4 research outputs found
The Study of the Effects of Mau Catchment Degradation on the Flow of the Mara River, Kenya
There is growing concern however, regarding land degradation in the Mara River Basin in Kenya, particularly deforestation in the headwaters; that is affecting the natural resource base and the river flows. Scientific studies are required to advise on policy issues, and to plan appropriate mitigation measures in the basin. This study utilized remote sensing and geographical information system (GIS) tools, and hydrological and ground-truth studies to determine the magnitude of the land-use/cover changes in the Mara River Basin, and the effects of these changes on the river flows over the last 30 years. The results of the studies indicate that land-use/cover changes have occurred in the basin. In 1973, for example, rangelands (savannah, grasslands and shrublands) covered 10,989 km2 (79%) of the total basin area. The rangelands have now been reduced to 7,245 km2 (52%) by 2000. The forest areas have been reduced by 32% over the same period. These changes have been attributed to the encroachment of agriculture, which has more than doubled (203%) its land area over the same period. To investigate the effects of land cover change on river flow, stream flow was generated from derived land cover thematic maps of 1973 and 2000 using the same rainfall and evaporation data of 1983 to 1992 period. The other model input datasets for topography and soils were held constant during the two runs. The differences in the generated hydrographs could only be associated to the changes in land cover, which was the only variable. The percentage difference between the mean annual stream flows of the two hydrographs was negligible at 0.01%. This study therefore concludes that land cover changes in the basin have changed the day to day flow characteristics of the Mara river but the annual flow volumes remain unaffected. There is need for urgent action to stem the land degradation of the Mara River Basin, including planning and implementing appropriate mitigation measures. Keywords: SWAT model, Mara River Basin, Hydrological Modelling, River Discharge
The Impacts of Water Abstraction in Tropical Rivers: A Case of South West Upper Tana Basin, Kenya.
The study to determine the impacts of water abstraction in South West Upper Tana Basin which is part of the larger Upper Tana basin was undertaken in four major rivers, Thika, Kimakia, Kiama and Chania. Data for this study was obtained from the Kenya Meteorological department (KMD), Water Resources Management (WRA) and questionnaire surveys. The questionnaires were administered in the period between January 2018 and December 2018 to determine the impacts of water abstraction in both dry and wet seasons. Regression and correlation analysis was used to determine the nature and strength of relationships between different variables. The results of the study indicate that the main impacts of water abstraction are hydrological, environmental and socio-economic. The hydrological impacts include reduced water levels, changes in stream morphology, decreased turbidity and reduced siltation. Socio-economic impacts include increased income from crop production and conflicts while environmental impacts were mainly changes in riparian vegetation. The study established that the best combination of impacts of water abstraction in the South West Upper Tana Basin were changes in water turbidity, decline in water levels, improved crop yields, changes in channel morphology and siltation with a coefficient correlation r of 0.57 and coefficient of determination R2 of 0.52. To mitigate these impacts, there is a need for better enforcement of legislations on water abstraction and the monitoring of the river basins to curb water over-abstraction. Public awareness campaigns and involvement of stakeholders could also minimize these impacts. Keywords: Water abstraction, hydrological impacts, socio-economic impacts, environmental impacts, South West Upper Tana Basin (SWUT). DOI: 10.7176/JEES/9-5-08 Publication date:May 31st 201
High-risk human papillomavirus prevalence in self-collected cervicovaginal specimens from human immunodeficiency virus (HIV)-negative women and women living with HIV living in Botswana.
BACKGROUND:The prevalence of high-risk human papillomavirus (hrHPV) is poorly described overall and in women living with HIV (WLWH) and HIV-negative women living in Botswana, a high HIV and cervical cancer-burden country. We conducted a pilot study of self-collection and high-risk HPV testing for cervical screening, from which data on HPV prevalence was available. METHODS:From five health facilities in the Kweneng East District, 1,022 women aged 30-49 years were enrolled to self-collect their cervicovaginal specimen for hrHPV testing by the Xpert HPV Test (Cepheid, Sunnyvale, CA, USA). Crude and age group-adjusted hrHPV prevalence by HIV status were calculated, and the relationship of hrHPV risk groups HPV16>HPV18/45>other hrHPV types) to the presence and severity of visible lesions. RESULTS:Of the 1,022 women enrolled, 1,019 (99.7%), 570 WLWH and 449 HIV-negative women, had hrHPV testing results. Crude hrHPV prevalences were 25.2% (95%CI = 21.2-29.4%) for HIV-negative women and 40.4% (95%CI = 36.3-44.5%) for WLWH. Age group-adjusted hrHPV prevalences were 23.7% (95%CI = 19.9-27.9%) for HIV-negative women and 41.3% (95%CI = 37.2-45.4%) for WLWH. Age group-adjusted prevalences of HPV16 (p<0.001), HPV18/45 (p<0.001), HPV31/33/35/52/58 (p<0.001), and HPV39/56/66/68 (p = 0.011) were greater among WLWH than HIV-negative women. Riskier hrHPV groups were more likely to have visible abnormalities (ptrend = 0.004) and visible abnormalities not eligible for cryotherapy (ptrend = 0.030). CONCLUSIONS:hrHPV infection was common among all women in the study living in Botswana, to a greater extent in WLWH than their HIV-negative counterparts. Strategies to triage hrHPV-positive women will be needed to avoid over-treating many women with benign hrHPV infections
Misdiagnosis of HIV treatment failure based on clinical and immunological criteria in Eastern and Central Kenya
Abstract Background Routine laboratory monitoring is part of the basic care package offered to people living with the Human Immunodeficiency Virus (PLHIV). This paper aims to identify the proportion of PLHIVs with clinical and immunological failure who are virologically suppressed and risk being misclassified as treatment failures. Methods A retrospective analysis of patient viral load data collected between January 2013 and June 2014 was conducted. Of the patients classified as experiencing either clinical or immunological failure, we evaluated the proportion of true (virological) failure, and estimated the sensitivity and specificity of the immunological and clinical criteria in diagnosing true treatment failure. Results Of the 27,418 PLHIVs aged 2–80 years on ART in the study period, 6.8% (n = 1859) were suspected of treatment failure and their viral loads analysed. 40% (n = 737) demonstrated viral suppression (VL < 1000 copies/ml). The median viral load (VL) was 3317 copies/ml (IQR 0–47,547). Among the 799 (2.9%) PLHIVs on ART classified as having clinical failure, 41.1% (n = 328) of them had confirmed viral suppression. Of the 463 (1.7%) classified as having immunological failure, 36.9% (n = 171) had confirmed viral suppression. The sensitivity of the clinical criteria in diagnosing true failure was 61% (CI 58%–65%) while that of the immunological criteria 38% (CI 35%–42%). The specificity of the clinical criteria was 34% (CI 30%–39%) while that of the immunological criteria 66% (61%–70%). Age below 20 years was associated with a high viral load (p < .001). Sex and ART regimen were not associated with the viral load. Conclusion Clinical and immunological criteria alone are not sufficient to identify true treatment failure. There is need for accurate treatment failure diagnosis through viral load testing to avoid incorrect early or delayed switching of patients to second-line regimens. This study recommends increased viral load testing in line with the Kenya’s ART guidelines