School-wide publications
Permanent URI for this collectionhttps://dspace.njala.edu.sl/handle/20.500.144402/140
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Item Reevaluating HLA-A2-restricted Lassa epitopes in human Lassa fever survivors(American Association of Immunologists, 2020-05-01) Sullivan, Brian MartinMany factors contribute to the selection of epitope-specific T cells. Often, candidate epitopes are generated through in silico prediction of various biological processes, mainly peptide generation and MHC binding, that are then tested in relevant biological assays. This is especially true of epitopes derived from BSL-4 pathogens or where relevant patient samples are difficult to obtain. Two previous studies identified CD8+ T cell epitopes from the Lassa virus glycoprotein through in silico prediction, experimental MHC binding assays, and epitope generation in HLA-A2 transgenic mice. Using samples from ten HLA-A\*02:01 Lassa fever survivors, we tested whether these previously described epitope-specific CD8+ T cells were present and their relation to the broader Lassa virus-specific T cell response. Using overnight stimulation assays, we detected robust LASV-specific responses to the glycoprotein and nucleoprotein, but only one of the three epitopes (GP60–68)shown to be present and protective in mice made a substantial contribution to the overall LASV-specific response. Using a more sensitive proliferation assay, we detected the remaining two epitopes in some individuals at a very low frequency. Overall, this study shows the limitations of epitope discovery through in silico prediction, MHC binding and transgenic mouse models and highlights the complex nature of T cell selection during natural infection of humans.Item A synoptic revision of Inversodicraea (Podostemaceae)(National Herbarium of the Netherlands, 2017-09-14) Cheek, MartinSix new species of Inversodicraea (I. feika from Sierra Leone, I. liberia from Liberia, and I. ebo, I. eladii, I. tchoutoi, and I. xanderi from Cameroon) are described as new to science in the context of a synoptic revision of this African genus, now comprising 30 species, including I. cussetiana comb. nov., newly transferred from Macropodiella. Inversodicraea is now equal in number of species to Ledermanniella (as redefined), as the largest genus of the family in Africa. Terete or slightly dorsiventrally flattened leaf petioles (not sheathing and/or stipulate) are newly discovered to distinguish the genus from Ledermanniella, in addition to the presence of scale-leaves. Inversodicraea boumiensis, I. annithomae, and I. bosii are redelimited in this paper. Examples of species hybrids are discussed. Eighteen species are point endemics. A key and IUCN 2012 standard conservation assessments for all species are included. 28 of the 30 species have been assessed as Threatened or Near Threatened. Hydroelectric projects are the biggest source of extinction risk to species of the genus, threatening 19 of the 30 species.Item A synopsis of Pseudovigna (Leguminosae: Papilionoideae) including a new species, P. sulaensis, from Sierra Leone(Springer Science+Business Media, 2011-12-01) Clark, R. P.Item Identification of Common CD8+T Cell Epitopes from Lassa Fever Survivors in Nigeria and Sierra Leone(American Society for Microbiology, 2020-04-06) Sakabe, SaoriThe high morbidity and mortality associated with clinical cases of Lassa fever, together with the lack of licensed vaccines and limited and partially effective interventions, make Lassa virus (LASV) an important health concern in its regions of endemicity in West Africa. Previous infection with LASV protects from disease after subsequent exposure, providing a framework for designing vaccines to elicit similar protective immunity. Multiple major lineages of LASV circulate in West Africa, and therefore, ideal vaccine candidates should elicit immunity to all lineages. We therefore sought to identify common T cell epitopes between Lassa fever survivors from Sierra Leone and Nigeria, where distinct lineages circulate. We identified three such epitopes derived from highly conserved regions within LASV proteins. In this process, we also identified nine other T cell epitopes. These data should help in the design of an effective pan-LASV vaccine.Item Cercospora leaf spot on cowpea-Sierra Leone(CAB International Publishing, 2013-09-01) Kanteh, S. M.Item Massively multiplexed microbial identification using resequencing DNA microarrays for outbreak investigation(SPIE, 2011-05-13) Łęski, Tomasz A.Multiplexed microbial diagnostic assays are a promising method for detection and identification of pathogens causing syndromes characterized by nonspecific symptoms in which traditional differential diagnosis is difficult. Also such assays can play an important role in outbreak investigations and environmental screening for intentional or accidental release of biothreat agents, which requires simultaneous testing for hundreds of potential pathogens. The resequencing pathogen microarray (RPM) is an emerging technological platform, relying on a combination of massively multiplex PCR and high-density DNA microarrays for rapid detection and high-resolution identification of hundreds of infectious agents simultaneously. The RPM diagnostic system was deployed in Sierra Leone, West Africa in collaboration with Njala University and Mercy Hospital Research Laboratory located in Bo. We used the RPM-Flu microarray designed for broad-range detection of human respiratory pathogens, to investigate a suspected outbreak of avian influenza in a number of poultry farms in which significant mortality of chickens was observed. The microarray results were additionally confirmed by influenza specific real-time PCR. The results of the study excluded the possibility that the outbreak was caused by influenza, but implicated Klebsiella pneumoniae as a possible pathogen. The outcome of this feasibility study confirms that application of broad-spectrum detection platforms for outbreak investigation in low-resource locations is possible and allows for rapid discovery of the responsible agents, even in cases when different agents are suspected. This strategy enables quick and cost effective detection of low probability events such as outbreak of a rare disease or intentional release of a biothreat agent.Item Assessment of the Quality of Newly Constructed Hand-Dug Well Usetd for Drinking and Their Treatment System at Kenema Town, Kenema District, Eastern, Sierra Leone(Science Publishing Group, 2023-05-25) Umaru, KannehThe tremendous increase in the human population increase the stress on both surface and groundwater and it is believed that at the beginning of human civilization itself, groundwater was the most trusted form of drinking water because of the filtering effect of the aquifer however, in the present world drinking water directly from the source without proper treatment is very tough and risky for the health. Kenema District is a district in the Eastern Province of Sierra Leone, its capital and largest city is Kenema City, which is the third most populous city in Sierra Leone, after Freetown and Bo Both the physical and chemical Parameters investigated are within the WHO acceptable limits, except one of bioteriological parameters (non- faecal coliform). Tables 1, 3, and 4 show high statistical mean values for the Non-Faecal Coliform bacteria in the hand dug wells. Diema Hand Dug Well (12.00 cfu/100ml), Ansarul Hand Dug Well (11.67 cfu/100ml) and the combined statistical mean value (10.78cfu/100ml) of the Non-Faecal Coliform bacteria and all the values fell out of World Health Organization (WHO) permissible limit. However, Islamic Hand Dug Well has a statistical mean value of 8.67 cfu/100ml of Non-Faecal Coliform Value which is within the WHO permissible limit (<10cfu/100ml). The combined statistical mean value for Diema, Islamic, and Ansarul hand dug well for the following physiochemical parameters (pH 7.14, Turbidity 2.46NTU, Conductivity 196.56, TDS 100.11mg, Ammonia 0.02mg/l, Nitrite 0.02mg/l, Nitrate 0.06mg/l, Phosphate 6.15mg/l, Cadmium 0.00gm/l, Copper 0.02mg/l, Iron 0.03mg/l and Zinc 2.67mg/l) are all within the World Health Organization permissible limits (Table 4). Non-faecal coliforms were discovered in all of the wells and boreholes examined and analyzed in a similar investigation to identify the bacteriological pollution of groundwater sources.Item Trends and spatial patterns of human immunodeficiency virus prevalence among men and women aged 15–49 in Sierra Leone: evidence from the 2008, 2013 and 2019 Demographic and Health Surveys(BMJ, 2025-08-01) Fornah, LovelBACKGROUND: Human immunodeficiency virus prevalence remains a major public health concern in Sierra Leone. This study examines the trends and spatial patterns of human immunodeficiency virus prevalence among men and women in Sierra Leone using data from the 2008, 2013, and 2019 Sierra Leone Demographic and Health Surveys (SLDHS). METHOD: We analyzed data from three SLDHS conducted in 2008, 2013, and 2019. Men and women aged 15-49 who tested for HIV were eligible. A trend analysis was used to examine the change in human immunodeficiency virus prevalence. Spatial autocorrelation and Moran's I statistic were used to assess the spatial distribution of human immunodeficiency virus prevalence. We used the 2019 SLDHS to determine the predictors of human immunodeficiency virus prevalence using geographically weighted regression. RESULTS: The study found that human immunodeficiency virus prevalence was 1.5% in 2008, 1.3% in 2013 and 1.7% in 2019. From 2008 to 2019, human immunodeficiency virus prevalence in the Western and Northwest regions increased, with a consistent rise in the Southern region and an increase in the Northern regions. We identified hotspots for human immunodeficiency virus prevalence in Koinadugu, Kono, Bo and Kailahun districts. In 2008 and 2013, the Kono district had the highest human immunodeficiency virus prevalence, while the western areas, Port Loko and Bombali districts had the highest risk in 2019. Our geographically weighted regression analysis indicated that, age 15-19, urban residence and no formal education were predictors of HIV prevalence in 2019. CONCLUSION: The human immunodeficiency virus prevalence across different districts is inconsistent, with Western areas having a higher prevalence while Southern and Northern regions showed varying trends. Hotspot regions were identified, with changes in high-risk areas over time. Predictors of human immunodeficiency virus prevalence in hotspot areas include age 15-19, urban residents and no formal education. The study suggests the need for prevention and intervention programmes for these high-risk areas and groups to reduce human immunodeficiency virus transmission in Sierra Leone.Item Evaluation of the Healthcare Waste Management at 34 Military Hospital, Sierra Leone(Science Publishing Group, 2025-07-16) Lebbie, SahrThe rapid growth of the world population and corresponding rapid global development in medicine have caused an increase in the amount of healthcare waste generated in health facilities, hence causing many problems for the public health and environment of many communities. Healthcare waste management is an integral part of the hygiene and infection control within a healthcare facility because its mismanagement leads to nosocomial infections. The specific objectives of this research were to identify types of healthcare waste segregation, to evaluate the degree of safety of healthcare handlers, to know the quantity of healthcare waste, and to know methods of treatment and disposal. Results from the study showed that the calculated volumes of the non-infectious (general), infectious (including pathological waste), and highly infectious (sharps) are 20,000 m3, 35,000m3 and 13,125m3 respectively, and a total volume of 68,125 m3 of healthcare waste is generated per week. These wastes were not segregated properly and were treated together in an enclosed incinerator with no proper measures. Statistical tests done showed that the quantity of wastes and the safety practices of service providers are associated with a high risk of infection. This showed that the public health and the environment can be negatively impacted. Furthermore, the government and its partners are making some effort to see an improvement in healthcare waste management at 34 Military Hospital; however, healthcare waste is still a major problem for healthcare providers, patients, public health, and the environment. Notwithstanding, various measures are needed to be considered in order to minimize these problems, including proper education and training for healthcare providers, provision of standard waste management equipment, consulting foreign expertise, adhering to color-coding according to INWMP, and public education.Item Construction and Testing of Solar Drying System as an Alternative to Sun Drying(2025-02-12) Massaquoi, Ibrahim**Background:** The traditional practice of sun-drying food grains has been utilised since ancient times, taking advantage of the sun as a primary energy source. However, sun drying presents challenges due to the relatively modest intensity of sunlight at the Earth's surface and the risks posed by pests and environmental factors. **Method:** This study involved the construction of a solar dryer measuring 4 ft by 2 ft, designed as a hygienic, environmentally friendly alternative to open sun drying. A comparative drying experiment was conducted using a 7.0 kg mass of pepper, which was dried simultaneously in the solar dryer and through traditional sun drying methods. During the five days, temperature and weight loss were measured at various intervals in both drying environments. **Results:** The data revealed that, on average, the temperature inside the solar dryer exceeded the ambient temperature by 25°C, representing a 46.1% increase. This significant temperature differential demonstrates the effectiveness of the solar dryer in enhancing the drying process. **Conclusion:** The findings indicated that the solar dryer provides a safe and clean method for food drying and considerably improves drying efficiency compared to traditional sun drying. This approach represented a promising alternative to food preservation practices.