collected hourly using miniaturized double net traps (DN-Mini), indoors and outdoors over 24-hour periods between June and December 2023. Concurrently, human activities indoors and outdoors were monitored half- hourly to correlate with mosquito collections. Nocturnal biting by An. arabiensis peaked from 1900 h –2300 h, while An. funestus peaked from 0100 h – 0300 h. Daytime host-seeking collections accounted for 14.8% of both species. Diurnal biting by An. arabiensis peaked between 0700 h – 1100 h, and between 1800 h and 1900 h, while for An. funestus, the peaks were observed between 1000 h – 1200 h, and between 1700 h – 1900 h. Plasmodium falciparum infections were detected in both day and night-time collections of An. arabiensis but not in An. funestus. Common daytime activities potentially exposing residents during peak biting hours included household chores, eating, sleeping (including due to sickness), resting under shades or verandas, and kids playing. From evenings onwards, exposures coincided with resting, chatting before bedtime, and kids playing. These findings show that the sole focus on interventions like ITNs that target nocturnal mosquito behaviours might be insufficient for elimination; hence, enhanced strategies targeting daytime biting mosquitoes supplemented with community engagement and education on the timing of mosquito activity are required to significantly reduce malaria transmission risk.
Leveraging Indigenous Vegetables to Combat Anaemia among Pregnant Women in Babati
(NM-AIST, 2025-08) Malley, Zuwena
Pregnancy related anaemia remains a significant public health concern in Tanzania particularly among women of reproductive age. Limited dietary iron intake is a major contributing factor, despite the availability of iron supplements. However, poor adherence to supplementation due to side effects, limited access, and inadequate health education has hindered efforts to address the problem. The study investigated the potential of indigenous vegetables as a dietary intervention to prevent and manage anaemia among pregnant women in Babati District, Manyara region. A cross-sectional study was conducted from June to August 2023 involving 340 pregnant women attending antenatal clinics at four health facilities in Babati District. Nutritional analysis was conducted on commonly consumed indigenous vegetables to assess their iron, vitamin C and phytate content. The findings revealed that indigenous vegetables such as amaranth, sweet potatoes leaves and blackjack are rich in iron and culturally accepted and locally accessible. However, their consumption was irregular due to limited awareness, seasonal availability and preferred for exotic vegetables. The study also found a significant association between frequent consumption of indigenous vegetables and higher haemoglobin levels among pregnant women. Respondents who consumed these vegetables at least three times a week had a lower prevalence of anaemia compared to those who consumed less frequently. Promotion of regular consumption of iron rich indigenous vegetables could serve as an effective, affordable, and culturally appropriate dietary strategy to reduce anaemia in pregnancy. The community nutrition education and support for local vegetable cultivation is recommended to enhance dietary diversity and maternal health outcomes.
Social Determinants of Physical Activity and Healthy Diet Consumption Among Adolescents Living With HIV in Ifakara town, Tanzania
(NM-AIST, 2025-08) Maganga, Justina
Insufficient physical activity and poor dietary habits are among the important risk factors for non-communicable diseases (NCDs) worldwide. While NCDs typically impact adults, these risk factors frequently emerge in adolescents, enhancing future NCD risk. In Tanzania, adolescents living with HIV (ALHIV) are at risk for NCDs due to HIV-related chronic inflammation and side effects of long-term antiretroviral therapy, as well as low physical activity and unhealthy eating. This qualitative study looked into the factors that influence physical activity and healthy diet consumption among ALHIV in Ifakara Town. A cross- sectional phenomenological qualitative study was conducted with ALHIV aged 15 to 19 and their parents and caregivers from the Kilombero and Ulanga Antiretroviral Cohort (KIULARCO). Between May and July 2024, 22 in-depth interviews with ALHIV were done, as were ten interviews with parents and caregivers. Thematic content analysis was carried out with NVivo 14 software. The coding approach employed both inductive and deductive coding techniques, with inductive codes obtained from the participants' tales and deductive codes developed using IDI guides and theoretical conceptions. The findings were theoretically categorized using the socio-ecological theory's intrapersonal, interpersonal, and community levels. Adolescents living with HIV and their parents/caregivers showed some awareness of physical activity and healthy eating and acknowledged the role of these behaviors in managing HIV and preventing NCDs. However, there were still gaps in their understanding. Physical activity among ALHIV was influenced by intrapersonal factors (limited time and inadequate knowledge); interpersonal (support from family and peers); and community-level (gender norms, negative perceptions, and lack of proper facilities). Similarly, healthy eating was shaped by intrapersonal factors (limited autonomy, weight concerns, and individual food preferences); interpersonal factors (low household income and having a large family); and community-level influences (the widespread availability of fast food). The findings highlight a range of factors influencing both physical activity and dietary habits of ALHIV. This study underscores the need to involve the community, parents, and caregivers in the efforts to create a supportive environment that promotes a better lifestyle for ALHIV and tackles the barriers to physical activity and healthy eating. To further emphasize and reinforce these two health behaviors in this population, physical activity and nutrition education need to be incorporated into HIV care guidelines and programs as part of day-to-day HIV care.
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.
Effect of Arbuscular Mycorrhizal Fungi on Banana Growth during Hardening Phase and Field Phase in Northern Tanzania
(NM-AIST, 2025-08) Mapunda, Hellen
Banana production contributes significantly to sustaining food security of the rural communities in Tanzania. However, yieldsin smallholder banana fields only represent 10% of the production potential due to recurrent drought stress, declining soil fertility, and increasing pests’ pressure. Many plant species, including bananas, benefit from the presence of Arbuscular mycorrhizal fungi (AMF). Previous research on banana plants inoculated with AMF has shown encouraging outcomes. However, numerous studies have examined this under laboratory and screen house conditions. In light of this, field-based validation remains limited. In this context, two experiments were conducted in the northern highlands of Tanzania. The first experiment examined the effect of inoculating banana plantlets (var. Williams and Grand Naine) with three AMF strains (Rhizophagus intraradices, Rhizophagus irregularis and Rhizophagus clarus) on plant growth under nursery conditions. The results indicate that there were significant (p<0.05) and positive effects of AMF strains inoculation on banana plant growth parameters, with Rhizophagus intraradices recording the promising results compared to the control treatment. In the second experiment validated the effects of AMF strains with respect to growth and yield characteristics. The results show that Rhizophagus intraradices outperformed the other two strains. Overall, the results of this study indicate that AMF can be a useful addition to banana nursery management practices, resulting in improved growth and development during the critical weaning and hardening phases and, as well as improved field establishing success. These findings may have positive consequences in banana production in the long-term. The findings could also aid in optimizing the conventional banana production techniques by integrating AMF inoculants for enhanced banana production.

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