Tephritid fruit flies are considered one of the world’s most notorious pests of horticultural crops, including mango (Mangefera indica L.) in Sierra Leone, causing extensive direct and indirect damage. A survey was c...Tephritid fruit flies are considered one of the world’s most notorious pests of horticultural crops, including mango (Mangefera indica L.) in Sierra Leone, causing extensive direct and indirect damage. A survey was conducted among 60 mango farmers in 7 districts in Sierra Leone between June and August, 2022, to assess their perceptions regarding fruit fly pest status and the current management options adopted for the control of this pest. Semi-structured questions designed in an open and closed-ended fashion were used for the study. The majority (83%) of the farmers were already aware of the fruit fly problem in the country with 62% perceiving it to be very severe. The majority (60%) of farmers, however, demonstrated poor knowledge of identifying fruit fly species, especially Bactrocera dorsalis, Ceratitis capitata, and Ceratitis cosyra. Farmers were more conversant about the direct damage symptoms to host fruits and the economic impact of fruit flies. A total of 32% of growers took no action to control fruit flies on their farms. Sixty-nine percent (69%) of the farmers adopted cultural control measures, like practicing prompt harvesting, collection and disposal of infested fruits, and weeding to maintain better sanitary conditions on their farms. Recommended fruit fly management strategies such as the use of botanicals and resistant varieties were either unknown or inaccessible to growers. A total of 52% applied chemicals that were not recommended for the control of fruit flies without considering their environmental and health risks. It is important to train fruit growers to improve their capabilities for fruit fly management through extension agents that are appropriate for helping them acquire basic knowledge of fruit fly pests and their management.展开更多
Background: Waste management in Western Area Rural (WAR), Sierra Leone, is plagued by infrastructural and socioeconomic challenges, leading to environmental and health hazards such as flooding, air pollution, and vect...Background: Waste management in Western Area Rural (WAR), Sierra Leone, is plagued by infrastructural and socioeconomic challenges, leading to environmental and health hazards such as flooding, air pollution, and vector-borne diseases. Despite awareness campaigns, informal methods like open dumping and burning dominate. This study applies the Theory of Planned Behaviour (TPB) to analyse how attitudes, subjective norms, and perceived behavioural control influence waste management practices and barriers to proper disposal with potential solutions. Methods: A quantitative approach was employed, using stratified random sampling and structured questionnaires to collect data from 333 participants across ten communities in Western Area Rural (WAR). Data were analyzed using descriptive and inferential statistics to examine the relationship between socio-demographic variables and waste management practices. Results: While 98.2% of respondents acknowledged the importance of waste management, limited perceived behavioural control driven by financial constraints (83.8%), inadequate education (83.2%), and insufficient infrastructure (66.4%) hindered effective waste disposal ultimately linking health and environmental risks, such as flooding and marine pollution from plastic waste. Most respondents (68.8%) lacked access to formal waste services, with disposal occurring primarily via open dumping (62.9%) and burning (17.9%). Subjective norms reinforced informal disposal, as community waste-burning remained an accepted practice. Women were disproportionately affected due to economic constraints and larger household sizes. Despite these challenges, 93.1% were willing to engage in community clean-up efforts, indicating strong pro-environmental attitudes constrained by structural barriers. Conclusion: Findings underscore the need for integrated waste management strategies informed by TPB, targeting attitudes through education, reshaping social norms through community-driven initiatives, and enhancing perceived behavioural control by improving infrastructure and financial accessibility. Addressing gender disparities, strengthening public-private partnerships, and expanding recycling and composting programs can foster sustainable waste management in resource-constrained settings.展开更多
Bemisia tabaci is a polyphagous herbivore that feeds on a wide range of horticultural and ornamental crops cultivated under diverse ecological zones. In Sierra Leone, B. tabaci is found to infest a wide range of veget...Bemisia tabaci is a polyphagous herbivore that feeds on a wide range of horticultural and ornamental crops cultivated under diverse ecological zones. In Sierra Leone, B. tabaci is found to infest a wide range of vegetable crops by directly feeding on phloem sap thereby inducing physiological disorders, and also serve as a vector to gemini viruses. Invariably the destructive feeding of B. tabaci affects the productivity and aesthetic values of vegetables and other horticultural crops and hence is considered a serious economic pest. A bioassay experiment was carried out by rearing B. tabaci populations on four vegetable crops under controlled laboratory conditions to determine its life table and demographic parameters. Results showed that the intrinsic rate of growth which measures the population size and growth pattern was highest for populations reared on tomato crops with the following values: rm 0.145 female female−1 day−1, the gross reproduction rate (Ro), and finite growth rate λ were highest for population reared on tomato, correspondingly the development period from egg-adult emergence was shortest with a value of 26 d. Conversely, the computed demographical parameters rm, λ and Ro for the population reared on sweet pepper were 0.106 female female−1 day−1 respectively, with a corresponding development period egg-adult emergence as 36d. The computed biological parameters for okra and garden egg varied with intermediary values between tomato and pepper host materials. The survivorship rates were quite significant for the smaller instars (Instars 1-III) with over 80% surviving to pre-pupa and pupa stage for the populations reared for all the test materials. High mortality was noticed for the pre-pupa and pupa stages as their survival rates were significantly low compared to the high survival rates of the smaller instars. Less than 50% of pupae failed to emerge to adults except for populations reared on tomato test materials where 52% emerged to adults. The study indicated tomato as the most suitable host among the four vegetable crops. Although life table and demographic parameters are invaluable information for forecasting pest populations and help in designing pest management efforts, further investigations such as the economic threshold and economic injury levels of B. tabaci population are requisite decision tools for sound pest management decisions of B. tabaci on these vegetable crops. The information obtained from this investigation would be quite relevant for extension service and pest management practitioners where mixed vegetable farming is a common practice.展开更多
Objective People in Western Africa suffer greatly from febrile jaundice, which is caused by a variety of pathogens. However, yellow fever virus(YFV) is the only pathogen under surveillance in Sierra Leone owing to the...Objective People in Western Africa suffer greatly from febrile jaundice, which is caused by a variety of pathogens. However, yellow fever virus(YFV) is the only pathogen under surveillance in Sierra Leone owing to the undeveloped medical and public health system there. Most of the results of YFV identification are negative. Elucidation of the pathogen spectrum is required to reduce the prevalence of febrile jaundice. Methods In the present study, we used Ion Torrent semiconductor sequencing to profile the pathogen spectrum in archived YFV‐negative sera from 96 patients in Sierra Leone who presented with unexplained febrile jaundice. Results The most frequently identified sequencing reads belonged to the following pathogens: cytomegalovirus(89.58%), Epstein‐Barr virus(55.21%), hepatitis C virus(34.38%), rhinovirus(28.13%), hepatitis A virus(20.83%), coxsackievirus(10.42%), Ebola virus(8.33%), hepatitis E virus(8.33%), lyssavirus(4.17%), leptospirosis(4.17%), chikungunya virus(2.08%), Crimean‐Congo hemorrhagic fever virus(1.04%), and hepatitis B virus(1.04%). Conclusion The distribution of sequencing reads suggests a broader spectrum of pathogens for consideration in clinical diagnostics and epidemiological surveillance in Sierra Leone.展开更多
The impact of summer cattle grazing on water quality during three very different climatic years in the Sierra Nevada was investigated. Water year 2009 had near normal precipitation;2010 had late precipitation and snow...The impact of summer cattle grazing on water quality during three very different climatic years in the Sierra Nevada was investigated. Water year 2009 had near normal precipitation;2010 had late precipitation and snowmelt;and 2011 had 150% above normal precipitation. Surface waters were tested for pathogenic bacteria indicators fecal coliform, E. coli, and total coliform before and after cattle were released onto summer grazing allotments. Water samples were collected from meadow stream sites up to 6 weeks before and up to 6 weeks after cattle grazing began. Streams passing through ungrazed meadow served as controls. Eight sample sites were between 1694 m and 2273 m in elevation;one site was lower at 1145 m in elevation. Samples were transported within 6 hours to a water analysis laboratory, where samples were analyzed following standardized laboratory methods. Results showed that individual site and total mean concentrations of E. coli in surface waters were within regulatory standards before cattle arrived during each of the 3 study years. After the beginning of grazing, mean E. coli counts increased as follows: 2009 from 8 to 240 CFU/100mL, 2010 from 7 to 561 CFU/10mL;2011 from 7 to 657 CFU/100mL (p < 0.05 all years). Total coliform bacteria and fecal coliform concentrations showed the same pattern. This study shows that cattle grazing in the high elevation Sierra Nevada results in a significant increase in indicator bacteria. This impact on the watersheds occurs despite widely variable annual climatic conditions.展开更多
Ebola virus disease reemerged in Western Africa in 2014.Chinese Center for Disease Control and Prevention dispatched the first Ebola virus（EBOV）detection team to run newly established Sierra Leone-China Friendship B...Ebola virus disease reemerged in Western Africa in 2014.Chinese Center for Disease Control and Prevention dispatched the first Ebola virus（EBOV）detection team to run newly established Sierra Leone-China Friendship Biological Safety Laboratory.The aims of study were to understand epidemiology,clinical manifestations and survival time of EBOV in patient＇s blood.A total of 913specimens were tested between March 11 and April20, 2015. EBOV positivity occurred in 7.37% of the blood and 0.53% in throat swabs.展开更多
Food safety, nutrition, health and wellbeing are inextricably linked. This study investigated the environmental, awareness and practices amongst both food vendors and consumers in and around Freetown the capital of Si...Food safety, nutrition, health and wellbeing are inextricably linked. This study investigated the environmental, awareness and practices amongst both food vendors and consumers in and around Freetown the capital of Sierra Leone. The population of the area has vastly out-grown the infrastructure laid down before and since independence. De-centralization of authority to local councils as recommended post-war has only been partial. The role of local versus central government in the planning and maintenance of water, sanitation and market-infrastructure and related policies was explored. This is a qualitative study that used semi-structured interviews with vendors, consumers and 29 key informants. Amongst an estimated population of 5386 actors in food services a sample size of 309 vendors, consumers in and around the 12 busiest market hubs in Western Area Urban and Rural Districts were sampled. Most of the respondents described “food safety” as “good-to-eat, well taken care-off, and free from germs”. The respondents cited that main causes to unsafe food are poor hygienic practices: 38%, contamination by flies: 28%, uncovered food/ improper handling/poor personal hygiene: 21%, and environmental factors, such as improper refuse disposal: 11%. Respondents expressed that consuming unsafe foods can lead to diarrhoea: 34%, food poisoning: 24%, vomiting: 17%, stomach ache/pain: 16%, or typhoid: 9%. Various measures to improve food safety were cited as hand washing: 60%, cleaning surroundings: 57%, covering food: 56%, washing utensils: 52%, covering hair: 42% and using a face mask: 32%. However almost 76% of food vendors interviewed were trading near gutters, where muddy/dirty water settled, with slippery floors, discarded plastic waste, flies and inadequate water, sanitation, and/or storage facilities. None of the food vendors had had any formal training on food safety. Despite progress recently made in solid and liquid waste management during the “Transform Freetown” agenda much more improvement in infrastructure and behaviour change is required. Similarly, despite improvements in formal market facilities the pattern of informal street trading remains the most prevalent especially for the poor. The link between “safe food” and good health was only partially understood, whilst the widespread application of recommended practices to reduce risks was lacking due in part to inadequate infrastructure. As the importance of food safety becomes better understood by administrators and the public the investments required in infrastructure and social and behavioural change will contribute towards a healthier environment and outcomes.展开更多
Ensuring availability and sustainable management of water and sanitation for all by 2030 is Goal 6 of the Sustainable Development Goals (SDGs). Since developing countries especially in Africa would struggle to meet th...Ensuring availability and sustainable management of water and sanitation for all by 2030 is Goal 6 of the Sustainable Development Goals (SDGs). Since developing countries especially in Africa would struggle to meet this target, this study was conceived. Hence, the study was designed to assess the water quality for physiochemical parameters around a mined out site in southern Sierra Leone with the view to determine their levels, determine related associations among indicators and explore environmental forensic options. A finite population correction factor was used to identify fifty (50) groundwater sources from one hundred and fifty two (152) in nine (9) sections of Moriba Town, in Moyamba District, Sierra Leone which constitute the sample size. The study assessed sixteen (16) physical and chemical indicators across the defined boundary of the sample size. Results indicated that almost 80% of all the indicators were in good agreement with water quality standards with the exception of three. Turbidity correlated strongly with , Al and ?and almost all other indicators did not show meaningful association. High values with significant variance of water quality indicators of physical to chemical ratio were observed for pH, temperature, electrical conductivity (EC) and total dissolved solids (TDS) but no such observation was noted for turbidity. On the whole, the water quality was judged to be good, although more pro active actions were encouraged by the local people and the mining company so as to reduce contamination in some areas.展开更多
Food safety and hygiene practices require a multisectoral approach including food, water, sanitation, waste management, transport, education, trade, policies and programs that enable safe food preparation, storage and...Food safety and hygiene practices require a multisectoral approach including food, water, sanitation, waste management, transport, education, trade, policies and programs that enable safe food preparation, storage and service. Unsafe food can cause illness keeping people from achieving their full potential and death. This was a descriptive study that uses a mixed method approach to derive insights into the characteristics of food vendors related to demography, knowledge, practices, infrastructure, compliance and recommendation for a policymaking framework. Using the Lemeshows’ sample size formula, 473 vendors from formal (restaurants) and informal (cookri-baffa/table top) sites were interviewed and observed. We found from discussions that respondents had a good understanding on how to keep food safe. However, observed practices were poor 93% handled food with their bare hands, 83% did not cover their hair, and 76% did not wear an apron whilst handling, preparing or serving food, 61% did not keep their finger nails clean or short and 57% did not wash their hand before preparing or serving food. Over half (51%) had access to a toilet but 32% reported their use required payment and emphasized their poor condition/inadequate management. Nearly half (47%) of the vending sites did not have a handwashing facility, with soap and water available. Only 7% reported having any authority oversight of food safety. Food safety and hygiene practices in most cookri shops and restaurants was ‘poor’ with very limited surveillance system in place by competent authorities for compliance of food operators. Hand washing, clean surroundings, and covered food were the most common and emphasized practices to mitigate the risks associated with unsafe food.展开更多
The soil resources of Sierra Leone remain an integral part of sustainable agricultural development but knowledge of the suitability of soils and their management requirements for a variety of land uses is still lackin...The soil resources of Sierra Leone remain an integral part of sustainable agricultural development but knowledge of the suitability of soils and their management requirements for a variety of land uses is still lacking to a greater extent. In this view, a detailed soil survey of three chiefdoms in Northern Sierra Leone was undertaken to evaluate the genesis of soils and interpret soil-landscape properties and their relationships using the toposequence and free style approach of soil survey. Three major soil types, viz, gravelly, gravel-free over gravel and gravel-free soils, formed either directly or indirectly from weathered and disintegrated parent materials of two geologic origins namely Rokel River Series (comprising of sandstone, shale and mudstone), and Granite and Acid Gneiss were identified. The gravelly soils are formed from sandstone and sandy shales of the Rokel River Series, which upon weathering released iron and hydrated oxides that hardened into plinthite upon drying. The gravel-free over gravel soils are formed from acid gneiss containing acid and intermediate igneous and metamorphic rocks, which upon weathering produced sandy clay textured soils whereas the gravel-free soils are derived from sedimentary rocks (shales and mudstones) of Rokel River Series, which upon weathering and action of organisms produced sandy clay loam and sandy clay textured soils. The gravel-free over gravel soils are mostly located in the summit and back slopes and show dark brown to dark yellowish-brown hue and moderate chroma, weak to moderate structure and absence of coarse fragments in the 0 - 40 cm layer, and a strong brown hue and high chroma, very weak fine angular blocky structure having abundance of coarse fragments from 40 cm and above. In these soils, the compactness of ironstone and sandstone gravels increases with depth. The gravel-free soils are found on three landscape positions, viz, back slopes, foot slopes and toe slopes. On the back and foot slopes, the soils are characterized by very dark brown to dark yellowish-brown hue and high chroma, sandy loam to sandy clay texture, coarse angular to moderate sub-angular blocky structure and absence of coarse fragments throughout the horizon. In these soils, the clay content and sand grain sizes were observed to increase with depth. On the toe slopes, the soils show black to greyish-brown hue and low chroma, silty loam to sandy loam, structureless and high water holding capacity.展开更多
Rainfall and temperature are the important variables that are often used to trace climate variability and change. A Perception study and analysis of climatic data were conducted to assess the changes in rainfall and t...Rainfall and temperature are the important variables that are often used to trace climate variability and change. A Perception study and analysis of climatic data were conducted to assess the changes in rainfall and temperature and their impact on crop production in Moyamba district, Sierra Leone. For the perception study, 400 farmers were randomly selected from Farmer-Based Organizations (FBOs) in 4 chiefdoms and 30 Agricultural Extension Workers (AWEs) in the Moyamba district were purposely selected as respondents. Descriptive statistics and Kendall’s test of concordance was used to analyze the data collected from the farmers and AEWs. Data for the analysis of variability and trends of rainfall and temperature from 1991 to 2020 were obtained from the Sierra Leone Meteorological Agency and Njala University and grouped into monthly, seasonal and annual time series. Regression analyses were used to determine the statistical values and trend lines for the seasonal and annual time series data. The Mann-Kendall test and Sen’s Slope Estimator were used to analyze the significance and magnitude of the trends respectively. The results of both studies show evidence of climate change in the Moyamba district. A substantial number of farmers and AEWs perceived a decrease in the annual rainfall amount, length of the rainy season, a late start and end of the rainy season, an increase in the temperature during the day and night, and a shortened harmattan period over the last 30 years. Analysis of the meteorological data shows evidence of variability in the seasonal and annual distribution of rainfall and temperature, a decreasing and non-significant trend in the rainy season and annual rainfall and an increasing and significant trend in seasonal and annual temperature from 1991 to 2020. However, the observed changes in rainfall and temperature by the farmers and AEWs partially agree with the results of the analyzed meteorological data. The majority of the farmers perceived that;adverse weather conditions have negatively affected crop production in the district. Droughts, high temperatures, and irregular rainfall are the three major adverse weather events that farmers perceived to have contributed to a substantial loss in the yields of the major crops cultivated in the district. In response to the negative effects of adverse weather events, a substantial number of farmers take no action due to their lack of knowledge, technical or financial capacity to implement climate-sensitive agricultural (CSA) practices. Even though few farmers are practicing some CSA practices on their farms, there is an urgent need to build the capacity of farmers and AEWs to adapt to and mitigate the negative impacts of climate change. The most priority support needed by farmers is the provision of climate-resilient crop varieties whilst the AEWs need training on CSA practices.展开更多
Slash-and-burn agriculture is the common practice for upland rice intercropping system in Sierra Leone and it has been blamed for the loss of forest vegetation across the country. Shortening of the fallow period in th...Slash-and-burn agriculture is the common practice for upland rice intercropping system in Sierra Leone and it has been blamed for the loss of forest vegetation across the country. Shortening of the fallow period in the Eastern region of Sierra Leone has implications on agricultural food production and the persistence of the remaining tropical rainforest. This study was therefore undertaken to assess: 1) the extent of reduction of the fallow period in the Nongowa Chiefdom of Kenema District;2) the causes of reduction in the fallow period;3) farmers’ perception of the relevance of fallow period and the implications of reduction of fallow period on crop production. The study revealed a drastic reduction of the fallow period in the chiefdom with a mean of 3.8 years which falls far below the country mean fallow period of 8.8 years as estimated by FAO. Farmers pointed out that the reduction of the fallow period was as a result of land scarcity due to competing land uses such as large scale commercial agriculture, logging, mining, charcoal burning and expansion of settlements. Farmers agreed that a fallow period of at least 10 years is necessary for upland rice production. Farmers were aware of the impact of reduction of the fallow period on upland rice production and were able to estimate rice yields based on the age of the fallow. Also, farmers have attempted to adapt to the constraints posed by shorter fallow periods by selection of rice varieties to suit the length of the fallow periods.展开更多
Lassa Fever is endemic to the eastern region of Sierra Leone. It is a haemorrhagic disease that is often transmitted from rats to humans and then human to humans. Ecological disturbances such as changes in land use in...Lassa Fever is endemic to the eastern region of Sierra Leone. It is a haemorrhagic disease that is often transmitted from rats to humans and then human to humans. Ecological disturbances such as changes in land use involving conversion of natural ecosystems to agriculture, mining or for urban expansion are reported to bring humans into close contact with animals such as the Mastomys rat that carries the Lassa Fever virus thereby posing health problems.The nature and extent of such ecological disturbances or land use changes within areas known to be endemic to Lassa Fever are not clearly understood from a research context in Sierra Leone. This study was therefore undertaken to identify the pattern of changes in land use and cropping practices and their potential to bring humans into close interactions with the Mastomys rat that is the host for the Lassa Fever virus. Four communities were chosen for the study, two rural (Lalehun and Majihun) and two urban (Lambayama section in Kenema City and Largo Square section in Segbwema Town). Different vegetation and land use/cropping practices were identified and observations were made on the pattern of changes at different times in the cropping year. There were four common vegetation and cropping practices found in all communities: upland rice intercropping, old fallow, young fallow, and swamp rice cultivation. The study revealed the variations in land use patterns and cropping practices between urban and rural settlements. Agro-forestry practices such as perennial cash crops cacao and rubber plantations were more common in rural communities. The study also revealed that while fallow vegetation persisted in rural areas there had been expansion of settlements into old fallow vegetation indicating a greater threat to the persistence of natural ecosystem in urban than in rural settlements. These disturbances resulted in habitat fragmentation and increased the likelihood of contact between humans and animal species (e.g. Mastomys rat) associated with various habitats.展开更多
This paper examines the potential contribution of the fisheries sector to national economic development in Sierra Leone, following the cessation of the recent Ebola virus disease (EVD). The tragic deaths of some 4000 ...This paper examines the potential contribution of the fisheries sector to national economic development in Sierra Leone, following the cessation of the recent Ebola virus disease (EVD). The tragic deaths of some 4000 persons, as a direct result of this epidemic, have also been accompanied by serious economic disruption to one of the world’s poorest countries, amounting to a loss of over USD 1 billion (20 per cent of annual Gross Domestic Product, GDP). Based on recent work undertaken by the New Partnership for Africa’s Development (NEPAD), an assessment was made of the potential contribution of one of the country’s major natural resource sectors—fisheries—to future economic recovery. It was confirmed that the fish resources of Sierra Leone have an estimated capitalised economic value of USD 735 million, and could potentially make an increased contribution to GDP under suitable conditions, over and above the current estimated level of 10 per cent. However, our results also show that with an overall “readiness assessment” score of 41/100, the sector is unlikely to realise its full potential unless a number of specific areas are addressed (based on analysis valid up to January 2016). These include an improvement in fisheries economic assessment, the upgrading of the fisheries governance and management framework, and the establishment of a fisheries development strategy and implementation plan to channel future investments and interventions in an appropriate sequence. Particular attention should be given early on to an increase in the quality and capacity of both public and private sector organisations relevant to roles and functions within a general process of fisheries sector reform. Finally, the fisheries policy evaluation approach used here is novel. While it has been applied to Sierra Leone for the intrinsic interest of that case, this demonstration also shows that it could be applied elsewhere in the future when reviewing fisheries policy.展开更多
In a bid to enhance the integrity and health of selected network of ecosystems and effectively manage them in Sierra Leone, a baseline assessment of butterfly diversity of two wetland ecosystems Mamunta Mayosso Wildli...In a bid to enhance the integrity and health of selected network of ecosystems and effectively manage them in Sierra Leone, a baseline assessment of butterfly diversity of two wetland ecosystems Mamunta Mayosso Wildlife Santuary (MMWS) and Sierra Leone River Estuary (SLRE) affected by different environmental stressors was undertaken as part of the Sierra Leone Wetland Conservation Project (SLWCP). We hypothesised that different environmental stressors affect butterfly communities in wetlands in Sierra Leone and the higher the stress the lower the butterfly diversity in an area. Sampling was conducted via field identification by wing patterns, flight mode, direct counts along transects and charaxes trapping. A total of 2300 individuals representing 95 species of butterflies were recorded. Though butterflies were evenly distributed at both sites, MMWS recorded the highest richness and abundance of butterflies during both seasons. This observation is reported to be because of high environmental stressors such as mining, agriculture and pollution from factories in the SLRE. The results further show that MMWS is made up of a mosaic of different vegetation patches that support higher diversity of butterfly species. This study also reveals that anthropogenic activities have a negative impact on butterfly diversity.展开更多
In this study,the Radio Direction Finding method is proposed for the detection of electromagnetic signals,in the VLF band,to try to anticipate the occurrence of potentially destructive geophysical events.The experimen...In this study,the Radio Direction Finding method is proposed for the detection of electromagnetic signals,in the VLF band,to try to anticipate the occurrence of potentially destructive geophysical events.The experimentation concerns the interception of electromagnetic anomalies in Sierra Leone,in the five-day time window,associated with seismic events that could potentially generate tsunamis.The area of investigation is Sierra Leone,whose coastline is subjected to tidal wave hazards triggered by earthquakes generated in the Mid-Atlantic Ridge.Although Sierra Leone is not affected by recurrent earthquakes,there is nevertheless a low probability,estimated at 2 percent,of the occurrence of destructive earthquakes in the next 50 years.Also in estimates,the risk of rogue and potentially damaging waves is estimated to strike the Sierra Leone coast at least once in the next 10 years.The Radio Direction Finding experiment carried out continuously 24/7,has shown a close relationship between increased radio-anomalies,in the frequencies of 6,000 Hz,a time window between electromagnetic anomaly detection and the imminence of an earthquake,and higher frequency times for the risk of earthquake occurrence in the Mid-Atlantic Ridge.展开更多
This study aimed to investigate the serological characteristics of Ebola virus(EBOV) infection during the late phase of the Ebola outbreak in Sierra Leone. In total, 877 blood samples from 694 suspected Ebola virus di...This study aimed to investigate the serological characteristics of Ebola virus(EBOV) infection during the late phase of the Ebola outbreak in Sierra Leone. In total, 877 blood samples from 694 suspected Ebola virus disease(EVD) cases assessed from March to December 2015, were analyzed via real-time reverse transcription polymerase chain reaction(RT-PCR) for viral RNA and enzyme-linked immunosorbent assay(ELISA) and Luminex to detect antibodies against EBOV. Viral load and EBOV-specific IgM/IgG titers displayed a declining trend during March to December 2015. Viral RNA load decreased rapidly at earlier stages after disease onset, while EBOV-specific IgM and IgG still persisted in 58.1%(18/31) and 93.5%(29/31) of the confirmed EVD patients and in 3.8%(25/663) and 17.8%(118/663) of the RNA-negative suspected patients in the later phase, respectively. Dynamic analysis of longitudinally collected samples from eight EVD patients revealed typically reversed trends of declining viral load and increasing IgM and/or IgG titers in response to the EBOV infection.The present results indicate that certain populations of Sierra Leone developed immunity to an EBOV infection in the late phase of the outbreak, providing novel insights into the risk assessment of EBOV infections among human populations.展开更多
Indiscriminate disposal of solid waste in dumpsites located within urban areas has proved to be a problem to nearby residents in most developing cities of the world, Freetown is no exception. Open dumps have environme...Indiscriminate disposal of solid waste in dumpsites located within urban areas has proved to be a problem to nearby residents in most developing cities of the world, Freetown is no exception. Open dumps have environmental safeguards;they can pose major public health threats and environmental effects in urban cities. Therefore, this paper presents the findings of a research carried out in Freetown municipal area in Sierra Leone to determine the environmental and health impacts of solid waste disposal at Granville Brook dumpsite on the surrounding human settlements. Data were collected from three hundred and ninety eight nearby dumpsite household residents (less than fifty metres) and two hundred and thirty three far away household residents (more than fifty metres) through the use of structured self-administered questionnaires. Interviews and personal observations were also used to collect some of the data. Descriptive statistics involving tables, graphs and figures were used to present and analyze the data. Results show that both nearby residents and far away residents suffered from related diseases such as malaria, chest pains, diarrhea and cholera, due to the location of the dumpsite closer to their settlements. As a result, this study highlights the need for the Freetown City Council to properly manage and relocate the dumpsite to a safe distance from all human settlements, and provide resettlement and environmental education programmes for all persons living less than fifty metres away from the dumpsite as interim measures.展开更多
Understanding the hydrologic budget is crucial in planning for community based water supply. The water budget includes rainfall intensity, groundwater recharge, interception, evapotranspiration, and surface runoff. Th...Understanding the hydrologic budget is crucial in planning for community based water supply. The water budget includes rainfall intensity, groundwater recharge, interception, evapotranspiration, and surface runoff. The percentage of rain going to recharge groundwater, rivers, and lakes is very important from the standpoint of human water consumption and ecosystems service. The objective of this work is to determine the recharge potential of groundwater in the Mokonde Community, Southern Sierra Leone. The community is dependent on wells as the main source of domestic water supply. This research need was born out of the absence of available data to show the relationship between rainfall amounts and groundwater recharge in the study area. In this study we monitored groundwater in a well at the United Methodist Church (UMC) compound at Ngegba Street. Automatic water logging devices were deployed to take readings in water level fluctuations every 15 minutes. Monitoring continued throughout the hydrological year of Sierra Leone. A rain gauge was deployed at neighboring UMC Primary School, and daily rainfall records taken at 9:00 a.m. Our team members also deployed at the well on a daily basis to collect data on abstraction of water. The results revealed, through a 29-year rainfall data and the Specific Yield, that 1170 mm of rainfall (48%) was the maximum potential of rainfall that would make groundwater a convenient source of water supply in the area. This demand was higher with the recent 1-year rainfall data. Increase in settlement had likely led to reduction in pervious area, and hence more and more rainfall needed for recharge. The time it took for maximum recharge (4 weeks) was shorter than that for maximum discharge (28 - 30 weeks). Groundwater flowed southwards towards the Gbengitay stream, which drained into the Tia River. These results would inform first step in delineating the water balance in the study area. Future studies could include the quality aspect, stream/river flow, interception and evapotranspiration. These pieces of information are required to help informed decision for water security.展开更多
文摘Tephritid fruit flies are considered one of the world’s most notorious pests of horticultural crops, including mango (Mangefera indica L.) in Sierra Leone, causing extensive direct and indirect damage. A survey was conducted among 60 mango farmers in 7 districts in Sierra Leone between June and August, 2022, to assess their perceptions regarding fruit fly pest status and the current management options adopted for the control of this pest. Semi-structured questions designed in an open and closed-ended fashion were used for the study. The majority (83%) of the farmers were already aware of the fruit fly problem in the country with 62% perceiving it to be very severe. The majority (60%) of farmers, however, demonstrated poor knowledge of identifying fruit fly species, especially Bactrocera dorsalis, Ceratitis capitata, and Ceratitis cosyra. Farmers were more conversant about the direct damage symptoms to host fruits and the economic impact of fruit flies. A total of 32% of growers took no action to control fruit flies on their farms. Sixty-nine percent (69%) of the farmers adopted cultural control measures, like practicing prompt harvesting, collection and disposal of infested fruits, and weeding to maintain better sanitary conditions on their farms. Recommended fruit fly management strategies such as the use of botanicals and resistant varieties were either unknown or inaccessible to growers. A total of 52% applied chemicals that were not recommended for the control of fruit flies without considering their environmental and health risks. It is important to train fruit growers to improve their capabilities for fruit fly management through extension agents that are appropriate for helping them acquire basic knowledge of fruit fly pests and their management.
文摘Background: Waste management in Western Area Rural (WAR), Sierra Leone, is plagued by infrastructural and socioeconomic challenges, leading to environmental and health hazards such as flooding, air pollution, and vector-borne diseases. Despite awareness campaigns, informal methods like open dumping and burning dominate. This study applies the Theory of Planned Behaviour (TPB) to analyse how attitudes, subjective norms, and perceived behavioural control influence waste management practices and barriers to proper disposal with potential solutions. Methods: A quantitative approach was employed, using stratified random sampling and structured questionnaires to collect data from 333 participants across ten communities in Western Area Rural (WAR). Data were analyzed using descriptive and inferential statistics to examine the relationship between socio-demographic variables and waste management practices. Results: While 98.2% of respondents acknowledged the importance of waste management, limited perceived behavioural control driven by financial constraints (83.8%), inadequate education (83.2%), and insufficient infrastructure (66.4%) hindered effective waste disposal ultimately linking health and environmental risks, such as flooding and marine pollution from plastic waste. Most respondents (68.8%) lacked access to formal waste services, with disposal occurring primarily via open dumping (62.9%) and burning (17.9%). Subjective norms reinforced informal disposal, as community waste-burning remained an accepted practice. Women were disproportionately affected due to economic constraints and larger household sizes. Despite these challenges, 93.1% were willing to engage in community clean-up efforts, indicating strong pro-environmental attitudes constrained by structural barriers. Conclusion: Findings underscore the need for integrated waste management strategies informed by TPB, targeting attitudes through education, reshaping social norms through community-driven initiatives, and enhancing perceived behavioural control by improving infrastructure and financial accessibility. Addressing gender disparities, strengthening public-private partnerships, and expanding recycling and composting programs can foster sustainable waste management in resource-constrained settings.
文摘Bemisia tabaci is a polyphagous herbivore that feeds on a wide range of horticultural and ornamental crops cultivated under diverse ecological zones. In Sierra Leone, B. tabaci is found to infest a wide range of vegetable crops by directly feeding on phloem sap thereby inducing physiological disorders, and also serve as a vector to gemini viruses. Invariably the destructive feeding of B. tabaci affects the productivity and aesthetic values of vegetables and other horticultural crops and hence is considered a serious economic pest. A bioassay experiment was carried out by rearing B. tabaci populations on four vegetable crops under controlled laboratory conditions to determine its life table and demographic parameters. Results showed that the intrinsic rate of growth which measures the population size and growth pattern was highest for populations reared on tomato crops with the following values: rm 0.145 female female−1 day−1, the gross reproduction rate (Ro), and finite growth rate λ were highest for population reared on tomato, correspondingly the development period from egg-adult emergence was shortest with a value of 26 d. Conversely, the computed demographical parameters rm, λ and Ro for the population reared on sweet pepper were 0.106 female female−1 day−1 respectively, with a corresponding development period egg-adult emergence as 36d. The computed biological parameters for okra and garden egg varied with intermediary values between tomato and pepper host materials. The survivorship rates were quite significant for the smaller instars (Instars 1-III) with over 80% surviving to pre-pupa and pupa stage for the populations reared for all the test materials. High mortality was noticed for the pre-pupa and pupa stages as their survival rates were significantly low compared to the high survival rates of the smaller instars. Less than 50% of pupae failed to emerge to adults except for populations reared on tomato test materials where 52% emerged to adults. The study indicated tomato as the most suitable host among the four vegetable crops. Although life table and demographic parameters are invaluable information for forecasting pest populations and help in designing pest management efforts, further investigations such as the economic threshold and economic injury levels of B. tabaci population are requisite decision tools for sound pest management decisions of B. tabaci on these vegetable crops. The information obtained from this investigation would be quite relevant for extension service and pest management practitioners where mixed vegetable farming is a common practice.
基金supported by grants from the National Key Research and Development Plan of China [2016TFC1202700,2016YFC1200903,and 2017YFC1200503]the China Mega‐Project for Infectious Disease [2017ZX10302301‐004,2017ZX100101,and 2017ZX10104001]
文摘Objective People in Western Africa suffer greatly from febrile jaundice, which is caused by a variety of pathogens. However, yellow fever virus(YFV) is the only pathogen under surveillance in Sierra Leone owing to the undeveloped medical and public health system there. Most of the results of YFV identification are negative. Elucidation of the pathogen spectrum is required to reduce the prevalence of febrile jaundice. Methods In the present study, we used Ion Torrent semiconductor sequencing to profile the pathogen spectrum in archived YFV‐negative sera from 96 patients in Sierra Leone who presented with unexplained febrile jaundice. Results The most frequently identified sequencing reads belonged to the following pathogens: cytomegalovirus(89.58%), Epstein‐Barr virus(55.21%), hepatitis C virus(34.38%), rhinovirus(28.13%), hepatitis A virus(20.83%), coxsackievirus(10.42%), Ebola virus(8.33%), hepatitis E virus(8.33%), lyssavirus(4.17%), leptospirosis(4.17%), chikungunya virus(2.08%), Crimean‐Congo hemorrhagic fever virus(1.04%), and hepatitis B virus(1.04%). Conclusion The distribution of sequencing reads suggests a broader spectrum of pathogens for consideration in clinical diagnostics and epidemiological surveillance in Sierra Leone.
文摘The impact of summer cattle grazing on water quality during three very different climatic years in the Sierra Nevada was investigated. Water year 2009 had near normal precipitation;2010 had late precipitation and snowmelt;and 2011 had 150% above normal precipitation. Surface waters were tested for pathogenic bacteria indicators fecal coliform, E. coli, and total coliform before and after cattle were released onto summer grazing allotments. Water samples were collected from meadow stream sites up to 6 weeks before and up to 6 weeks after cattle grazing began. Streams passing through ungrazed meadow served as controls. Eight sample sites were between 1694 m and 2273 m in elevation;one site was lower at 1145 m in elevation. Samples were transported within 6 hours to a water analysis laboratory, where samples were analyzed following standardized laboratory methods. Results showed that individual site and total mean concentrations of E. coli in surface waters were within regulatory standards before cattle arrived during each of the 3 study years. After the beginning of grazing, mean E. coli counts increased as follows: 2009 from 8 to 240 CFU/100mL, 2010 from 7 to 561 CFU/10mL;2011 from 7 to 657 CFU/100mL (p < 0.05 all years). Total coliform bacteria and fecal coliform concentrations showed the same pattern. This study shows that cattle grazing in the high elevation Sierra Nevada results in a significant increase in indicator bacteria. This impact on the watersheds occurs despite widely variable annual climatic conditions.
基金supported by a China Mega-Project for Infectious Disease(2011ZX10004-101,2012ZX10004215)Major Program of the National Natural Science Foundation of China(81590763)a SKLID Development Grant(2012SKLID102)
文摘Ebola virus disease reemerged in Western Africa in 2014.Chinese Center for Disease Control and Prevention dispatched the first Ebola virus（EBOV）detection team to run newly established Sierra Leone-China Friendship Biological Safety Laboratory.The aims of study were to understand epidemiology,clinical manifestations and survival time of EBOV in patient＇s blood.A total of 913specimens were tested between March 11 and April20, 2015. EBOV positivity occurred in 7.37% of the blood and 0.53% in throat swabs.
文摘Food safety, nutrition, health and wellbeing are inextricably linked. This study investigated the environmental, awareness and practices amongst both food vendors and consumers in and around Freetown the capital of Sierra Leone. The population of the area has vastly out-grown the infrastructure laid down before and since independence. De-centralization of authority to local councils as recommended post-war has only been partial. The role of local versus central government in the planning and maintenance of water, sanitation and market-infrastructure and related policies was explored. This is a qualitative study that used semi-structured interviews with vendors, consumers and 29 key informants. Amongst an estimated population of 5386 actors in food services a sample size of 309 vendors, consumers in and around the 12 busiest market hubs in Western Area Urban and Rural Districts were sampled. Most of the respondents described “food safety” as “good-to-eat, well taken care-off, and free from germs”. The respondents cited that main causes to unsafe food are poor hygienic practices: 38%, contamination by flies: 28%, uncovered food/ improper handling/poor personal hygiene: 21%, and environmental factors, such as improper refuse disposal: 11%. Respondents expressed that consuming unsafe foods can lead to diarrhoea: 34%, food poisoning: 24%, vomiting: 17%, stomach ache/pain: 16%, or typhoid: 9%. Various measures to improve food safety were cited as hand washing: 60%, cleaning surroundings: 57%, covering food: 56%, washing utensils: 52%, covering hair: 42% and using a face mask: 32%. However almost 76% of food vendors interviewed were trading near gutters, where muddy/dirty water settled, with slippery floors, discarded plastic waste, flies and inadequate water, sanitation, and/or storage facilities. None of the food vendors had had any formal training on food safety. Despite progress recently made in solid and liquid waste management during the “Transform Freetown” agenda much more improvement in infrastructure and behaviour change is required. Similarly, despite improvements in formal market facilities the pattern of informal street trading remains the most prevalent especially for the poor. The link between “safe food” and good health was only partially understood, whilst the widespread application of recommended practices to reduce risks was lacking due in part to inadequate infrastructure. As the importance of food safety becomes better understood by administrators and the public the investments required in infrastructure and social and behavioural change will contribute towards a healthier environment and outcomes.
文摘Ensuring availability and sustainable management of water and sanitation for all by 2030 is Goal 6 of the Sustainable Development Goals (SDGs). Since developing countries especially in Africa would struggle to meet this target, this study was conceived. Hence, the study was designed to assess the water quality for physiochemical parameters around a mined out site in southern Sierra Leone with the view to determine their levels, determine related associations among indicators and explore environmental forensic options. A finite population correction factor was used to identify fifty (50) groundwater sources from one hundred and fifty two (152) in nine (9) sections of Moriba Town, in Moyamba District, Sierra Leone which constitute the sample size. The study assessed sixteen (16) physical and chemical indicators across the defined boundary of the sample size. Results indicated that almost 80% of all the indicators were in good agreement with water quality standards with the exception of three. Turbidity correlated strongly with , Al and ?and almost all other indicators did not show meaningful association. High values with significant variance of water quality indicators of physical to chemical ratio were observed for pH, temperature, electrical conductivity (EC) and total dissolved solids (TDS) but no such observation was noted for turbidity. On the whole, the water quality was judged to be good, although more pro active actions were encouraged by the local people and the mining company so as to reduce contamination in some areas.
文摘Food safety and hygiene practices require a multisectoral approach including food, water, sanitation, waste management, transport, education, trade, policies and programs that enable safe food preparation, storage and service. Unsafe food can cause illness keeping people from achieving their full potential and death. This was a descriptive study that uses a mixed method approach to derive insights into the characteristics of food vendors related to demography, knowledge, practices, infrastructure, compliance and recommendation for a policymaking framework. Using the Lemeshows’ sample size formula, 473 vendors from formal (restaurants) and informal (cookri-baffa/table top) sites were interviewed and observed. We found from discussions that respondents had a good understanding on how to keep food safe. However, observed practices were poor 93% handled food with their bare hands, 83% did not cover their hair, and 76% did not wear an apron whilst handling, preparing or serving food, 61% did not keep their finger nails clean or short and 57% did not wash their hand before preparing or serving food. Over half (51%) had access to a toilet but 32% reported their use required payment and emphasized their poor condition/inadequate management. Nearly half (47%) of the vending sites did not have a handwashing facility, with soap and water available. Only 7% reported having any authority oversight of food safety. Food safety and hygiene practices in most cookri shops and restaurants was ‘poor’ with very limited surveillance system in place by competent authorities for compliance of food operators. Hand washing, clean surroundings, and covered food were the most common and emphasized practices to mitigate the risks associated with unsafe food.
文摘The soil resources of Sierra Leone remain an integral part of sustainable agricultural development but knowledge of the suitability of soils and their management requirements for a variety of land uses is still lacking to a greater extent. In this view, a detailed soil survey of three chiefdoms in Northern Sierra Leone was undertaken to evaluate the genesis of soils and interpret soil-landscape properties and their relationships using the toposequence and free style approach of soil survey. Three major soil types, viz, gravelly, gravel-free over gravel and gravel-free soils, formed either directly or indirectly from weathered and disintegrated parent materials of two geologic origins namely Rokel River Series (comprising of sandstone, shale and mudstone), and Granite and Acid Gneiss were identified. The gravelly soils are formed from sandstone and sandy shales of the Rokel River Series, which upon weathering released iron and hydrated oxides that hardened into plinthite upon drying. The gravel-free over gravel soils are formed from acid gneiss containing acid and intermediate igneous and metamorphic rocks, which upon weathering produced sandy clay textured soils whereas the gravel-free soils are derived from sedimentary rocks (shales and mudstones) of Rokel River Series, which upon weathering and action of organisms produced sandy clay loam and sandy clay textured soils. The gravel-free over gravel soils are mostly located in the summit and back slopes and show dark brown to dark yellowish-brown hue and moderate chroma, weak to moderate structure and absence of coarse fragments in the 0 - 40 cm layer, and a strong brown hue and high chroma, very weak fine angular blocky structure having abundance of coarse fragments from 40 cm and above. In these soils, the compactness of ironstone and sandstone gravels increases with depth. The gravel-free soils are found on three landscape positions, viz, back slopes, foot slopes and toe slopes. On the back and foot slopes, the soils are characterized by very dark brown to dark yellowish-brown hue and high chroma, sandy loam to sandy clay texture, coarse angular to moderate sub-angular blocky structure and absence of coarse fragments throughout the horizon. In these soils, the clay content and sand grain sizes were observed to increase with depth. On the toe slopes, the soils show black to greyish-brown hue and low chroma, silty loam to sandy loam, structureless and high water holding capacity.
文摘Rainfall and temperature are the important variables that are often used to trace climate variability and change. A Perception study and analysis of climatic data were conducted to assess the changes in rainfall and temperature and their impact on crop production in Moyamba district, Sierra Leone. For the perception study, 400 farmers were randomly selected from Farmer-Based Organizations (FBOs) in 4 chiefdoms and 30 Agricultural Extension Workers (AWEs) in the Moyamba district were purposely selected as respondents. Descriptive statistics and Kendall’s test of concordance was used to analyze the data collected from the farmers and AEWs. Data for the analysis of variability and trends of rainfall and temperature from 1991 to 2020 were obtained from the Sierra Leone Meteorological Agency and Njala University and grouped into monthly, seasonal and annual time series. Regression analyses were used to determine the statistical values and trend lines for the seasonal and annual time series data. The Mann-Kendall test and Sen’s Slope Estimator were used to analyze the significance and magnitude of the trends respectively. The results of both studies show evidence of climate change in the Moyamba district. A substantial number of farmers and AEWs perceived a decrease in the annual rainfall amount, length of the rainy season, a late start and end of the rainy season, an increase in the temperature during the day and night, and a shortened harmattan period over the last 30 years. Analysis of the meteorological data shows evidence of variability in the seasonal and annual distribution of rainfall and temperature, a decreasing and non-significant trend in the rainy season and annual rainfall and an increasing and significant trend in seasonal and annual temperature from 1991 to 2020. However, the observed changes in rainfall and temperature by the farmers and AEWs partially agree with the results of the analyzed meteorological data. The majority of the farmers perceived that;adverse weather conditions have negatively affected crop production in the district. Droughts, high temperatures, and irregular rainfall are the three major adverse weather events that farmers perceived to have contributed to a substantial loss in the yields of the major crops cultivated in the district. In response to the negative effects of adverse weather events, a substantial number of farmers take no action due to their lack of knowledge, technical or financial capacity to implement climate-sensitive agricultural (CSA) practices. Even though few farmers are practicing some CSA practices on their farms, there is an urgent need to build the capacity of farmers and AEWs to adapt to and mitigate the negative impacts of climate change. The most priority support needed by farmers is the provision of climate-resilient crop varieties whilst the AEWs need training on CSA practices.
文摘Slash-and-burn agriculture is the common practice for upland rice intercropping system in Sierra Leone and it has been blamed for the loss of forest vegetation across the country. Shortening of the fallow period in the Eastern region of Sierra Leone has implications on agricultural food production and the persistence of the remaining tropical rainforest. This study was therefore undertaken to assess: 1) the extent of reduction of the fallow period in the Nongowa Chiefdom of Kenema District;2) the causes of reduction in the fallow period;3) farmers’ perception of the relevance of fallow period and the implications of reduction of fallow period on crop production. The study revealed a drastic reduction of the fallow period in the chiefdom with a mean of 3.8 years which falls far below the country mean fallow period of 8.8 years as estimated by FAO. Farmers pointed out that the reduction of the fallow period was as a result of land scarcity due to competing land uses such as large scale commercial agriculture, logging, mining, charcoal burning and expansion of settlements. Farmers agreed that a fallow period of at least 10 years is necessary for upland rice production. Farmers were aware of the impact of reduction of the fallow period on upland rice production and were able to estimate rice yields based on the age of the fallow. Also, farmers have attempted to adapt to the constraints posed by shorter fallow periods by selection of rice varieties to suit the length of the fallow periods.
文摘Lassa Fever is endemic to the eastern region of Sierra Leone. It is a haemorrhagic disease that is often transmitted from rats to humans and then human to humans. Ecological disturbances such as changes in land use involving conversion of natural ecosystems to agriculture, mining or for urban expansion are reported to bring humans into close contact with animals such as the Mastomys rat that carries the Lassa Fever virus thereby posing health problems.The nature and extent of such ecological disturbances or land use changes within areas known to be endemic to Lassa Fever are not clearly understood from a research context in Sierra Leone. This study was therefore undertaken to identify the pattern of changes in land use and cropping practices and their potential to bring humans into close interactions with the Mastomys rat that is the host for the Lassa Fever virus. Four communities were chosen for the study, two rural (Lalehun and Majihun) and two urban (Lambayama section in Kenema City and Largo Square section in Segbwema Town). Different vegetation and land use/cropping practices were identified and observations were made on the pattern of changes at different times in the cropping year. There were four common vegetation and cropping practices found in all communities: upland rice intercropping, old fallow, young fallow, and swamp rice cultivation. The study revealed the variations in land use patterns and cropping practices between urban and rural settlements. Agro-forestry practices such as perennial cash crops cacao and rubber plantations were more common in rural communities. The study also revealed that while fallow vegetation persisted in rural areas there had been expansion of settlements into old fallow vegetation indicating a greater threat to the persistence of natural ecosystem in urban than in rural settlements. These disturbances resulted in habitat fragmentation and increased the likelihood of contact between humans and animal species (e.g. Mastomys rat) associated with various habitats.
文摘This paper examines the potential contribution of the fisheries sector to national economic development in Sierra Leone, following the cessation of the recent Ebola virus disease (EVD). The tragic deaths of some 4000 persons, as a direct result of this epidemic, have also been accompanied by serious economic disruption to one of the world’s poorest countries, amounting to a loss of over USD 1 billion (20 per cent of annual Gross Domestic Product, GDP). Based on recent work undertaken by the New Partnership for Africa’s Development (NEPAD), an assessment was made of the potential contribution of one of the country’s major natural resource sectors—fisheries—to future economic recovery. It was confirmed that the fish resources of Sierra Leone have an estimated capitalised economic value of USD 735 million, and could potentially make an increased contribution to GDP under suitable conditions, over and above the current estimated level of 10 per cent. However, our results also show that with an overall “readiness assessment” score of 41/100, the sector is unlikely to realise its full potential unless a number of specific areas are addressed (based on analysis valid up to January 2016). These include an improvement in fisheries economic assessment, the upgrading of the fisheries governance and management framework, and the establishment of a fisheries development strategy and implementation plan to channel future investments and interventions in an appropriate sequence. Particular attention should be given early on to an increase in the quality and capacity of both public and private sector organisations relevant to roles and functions within a general process of fisheries sector reform. Finally, the fisheries policy evaluation approach used here is novel. While it has been applied to Sierra Leone for the intrinsic interest of that case, this demonstration also shows that it could be applied elsewhere in the future when reviewing fisheries policy.
文摘In a bid to enhance the integrity and health of selected network of ecosystems and effectively manage them in Sierra Leone, a baseline assessment of butterfly diversity of two wetland ecosystems Mamunta Mayosso Wildlife Santuary (MMWS) and Sierra Leone River Estuary (SLRE) affected by different environmental stressors was undertaken as part of the Sierra Leone Wetland Conservation Project (SLWCP). We hypothesised that different environmental stressors affect butterfly communities in wetlands in Sierra Leone and the higher the stress the lower the butterfly diversity in an area. Sampling was conducted via field identification by wing patterns, flight mode, direct counts along transects and charaxes trapping. A total of 2300 individuals representing 95 species of butterflies were recorded. Though butterflies were evenly distributed at both sites, MMWS recorded the highest richness and abundance of butterflies during both seasons. This observation is reported to be because of high environmental stressors such as mining, agriculture and pollution from factories in the SLRE. The results further show that MMWS is made up of a mosaic of different vegetation patches that support higher diversity of butterfly species. This study also reveals that anthropogenic activities have a negative impact on butterfly diversity.
文摘In this study,the Radio Direction Finding method is proposed for the detection of electromagnetic signals,in the VLF band,to try to anticipate the occurrence of potentially destructive geophysical events.The experimentation concerns the interception of electromagnetic anomalies in Sierra Leone,in the five-day time window,associated with seismic events that could potentially generate tsunamis.The area of investigation is Sierra Leone,whose coastline is subjected to tidal wave hazards triggered by earthquakes generated in the Mid-Atlantic Ridge.Although Sierra Leone is not affected by recurrent earthquakes,there is nevertheless a low probability,estimated at 2 percent,of the occurrence of destructive earthquakes in the next 50 years.Also in estimates,the risk of rogue and potentially damaging waves is estimated to strike the Sierra Leone coast at least once in the next 10 years.The Radio Direction Finding experiment carried out continuously 24/7,has shown a close relationship between increased radio-anomalies,in the frequencies of 6,000 Hz,a time window between electromagnetic anomaly detection and the imminence of an earthquake,and higher frequency times for the risk of earthquake occurrence in the Mid-Atlantic Ridge.
基金supported by National Mega project for Infectious Disease,Ministry of Science and technology(Grant Nos.2016ZX10004222-002,2016ZX10004222-003)National Natural Science Foundation of China(Grant Nos.81373141 and 81401312)National key project of Ebola research,National Natural Science Foundation of China(NSFC,Grant No.81590763)
文摘This study aimed to investigate the serological characteristics of Ebola virus(EBOV) infection during the late phase of the Ebola outbreak in Sierra Leone. In total, 877 blood samples from 694 suspected Ebola virus disease(EVD) cases assessed from March to December 2015, were analyzed via real-time reverse transcription polymerase chain reaction(RT-PCR) for viral RNA and enzyme-linked immunosorbent assay(ELISA) and Luminex to detect antibodies against EBOV. Viral load and EBOV-specific IgM/IgG titers displayed a declining trend during March to December 2015. Viral RNA load decreased rapidly at earlier stages after disease onset, while EBOV-specific IgM and IgG still persisted in 58.1%(18/31) and 93.5%(29/31) of the confirmed EVD patients and in 3.8%(25/663) and 17.8%(118/663) of the RNA-negative suspected patients in the later phase, respectively. Dynamic analysis of longitudinally collected samples from eight EVD patients revealed typically reversed trends of declining viral load and increasing IgM and/or IgG titers in response to the EBOV infection.The present results indicate that certain populations of Sierra Leone developed immunity to an EBOV infection in the late phase of the outbreak, providing novel insights into the risk assessment of EBOV infections among human populations.
文摘Indiscriminate disposal of solid waste in dumpsites located within urban areas has proved to be a problem to nearby residents in most developing cities of the world, Freetown is no exception. Open dumps have environmental safeguards;they can pose major public health threats and environmental effects in urban cities. Therefore, this paper presents the findings of a research carried out in Freetown municipal area in Sierra Leone to determine the environmental and health impacts of solid waste disposal at Granville Brook dumpsite on the surrounding human settlements. Data were collected from three hundred and ninety eight nearby dumpsite household residents (less than fifty metres) and two hundred and thirty three far away household residents (more than fifty metres) through the use of structured self-administered questionnaires. Interviews and personal observations were also used to collect some of the data. Descriptive statistics involving tables, graphs and figures were used to present and analyze the data. Results show that both nearby residents and far away residents suffered from related diseases such as malaria, chest pains, diarrhea and cholera, due to the location of the dumpsite closer to their settlements. As a result, this study highlights the need for the Freetown City Council to properly manage and relocate the dumpsite to a safe distance from all human settlements, and provide resettlement and environmental education programmes for all persons living less than fifty metres away from the dumpsite as interim measures.
文摘Understanding the hydrologic budget is crucial in planning for community based water supply. The water budget includes rainfall intensity, groundwater recharge, interception, evapotranspiration, and surface runoff. The percentage of rain going to recharge groundwater, rivers, and lakes is very important from the standpoint of human water consumption and ecosystems service. The objective of this work is to determine the recharge potential of groundwater in the Mokonde Community, Southern Sierra Leone. The community is dependent on wells as the main source of domestic water supply. This research need was born out of the absence of available data to show the relationship between rainfall amounts and groundwater recharge in the study area. In this study we monitored groundwater in a well at the United Methodist Church (UMC) compound at Ngegba Street. Automatic water logging devices were deployed to take readings in water level fluctuations every 15 minutes. Monitoring continued throughout the hydrological year of Sierra Leone. A rain gauge was deployed at neighboring UMC Primary School, and daily rainfall records taken at 9:00 a.m. Our team members also deployed at the well on a daily basis to collect data on abstraction of water. The results revealed, through a 29-year rainfall data and the Specific Yield, that 1170 mm of rainfall (48%) was the maximum potential of rainfall that would make groundwater a convenient source of water supply in the area. This demand was higher with the recent 1-year rainfall data. Increase in settlement had likely led to reduction in pervious area, and hence more and more rainfall needed for recharge. The time it took for maximum recharge (4 weeks) was shorter than that for maximum discharge (28 - 30 weeks). Groundwater flowed southwards towards the Gbengitay stream, which drained into the Tia River. These results would inform first step in delineating the water balance in the study area. Future studies could include the quality aspect, stream/river flow, interception and evapotranspiration. These pieces of information are required to help informed decision for water security.
