University of Botswana Graduate theses and dissertations http://hdl.handle.net/10311/1221 2026-07-11T06:38:27Z 2026-07-11T06:38:27Z Keagakae, Kenewang http://hdl.handle.net/10311/2471 2022-09-22T00:01:51Z 2020-10-01T00:00:00Z

Geospatial assessment of land degradation: a case study of Selebi Phikwe and Mmadinare area, Botswana Keagakae, Kenewang Botswana is one of Sub-Saharan Africa drylands that are prone to land degradation. Land degradation is among others linked to pressure from conflicting land uses and cyclical droughts. This study aimed to assess land degradation in Bobirwa sub-district in the Selebi Phikwe and Mmadinare area that has been noted to experience resource depletion. The study assessed the spatial and temporal dimensions of land degradation and its drivers over a period of 48 years (1971 to 2019), applied decrease in vegetation cover as the main indicator in addition to others such as bush encroachment. Evidence was gathered using geospatial information technology, social and biophysical surveys and from secondary data. Image classification, vegetation indices and thermal radiation were applied to detect and map land degradation as appropriate using 1971 Air photographs, 1990 Landsat Thematic Mapper (TM), 2010 Landsat 7 Enhanced Thematic Mapper Plus (ETM+) and 2019 Landsat 8 Operational Land Imager (OLI) imagery. The established evidence was integrated using Geographical Information Systems (GIS) and related to rainfall, livestock rearing, human population, and land-use pressure, especially mining activity. Four levels of degradation according to severity were established; highly degraded; moderately degraded; slightly degraded and non-degraded. Results showed that by 1971 the study was dominated by the non-degraded level of degradation but in subsequent years the area remained predominantly under moderately degraded. Highly degraded areas were confined to drainage systems and the vicinity of settled areas. These results formed the basis for modelling the likely status of land degradation by 2030. The study concluded that mining and resulting land-use pressure, especially overgrazing and deforestation intensified land degradation during periods of below-average rainfall. These findings will contribute further to the discussions on the role of human and climatic factors on the process of land degradation in semi-arid lands and the need to put in place appropriate management systems. A dissertation submitted to the Dept. of Environmental Science, Faculty of Science, University of Botswana in partial fulfillment of the requirement of the degree of Masters in Environmental Science. Citation: Keagakae, K. (2020) Geospatial assessment of land degradation: a case study of Selebi Phikwe and Mmadinare area, Botswana, University of Botswana.

2020-10-01T00:00:00Z Hafashimana, Nathanael http://hdl.handle.net/10311/2470 2022-09-22T00:01:12Z 2020-03-31T00:00:00Z

Modelling the effects of land use/cover change and rainfall variability on landslide hazards: the case of Nyabihu district, Rwanda Hafashimana, Nathanael Landslides have become the environmentally recognized hazard in hilly regions of Rwanda such as Nyabihu district. They are often characterized by the downslope movement of debris or other earth materials which damage or destroy everything found in their way such as infrastructures, croplands, and even cause a number of deaths. The intense rainfall has been noticed as the main trigger of landslides in Rwanda, together with land use/cover change. Therefore, the objectives of this study were; to assess the land cover change effects on landslide occurrences, evaluate the rainfall variability and its effects on landslide occurrences, and predict the occurrence of landslides in the study area. Land use/cover maps of 2005 and 2015 were generated and overlaid with mapped landslides. Maximum likelihood classification was used to classify the Landsat satellite images, and Mann Kendall test was used to assess the rainfall trends. The results revealed a remarkable decrease of agricultural land, while all other land use/cover types have increased along the mentioned period. It was noted that most of the landslides occurred in agricultural land. Also, areas with high rainfall were noted to have experienced more landslides than those with low rainfall. Despite the relation of rainfall to landslide occurrences, the rainfall variability over a period of time did not always correspond to the variation in landslide occurrences. The study also indicated the influence of controlling factors (such as slope, soil depth, and distance to road) on landslide occurrences. The occurrence of landslides was also predicted using logistic regression model. The model showed that an increase in slope angle increases the chances to landslide occurrences, while the changes in land use/cover, and rainfall do not necessarily imply the increase in landslide occurrences, though they significantly relate to landslide occurrences. The study results are expected to be useful for alerting landslide hazard management decisions, land use planning and management regulations so as to minimize the likely landslide occurrences and their resultant impacts. A dissertation submitted to the Dept. of Environmental Science, Faculty of Science, University of Botswana in partial fulfillment of the requirement of the degree of Masters in Environmental Science. Citation: Hafashimana, N. (2020) Modelling the effects of land use/cover change and rainfall variability on landslide hazards: the case of Nyabihu district, Rwanda, University of Botswana.

2020-03-31T00:00:00Z Kurenzvi, Lineage http://hdl.handle.net/10311/2453 2022-07-27T00:01:58Z 2020-03-01T00:00:00Z

Prevalence of cryptosporidium parvum, giardia intestinalis and molecular characterization of rotavirus assoceated with diarrhea in children below five years old in Gaborone, Botswana Kurenzvi, Lineage Background: Diarrhea remains a major cause of mortality and morbidity in children under the age of five years across the globe. In Botswana, the control of diarrheal diseases aims at reducing the burden caused by diarrhea as well as improving the quality of lives of children. Despite all these efforts, gastroenteritis is still one of the major causes of death and illnesses in young children in Botswana. To ensure the acceleration towards the reduction of diarrhea in children, recent information on pathogens causing the disease should be documented. The aim of this study was to determine the occurrence of Cryptosporidium parvum, Giardia intestinalis and molecular characteristics of rotaviruses in Botswana. Methods: A case study was carried out on 200 stool specimens from symptomatic pediatric patients and 100 asymptomatic children under the age of five years from selected hospitals and clinics in Gaborone. The Ziehl Neelsen staining technique was used for detection of Cryptosporidium parvum and wet mount procedure for detection of Giardia intestinalis. Confirmation of samples that tested negative for the parasites was done using immunochromatographic assay. The enzyme-linkedimmunosorbent assay was used to screen for rotavirus. Rotavirus electrophoretypes from ELISA positive specimens were detected by polyacrylamide gel electrophoresis. Molecular characterization of rotavirus was conducted by reverse transcriptase-polymerase chain reaction using genotype specific primers that target VP4 and VP7. Selected PCR amplicons were sequenced and analyzed by Clustal W. Distance matrices were constructed by using the Kimura 2 parameter nucleotide substitution model in MEGA 6.06. Phylogenetic analysis was carried out by utilizing the neighbor joining model with 1000 bootstrap replicates and sequences were compared with reference strains from GenBank using the Basic Local Alignment Search Tool. Results: Prevalence rates of 20.5% (41/200), 16.5% (33/200) and 11.0% (22/200) in diarrhea cases were observed for Cryptosporidium parvum, Giardia intestinalis and rotavirus, respectively. Four percent (n=8) of diarrheic specimens had multiple infections. Peak infections of G. intestinalis and C. parvum were frequently observed during hot and rainy season, while peak prevalence for rotavirus occurred in April and July. For rotavirus, long electrophoretypes occurred more frequently (56.25%) than short electrophoretypes (25%). The most G/P combination observed was GIP[8] (7/15, 46.7%) followed by G2P[4] (2/15, 13%) and G3P[8] (1/15, 7%). One mixed strain, G1+G2P[4,8], was found in 13% (2/15) of case samples. Twenty percent of the specimens were non-typeable. Phylogenetic analysis of VP4 and VP7 sequences clustered rotavirus strains from Botswana within G1 lineages 1 and 2, G3-lineage 1, P[8] lineage 3 and P[4] lineage 5 together with Southern African strains, but distantly related to Rotarix. Conclusion: This study suggests that Cryptosporidium parvum, Giardia intestinalis and rotavirus are important pathogens in the burden of diarrhea in children below the age of five years in Botswana. Rotavirus strain diversity was similar to that previously observed worldwide. Findings in this study suggests that rotavirus surveillance is an important tool to assess the impact of the ongoing vaccination program. Monitoring of circulating rotavirus strains is essential for assessment of effectiveness of current vaccines in Botswana. A dissertation submitted to the Dept. of Biological Sciences, Faculty of Science, University of Botswana in partial fulfillment of the requirement of the degree of Masters in Science (Applied Microbiology). Citation: Kurenzvi, L. (2020) Prevalence of cryptosporidium parvum, giardia intestinalis and molecular characterization of rotavirus assoceated with diarrhea in children below five years old in Gaborone, Botswana, University of Botswana.

2020-03-01T00:00:00Z Brooks, Blondie O. http://hdl.handle.net/10311/2441 2022-06-15T00:01:24Z 2020-03-01T00:00:00Z

A validated analytical method for the determination of lumefantrine in selected time modulated dried blood spot samples from malaria patients in Botswana Brooks, Blondie O. A simple liquid chromatography- diode array detector (LC-DAD) method for the determination of lumefantrine in whole blood collected in dried blood spot (DBS) filters was developed and validated. The validation was done using the United States Food and Drug Administration (USFDA) guidelines. Sample preparation was done using solid liquid extraction (SLE) followed by separation using high performance liquid chromatography (HPLC) and diode array detection (DAD). Separation was done at 25ºC using an XTerra C18 column with dimensions of 50 mm x 4.6 mm x 5μm (length x internal diameter x particle size) and a binary solvent system of acetonitrile and water adjusted to pH of 2.3 with formic acid as the mobile phase. The mobile phase was pumped at a flow rate of 0.570 mL/min using a gradient elution program. The analysis time was 2 minutes and the calibration curve obtained was linear over the concentration range of 1-8 μg/mL with a correlation coefficient (R2) of 0.9980. The limit of detection (LOD) and the lower limit of quantification (LLOQ) were 0.4 and 0.8 μg/mL respectively. The extraction efficiency estimated as percent recovery was greater than 60 %. Both the intra and inter-day precision of this method were ˂ ±15% as prescribed by the USFDA guidelines. The method was successfully applied for the quantification of lumefantrine in time modulated dried blood spot samples, previously collected from patients on malarial treatment with the artemisinin/ lumefantrine combination therapy. A dissertation submitted to the Dept. of Chemistry, Faculty of Science, University of Botswana in partial fulfillment of the requirement of the degree of Masters in Analytical Chemistry. Citation: Brooks, B.O. (2020) A validated analytical method for the determination of lumefantrine in selected time modulated dried blood spot samples from malaria patients in Botswana, University of Botswana.

2020-03-01T00:00:00Z