Department of Biological Sciences
Permanent URI for this collectionhttps://dspace.njala.edu.sl/handle/20.500.144402/136
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Item Discovering Karima (Euphorbiaceae), a New Crotonoid Genus from West Tropical Africa Long Hidden within Croton(Public Library of Science, 2016-04-06) Cheek, MartinCroton scarciesii (Euphorbiaceae-Crotonoideae), a rheophytic shrub from West Africa, is shown to have been misplaced in Croton for 120 years, having none of the diagnostic characters of that genus, but rather a set of characters present in no known genus of the family. Pollen analysis shows that the new genus Karima belongs to the inaperturate crotonoid group. Analysis of a concatenated molecular dataset combining trnL-F and rbcL sequences positioned Karima as sister to Neoholstia from south eastern tropical Africa in a well-supported clade comprised of genera of subtribes Grosserineae and Neoboutonieae of the inaperturate crotonoid genera. Several morphological characters support the relationship of Karima with Neoholstia, yet separation is merited by numerous characters usually associated with generic rank in Euphorbiaceae. Quantitative ecological data and a conservation assessment supplement illustrations and descriptions of the taxon.Item Specialization in ethnomedicinal plant knowledge among herbalists in the forest region of Rivercess County, Liberia(Academic Journals, 2017-04-10) Lebbie, Aiah R.The ethnomedicinal uses of plants reported by 22 herbalists in the Rivercess County of Liberia show a rich knowledge of medicinal plant usage for both common and less common health problems. We set out with the objectives of documenting the ethnomedicinal plant knowledge and assessing gender differences in the use of the plants by male and female herbalists. Through semi-structured interviews conducted with herbalists, a total of 112 species belonging to 52 families in 93 genera were recorded to be in use. Seven plant families were known to account for 43.9% of the total number of species utilized including Annonaceae, Apocynaceae, Costaceae, Rubiaceae, Euphorbiaceae, Fabaceae and Verbenaceae. Traditional herbalists comprising male (64%) and female (36%) possessed extensive knowledge of the use of these plants, with male and female herbalists showing specializations in several categories of health problems based on their knowledge of medicinal plants. Female herbalists possessed a slightly higher knowledge of ethnomedicinal plants than male herbalists. Many ailments were reported with a large number of the plants utilized for malaria, snakebites, ulcer, spiritual/witchcraft, infection and diarrhoea. New and unrecorded ethnomedicinal uses for several plants were documented, including Tetraberlinia tubmaniana J. Léonard, Delpydora gracilis A.Chev., Campylospermum subcordatum (Stapf) Farron, Cyathula prostrata Blume, Heisteria parvifolia Sm., Keetia rufivillosa (Robyns ex Hutch. & Dalz.) Bridson, Pavetta sonjae W.D.Hawth., Chrysophyllum pentagonocarpum Engl. & K.Krause, Placodiscus pseudostipularis Radlk, and the naturalized plant, Caladium bicolor (Aiton) Vent. Further documentation of this knowledge is recommended, with the goal of assessing gender differences in the use of medicinal plants in Liberia. Key words: Ethnomedicine, medicinal plants, herbalists, remedies, Liberia.Item Ledermanniella yiben sp. nov. (Podostemaceae), Critically Endangered at the proposed Yiben Reservoir, Sierra Leone(Springer Science+Business Media, 2017-06-01) Cheek, MartinIn the course of a botanical baseline survey for the proposed Yiben Hydroelectric Dam on the Seli River, upriver of the Bumbuna Dam, Sierra Leone, in April 2016, the second and third authors encountered a species of Podostemaceae, van der Burgt 1992. The plants were scattered densely along the gneissic rock bed of the river, then at its seasonal lowest level, largely dry, and with only a small channel of moving water, it being the end of the dry season. The plants were 20 – 50 cm diameter, spaced at distances of up to 50 cm apart from each other, with bare gneissic base rock in between, and appear restricted to the vicinity of a single set of rapids.Item Lebbiea (Podostemaceae-Podostemoideae), a new, nearly extinct genus with foliose tepals, in Sierra Leone(Public Library of Science, 2018-10-05) Cheek, MartinLebbiea grandiflora (Podostemaceae), a rheophytic herb from the Sewa River rapids in Sierra Leone, is described as a new species. It is the first new African genus of Podostemaceae published for 30 years. First collected in May 2017, the species is assessed as Critically Endangered using the IUCN 2012 standard. It is on the edge of extinction with a small population at a single site threatened by deposition of gravel and sand from alluvial gold and diamond mining upstream, and a planned hydro-electric dam. The new genus is unique in Podostemaceae in a) its highly developed and robust style-stigma structure in which the bases of the two style-stigmas unite to form a bifurcate funneliform-cylindrical structure, with a reflexed, blade-like apex that extends half-way around the perimeter of the ovary-fruit towards the base of the ovary-fruit, b) a specialised andropodium, with robust, self-supporting capacity, having differentiated thickened central, and angled, thinner marginal areas (in other Podostemaceae the andropodial structures are undifferentiated), c) the pillar-like haptera which completely elevate the crustose root above the substrate. Lebbiea is placed in Podostemoideae, necessitating amplification of the delimitation of that subfamily in which it is additionally unique in having the foliose tepals characteristic of the basal subfamilies Weddellinoideae and Tristichoideae.Item Development of in vitro propagation protocol for some recalcitrant cassava (Manihot esculenta Crantz) genotypes in Sierra Leone(Academic Journals, 2018-05-02) Sesay, Janatu VeronicaA study on rapid propagation of cassava through tissue culture was conducted with three elite cassava genotypes: Slicass 6, Slicass 11 and Cocoa from Sierra-Leone. They showed slow growth in Murashige & Skoog (MS) basal medium which was proven to be optimal for a vast number of cassava accessions. Prior to mutation induction, a large population needs to be produced for mutagen susceptibility test and for mutant population development. The ultimate objective of this study was to investigate the effects of plant growth regulators on the shoot development of three cassava genotypes. In vivo shoot tips were sterilized and sub-cultured on MS media supplemented with six combinations of plant growth regulators (PGRs) at different concentrations. The results showed that from all media used, the MS medium with 1.0 mg/L α-naphthalene acetic acid (NAA) showed the best response for rooting (5.50), fresh weight (0.29 g), root number (10.00) and plantlet height (3.81 cm), while 0.1 mg/L 6-benzylaminopurine (BAP) was found to be more favourable to shoot development of leaves (6.38). The highest plant height and fresh weight were 3.81 cm and 0.29 g, respectively for Cocoa at 1.0 mg/L α-naphthalene acetic acid (NAA), 10.00 roots for Slicass 6 at 1.0 mg/L, 6.37 leaf numbers for Slicass 11 at 0.1 mg/L 6-benzylaminopurine (BAP) and 5.6 at 1.0 and 1.5 mg/L α-naphthalene acetic acid (NAA). These observations indicate that a supplement of 0.1 mg/L 6-benzylaminopurine (BAP) in MS medium can be useful in propagation of recalcitrant cassava and low concentration of α-naphthalene acetic acid (NAA) will be beneficial in root induction prior to acclimatization with promotion in recovery of the ex vitro plants before field assessment. Key words: Cassava, Manihot esculenta, propagation, shoot tip, 6-benzylaminopurine (BAP), α-naphthalene acetic acid (NAA).Item Isolation of Angola-like Marburg virus from Egyptian rousette bats from West Africa(Nature Portfolio, 2020-01-24) Amman, Brian RMarburg virus (MARV) causes sporadic outbreaks of severe Marburg virus disease (MVD). Most MVD outbreaks originated in East Africa and field studies in East Africa, South Africa, Zambia, and Gabon identified the Egyptian rousette bat (ERB; Rousettus aegyptiacus) as a natural reservoir. However, the largest recorded MVD outbreak with the highest case-fatality ratio happened in 2005 in Angola, where direct spillover from bats was not shown. Here, collaborative studies by the Centers for Disease Control and Prevention, Njala University, University of California, Davis USAID-PREDICT, and the University of Makeni identify MARV circulating in ERBs in Sierra Leone. PCR, antibody and virus isolation data from 1755 bats of 42 species shows active MARV infection in approximately 2.5% of ERBs. Phylogenetic analysis identifies MARVs that are similar to the Angola strain. These results provide evidence of MARV circulation in West Africa and demonstrate the value of pathogen surveillance to identify previously undetected threats.Item Predicting the adoption of improved cassava varieties in Sierra Leone(Academic Journals, 2021-02-15) Sesay, Janatu VeronicaIn Sierra Leone cassava plays a major role in households’ food and income security. Plant breeders have concentrated on improved varieties with an increasing yields per unit area. This study was designed to identify factors that influence adoption or rejection of improved cassava cultivars by growers. Data were collected using questionnaires, focus group discussions and field walks; locations were selected using multistage stratified random sampling. Logistic regression was used to model uptake of improved varieties. Most farmers usually grow several cultivars and just over half have included an improved variety. Of the six improved varieties released in 2005 by the Sierra Leone Agricultural Research Institute, only SLICASS 4, was widely adopted and three were not recorded in the study. Preferred characteristics are; high yield, sweet taste, early maturity and good cooking quality. Cultivars are more likely to be adopted where; cassava is a major crop, households are experienced in cultivating cassava, they have access to research, contact with extension agents and access to cassava markets. Improved cultivars are less likely to be adopted by small households with few resources. Cassava breeders should recognize what farmers find desirable but success will depend on; communicating research, having active extension agents and good access to markets. Key words: Adoption, improved varieties, cassava, Sierra Leone.Item The use of condoms and other birth control methods among sexually active school-going adolescents in nine sub-Saharan African countries(BioMed Central, 2022-12-16) James, Peter BaiBACKGROUND: Adolescents in sub-Saharan Africa still face sexual and reproductive health challenges. Contraceptives have been used to address these challenges. Despite efforts at national and global levels, contraceptive uptake among young people in Africa remains a challenge due to personal, societal, and health systems-based barriers. We estimated the prevalence and correlates of condom use and other birth control methods among sexually active school-going adolescents in nine sub-Saharan African (SSA) countries. METHODS: We conducted a secondary analysis of the Global School-based Student Health Surveys (GSHS) datasets pooled from nine SSA countries. We included a sample of 27,504 school-going adolescents 11 years and younger and 18 years and older. We employed meta-analysis using a random-effects model to estimate the total prevalence of the use of condoms, other birth control methods other than a condom and any birth control method at last sexual intercourse. We conducted complex sample descriptive and logistic regression analyses to determine the characteristics and determinants of not using condoms and other birth control methods among sexually active school-going adolescents in nine sub-Saharan African countries, respectively. RESULTS: More than half \[n = 4430, 53.8% (43.9-63.8)\], two-fifth \[n = 3242, 39.5% (33.2-45.9) and two-thirds of adolescents \[n = 4838, 65.6% (57.5-73.7)\] of sexually active in school adolescents across the nine sub-Saharan African countries used condom, other birth control methods and any form birth control method during their last sexual intercourse, respectively. The non-use of condoms at last sex was associated with being younger (less than 16 years) \[AOR = 1.48;95%CI: 1.12-1.94\], early sexual debut \[AOR = 1.81(1.47-2.22)\], having two or more sexual partners \[AOR = 1.30(1.06-1.58)\] and no/minimal parental support \[AOR = 1.54(1.17-2.03)\]. The non-use of other birth control methods at last sex was associated with being male \[AOR = 1.37 (1.09-1.73)\], early sexual debut \[AOR = 1.83(1.48-2.27) and having no parental support \[AOR = 1.64(1.34-2.00)\]. CONCLUSION: Contraceptive need among sexually active school adolescents in the nine sub-Saharan African countries is high. Such a need calls for the development of country-specific and or the review of existing school-based sexual health education and youth-friendly sexual and reproductive health interventions that target risky adolescents and promote adolescent-parent effective communication, connectedness and support.Item Sexual risk behaviour among school-going adolescents in Sierra Leone and Liberia: a secondary analysis of the 2017 Global school-based student health surveys(BioMed Central, 2022-12-24) James, Peter BaiBACKGROUND: Sierra Leone and Liberia have experienced civil wars and, recently, Ebola outbreaks that led to profound economic hardship, psychopathologies and family disruptions. These factors are associated with sexual risk behaviours among youths. However, there is very little information on sexual risk behaviour among Sierra Leonean and Liberian school-going adolescents. The present study assessed the prevalence and determinants of sexual risk behaviours among school-going adolescents (10-19 years) in Sierra Leone and Liberia. METHOD: We used publicly available nationally representative cross-sectional datasets of the 2017 Sierra Leone and Liberia Global school health survey. The sample consisted of 2798 and 2744 school-going adolescents from Sierra Leone and Liberia, respectively. Complex sample descriptive and regression analysis was used to analyse our data. RESULTS: The majority of adolescents in the two countries were involved in multiple sexual risk behaviour (80.2%), with a higher prevalence observed in Sierra Leone (85.2%) than in Liberia (75.3%). Liberian adolescents showed lesser odds of indulging in multiple sexual risk behaviours than their Sierra Leonean counterparts (AOR = 0.572; 95%CI: 0.345-0.946). Male, compared to females, were more likely to engage in multiple sexual risk behaviour (AOR = 2.310;95%CI:1.543-3.458), with a similar pattern observed in both countries. Alcohol use was associated with multiple sexual risk behaviour (AOR = 3.064; 95%CI: 2.137-4.392). Also, in Sierra Leone and Liberia, adolescents with one and two or more forms of psychological distress were more likely to have ever had sex than those who did not show any form of psychological distress. Missing class/school was associated with multiple sexual risk behaviour (AOR = 1.655; 95%CI:1.133-2.418). Peer support was only found to be a protective factor against no condom use among Liberian adolescents (AOR = 0.608; 95%CI: 0.435-0.850). Less parental support was only associated with ever had sex among adolescents in Sierra Leone (AOR = 2.027; 95%CI: 1.322-3.107) but not in Liberia (AOR = 1.034; 95%CI: 0.650-1.644). CONCLUSION: Our study found a high sexual risk behaviour among school-going adolescents in Sierra Leone and Liberia. Our finding highlights the need to strengthen sexual and reproductive health education in schools and communities that incorporate mental health promotion activities tailored to this group.Item Knowledge, Attitudes and Practices Assessment on Bat-Borne Zoonotic Diseases Among the People of Moyamba District, Sierra Leone(Dove Medical Press, 2023-07-01) Williams, Samuel Maxwell Tom**Background:** Bats are considered wildlife species of public health concern, as they are known to host various pathogenic agents, and their interactions with humans are potential routes of pathogen spillover. A high level of knowledge on Bat-borne Zoonotic Diseases (BZD), their causative agents, signs, symptoms, mode and pattern of transmission, health attitudes, and practices towards the disorders are vital parameters in handling them. This study aimed to look into BZD knowledge, public attitudes, and behaviour. **Methods:** We surveyed the 14 chiefdoms of Moyamba district. A total of 421 participants were randomly sampled using closed-ended questionnaire. Simple linear regression analysis was used to determine the effects of gender, age, education, and livelihood opportunities on BZD knowledge (at 95% confidence interval and alpha value = 0.05). The findings were analysed and correlated with a scientific and public health perspective to assess the breadth of knowledge and awareness of BZD among the people of Moyamba district. **Results:** The findings from the study show a low level of knowledge on BZD among the people of the Moyamba district, with only 119 (28.3%) individuals that had some knowledge about BZD. Of those that knew about BZD, 94 (79.0%) had very little knowledge, 24 (20.2%) had a fair amount, and 1 (0.8%) had a great deal of knowledge about BZD. The primary mode of knowledge dissemination was through social media platforms. **Conclusion:** The level of knowledge about BZD is also very low. As a result of these findings, policymakers, health professionals, and environmental educators will be compelled to develop strategies to reduce the risk of BZD transmission in Sierra Leone's population.