PhD Theses and Dissertations [LiSBE]

Permanent URI for this collection${dspace.ui.url}/handle/20.500.12479/6

Browse

Now showing 1 - 20 of 93

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.
Enhanced one Health surveillance approaches to guide the elimination of dog-mediated rabies in Tanzania
(NM-AIST, 2023-08) Lushasi, Kennedy
Rabies causes approximately 59 000 human deaths worldwide annually. A global target of zero human deaths from dog-mediated rabies has been set for 2030, and large-scale control programs are now advocated. However, there is limited surveillance and guidance on how rabies surveillance can be improved to increase the detection of rabid animals or to guide the management of rabies control programmes once elimination has been achieved or when its approached. Challenges to rabies elimination were investigated by undertaking detailed epidemiological studies collecting data from 2010/2011 to 2022; and enhancing surveillance using Integrated Bite Case Management (IBCM) across different settings in Tanzania from 2018 to 2022. In 24 districts, local government health and veterinary workers were trained to collect data through implementing IBCM, comprising risk assessments of bite patients by health workers and investigations of suspected rabid animals by livestock field officers. In addition, contact tracing was used to identify rabid animals, human rabies exposures and deaths, with additional whole-genome sequencing of viruses from rabies positive samples in 13 districts of Lindi and Mtwara region, including Pemba Island. From these data, transmission chains were probabilistically inferred, estimated case detection, quantified the public health burden in terms of numbers of rabies exposures, animal rabies cases, human rabies deaths and evaluated the impact and cost-effectiveness of a One Health approach to rabies surveillance and control. Reporting of bite patients at high risk of rabies exposure increased following the introduction of IBCM. Between 2011 and 2019, 688 probable exposures were identified in Southeast Tanzania, including 47 rabies deaths. Of 549 probable animal rabies cases identified: 303 were domestic dogs (55.2%) and 221 jackals (40.3%). Dog-to-dog transmission accounted for 40.1% of inferred transmission events, and wildlife-to-wildlife transmission accounted for approximately 32.6%, with the remainder from cross-species transmission. On Pemba Island, five transmission chains circulated from 2010. Rabid dogs, human exposures and deaths declined following the introduction and improved implementation of dog vaccination campaigns, and these transmission chains were eliminated by May 2014. In 2016 two introductions of dog rabies cases to the island that seeded re-emergence were identified. The ensuing outbreak was eliminated by October 2018 through reinstated island-wide dog vaccination. While post-exposure vaccines were highly cost-effective ($256 per death averted), their accessibility was limited and only dog vaccination interrupted transmission. A combined One Health approach rapidly eliminated rabies, was highly cost-effective ($1657 per death averted) and saved 20-130 families from rabid dog bites annually. Overall, IBCM greatly improved rabies detection and can be used to monitor the impact of mass dog ii vaccinations. In Tanzania domestic dogs appear to be the critical reservoir host of rabies, even in settings with evidence of wildlife transmission. Dog vaccination suppressed rabies in both dog and wildlife populations and reduced both public health and conservation risks. A One Health approach underpinned by dog vaccination and post exposure prophylaxes to animal bite patients is an efficient, cost-effective, equitable and feasible approach to rabies elimination, but needs scaling up across connected populations to sustain the benefits of elimination, as seen on Pemba, and for similar progress to be achieved elsewhere.
Dietary Practices, Nutritional status, Risk of exposure to aflatoxins and Pesticide among adolescents in Boarding - high schools in Kilimanjaro, Tanzania
(NM-AIST, 2023-08) Nicholaus, Calista
School feeding in low income countries relies mainly on cereals and legumes. Cereals are low in nutrients and its overdependence can lead to poor nutrient intake. Cereals and legumes are susceptible to aflatoxins contamination, causing both acute and chronic toxicity in human. The use of pesticide has been one of the measures to control aflatoxins. Inappropriate pesticides use may result to unacceptable residues in grains. A cross sectional study was conducted to assess dietary practices, nutrition status, the risks of exposure to aflatoxins and pesticide among adolescents through consumption of school meals in Kilimanjaro region. Food frequency questionnaires and 24 hours’ dietary recalls were used to collect food consumption information. Nutrition status was assessed using anthropometry and test of hemoglobin levels. World Health Organization. Arthro plus and Nutri survey software were used to analyze anthropometry and dietary data respectively. Aflatoxin and pesticide residues were analyzed using High Performance Liquid chromatography (HPLC), and Gas Chromatography Mass spectrometer (GC-MS), respectively. Results shows that, maize based food and beans were consumed on daily basis with low intake of animal sources, vegetables and fruits. Mean intake of Vitamin C, iron, calcium and zinc were below the Recommended Daily Allowance (RDA). The average carbohydrates, fats and proteins intake were slightly higher than RDA for adolescents. Overall 23.1% of the adolescents were anemic, 25% overweight and 6.1% obese. Total aflatoxins contamination ranged from 0.20 - 438.53 μg/kg and aflatoxin B1 (AFB1) ranged from 0.44 μg/kg to 35.89 μg/kg. The highest exposure to total aflatoxins ranged from 0.70-973.45 ng/kg/bw/day and AFB1 ranged from 0.05-81.06 ng/kg/bw/day. Pesticide residues in all samples were below the detection limits, implying no risk to pesticide exposure among the studied individuals. Inadequate nutrients intake and the pronounced risk of exposure to aflatoxins could have been contributed by a monotonous cereal and legume based diet in boarding schools. The no detects of pesticide residues might have been contributed by degradation of pesticide due to the prolonged storage, milling process, and uses of silos for storage. The relevant ministries should consider food diversification and routine risk assessments of the susceptible crops throughout the value chain as a long-term intervention plan.
Field margin Plants support arthropod natural enemies in smallholder common bean farming systems in northern Tanzania
(NM-AIST, 2023-08) Ndakidemi, Baltazar
Field margin plants provide habitats and food resources for natural enemies of pests (NEs), but their potential is poorly understood, particularly in the tropics and on smallholder farms. The experiments were conducted to test the potential of field margin plants on NEs. Sentinel plants were developed to collect Aphis fabae and Maruca vitrata parasitoids. Aphidius colemani was identified as the primary parasitoid of A. fabae. The dominant M. vitrata larval parasitoids were the Braconidae and Dolichogenidea, while the Platygastridae were the abundant egg parasitoids. The survey of field margins for plant-NE interactions in bean fields found that NEs most often interacted with Bidens pilosa (15.4%) and Euphorbia heterophylla (11.3%). Flowering plant species (Bidens pilosa, Lantana camara, Euphorbia heterophylla and Ageratum conyzoides) supported NEs out of bean growing season. In cage trials with an aphid- infested bean plant and a single flowering margin plant, the survival of A. colemani was more significant in the presence of E. heterophylla than B. pilosa, Tagetes minuta and Hyptis suaveolens. UV-fluorescent dye was applied to flowers of specific field margin plant species and NE was sampled from within the bean crop and field margins using sweep-netting and pan- traps, respectively. Captured insects were examined for the presence of the dye, indicative of a prior visit to the margin. Lady beetles and assassin bugs were abundant in plots with B. pilosa margins, hoverflies with T. minuta and Parthenium hysterophorus margins, and lacewings with T. minuta and B. pilosa margins. NEs were also sampled from high and low plant diversity bean fields using sweep netting and coloured sticky traps, comparing monocropped and intercropped farms. Overall, high-plant diversity fields had higher NEs than low-diversity fields. The field margin had a significantly higher number of NEs than the crop field. However, marginally higher populations of NEs in intercropping than in monocropping were observed, although the effect was not significant. To confirm that NE communities on farms predated Aphis fabae, we extracted and amplified A. fabae DNA from predatory insects. Fourteen lady beetle larvae, two lacewing larvae, and one assassin bug analyzed were found to contain A. fabae DNA, indicating all these groups can regulate the significant aphid pest of beans, A. fabae. A. colemani was a parasitoid that emerged from several non-aphid species collected from the field margins. Overall, NEs benefitted from field margin plants; those possessing extra floral nectaries had an added advantage. Thus, smallholder farmers protect the field margins for the added benefit of natural pest regulation in their fields and thus for food security and enhancing their livelihoods.
Process evaluation of Community-Based continuous mass dog vaccination delivery Strategies in the Mara region of Tanzania
(NM-AIST, 2023-08) Duamor, Christian
Rabies can be eliminated if coverage of domestic dog vaccination is sustained above 40% all year-round for five-seven consecutive years. Current approaches usually fail to achieve this required vaccination coverage and an alternative, a community-based continuous mass dog vaccination (CBC-MDV) approach, was designed and piloted in the Mara region of Tanzania. This thesis used mixed, qualitative, quantitative and participatory methods to evaluate the development and delivery of the CBC-MDV approach over two years to generate evidence to inform the optimization of the design prior to its evaluation in a full-scale randomized control trial. Specifically, it investigated the feasibility and fidelity of delivery and potential effectiveness of the CBC-MDV strategies, drivers of innovations in the implementation process, whether and how community engagement can be used to address barriers to participation in mass dog vaccination (MDV) campaigns and what factors will determine the normalization of CBC-MDV as the standard approach for delivering MDV in Tanzania. Qualitative data were analyzed using thematic analysis, both inductive and deductive. Quantitative data on delivery of CBC-MDV were analyzed descriptively. Regression analysis was used to identify population-related factors that have implications for participation in MDV. Two-proportion Z-tests and Mann-Whitney U test were used to assess whether the community engagement strategies were effective and can address barriers to participation in MDV campaigns. The findings showed that the development process of CBC-MDV was iterative and involved cross-sectoral participation but without the direct involvement of communities. In relation to feasibility, fidelity and potential effectiveness, CBC-MDV was delivered with 69% fidelity and performed better in terms of sustaining high vaccination coverage compared to the centralized approach. Design-, implementer- and context-related factors influenced delivery and effectiveness of the CBC-MDV strategies. We found that the community engagement activities positively influenced factors that underpin participation in MDV campaigns. In relation to integrating and sustaining the new approach in practice, CBC-MDV was well understood, accepted, operationalized with relative ease and positively appraised compared to the centralized approach. We conclude that it was feasible to deliver CBC-MDV in the context of Tanzania, it can be sustained in practice, and barriers to participation in mass dog vaccination can be addressed through community engagement processes. However, community participation in the design, delivery and evaluation of CBC-MDV is needed to foster ownership and sustainability of the intervention.
Designing a novel method for brain volume quantification in investigating childhood brain atrophy and its functional effects
(NM-AIST, 2023-08) Sungura, Richard
Brain atrophy is a result of volume loss commonly indicated by brain parenchyma separation from calvarium on neuroimaging. The prevalence of childhood brain atrophy has not been determined globally. Despite sporadic reports, surprisingly little is known about the prevalence, risk factors, and functional effects, except in children's brains associated with epilepsy. There is currently no published alternative to high-priced automated technologies for reproducible manual quantification of brain volume. The primary aim of the study was to develop a manual diagonal brain fraction (DBF) formula for quantifying and grading brain volume to evaluate the effects of brain atrophy among children in the selected East African Countries-Northern Tanzania and Rwanda. Children in Northern Tanzania and Rwanda were analysed for evidence of brain atrophy using one-dimension linear radiological techniques and a newly developed formula, revealing a prevalence of 14.06% and 22% respectively. There were four distinct grades of disease severity. Head trauma, neonatal hypoxia, central nervous system infections, and increased intracranial pressure were cited as potential inducers of the atrophy. Significant alterations in brain waves were observed using EEG, which proved the altered functional implications of brain atrophy. These included, for example, decreased Delta/Alpha ratios (DAR) and higher beta activity. There is a negative relation between brain volume and IQ test scores in atrophied brain. Brain atrophy was also found to be strongly related to the presence of convulsive disorders. The results of this study conclude that, childhood brain atrophy is quite widespread among the population that was studied. The DBF is a straightforward technique for evaluating overall brain volume. Possible risks of brain atrophy in children include birth injury, central nervous system infection, head trauma and increased intracranial pressure. Beta activities such as Beta/Alpha ratio (BAR) may serve as brain atrophy bio-markers while the Delta/Alpha ratio (DAR) is trivial in brain atrophy settings. Damage to the brain's neurocognitive functions is reflected by lower-than-average IQ percentile score for age in atrophied brains. As a result, it is critical to develop methods of protecting children's mental health from potential risks.
Community antibiotic usage and the characterization of antibiotic resistance among common bacterial isolates in selected rural and urban districts of the DODOMA Region, Central TANZANIA
(NM-AIST, 2023-07) Mabilika, Richard
Antibiotic resistance threatens the treatment of bacterial infections globally. This cross- sectional study was conducted from August 2019 to May 2021 in Dodoma. The aim was to understand the prevalence and determinants of self-medication with antibiotics (SMA), antibiotic dispensing in community drug outlets, antibiotic prescribing in primary health care facilities and determine resistance profiles of bacterial pathogens in primary health care facilities (PHCF). Regarding SMA, 430 respondents were interviewed in Chemba District Council (rural) (161/430) and Dodoma City Council (urban) (269/430). The prevalence of SMA was 23.6% (38/161) and 23.4% (63/269) in the rural and urban respondents respectively. A shorter perceived distance to a health care facility than to a drug outlet was associated with decreased SMA practices among participants. Furthermore, 643 drug purchases were recorded in Accredited Drug Dispensing Outlets (ADDO) and community pharmacies, 84.1 % (541/643) were in Dodoma City Council (urban) and only 24.9% (160/643) purchased antibiotics. Antibiotics were dispensed in ADDO without prescriptions and beyond jurisdiction. Children <5 years accounted for over 45% (474/1021) of all the consultations recorded in the primary health care facility (PHCF); 76.3% (779/1021) of the consultations had an antibiotic with up to 55% (429/779) adherence to Standard Treatment Guidelines (STG). Pneumonia and respiratory symptoms were 16 times (adjusted OR=15.918; 95% CI: 2.151, 17.973; p = 0.007) and almost 2 times (adjusted OR=1.709; 95% CI: 1.129, 2.587; p = 0.011) more likely to prompt antibiotics, respectively. Furthermore, 621 clinical specimens were collected from out-patients in Chemba District Council (38.1%; 237/621) and Dodoma City Council (61.9%; 384/621) respectively. S. aureus (44) and E. coli (35) were the most prevalent isolates. There were high resistance rates of E. coli and S. aureus against ampicillin, ciprofloxacin and trimethoprim/sulfamethoxazole: 31.8% (14/44) of S. aureus were methicillin-resistant (MRSA). This study reports high SMA among those living close to community drug outlets, high un-prescribed antibiotic dispensing in ADDO, poor adherence to STG and relatively lower methicillin-resistant Staphylococcus aureus (MRSA) levels in PHCF. The study calls for more concerted efforts against the misuse of antibiotics as a means of confronting the emergence and spread of antibiotic resistance.
Machine learning model for prediction of malaria in low and high endemic areas of Tanzania
(NM-AIST, 2023-08) Mariki, Martina
Presumptive treatment and self-medication with anti-malaria drugs is a common practice in most limited resource settings that hinders proper management of malaria. However, these approaches have been considered unreliable due to the unnecessary use of malaria medication and untreated diseases that relate to malaria. This study aimed to develop a machine-learning model for malaria diagnosis using patients’ symptoms and non-symptomatic features in high and low endemic areas of Tanzania. The malaria diagnosis dataset with 2556 patient’s records and 36 features was collected in two regions of Tanzania: Morogoro and Kilimanjaro from 2015 -2019. Machine learning classifiers with the k-fold cross-validation methods were used to train and validate the model. To improve the performance of the diagnostic model, important features for malaria diagnosis were selected, and it was observed that the ranking of features differs among regions and when combined dataset. Significant features selected are residence area, fever, age, general body malaise, visit date, and headache. Random Forest and Decision Tree algorithms were the best performing classifiers in modelling malaria diagnosis datasets and attained 96%, 99% and 98% prediction accuracy for Kilimanjaro, Combined and Morogoro dataset respectively. These best-performing classifiers were evaluated using the unseen malaria diagnosis dataset and performed well in classifying malaria patients from sick patients. The final developed model showed that only a specific combination of features can predict malaria accurately. The results of this study revealed that malaria diagnosis using patients’ symptoms and demographic features is possible. Also, the study results offer additional knowledge and shed light on the state diagnosis of malaria in the country. The developed machine learning model enables prediction of patient’s malaria state using symptoms observed and non- symptomatic features before prescription of anti-malaria drugs. Apart from that the output of this study will be a necessary step in designing a malaria diagnosis decision support system through the developed model. Furthermore, towards reducing drug resistance, the results of this study can be used by the policymakers and the Ministry of Health for better management of malaria disease in health facilities and drug dispensing outlets to avoid self-medication and presumptive treatment.
Prevalence and risk factors for Q fever, spotted fever group rickettsioses, and typhus group rickettsioses in a pastoralist community of northern Tanzania, 2016–2017
(John Wiley & Sons Ltd., 2024-01-12) Moorthy, Ganga; Rubach, Matthew; Maze, Michael; .Refuerzo, Regina; Shirima, Gabriel; Lukambagire, AbdulHamid; Bodenham, Rebecca; Goldwasser, Shama; Thomas, Kate; Sakasaka, Philoteus; Mkenda, Nestory; Bowhay, Thomas; Perniciaro, Jamie; Nicholson, William; Kersh, Gilbert; Kazwala, Rudovick; Mmbaga, Blandina; . Buza, Joram; Maro, Venance; Haydon, Daniel; Crump, John; Halliday, Jo
Background: In northern Tanzania, Q fever, spotted fever group (SFG) rickettsioses, and typhus group (TG) rickettsioses are common causes of febrile illness. We sought to describe the prevalence and risk factors for these zoonoses in a pastoralist community. Methods: Febrile patients ≥2 years old presenting to Endulen Hospital in the Ngorongoro Conservation Area were enrolled from August 2016 through October 2017. Acute andconvalescent blood samples were collected, and a questionnaire was administered. Sera were tested by immunofluorescent antibody (IFA) IgG assays using Coxiella burnetii (Phase II), Rickettsia africae, and Rickettsia typhi antigens. Serologic evidence of exposure was defined by an IFA titre ≥1:64; probable cases by an acute IFA titre ≥1:128; and confirmed cases by a ≥4-fold rise in titre between samples. Risk factors for exposure and acute case status were evaluated. Results: Of 228 participants, 99 (43.4%) were male and the median (interquartile range) age was 27 (16–41) years. Among these, 117 (51.3%) had C. burnetii exposure, 74 (32.5%) had probable Q fever, 176 (77.2%) had SFG Rickettsia exposure, 134 (58.8%) had probable SFG rickettsioses, 11 (4.8%) had TG Rickettsia exposure, and 4 (1.8%) had probable TG rickettsioses. Of 146 participants with paired sera, 1 (0.5%) had confirmed Q fever, 8 (5.5%) had confirmed SFG rickettsioses, and none had confirmed TG rickettsioses. Livestock slaughter was associated with acute Q fever (adjusted odds ratio [OR] 2.54, 95% confidence interval [CI] 1.38–4.76) and sheep slaughter with SFG rickettsioses case (OR 4.63, 95% CI 1.08–23.50). Discussion: Acute Q fever and SFG rickettsioses were detected in participants with febrile illness. Exposures to C. burnetii and to SFG Rickettsia were highly prevalent, and interactions with livestock were associated with increased odds of illness with both path- ogens. Further characterisation of the burden and risks for these diseases is warranted.
Epidemiology of intestinal schistosomiasis and efficacy of single versus repeated dose praziquantel treatments among schoolchildren in Rorya district, Northwestern Tanzania
(NM-AIST, 2018-12) Munisi, David
In Schistosoma mansoni endemic areas, administering repeated treatments may increase praziquantel cure rate (CR) and egg reduction rate (ERR), thereby improving morbidity reduction and hastening achievement of transmission control in these areas. This was a longitudinal study which investigated the efficacy of single versus repeated praziquantel treatments of S.mansoni infections and its impact on undernutrition and anaemia. Stool samples were collected from 513 schoolchildren and examined for S.mansoni infections using the Kato-Katz method. Questionnaires were used to collect socio- demographic data, risk factors, knowledge, attitude and practices on schistosomiasis. Nutritional status was determined by anthropometry. Blood samples were collected and examined for malaria parasites and haemoglobin levels using the Giemsa stain and HaemoCue methods, respectively. The prevalence of S.mansoni, malaria, stunting, wasting and anaemia were 84.01%, 9.16%, 38.21%, 14.42% and 29.43%, respectively. The geometric mean (GM) egg per gram of stool for S.mansoni was 167.13 (95%CI: 147.19–189.79) eggs per gram of stool. Village of residence, parent’s level of education, toilet use and treatment history were predictors of S.mansoni infection. A total of 431 S.mansoni infected schoolchildren were randomized to either receive a single or repeated 40mg/kg dose of praziquantel. At 8 weeks post baseline treatment, CR was higher among those on repeated dose (93.10%) than those on a single dose (68.68%, p0.05), with significant increase in mean haemoglobin (p0.05). Majority (93%) of participants mentioned using lake water for domestic chores. Although toilet ownership was high (84.61%), regular toilet use was low (55.31%). To be of sustained benefit, repeated dose praziquantel treatments should be coupled with other control measures that aim at reducing the rate of re-infection and environmental contamination.
Assessment of pastoralists’ vulnerability to trypanosomiasis and effects of climate on tsetse and trypanosomes distribution in Tanzania’s Maasai steppe
(NM-AIST, 2017-12) Nnko, Happiness
For decades, pastoralists have had their adaptation strategies that enable them to thrive in harsh environments. However, changing climate and land management regimes, coupled with under-investments in pastoral areas, threaten to overwhelm pastoralists’ traditional adaptation methods. This could potentially increase vulnerability of pastoral communities to multiple stressors, including trypanosomiasis. Trypanosomiasis is caused by a parasitic protozoan of Trypanosoma spp where tsetse flies are the main vector. Trypanosomiasis is a neglected tropical disease, yet a disease of public health and socio-economic concern. It exacerbates economic hardships due to loss of livestock or through additional costs needed to control and treat the disease. Despite these concerns, information about where and when to expect high burden of tsetse flies and trypanosomes remain limited, and control strategies, if offered, are often ineffective. This study therefore assessed pastoralists’ vulnerability to trypanosomiasis, seasonality of tsetse fly abundance, prevalence of trypanosome infections in the vector, and potential impacts of climate change on tsetse fly distribution. The study incorporated social and ecological analytical techniques including ArcGIS 10.4, polymerase chain reaction (PCR) and species distribution modelling (SDM). Emboreet and Loibor-Sireet Wards in Simanjiro district were identified as the most vulnerable locations to trypanosomiasis. Three tsetse fly species (Glossina m. morsitans, Glossina pallidipes and Glossina swynnertoni) and three trypanosome species (T.vivax, T.congolense and T. brucei) were found in the study area. Tsetse fly relative abundance and trypanosome prevalence peaked in July and October, respectively. Maximum and minimum temperature negatively affected abundance of G. m. morsitans and G. swynnertoni, respectively. Trypanosome prevalence was negatively correlated with tsetse abundance but positively correlated with temperature. The climate tsetse fly relationships were used in the SDM to show that by the year 2050, the habitable area of G. m. morsitans, G. pallidipes and G. swynnertoni may decrease to 23.13%, 12.9% and 22.8% of current suitable habitat (19 224.58 km2 , 7113.37 km2 and 32 335.27 km2 ), respectively in the study area. These results provide useful information to inform communities, health and livestock development sectors and tsetse fly control units on where and when to expect the highest risk of trypanosomiasis infection in the Maasai Steppe and plan accordingly. ii Keywords: Pastoralist, vulnerability, trypanosomiasis, adaptation, tsetse, trypanosome prevalence, seasonality, SDM, Maasai Steppe, Tanzania
Risk assessment for dietary exposure of pesticides among vegetables consumers in Arusha, Tanzania
(NM-AIST, 2019-03) Kiwango, Andrew
Information on the extent of pesticide residues in vegetables from Tanzania and risk of dietary exposure to these residues among vegetable consumers is limited. This research assessed the risk of dietary exposure of pesticide residues in vegetable farmers and individuals with non-communicable disorders in Arusha. Face-to-face interviews were conducted to assess pesticide application practices. Observations were made to assess effectiveness of vegetable processing practices at household level, in reducing pesticide residues. Two-point 24 hour recalls and food frequency questionnaire techniques were used to determine vegetable consumption. Raw and ready-to-eat vegetables were sampled and analyzed for pesticide residues using Gas Chromatography-Mass Spectroscopy. Dietary exposure to pesticide residues was estimated. The results showed that vegetables were contaminated with organophosphates, pyrethroids organochlorines, carbamates and benzoic acid pesticides. Endosulfan and dieldrin which are banned for use in agriculture in Tanzania were quantified in the vegetables at levels above their respective Maximum Residue Levels. Exposure estimations showed that 18.6% of vegetable farmers are at risk of exposure to organophosphates [Hazard index (HI); 1.19], mainly contributed by dimethoate. Individuals with NCDs are at risk of exposure to organophosphates (HI; 1.12) and organ chlorines (HI; 1.08) mainly attributed to exposure to chlorpyrifos and endosulfan, respectively. Dietary exposures of pesticides are significantly associated with lack of advice from agricultural extension officers (adjusted odds ratio (AOD) = 6.56; P = 0.031), over-dosage of pesticides in vegetables (AOD = 3.751; P = 0.038) and lack of professional training on pesticide application practices (AOD = 3.37; P = 0.043). Washing vegetables in a bowl two or more times with changing the washing water after one use, (χ 2 (1) = 6.56; P = 0.01) or peeling (χ 2 (1) = 6.949; P = 0.008 is significantly associated with low levels of pesticides in ready to eat vegetables. Poor practices in washing of minor ingredients (tomato, carrot, sweet pepper and onions) such as washing by water that was previously used to wash the major ingredients has significant association with the occurrence of pesticide residues in vegetables (χ 2 (1) = 25.55; P = 0.001. Based on the findings of this study it is necessary to ensure continuous monitoring of pesticide residues in vegetables and training growers on good agricultural practices and best practices on vegetable handling at household level.
Efficacy of a reduced dose of multiple micronutrient powder supplementation among children aged 6-59 months in arusha district, Tanzania
(NM-AIST, 2019-03) Kejo, Dyness
Iron deficiency anaemia is the most prevalent nutritional problem affecting children underfive years old in the developing countries. The deficiency is a result of inadequate intake and insufficient absorption of iron-rich foods that may be caused by diseases or dietary factors prevalent in rural areas. The most appropriate approach for solving the problem in rural settings is the use of Multiple Micronutrient Powder supplements (MNP). The recommended supplementary dose is one (1) sachet per day. However, in areas where resources are limited, the recommended weekly dose of seven sachets is considered expensive. The aim of this study was to assess the efficacy of a lower weekly dose, say three sachets of a MNP for dietary supplementation of complementary foods in Arusha district. A community-based longitudinal study with the intent to assess this efficacy was adopted for this study. Subjects were randomized into four intervention groups and given a Multiple Micronutrient Powder in different doses for six months. Anthropometric measurement, dietary assessment and haemoglobin levels were collected during the intervention involving 436 children under five years old in Arusha district of Tanzania. At baseline, 84.6% of the children were anaemic. Low birth weight and dietary factors (non-consumption of iron rich foods like meat, vegetable, and fruits) were predictors of anaemia. At the end of the intervention, haemoglobin levels were significantly higher in the groups which received three to five sachets of micronutrient powder per week than in children who received one or two sachets per week. Prevalence of infectious diseases was reduced significantly (p < 0.05) from 65% to 30.5% and anaemia, from 100% to 43.0% in all the groups. Two-thirds of mothers expressed willingness to pay for the micronutrient powder at the selling price of 150 TZS per sachet. However, the willingness to pay was associated with socio-demographic and economic characteristics of the participants. This study provides evidence that three to five sachets of MNP per week is an efficacious treatment for anaemia among children under-five years old in Arusha district. Families in low-income communities should be advised to use at least the lower weekly dose of 3 sachets to achieve the desired outcomes.
Risk assessment for dietary exposure of pesticides among vegetables consumers in Arusha, Tanzania
(NM-AIST, 2019-03) Kiwango, Purificator
Information on the extent of pesticide residues in vegetables from Tanzania and risk of dietary exposure to these residues among vegetable consumers is limited. This research assessed the risk of dietary exposure of pesticide residues in vegetable farmers and individuals with non-communicable disorders in Arusha. Face-to-face interviews were conducted to assess pesticide application practices. Observations were made to assess effectiveness of vegetable processing practices at household level, in reducing pesticide residues. Two-point 24 hour recalls and food frequency questionnaire techniques were used to determine vegetable consumption. Raw and ready-to-eat vegetables were sampled and analyzed for pesticide residues using Gas Chromatography-Mass Spectroscopy. Dietary exposure to pesticide residues was estimated. The results showed that vegetables were contaminated with organophosphates, pyrethroids organochlorines, carbamates and benzoic acid pesticides. Endosulfan and dieldrin which are banned for use in agriculture in Tanzania were quantified in the vegetables at levels above their respective Maximum Residue Levels. Exposure estimations showed that 18.6% of vegetable farmers are at risk of exposure to organophosphates [Hazard index (HI); 1.19], mainly contributed by dimethoate. Individuals with NCDs are at risk of exposure to organophosphates (HI; 1.12) and organ chlorines (HI; 1.08) mainly attributed to exposure to chlorpyrifos and endosulfan, respectively. Dietary exposures of pesticides are significantly associated with lack of advice from agricultural extension officers (adjusted odds ratio (AOD) = 6.56; P = 0.031), over-dosage of pesticides in vegetables (AOD = 3.751; P = 0.038) and lack of professional training on pesticide application practices (AOD = 3.37; P = 0.043). Washing vegetables in a bowl two or more times with changing the washing water after one use, (χ 2 (1) = 6.56; P = 0.01) or peeling (χ 2 (1) = 6.949; P = 0.008 is significantly associated with low levels of pesticides in ready to eat vegetables. Poor practices in washing of minor ingredients (tomato, carrot, sweet pepper and onions) such as washing by water that was previously used to wash the major ingredients has significant association with the occurrence of pesticide residues in vegetables (χ 2 (1) = 25.55; P = 0.001. Based on the findings of this study it is necessary to ensure continuous monitoring of pesticide residues in vegetables and training growers on good agricultural practices and best practices on vegetable handling at household level.
Influence of Rhizobia Inoculation and supplementation with phosphorus and potassium in soybean-maize intercropping system
(NM-AIST, 2017-12) Nyoki, Daniel
A field experiment was carried out at Tanzania Coffee Research Institute (TaCRI) farm, for two consecutive years (2015 and 2016). The objective of this study was to assess the effects of cropping systems, Rhizobium inoculation and fertilization with P and K on farm productivity of both soybean and maize. The experiment was laid out in split-split plot design with 2 x 4 x 7 factorial arrangements and replicated thrice. The main plots comprised two rhizobia inoculation treatments, while the sub plots were comprised of: Maize pure stand (75 x 60 cm); Soybean pure stand (75 x 40 cm); maize-soybean intercropping (75 x 60 cm and 75 x 20 cm), maize and soybean respectively; and the last cropping system was maize-soybean intercropped (75 x 60 cm and 75 x 40 cm), maize and soybean respectively. The sub-subplots were assigned the following fertilizer levels (kg ha-1 ): control (0 kg ha-1 ); 20 K; 40 K; 26 P; 52 P; 26 P + 20 K; 52 P + 40 K. The 3-way analysis of variance (ANOVA) in factorial arrangement was performed. The STATISTICA software program was used. The fisher’s least significance difference (L.S.D.) was used to compare treatment means at p = 0.05 level of significance. The results indicated that rhizobia inoculation and fertilization of crops with P and K significantly improved mineral composition in the rhizosphere soil of soybean; nutrient uptake in soybean shoots; nitrogen fixation and chlorophyll concentration in soybean. Furthermore, rhizobia inoculation and P and K fertilization significantly improved plant growth and final yield of both soybean and maize. Cropping systems were also assessed and found that intercropping was advantageous since the values of land equivalent ratios (LER) were greater than one. In general, several parameters tested in this study have shown to perform better in combined lower rates (20 kg K ha-1 +26 kg P ha-1 ) of P and K. It is therefore recommended that the combined lower rates of these fertilizers should be adopted and be used by farmers in areas with similar characteristics as that of study area.
Land cover correlates of Tsetse distribution and its implications for cattle movement and Trypanosomiasis control in the Maasai steppe
(NM-AIST, 2017-12) Ngonyoka, Anibariki
Anthropogenic activities changes ecosystem structure, and alter the vital rates of vectors, host-vector interaction and consequently disease transmission dynamics across the landscape. This research examined the participatory epidemiology to elicit Maasai pastoralist knowledge on land use changes, cattle grazing patterns and trypanosomiasis control. Furthermore, abundance and infection rates were determined in relation to age of tsetse flies, habitat types, host presence and predicted potential spatial distribution patterns in the Maasai Steppe of northern Tanzania. Tsetse abundance was obtained through geo-referenced straps, host counts around trap sites, between July 2014 and November 2015 in selected habitats across four villages: Emboreet, Loiborsireet, Kimotorok and Oltukai adjacent to protected areas. PCR identification of trypanosome species performed an to establish the infection rates. Extraction of monitored Normalized Difference Vegetation Index (NDVI) data derived from Moderate Resolution Imaging Spectrometer (MODIS) were performed asses vegetation cover changes. Presence only niche modelling approach used to predict spatial distribution of tsetse species through integration of heterogeneous biophysical factors across the entire landscape with tsetse presence data. Our findings show the variation of tsetse fly species abundance and infection rates among habitats in surveyed villages in relation to NDVI and host abundance. Results show higher tsetse fly abundance in Acacia-swampy ecotone, open woodland and riverine habitats. Tsetse species abundance was inconsistent among habitats in different villages. Emboreet was highly infested with Glossina swynnertoni (68%) in ecotone and swampy habitats followed by G. morsitans (28%) and G. pallidipes (4%) in riverine habitat. In the remaining villages, the dominant tsetse fly species by 95% was G. pallidipes in all habitats. Trypanosoma vivax was the most prevalent species in all infected flies (95%) with few observations of co-infections (with T. congolense or T. brucei). The relationship of tsetse with abundance of wildlife and livestock was more complex, as we found positive and negative associations depending on the host and fly species. Furthermore, niche modelling of tsetse species provides the hotspots for tsetse infestations and infections and hence plan for cost effective eco-health intervention approaches to increase the resilience of pastoral communities against Trypanosomiasis.
Occurrence, seasonal variation and management of Tomato leafminer (Tuta Absoluta Meyrick.) in Tanzania
(NM-AIST, 2019-03) Zekeya, Never
Tomato leafminer [Tuta absoluta, Meyrick. (Lepidoptera: Gelechiidae)] is a notorious pest that causes massive losses in Solanaceae’s crops including tomato (Solanum lycopersicum L.). This study was conducted to evaluate the occurrence, damage incidences, host range, population dynamics and developed bio-control strategies for managing T. absoluta in Tanzania. Field surveys were conducted in thirteen tomato production regions of Tanzania by purposively sampling one region and one district from each region then three villages were randomly selected for field survey. Optima lures was deployed per plot (0.5 acre) and number of adult moths trapped were counted after 7 days. To identify host of T. absoluta, in each selected village number and types of crops damaged per plot were recorded. Ten plants per plot were randomly selected to determine the rate of T. absoluta damage per plant by counting number of damaged leaves/fruits per plant in each plot and expressed as percentage damage. However, botanical extracts against T. absoluta larvae was conducted in laboratory by using four plant species extracted by using organic solvents. Different concentrations of extract were tested against 10 second instar larvae of T. absoluta that were selected randomly. Mortality rate, pupation rate and adult emergence rate were recorded at interval of 24h. Results indicated that T. absoluta was present in 13 regions surveyed and proliferates in 12 host plants including tomato, potato, nightshade, pepper and some weed species particularly Solanum incanum. Population density of T. absoluta was high in Iringa compared to Arusha and Morogoro and the dry season exhibited higher number of T. absoluta than in rainy season in all regions surveyed. The study on T. absoluta management revealed that, the pest can be controlled by using locally available entomopathogenic fungi (Patent No. TZ/P/2018/000035), plant extracts from Bersama abyssinica stem bark, Commiphora africana leaves, Tergetes minuta seeds and Moringa oleifera essential oil from seeds and cultivation of four accessions of tomato landraces namely BKM-22, KGM-5, HSK-4 and HSK-38. Application of the developed bio–control strategies caused 60% to 80% mortality of adults and larvae of T. absoluta in the laboratory and open field conditions. The identified bio-control strategies and resistance tomato landraces are recommended for further analysis and for consideration as remedies against T. absoluta in tomato in Tanzania.
Understanding human-carnivore conflict over livestock depredation and its implications for conservation in the Tarangire-Simanjiro ecosystem, Northern Tanzania
(NM-AIST, 2017-12) Mkonyi, Felix
Human-carnivore conflict is one of the threats facing large carnivores across the globe and can have a significant negative financial impact on local people’s livelihoods. Semi-structured interviews were conducted with 300 respondents to examine the level of reported conflict with large carnivores over depredation on livestock, and to assess the key drivers of any such conflict, the financial livestock losses to local communities, the perceived effectiveness of current conflict mitigation strategies and local perceptions and attitudes towards the main carnivore conflict species in the Tarangire-Simanjiro ecosystem in northern Tanzania. Additionally, a spoor-based occupancy modelling approach that incorporates detection probability was used to assess the occurrence of four focal carnivore taxa, and to identify the key environmental and anthropogenic drivers of their occurrence. Of the 300 respondents, 75% reported losses of their livestock to wild predators over the past 1.5 years, which represents an annual loss rate of 1.4% of their livestock holdings. The overall financial loss due to livestock depredation was estimated to be US$ 141,847 (US$ 633/household/year). Reported depredation frequency by all large carnivore species increased significantly with increasing number of livestock owned, respondent’s residency time, distance from the park boundary and declined significantly with increasing education, number of herders and improved fortified boma for cattle. Three-quarters of respondents (79%) held negative attitudes towards large carnivores due to risks of wildlife damage, particularly livestock depredation, while 20% were generally positive linked to potential ecotourism benefits. Education, years at residency and knowledge were the most influential determinants (though dependent on species) of attitudes towards large carnivores than landscape, demographic or economic factors. Fortified bomas (97.7%) and adult herders (71%) were perceived to be the most effective intervention methods to reduce night and daytime depredations respectively. Overall occurrence was estimated at 0.85 (SE = 0.06) for hyena, 0.82 (SE = 0.15) for cheetah, 0.55 (SE = 0.10) for lion and 0.61 (SE = 0.21) for leopard. Lion occurrence was negatively associated with distance to park boundary. Hyena occurrence was positively associated with human population density and negatively associated with bushland, while cheetah and leopard occurrences were positively associated with grassland. These results suggest that lions may be more vulnerable to human impacts than other species, while hyenas may benefit from vicinity to humans. This study provides targeted areas to prioritize for future carnivore conservation efforts and mitigation efforts regarding human-carnivore conflict.
Application of estuarine ecohydrology approach for Studying the key hydrological and ecological Processes of the Wami estuary, Tanzania
(NM-AIST, 2017-12) Kiwango, Halima
This study was conducted in the Wami Estuary in Saadani National Park (SANAPA) to understand the key hydrological and ecological processes that influence the ecosystem functioning. It focused at the dynamics of water quantity, quality and their impact to the organisms, the fate of riverine nutrients and the role of the mangrove ecosystem. Data obtained from the fieldwork, laboratory analyses and secondary sources were used to assess the estuarine condition. The land-ocean Interaction in the Coastal Zone (LOICZ) and UNESCO- Estuarine Ecohydrology (UEE) models were used to study the nutrients processing within the estuarine food web, estimating the nutrients budget, the residence time and the net ecosystem metabolism (NEM). The results indicate the declining trend of freshwater flow to the estuary particularly during the dry season and increasing sediment loading that result to seasonal and tidal variations in the plankton community structure. Seasonal variations in salinity gradient indicate a highly stratified system and a well- mixed system during the wet and dry seasons respectively. The model results indicate the estuary shifts from an autotrophic, denitrifying, flushed in ~ 0.5 day and freshwater-dominated to a heterotrophic, nitrifying, flushed in ~ 7 days, marine-water dominated system from the wet to dry season. The presence of mangroves doubles the shrimp and phytoplankton communities. The mangroves trapped about 12% of the riverine sediments during the wet season while during the dry season the riverine sediment sediment inflow accounted for only 10% of the sediment trapped. The mangrove litter contributes to nutrient recycling whereby crabs recycled 57% of the mangrove litter, 32% was exported to the estuary and 11% remained to decomposed in the mangrove floor. The findings indicate that water quality parameters are within the acceptable levels recommended to sustain a healthy aquatic ecosystem. The study provides a scientific understanding of the Wami Estuary ecosystem functioning for proper management and decision-making process. It recommends an effective governance mechanism in the Wami River basin, emphasizing on sustainable use of water, and reducing sediment loading. Under the worst-case scenario, SANAPA should construct a water reservoir to serve for the estuarine ecosystem, wildlife, and people during the dry season.
Prevalence and correlates of overweight and obesity among primary school children in Ilala and Mkuranga districts, Tanzania
(NM-AIST, 2023-08) Pacific, Renatha
Overweight and obesity are increasing among school children and are currently considered as significant public health problems. Therefore, this study aimed to determine the prevalence of overweight and obesity in school children (10-13 years) and their correlates, to inform policy for action in order to reduce the magnitude and consequences of the problems. A cross sectional study design was conducted in Ilala and Mkuranga districts of Tanzania between July 2019 and December 2020 among 406 school children, 36 parents/guardians, and 9 teachers. Standardized questionnaires were used for data collection and laboratory analysis was performed to determine actual fatty acids and sugar contents of foods commonly consumed by school children in the study areas. Height and weight measurements were performed by using the World Health Organization standard procedures. The general prevalence of overweight and obesity based on BMI-for-age indicator was 22.6% higher in private than in public schools (32.4% vs. 14.8%, p<0.001). Dietary habits of school children were characterized by low fruit, vegetable, and milk intake. Overweight and obesity among school children correlated significantly with moderate consumption of soda/carbonated drinks (AOR 0.38, 95% CI 0.19- 0.85), high consumption of fruit/fruit-flavored juices (AOR 0.21, 95% CI 0.07-0.67), local ice cream (AOR 0.41, 95% CI 0.17-0.95), and low dietary diversity (AOR 0.57, 95% CI 0.44- 0.75). Other predictors were moderate consumption of potato chips (AOR 2.27, 95% CI 1.07- 4.81) and having overweight/obese parent (AOR 10.11, 95% CI 2.72-37.65). In addition, sedentary behavior, such as listening to music and/or radio for >2 hours/week (OR 2.7, 95% CI 1.2-6.1) and low physical activity such as walking for exercise <2 hours/week (OR 2.1, 95% CI 1.1-4.1) were risk factors for overweight/obesity while rope skipping for >2 hours/week (OR 0.14, 95% CI 0.03-0.7) was protective. Saturated fatty acids, such as palmitic acid (C16:0), were found in abundance in all food samples while sucrose and saccharin concentrations varied considerably between products. Findings from this study showed that the food environment may be a contributing factor to overweight/obesity among school children. This study informs relevant authorities to take appropriate actions to minimize health risks associated with overweight and obesity in school children.

Browse

Recent Submissions