The significant effect of slope in the spatial rainfall vari- ability in the Central Rift Valley could be attributed to the role of steeper slopes in providing stronger oro- graphic lifting and hence higher rainfall (Buytaert et al. 2006). The relatively less R 2 value of 0.29 looks less sat- isfactory predictor, but other historical studies with such low R-squared values reported the regression model as the best predictor variable. For example, Basist et al. (1994) studied statistical relationship between topog- raphy and precipitation pattern, in Hawaii, using mul- tiple regression and found that the model with R 2 value of 0.31 (slope orientation independent variable) as statisti- cally significant and best predictor of the annual precipita- tion pattern. The same study (Ibid) in Kenya reported the R 2 value of 0.39 (elevation independent variable) as the only significant topographic predictor of mean annual pre- cipitation. Similarly, with the R 2 value of 0.22, they found statistically significant bivariate relationship between slopes and mean annual relationship in Norway.
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The Ethiopian Central Rift Valley is part of the Great African Rift Valley and is located between 38°00’-39°30’ east longitude and 7°00’-8°30’ north latitude. The CRV has an arid to semi-arid climate, although the highlands on the eastern and western escarpments of the valley are sub-humid. From the escarpments the lakes on the rift floor are fed by rivers, of which Meki and Katar river are the most important. The four major lakes are Lake Ziway, Lage Langano, Lake Abyata and Lake Shala of which the latter is a sub-catchment of the CRV. Lake Ziway and Lake Langano drain to Lake Abyata, a terminal lake, by the Bulbula and Horakelo river, respectively. Lake Abyata and Shala together form a National Park that is primarily created for its aquatic bird life. Until now, only a part of the 87.000 ha park is protected and fenced. The park is heavily threatened by the invading human and cattle population.
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Background: In Central Rift Valley (CRV) of Ethiopia, renewable land resources are under pressure. Acacia woodland clearance, frequent cultivation, crop residue removal and mono-cropping are among the major land mis-management practices in the area. This has largely been affecting the soil quality. The current study is aimed at assessing the impact of Acacia woodland conversion, and the subsequent mis-managements on selected soil physical properties, and their relation to the prevailing wind erosion in the area. For this study, four land use/land cover types, namely protected woodland (PWL), managed pastureland (MPL), parkland agroforestry (PAF) and treeless cropland (TLCL) were considered. Results: Higher (P < 0.001) macro-aggregates (>0.25 mm) fraction of soil was found under PWL and MPL while higher fraction of micro-aggregates (0.053 – 0.25 mm) of soil was found under PAF and TLCL. Soil under PAF and TLCL had higher (P < 0.001) proportion of aggregates of < 1 mm, implying potential susceptibility of the soil to wind erosion. Higher soil bulk density (BD) was found in the most top layer (0 – 15 cm) of TLCL and PAF, and this could be attributed to the trampling effect by animals freely released to these land use types.
Tomato production reached more than 163.4 million tons cultivated on more than 4.6 million hectares of land worldwide, FAO . In Ethiopia, there is 6,298.63 hectares area coverage with an annual production of 28,364.83 tones, CSA . There is also large-scale production of tomato in the central rift valley (CRV) under irrigated and rain-fed conditions having unlimited potentials for expansion if certain production constraints are avoided. Despite its rapid spread across the different localities and agro-ecologies, the production and productivi- ty remain low. Several biotic and abiotic factors are impacting its production. Among the biotic factors, plant diseases caused by plant-parasitic nematodes (PPN) are a costly burden. There are over 4100 species of PPN currently identi- fied, collectively, causing an estimated loss of $80 - $118 billion per year in damage to crops. Off these species, 15% of them are the most economical species directly targeting plant roots of major agricultural crops and prevent water and nutrient uptake resulting in reduced agronomic performance, overall quality and yields, Bernard et al . . In nature, plants are rarely, if ever, subject to the influ- ence of only one potential pathogen and this is especially true of soil-borne pa- thogens like fusarium wilt ( Fusarium oxysporum ) whereby further opportunities exist for interactions with other microorganisms occupying the same ecological niche, Back et al . .
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Figure 1 presents the Central Rift Valley (CRV) region where this study was conducted. Geographically, CRV is located between 38º15’E and 39º25’E and 7º10’N and 8º30’Ncoordinates. The CRV in Ethiopia makes an area of about 1.3Mha and encompasses four large lakes, Ziway, Abijata, Shala and Langano (Hengsdijk and Jansen 2006 ).This is a section of the Main Ethiopian Rift comprises a significant part of the great African Rift Valley system that stretches from the Red Sea to Mozambique crossing Ethiopia, Kenya and Tanzania. It is divided into three subsystems: Chew Bahir (Lake Stephanie), the CRV and the Afar triangle (Muzein 2006). The central rift valley comprising Ziway-Langano-Abijata-Shalla Lakes from the Ethiopian rift valley basin and the lower sub-basin comprising Hawassa- Abaya-Chamo-Chew-Bahir lakes. These lakes, which once formed one large water body, support important biodiversity resources that have global significance. The CRV basin contains unique fauna and flora species of which a significant number are endemic. The area is an important breeding and feeding site for some rare species of resident and migratory birds. A good example is Lake Abijata and Lake Shala form together a National Park, which has been submitted as candidate site by the Ethiopian Government to the Ramsar convention on wetlands.
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The accessions were planted for the first time at three sites in Central Rift valley of Kenya; Kericho (Soin), Nakuru (Subukia), and Baringo (Marigat) districts of central Rift Valley in Kenya (Table 2). The cassava germplasm were selected because of their high yields, disease resistance and popularity. The accessions were planted in a randomized complete block design (RCBD) with three replications. The plot sizes were 3 M × 4 M while the plant spacing was 1 M × 1 M giving twelve plants per plot. Cassava cuttings measuring 15 cm long from each variety were planted in five rows. No fertiliz- ers or herbicides were applied during the course of the experiment. For Nakuru and Kericho sites, the trials were rain fed while at Baringo, the trial was under irrigation which was done twice in a week. Destructive sampling of the plants was done at 13th month after planting.
According to Ethiopian Central Statistical Agency’s (CSA) reports  , the total population of Arsi Negele district was 137,228; 198,307; 260,129 and 338,967 respectively (c and p indicating censuses and projections, respectively). These reports showed that the population of the district has increased by more than double between 1994 and 2016. The land forms in the study area cover flat slopes in the rift floor including four major lakes; and extend to the eastern es- carpment of the central rift valley of Ethiopia with gentle slopes and mountains. The dominant soil types are andosols and nitosols . The major livelihoods are crop cultivation (wheat, maize, tef) and livestock rearing (cattle, goats and sheep). The former dominates in the midland and highland agro-ecologies and the latter in the lowland agro-ecology. The forests in highland agro-ecology and the woodlands in lowland agro-ecology have been declined from time to time due to population growth, agricultural expansion and fuelwood collection .
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As a result, communities have started establishing area exclosures as a promising practice in different parts of the country with the aim of fighting against land degradation and promoting their re-vegetation to prevent further degradation (Emiru et al., 2003). Nevertheless, in many cases success is obstructed by lack of clear management guide lines and consequently, communities did not benefited as expected. This is often manifested in communities’ lack of decision making power in the management and utilization of the resources and limitation in the rights to use grass and wood produced in the area exclosures. This adversely affects the sense of ownership and community commitment for effective protection and sustainable management of the resources. It is argued that the problem is still not adequately addressed and communities are uncertain about the future of land tenure and land use policy. Consequently, various challenges have been faced on the effectiveness of exclosure management in the country. Based on these premises, this study was conducted to investigate the effectiveness of exclosure in achieving the goal of environmental conservation and improving community livelihood strategies in the central rift valley area of Ethiopia.
In the Cheleleka wetland watershed, large expansions of new land uses were made mostly through the displacement of the original forests and pasture land. For example, using remote sensing and Geographic Information System (GIS) methods, Gessesse (2007), es- timated an alarming 82% forest decline in the area when comparing 1972 forest cover to 2000. In many cases, this conversion occurred without evaluating the land use capacity, thus exposing the new cultivated fields to a high level of degradation. Moreover, the erosion and sedimentation processes disrupt the hydrological balance in the study watershed. In contrast to other lakes in the Rift Valley of Ethiopia, the level of Lake Hawassa has been increasing while the Cheleleka wetland is unfortu- nately drying up. Thus the increasing discharge from the wetland through the ‘TikurWuha’ River is partially re- lated to the activities of erosion and the sedimentation processes in the Cheleleka watershed (Gessesse 2007; Tenalem et al. (2007); Kebede et al. (2014)).
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from nearby area closure. Regeneration of trees and grasses, woodland conservation and a reduction of soil erosion were considered as the major positive changes observed after the establishment of area closures. Similar findings were reported by Emmiru, et al. (2006) and Ambachew (2006). Based on finding of this study, the benefits of area closure can be categorize into four: (1) use of grasses for house/ bee hive cover, and cattle feed during drought season by using ‘cut– and- carry approaches, and sources of traditional medicine. (2) Rejuvenation of some tree species which did not exists outside the closure areas or found at a distance, which have importance as construction materials and uses for social welfare for instance leaves/fruits of Cordiaafricana is used during wedding ceremony by Oromo people. (3) Regeneration of different woody species and grasses have reduced soil erosions affecting the areas. (4) Direct economic benefits from tourists visiting Abjatta-Shalla Lakes National Park, where 25 year-old area closure was located, and from many resort lodges and hotels existing along lakes in the Rift valley area. Expanding of these direct and indirect benefits of area closures would encourage local peoples’ commitment for supporting future area closure interventions. However, to achieve this, there should be clearly defined scheme for benefit sharing mechanism from area closures to the local communities.
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A study was conducted with the objectives of investigating the effect of climate change and varia- bility on the livelihood of the local community in Arsi Negele District, Central Refit Valley Region of Ethiopia using group discussions, structured questionnaire and personal observations. The trends of climate change and variability in the study area showed gradual change. Erratic rainfall, fre- quent rain delay, heavy and un-seasonal rainfall, drought, and seasonal variations are indicators of climate change. The pattern of temperature, rainfall, and high wind caused the reduction of agricultural production and productivity, shortage of water, drying of shrubs and other vegeta- tions, which affect the livelihood of the community. The problem is more sensitive for the women, poor, children, large sized family, and landless farmers. Thus, the vulnerability of climate change is more accelerated by massive expansion of agricultural land, the increment of landlessness fami- lies and huge water shortage in the study area. Moreover this study advocating climate change and variability has accelerated the degradation of natural environment and strongly affects the com- munity’s life style over time. Though, as stated above this study was conducted using some and simple research variables to demonstrate the problem. But, it is used as an initial thought for fur- ther and detailed investigations about the issue. Therefore, stakeholders required to take in hand these challenges both from short and long-term policy perspective to reduce susceptibility of next generation.
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In Ethiopia, purple blotch ( Alternaria porri ) and downy mildew ( Peronospora destructor ) diseases are considered as the major constraints of onion production and productivity, Wondirad et al . . Purple blotch is prevalent in all onion- growing areas of the country. It attacks leaves, bulb and seed stalks and subse- quently reduces yield and quality. Since 2018, however, a new disease symptom, which confuses with purple blotch disease, was observed in the central rift valley areas of Ethiopia. The disease typically attacks leaf, which starts with round to oval small spots that later coalesce to form blighting to leaf tissue. The lesion turns brown to tan, for some time; the disease was probably misdiagnosed as purple blotch since their symptoms are very similar. Samples submitted to the plant pathology laboratory of Melkassa Agricultural Research Center of Ethio- pian Institute of Agricultural Research (EIAR) revealed the presence of stem- phylium leaf blight (SLB).
Rift Valley fever virus (RVFV) is an arthropod-borne pathogen that primarily affects ruminants in eastern and sub- Saharan Africa (7, 16). While periodic outbreaks of Rift Valley fever have resulted in significant losses to the African livestock industry, it has only been during the past decade that the international community has appreciated the potential dangers of the disease. In particular, recent outbreaks in the Middle East have demonstrated the potential of the disease to spread beyond the African continent (4) (Fig. 1). Moreover, other considerations, such as RVFV’s recent classification as a po- tential bioterrorist agent (55), have renewed interest in the study of the virus as well as in the development of prophylactic measures to contain future outbreaks. Another important fac- tor in recent Rift Valley fever outbreaks is the increasing number of human fatalities. Human symptoms of this disease range from photophobia and headaches to retinitis and en- cephalitis (18, 19). While Rift Valley fever was originally as- sociated with livestock, recent outbreaks in Kenya have re- sulted in increased fatality rates among humans, thereby presenting an increased threat to public health (2, 11).
Rift valley fever virus (RVFV) is an arthropod-borne virus that causes serious illness in both animals and humans. RVFV is transmitted by direct contact with infectious tissues or by the bites of infected mosquito species of the Aedes and Culex genuses. Its distribution in tropical forests in central Africa is poorly documented. We assessed the current circulation of RVFV among livestock and humans in the Central African Republic (CAR) by detecting anti-RVFV immunoglobulin M (IgM) and immunoglobulin G (IgG) antibodies in sheep, cattle and goats and in people living in Bangui who were considered at risk. We also sequenced the complete genomes of two local strains, one isolated in 1969 from mosqui- toes and one isolated in 1985 from humans living in forested areas. Sheep were the most frequently infected ruminants. IgM antibodies were found only during the rainy season; the frequency of IgG antibodies did not differ according to season. No evidence of recent RVFV infection was found in humans at risk; however, 16.7% had evidence of past infec- tion. Phylogenetic analysis showed a perfect match of CAR strains with the East/Central African cluster. Our results confirm current circulation of RVFV in CAR. Further studies should be conducted to determine the vectors involved and the virus reservoirs.
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Whilst locally common, e.g. in the Huri Hills (Class et al. 1994) and Chyulu Hills (SpaÈth et al. 2000, 2001), rocks representing possible primary magmas (mg-number > 65) are normally relatively scarce in the Kenya rift (Macdonald 1994; Macdo- nald et al. 2001). The overwhelming majority of basalts have compositions consistent with substantial polybaric fractiona- tion of olivine-dominated assemblages from primary magmas. Karson & Curtis (1989) pointed out the requirement that the emplacement of huge volumes of magma in the rift has been accompanied by the formation of at least three to four times as much ma®c and ultrama®c cumulates. The fact that the greatest volumes of basalts in the rift straddle the critical plane of silica-saturation (which becomes operative at ¹ 24 km depth) indicates that a considerable proportion of the cumulates must have formed at, or close to, the crust±mantle boundary, maintaining crustal thickness by underplating.
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Rift Valley fever (RVF) is a zoonotic vector-borne viral disease that mainly affects domesticated ruminants and humans. Rift Valley fever is responsible for high mortality rates in newborn and juvenile ruminants, and abortions in pregnant animals . Human infections may vary from an asymptomatic to mild febrile illness, but 1% of them may develop into severe encephalitis, haemorrhagic fever and death . Its causal agent, RVFV, belongs to the genus Phlebovirus within the family Phenuiviridae. Unlike most phleboviruses, which are primarily transmit- ted by sand flies, RVFV is transmitted predominantly by infected mosquito bites .
Rift Valley fever virus (RVFV) is a mosquito-borne zoonotic bunyavirus of the genus Phlebovirus and a serious human and veterinary pathogen. RVFV contains a three-segmented RNA genome, which is comprised of the large (L), medium (M), and small (S) segments. The proteins that are essential for genome replication are encoded by the L and S segments, whereas the structural glycoproteins are encoded by the M segment. We have produced BHK replicon cell lines (BHK-Rep) that maintain replicating L and S genome segments. Transfection of BHK-Rep cells with a plasmid encoding the structural glycoproteins results in the efficient production of RVFV replicon particles (RRPs). To facilitate monitoring of infection, the NSs gene was replaced with an enhanced green fluorescent protein gene. RRPs are infectious for both mammalian and insect cells but are incapable of autonomous spreading, rendering their application outside biosafety containment completely safe. We demonstrate that a single intramuscular vaccination with RRPs protects mice from a lethal dose of RVFV and show that RRPs can be used for rapid virus neutralization tests that do not require biocontainment facilities. The methods reported here will greatly facilitate vaccine and drug development as well as funda- mental studies on RVFV biology. Moreover, it may be possible to develop similar systems for other members of the bunyavirus family as well.
Increased agricultural production is an urgent issue. Projected global population is 9 million people by mid of this century. Estimation projects death of 1 million people for lack of food quality (micronutrient deficit) and quantity (protein deficit). Majority of these people will be living in developing countries. Other global challenges include shrinking cultivable lands, salinity, and flooding due to climate changes, new emerging pathogens, and pests. These affect crop production. Furthermore, they are major threats to crop genetic resources and food security. Genetic diversity in cultivated crops indicates gene pool richness. It is the greatest resource for plant breeders to select lines that enhance food security. This study was conducted by Masinde Muliro University to evaluate genetic diversity in 19 cowpea accessions from Kenya national gene bank. Accessions clustered into two major groups. High divergence was observed between accessions from Ethiopia and Australia and those from Western Kenya. Upper Volta accessions were closely related to those from Western Kenya. Low variation was observed between accessions from Eastern and Rift Valley than those from Western and Coastal regions of Kenya. Diversity obtained in this study can further be exploited for the improvement of cowpea in Kenya as a measure of food security.
Rift Valley fever (RVF) is an acute febrile arthropod- borne viral disease of man and animals caused by a member of the Phlebovirus genus, one of the five gen- era in the family Bunyaviridae. RVF virus (RVFV) is transmitted between animals and human by mosqui- toes, particularly those belonging to the Culex, Ano- pheles and Aedes genera [1,2]. Transmission is mostly horizontal, but a vertical mode was described for some Aedes species [3,4]. RVFV is carried in the eggs of Aedes mosquitoes which breed in isolated depressions called dambos found in the vast grassland areas. At flooding of the dambos during periods of extensive and widespread rainfall, the eggs of the Aedes mosqui- toes hatch and the subsequent adults transmit the virus to domestic animals including sheep, goats, cat- tle, camels, and buffalos . These depressions also serve as good habitats for Culex and Anopheles mos- quito species. When Aedes mosquitoes infect domestic animals with RVFV, virus amplification occurs in these vertebrate hosts, leading to propagation into various Culex and Anopheles species that are capable of trans- mitting the virus to a wider area beyond the area of the original outbreaks by wind-borne dispersal . Although RVFV is, in most cases, transmitted to humans by mosquitoes, it may also be transmitted through direct contact with secretions of infected ani- mals and meat. The professional nature of some groups, such as doctors and veterinarians working in slaughterhouses, made them more vulnerable than others to infection (because the virus is not vital out- side the body). Good cooking of meat may help to eliminate the virus from it .
Summary: Ensuring the successful inactivation of select agent material is critical for maintaining compliance with federal regulations and safeguarding laboratory personnel from exposure to dangerous pathogens. Rift Valley fever virus (RVFV), naturally transmitted by mosquitoes, is classified as a select agent by the CDC and USDA due to its potential to cause significant economic losses to the livestock industry and its demonstrated potential to emerge into naïve geographic areas. Herein we describe several effective inactivation procedures for RVFV infected mosquito samples. We also demonstrate the vaccine strain MP-12 can be used as an appropriate analog for inactivation testing and describe a method of validating inactivation using Amicon filters. Briefly, we show the following inactivation methods are all effective at
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