PhD Theses and Dissertations [LiSBE]

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Morpho-physiological perfomance of common beans (phaseolus vulgarisl.) cultivars under rhizobial inoculation and water stress condition in Arusha, Tanzania
(NM-AIST, 2017-12) Vincent, Eutropia
The aim of this study was to identify common bean cultivars which can grow/yield better under rhizobial inoculation and at limited water condition. To attain the goal, two seasons field experiment and one season screen house experiment were conducted at Agricultural Seed Agency (ASA) in Arusha Tanzania in the year 2014 /2015 and 2016. The experiment was a split-split plot with three replications, two levels of rhizobia, two stress levels and five cultivars of P. vulgaris (L.) (KAT B9, KAT B1, F9 Kidney Selection, F8 Drought line and JESCA). Stress periods of 10 days were imposed at vegetative and flowering stages of plant growth. Results showed that proline content was high in inoculated and water stressed plants. Concentrations of flavonoids and anthocyanins were higher in non-inoculated water stressed treatments. Leaf chlorophyll content, relative leaf water content and electrolyte leakage were higher in rhizobial inoculated and non-water stressed treatments. The nutrients uptake was higher in rhizobial inoculation and non-water stressed treatments. Rhizobial inoculation significantly increased growth parameters and seed yields while water stress significantly reduced growth parameters at both growth stages. F8 Drought Line and JESCA varieties significantly recorded higher proline content in field experiment and KAT B1 in the screen house experiment. Varieties F8 Drought line, JESCA and F9 Kidney Selection significantly recorded higher flavonoids and anthocyanins content in both experiment. Leaf chlorophyll content was significantly higher in F9 Kidney Selection and KAT B1 than in F8 Drought Line and JESCA. Cultivars F9 Kidney Selection, F8 Drought Line and JESCA had significantly higher relative leaf water content than other cultivars. However, varieties KAT B9 and KAT B1 significantly increased percentage in electrolyte leakage.Varieties F9 Kidney Selection, F8 Drought Line and JESCA significantly recorded higher uptake of N, P, K, Ca and Mg. Varieties F9 Kidney Selection, F8 Drought Line and JESCA had significantly superior measurements reflected in increased plant height, shoot and root dry weight and seed yields. Significant interactions were observed between rhizobial inoculation, water stress and bean varieties. Cultivars F9 Kidney Selection, F8 Drought line, JESCA and KAT B1 showed highest level of tolerance against the water stress. With these observations, cultivars F9 Kidney Selection, F8 Drought line, JESCA and KAT B1 can be promoted for production especially in drought prone areas.
Genetic characterization of jute mallow (corchorus spp.): a traditional African vegetable
(NM-AIST, 2017-12) Ngomuo, Munguatosha Samwel
Jute mallow (Corchorus spp.) is a very nutritious traditional leafy vegetable. Its leaves contain an average of 15% dry matter,4.8 g of protein, 259 mg of calcium, 4.5 mg of iron, 4.7 mg of vitamin A, 92 μg of folate, 1.5 mg of nicotinamide and 105 mg of ascorbic acid per 100g of leaves. In spite of its nutritional importance, cultivation of Jute mallow is limited due to lack of scientific information with regard to available cultivars and their adaptation to specific environments. The aim of this study was to analyze the genetic diversity and evaluate the accessions which are well adapted to specific environment for leaf and seeds production. Ninety accessions were evaluated in the field trial experiments for two growing seasons. ISSR and SSR markers were employed for molecular characterization as well as leaf and seed yield evaluation. The results showed significant (p<0.01) variability in accessions in all morphological traits. Traits such as plant height (r=0.448), petiole length (r=0.237), primary branches (r=0.319) and number of leaves per plant (r=0.333) were significantly (p<0.01) correlated with biomass yield. First five Principal components (PCs) with Eigen values ≥1 explained 72.9% of the total variability in the accessions. Cluster analysis grouped the accessions into five major clusters mainly based on their origin. Number of alleles per locus ranged from 2-4 with an average of 2.63 alleles per locus. Polymorphic information content (PIC) ranged from 0.278 in primer SSR17 to 0.78 in primer SSR24. Average Nei‘s gene diversity (h) and Shannon‘s information index (I) were 0.348 and 0.557, respectively. In ISSR markers a total of 85 bands were amplified and average polymorphic bands per primer was 2.75. PIC values ranged from 0.39 to 0.76 with average of 0.53. The highest Nei‘s pair wise genetic distance (0.431) was observed in East African accessions. UPGMA cluster analysis grouped the accessions into five main clusters at genetic similarity coefficient of 0.53. In terms of leaf and seed yield, significant (p<0.01) differences among the accessions in all traits was observed. Leaf fresh weight ranged from 18.3g/plant to 121.3g/plant in accessions TOT 6747 and TOT 8532, respectively. Seed yield ranged from 1.0g/plant to 35.5g/plant in accessions TOT 7980 including eight others and TOT 7866, respectively. Evaluation of genetic diversity and the agronomic traits for leaf and seed yield in this germplasm has revealed useful information for breeders in their efforts to improve the yield as well as selection of accessions with good agronomic traits. It is recommended that detailed study to document ethnomenclacture, ethnobotanical uses, progress towards domestication and challenges faced by farmers be conducted.
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.
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
Design of burner and study of combustion characteristics of pyrolysis oil from biomass
(NM-AIST, 2017-12) Lujaji, Frank Clement
Conversion of biomass to fuel provides a positive contribution for fossil fuel replacements. In addressing challenges associated with the combustion of pyrolysis oil (bio-oil), this research aimed at developing a burner system that would handle the atomization and combustion of biooil. This research started by conducting a spray study in order to explore the potential for bio-oil combustion in industrial furnaces. Spray experiments were conducted by using different sizes of externally mixed nozzles with bio-oil and ethanol blends. Results revealed that it is possible to spray bio-oil/ethanol mixtures containing as high as 40% bio-oil that has a low water content (12.6%). The design of the furnace for the combustion of bio-oil followed, this was done based on the industrial standard methods. The furnace was modelled in a computer aided design (CAD) software, the design analysis and engineering drawings were prepared followed by the fabrication and instrumentation. The furnace was then tested with bio-oil and diesel fuel prior to full scale combustion study. Building on the spray study, the comparative study of bio-oil and diesel combustion at different equivalence ratio values were conducted. It was revealed that it is possible to burn neat bio-oil in a tunnel-like furnace with a self sustaining flame. Bio-oil combustion recorded higher, carbon monoxide (CO), nitrogen oxides (NOx) and hydrocarbon (HxCy) emissions when compared to those of diesel. A follow-up combustion study with oxygen enriched atomization revealed that it was possible to fire neat bio-oil with a significant reduction of pollutants emissions. ii Based on the results from this research, it can be concluded that it is possible to burn 100% biooil in an industrial sized burner. On the other hand, oxygen enriched combustion help in reducing emissions levels in the exhaust. Therefore, the use of bio-oil as fuel in an industrial scaled furnace is now possible.
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.
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.
Evaluation of maize accessions for diversity, yield and tolerance to maize lethal necrosis disease in Tanzania
(NM-AIST, 2017-12) Kabululu, Mujuni Sospeter
Maize (Zea mays L.) is among the most important crops in Tanzania with still low average yield of 1.2 metric tonnes per hectare as compared with potential yields of 4 to 5 metric tonnes per hectare. Low yield is due to a number of factors including pests and diseases. Recently, East Africa has been hard hit by a new deadly disease of maize called Maize Lethal Necrosis Disease (MLND). The disease started in Kenya in 2011 and later spread to other countries including Tanzania and it continues to spread fast in other countries. It is caused by a combination of two viruses i.e., Maize chlorotic mottle virus (MCMV) and any other Potyvirus, with Sugarcane mosaic virus (SCMV) reported for East Africa. The aim of this study was to evaluate genetic diversities of maize accessions (focusing more on landraces) with respect to their MLND resistance and optimum yield in Tanzania. Fifty one maize landraces from National Plant Genetic Resources Centre (NPGRC) in Tanzania, thirty four commercial varieties as checks for yield and thirteen elite lines from CIMMYT Kenya as checks for resistance against MLND were used. Three field experiments were conducted at Tengeru, Mlangarini and Selian in Tanzania for genetic diversity study and MLND evaluation, one field experiment was conducted at Naivasha Kenya for MLND evaluation. Molecular study was conducted at Nelson Mandela African Institution of Science and Technology in Tanzania. Significant (p < 0.05) variations were observed among the tested accessions and an OPV Situka 1 and a hybrid DH 04 were the best yielding varieties across Tengeru, Mlangarini and Selian with 116.01g and 115.90g per plant respectively. Landraces TZA 2793 and TZA 5170 were among the highest yielding accessions with 100.46g and 99.80g per plant respectively. The allele distribution and frequency associated with quantitative trait loci for SCMV resistance were detected with landraces and TZA 2793 as well as TZA 3544 expressed low MLND progression across Mlangarini and Naivasha. The results of significant genetic diversity and response against MLND of maize landraces tested in this study calls for further investigation to ascertain their utilization in breeding and crop improvement.
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.
Ecological effects of selected invasive plants and their nature based management approaches
(NM-AIST, 2017-12) Ngondya, Issakwisa Bernard
Biological invasions are one of the major threats to most ecosystems as they often suppress native plant species. This suppressive effect is usually costly and irreversible hence calling for effective management strategies that are ecologically safe and appropriate at local level. This research work aimed at assessing the ecological effects of the invasive weeds Tagetes minuta and Gutenbergia cordifolia on native vascular plants and development of the nature-based management solutions for the two invasives. To understand if T. minuta and G. cordifolia have any effects on native plant communities and soil chemistry, the study compared native vascular plant species abundance, richness, cover, height and soil chemistry of the Ngorongoro ecosystem by sampling systematically along a continuum of invasion gradient from uninvaded to highly invaded areas in the Ngorongoro crater. It further identified the most dominant co-existing native vascular plant in the field (Cynodon dactylon) that can be facilitated to out-compete the two weeds. The results indicated that the two invasive weeds decreased native species abundance, ground cover and richness while increasing native vegetation height. Soil available Phosphorus, Nitrogen, and Cation Exchange Capacity levels were also influenced by invasions of either and/or both T. minuta and G. cordifolia. The competitive effects of the observed most dominant native vascular plant (Cynodon dactylon) on the growth and development of the two weeds was tested experimentally in both screen house and field plots using a completely randomized and randomized block design respectively in order to identify the most suppressive C. dactylon density. It was observed that increasing densities of C. dactylon strongly reduced the growth and development of T. minuta and G. cordifolia. The allelopathic experiments were done in both laboratory and screen house to identify the effective Desmodium root/ leaf extract concentration that can impair the growth and germination of T. minuta and G. cordifolia as a second management approach. Generally, seedlings treated with higher D. uncinatum leaf extracts (≥62.5%) were half as tall, had one-third the weight and half the leaf chlorophyll content compared to those treated with lower concentrations. Based on the field, screen house and laboratory experiments, the suppressive effects of the two invasives are evident hence necessitating their management. Although needs to be scaled up in the field, this study has devised and tested two novel nature-based management approaches that have proven to be functional.
Optimal model formula for ensuring nutritional adequacy for infants and young children (6 – 23 months)
(NM-AIST, 2018-08) Makori, Nyabasi
Infant and young child feeding practices rank among the most effective interventions to promote child growth and development. Improving the quality of complementary food has been observed as an important strategy for promoting child growth in resource-poor settings. Therefore, the objective of this study was to design a safe and nutritious model formula that meets nutritional requirement for infants and young children aged 6 – 23 months. The objective was achieved by conducting a cross-sectional study aimed to assess the nutritional status of 394 children and identify factors associated to under-nutrition. Then, complementary flours were collected randomly from selected households and analyzed for macro- and micro-nutrients, phytate content and presence of aflatoxins. Exposure assessment was done to evaluate the contribution of aflatoxins exposure on nutritional status of children. Finally, the model formula was designed using commonly consumed foods to meet the nutritional requirements for children. Data analysis was performed by using SPSS (IBM version 21), ENA for smart, Microsoft Excel and LINDO (version 6.1). The results showed that prevalence of stunting was 40.4% (95% CI; 29.8% - 50.9%). Children aged between 12 - 23 months were more stunted compared to those aged between 6 – 11 months (p ≤ 0.001). The age of introducing complementary foods (AOR = 13.3, 95%CI, 2.6 – 67.6), maternal education (AOR = 5.5, 95% CI, 1.0 – 9.8) and residence in Chamwino district (AOR = 3.2, 95%, 1.3 – 5.9) were identified as factors associated with stunting. Analysis of cereal-based complementary foods indicated that protein and fat content ranged from 1.17 - 11.17 g/100 g and 0.61 - 11.19 g/100 g respectively. A significant difference in protein content between composite cereals and other types of complementary foods was observed (p ≤ 0.001). Sorghum had the highest iron and phytate content of 8.37 mg/100 g and 1176.8 mg respectively. Aflatoxins contamination was detected in 42.5% of home-made complementary flours at the levels ranging from 0.3 μg/kg to 2,128 μg/kg. There was a significant association between stunting and infants dietary exposure to aflatoxin B1 (p = 0.05, 95% CI; 0.019 - 0.028). Cereal-based complementary foods consumed by the studied children were observed to have dual burdens in a sense that they contained high level of phytate and being contaminated with aflatoxins to the levels of health concern that may contribute to impairment of growth. Developed optimized model formula serves as a basis for ensuring adequate nutrient intake, minimized intake of phytate and reduced dietary exposure of infants
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.
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 Zadock
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 sociodemographic 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%, p<0.001). Likewise, ERR was higher among those on repeated dose (97.54%) than on a single dose (87.27%, p=0.0062). GM epg was lower among those on repeated dose (1.30 epg) than those on single dose (3.18 epg, p=0.036). At eight months post baseline treatment, the rate of re-infection was about 83% and 77% among those on repeated and single treatments, respectively. No significant difference was observed in the prevalence of stunting between the two treatment regimens (p>0.05), with significant increase in mean haemoglobin (p<0.05) but without significant difference between treatments (p>0.05). 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.
Colorectal cancer epidemiology in Tanzania: patterns in relation to dietary and lifestyle factors
(NM-AIST, 2019-01) Kamanga, Leonard
Chronic non-communicable diseases are increasingly captured as contributing to morbidity and mortality in low and middle income countries. This study has designed to investigate the epidemiology of colorectal cancer and the potential modifiable local risk factors in Tanzania. A cross sectional retrospective chart audit study was conducted to establish the pattern and distribution of colorectal cancer, The Food Frequency Questionnaire and the Step® survey tool were used to collect data. Descriptive statistics, Chi square tests and regression analysis were employed and augmented by data visualization to display risk variable differences. Tanzania‘s colorectal cancer incidence has increased six times in the last decade in which major towns and cities of Dar es Salaam (20.2 per 100 000), Pwani (7.2 per 100 000), Kilimanjaro (4.4 per 100 000), Arusha (4.2 per 100 000) and Morogoro (3.6 per 100 000) had the highest percentage. This study reported that, almost 45% of the participants were hypertensive. Two major dietary patterns, namely ―healthy‖ and ―western‖, existed among the study sample. Obesity was found in 25% of participants, whereas overweight was present in 28%; of note, the prevalence was higher in females (26.9%) than in males (23.6%) respectively. The prevalence of alcohol consumption was 21.5%, with a significantly lower rate of smoking (12.2%) noted within the study subjects. Both alcohol consumption and tobacco smoking were more common in men than women (22.7 vs. 20.6% and 24.5 vs. 3.2%, respectively). The prevalence of vigorous, moderate, and low physical activity for both sexes was 18.6%, 54.1% and 42.3%, respectively. Evidence from this study demonstrated that, lifestyle factors, such as diet, obesity, tobacco smoking, alcohol consumption, and sedentary behaviors, have a significant role in the rising trend of non communicable diseases and colorectal cancer in Tanzania. We recommend a large longitudinal study with robust methodology which can establish cause and effect relationships between specific lifestyle behaviors and the prevalence of colorectal cancer.
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.
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.
Risk assessment for dietary exposure of pesticides among vegetables consumers in Arusha, Tanzania
(NM-AIST, 2019-03) Kiwango, Purificator 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 organochlorines (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 water, sanitation and hygiene interventionson common infections and nutritional status amongunder-five children in semi-pastoral communities, Arusha
(NM-AIST, 2019-03) Mshida, Hoyce Amini
Under-nutrition and common infections among children aged below five years in semi-pastoral communities of northern Tanzania could be contributed by poor water, sanitation and hygiene (WASH) practices. The burden of these practices to the health of children under-five years seem to be given less consideration and much focus is on curative measures, vaccination and food supplementation. WASH interventions have been reported elsewhere to reduce the problems of under-nutrition and common infections among this age group. However, no any WASH intervention done in semi-pastoral communities to reduce the problems of under-nutrition and common infections among children under-five years. This study assessed the influence of WASH interventions on common infections and nutritional status among children under-five years in semi-pastoral communities of Arusha, Tanzania. The study reviewed hospital attendance registers from Monduli and Longido District hospitals for year 2013 to 2015 to identify the existing trends of common infections among under-five children, followed by a household survey where a total of 310 mother-child pairs were randomly selected and data on child morbidity, WASH practices, cultural and socio-demographic characteristics was collected through facilitated interviews. Anthropometric measurements and hemoglobin levels of under-five children were taken. Thereafter, participants from Longido District were divided into intervention and control groups. The intervention group was provided with WASH package consisting of health education and nano-filters for filtering drinking water. The control group continued with their normal WASH practices. After six months follow up, assessment to determine the effectiveness of the interventions on diarrhea prevalence and nutritional status among under-five children was done. Samples of fresh milk ready to feed children and drinking water from storage containers were also tested to see status of E. coli in samples from the two groups. About two third of under-five patients attended the hospitals were suffering from infectious diseases. Household survey revealed that 87% of respondents did not have toilets and 96% of those with no toilets were practicing open defecation. About 12% of respondents reported washing hands with soap during critical moments while 46% of respondents reported using unsafe surface water for domestic purposes. Again, 31.6% of under-five children were stunted, 61.2% were anemic while 15.5% had suffered from diarrhea two weeks preceding survey. Children fed on complementary foods kept in calabash/kibuyu (p < 0.001) had increased risk of suffering from diarrhea. Use of surface water for domestic purposes was ii strongly associated with diarrhea, stunting and/or under-weight (p < 0.001). After intervention, incidences of diarrhea (p = 0.03) and rate of underweight (p = 0.02) were significantly reduced among under-five children when compared to those from the control group. Conclusion: Use of surface water for domestic purposes, storage of complementary foods in calabash/kibuyu, and lack of formal education among mothers of under-five children were found to contribute significantly to diarrhea and under-nutrition among this participant population. This study highlights the need for health education promotion and treatment of drinking water at the point of use to address the problems of under-nutrition and common infections among children under-five years in semi pastoral communities and similar settings.
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.
Characterization of mutations in drug resistant tuberculosis and diagnostic challenges in referral health facilities, Tanzania
(NM-AIST, 2019-03) Mnyambwa, Nicholaus Peter
Tuberculosis remains one of the world’s deadliest infectious diseases in resource-limited settings, including Tanzania. Diagnostic challenges and minimal information on resistant tuberculosis complicate building effective management strategies. The current study employed whole genome shotgun sequencing and genotyping methods to characterize genetics of drug resistant tuberculosis strains and diagnostic impedes of tuberculosis in Tanzania. A total of 134 positive sputa from collected at Central Tuberculosis Reference Laboratory from different parts of the country. Forty patients were regarded as multi-drug resistant tuberculosis (MDR-TB), of which 18 (45%) were classified as relapse cases. The remaining 94 were smear-positive culture-negative samples and treated as susceptible tuberculosis. Sequence analysis of 40 MDR-TB isolates identified a set of genetic markers (including additional variants) in the following known drug-resistant genes: katG, inhA, embCAB, ethA, inhA, rpoB, rpoC, rpsL, gyrA, eis, and pncA. Additionally, there was evidence of positive selection in other three novel genomic regions namely: ndhC, ndhI and ndhK. Sequence analysis also identified one isolate of M. yongonense, the first case to be described in Tanzania, suggesting that the patient was misdiagnosed with multi-drug resistant tuberculosis. Out of 94 smear-positive but culture negative sputa, 25 (26.60%) were GeneXpert® mycobacteria TB positive. Repeat-culture identified 11/94 (11.70) as culture positive, of which 5 were Capilia TB-Neo positive and confirmed by GenoType MTBC to be Mycobacterium tuberculosis/Mycobacterium canettii. The remaining 6 Capilia TB-Neo negative samples were typed by GenoType® CM/AS and identified 3 (3.19%) nontuberculous mycobacteria, 2 Gram positive bacteria, and 1 isolate tested negative, together, making a total of 6/94 (6.38%) confirmed false smear-positives. Overall, 28/94 (29.79%) isolates were confirmed TB cases while 60 (63.83%) remained unconfirmed tuberculosis cases. These findings on misdiagnosis and the suggestive of novel resistance-associated mutations in resistant tuberculosis emphasize the need for accurate molecular diagnostic tests for delineating the tuberculosis cases and their drug susceptibility profiles in clinical settings.

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