Lake Zeway Research Articles

Older children are at increased risk of Plasmodium vivax in south-central Ethiopia: a cohort study

BackgroundBetter understanding of the distribution of Plasmodium vivax and its risk factors could be used to prevent and control malaria infection. Therefore, the aim of this study was to characterize the distribution and risk factors of P. vivax, and to compare them with Plasmodium falciparum occurrence in south-central Ethiopia.MethodsA cohort of 34,548 individuals were followed for 121 weeks between 2014 and 2016 as part of larger cluster randomized controlled trial to evaluate the effect of long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) on malaria prevention in Ethiopia. Weekly home visit (active search) and patient self- report to health post (passive search) between the weekly home visits were used to register malaria cases. A blood sample was collected by finger prick and malaria was diagnosed using rapid diagnostic test (RDT). Generalized estimating equation (GEE) Poisson model that accounts for repeated measure of malaria episodes was applied to assess the risk factors of P. vivax episode.ResultsThe overall incidence rate of P. vivax was 7.4 episodes per 1000 person-years of observation. The study showed households closer to the lake Zeway and Bulbula river (potential mosquito breeding sites) were more at risk of P. vivax infection (incidence rate ratio (IRR): 1.33; 95% CI = 1.23–1.45). Furthermore, the age group under 5 years (IRR: 1.40, 95% CI = 1.10–1.79), the age group 5–14 years (IRR: 1.27, 95% CI = 1.03–1.57), households with less educated household head (IRR: 1.63, 95% CI = 1.10–2.44) and house roof made of thatch/leaf (IRR: 1.35, 95% CI = 1.11–1.65) were at higher risk for P. vivax. Similar explanatory variables such as distance from the breeding sites, age group (under 5 years but not 5–14 years old), educational status and type of housing were also found to be the predictors of P. falciparum incidence.ConclusionHouseholds living closer to a mosquito breeding site, age group under 15 years, less educated household heads and thatch/leaf roof housing were the risk factor for P. vivax. The result of this study can be used for tailored interventions for malaria control and prevention by prioritizing those living close to potential mosquito breeding site, enhancing bed net use of children less than 15 years of age, and improving housing.

English

Although fish is economically and socially important, its marketing chain and their characteristics have not yet been studied and analyzed for Lake Zeway, Central Ethiopia, where great potential of fish production exists. The study was initiated to investigate the fish marketing chain in this area. This was done by identifying the marketing channels of fish and the major factors influencing its market supply. Data were collected from 90 households and 24 traders using a simple random sampling method. Results indicate that fishers, fishery cooperatives, retailers, wholesalers and consumers were the main actors of the fish marketing channel. Among the explanatory variables included in the econometric model, five variables (income from non-fish marketing, access to extension service, access to credit, price of fishes and access to market) were found to significantly influence the marketable supply of fish. The study identified the need for policy interventions by the Ethiopian government to improve storage and transportation systems as well as render other services like training, which would encourage fishers to be legal in order to improve harvesting and marketing of fish in the study area.   Key words: Fish, fish marketing, Lake Zeway, market chain, multiple linear regression analysis.&nbsp

Structure, Conduct and Performance of Fish Market in Central Ethiopia

The study aimed at analyzing the structure, conduct and performance of fish market in Lake Zeway, Central part of Ethiopia. A total of 24 traders from 6 markets were selected for the study purposively. Data analysis was carried out using descriptive statistics, for Structure, Conduct and Performance (SCP) approach. According to the results, there were five kinds of fish marketing chains in the study area. The fish market was oligopolistic in nature which controlled by few large wholesalers because of capital barriers to massively enter into the fish trade. The share of margins showed that retailers got the highest margin that all of the fish market agents in the study area. The study recommended necessary government interventions to make the fish market operate efficiently.

Analysis of Organochlorine Residues in a Farmland Soil near Lake Zeway, Ethiopia

Analysis of Organochlorine Residues in a Farmland Soil near Lake Zeway, Ethiopia

Wetland ecosystems in Ethiopia and their implications in ecotourism and biodiversity conservation

Wetlands are ecosystems in which water covers the land. They provide economical, ecological, societal and recreational benefits to humans. Although complete documentation is lacking, wetlands make a significant part of Ethiopia covering an area of 13,700 km2. Wetlands with a great potential for ecotourism development in the country include the rift valley lakes, the floodplains in Gambella, the Awash River Gorge with spectacular waterfalls, the Lake Tana and the Lake Ashenge, the Wenchi Crater Lake and the Wetlands in Sheko district are among others. Similarly, the Wetlands of Ethiopia are home to various aquatic biodiversity. Some of the biodiversity potential areas are the Cheffa Wetland and Lake Tana basin in the North, the rift valley lakes namely, Lake Zeway, Abaya and Chamo, and the Baro River and the Dabus Wetland in the Western Ethiopia. However, the wetlands in the country are impacted by a combination of social, economic, development related and climatic factors that lead to their destruction. Correspondingly, the wetlands holding a considerable biodiversity potential in the country lack adequate management. To address the challenges and enhance the wetland’s role in ecotourism and biodiversity, a sustainable form of wetland resource use should be developed. As a result, integrating wetlands with ecotourism and developing as livelihood option for local communities is important for sustainable conservation of wetlands. Awareness rising, empowering stakeholders involved in wetland resource conservation, enhancing stakeholders’ participation, undertaking the restoration of degraded wetlands and promoting scientific studies on wetlands of the country are crucial to conserve wetlands and at the same time promote their ecotourism and biodiversity importance. Moreover, implementing the integrated wetland resource management approach and addressing policy, management and coordination issues that arise on wetland resource conservation aids to promote the significance of wetlands in ecotourism and biodiversity conservation in Ethiopia. Key words: Wetlands, ecotourism, biodiversity conservation, implication, Ethiopia.

English

A cross sectional study was conducted from November to June 2014/2015 in fish harvested for human consumption at Lake Zeway with the objective of isolating Edwardsiella tarda and Escherichia coli important pathogens and contaminants its products. Three hundred tissue samples comprising Spleen, Liver and Intestine were collected from 100 fish (12 Clarias gariepenus and 88 Oreochromis niloticus) originated from lake Zeway. Escherchia coli were isolated from spleen, liver, and the intestine of 12 out of 100 (12%) while E. tarda was isolated 4 out of 100 (4%) randomly examined fish. The higher percentage of both bacteria was isolated from intestinal samples than those isolated from liver and spleen samples. The E.tarda isolates appeared as small scatter pinkish colonies with black center while isolated colonies from E. coli were yellowish white on Xylose deoxycholate agar (XLD) after 24 h of incubation at 37°C Both types of isolates were gram negative short to medium rods, motile, catalase positive and oxidase negative. In biochemical test, both of the two types of typical isolates were positive for indole and Methyl red test and negative for Vagos proskaur test and unable to utilize Simmon’s citrate test. In addition to this, E. tarda ferments sodium thiosulfate and result its byproduct of H2S production (blackening) on TSI test which were absent in E.coli. The distribution of E.tarda and E.coli infection among the three organs examined indicate both bacteria were isolated most frequently from intestine followed by spleen and liver with significance difference (P 0.05) indicating that sex has no role in influencing the exposure these bacteria. The isolation of E.tarda and Escherchia coli from wild fish population of Lake Zeway destined for human consumption in the current study indicated that E. tarda and Escherchia coli are a potential threat for fish and public health. Key word: Catfish, Escherchia coli, Edwardsiella tarda, intestine, liver, spleen tilapia, zeway.

Study on Helminth Parasites in Tilapia nilotica from Lake Zeway, Ethiopia

A cross sectional study was conducted in Lake Zeway on helminth parasites in Tilapia nilotica to determine the infection rate of helminth parasites. Gillnets were set in the evenings and retrieved in the mornings and fish were randomly sampled in fish production and marketing industry that were brought from different angles of the lake. The mesentery and the gastrointestinal tract were carefully separated and examined. Out of 400 specimens, 277 were examined 277(69.25%) infected with Clinostomum species. Metacercariae were found in the mesentery, and gastrointestinal tract, the brachial cavity, between the pharyngeal teeth and ventral side of cranium, and muscle. Immature and adult cestodes of the genus Bothriocephalus were found in the lumen of intestines with the proportion of (43)10.75% and (6)1.5% respectively of the diagnosed samples of fish 49(12.25%). Comprehensive information on existing fish parasites in Ethiopia and their epidemiological aspects is scanty. However, to decrease the infestation rate and break the life cycle of the parasite, proper waste disposal system and sanitation measures must be implemented. Key w ords : Bothriocephalus, Clinostomum, Helminth Parasites, Lake Zeway and Tilapia nilotica.

Minerals Content and Fatty Acids Profile of Nile Tilapia (Oreochromis niloticus) Fillet from Lake Zeway: Effect of Endogenous Factors

This study was aimed to investigate the influence of age and sex on minerals content and fatty acids profile of Nile Tilapia (Oreochromis niloticus) fillet. Samples were cool transported from Lake Zeway to Food Science and Nutrition laboratory of Addis Ababa University. Minerals content were analyzed using Flame Atomic Absorption spectrophotometer and Fatty acid profile was determined using gas chromatography. Female fish contained significantly (p 0.05) on Iron and Zinc content. Monounsaturated fatty acids constituted the largest proportion of total unsaturated fatty acids in both sexes. Oleic acid was relatively higher in female than male. Conversely, the polyunsaturated fatty acids were higher in male as compared to female.

RETRACTED ARTICLE: Screening for the presence and prevalence of Edwardsiella tarda infection in fish harvested from Lakes Zeway and Langano, Southern Oromia, Ethiopia

AbstractA study was carried out from October 2009 to April 2010 with the objective of isolating E. tarda an important fish pathogen from fish harvested for human consumption from Lake Zeway and Langanoo. A total of 372 tissue samples (three from each fish) comprising liver, intestine and kidney were collected from 124 fish (Clarias gariepinus and Oreochromis niloticus). Distribution of E. tarda infection among these three organs examined indicated that E. tarda was isolated most frequently from liver (6.5%) followed by intestine (2.4%) and kidney (0.8%) with significant difference. Statistical significant differences (p 0.05). The current study is signified that E. tarda infection is a potential threat to the fishery sector and public health. Therefore...

Isolation and Identification of Edwardsiella tarda from Lake Zeway and Langano, Southern Oromia, Ethiopia

A study was carried out from October, 2009 to April, 2010 with the objective of isolating Edwardsiella tarda an important fish pathogen from fish harvested for human consumption from Lake Zeway and Langanoo. A total of 372 tissue samples (three from each fish) comprising liver, intestine and kidney were collected from 124 fish (Clarias gariepinus and Oreochromis niloticus originated from Lake Langanoo and Zeway. Distribution of E. tarda infection among the three organs examined indicated that E. tarda was isolated most frequently from liver (6.5%) followed by intestine (2.4%) and kidney (0.8%) with significant difference among organs. Statistical significant differences (P 005) indicating that both sexes are equally susceptible. The isolation of Edwarsiella from wild fish population of Lakes Zeway and Langano destined for human consumption in the current study is indicates that E. tarda is a potential threat of both the fishery sector/aquaculture and public health. Finally, as is the case for any infectious fish pathogen, there is limited information on E. tarda of fish in Ethiopia and hence further study to have comprehensive information on the agent is forwarded.

Abundance and Temporal Patterns in Wetland Birds in and Around Lake Zeway, Ethiopia

Abundance and Temporal Patterns in Wetland Birds in and Around Lake Zeway, Ethiopia The aim of the study was to describe the abundance and temporal patterns of wetland bird species in and around Lake Zeway, an Important Bird Area and potential Ramsar site in Ethiopia. Nine years of wetland bird data of the area, collected by the African Waterbird Census, were used for the study. Surveys were made to examine the bird abundance, diversity and temporal patterns. We recorded 129 wetland bird species from 23 families; including two globally vulnerable and 6 near threatened species. The results revealed no clear trend or pattern in the abundance of the birds.

Fisheries Baseline Survey Describing Status of Fisheries in Lake Zeway, Ethiopia

Lake Zeway, the fourth largest lake in Ethiopia, is the most exploited lake for fishery, irrigation, recreation, and tourism. Fishery sustainability of this Lake is reported under threat because of fishing pressure among others. This survey was aimed to update the Lake’s fisheries baseline information which will be used in fisheries management. The primary data was collected during intensive fishing, August 7-21, 2013 in all three districts bordering the Lake. Papers were reviewed to assess the change in fish species composition and total catch. The baseline survey included fishermen’s socio-demographic, educational status, fishing experience, purpose of fishing, condition of employment, fishing activities, fishing boat and fishing gears inventory. Data were analyzed using Statistical Package of Social Science (SPSS). A total of 1021 fishermen (99.9% male), 43 major landing sites and 14 fishermen cooperatives operating on the Lake were observed during the survey. Among the respondent fishers, 494 (48.4%) were members of the cooperatives while 521 (51%) were not. The livelihoods of 4,632 people were known to directly depend on fishing activities on Lake Zeway including the interviewed fishers. Number of fishermen and all fishing gears operating on the lake increased except for gillnets as compared to the 1993 baseline survey report. However, secondary data shows that total fish landing from the lake is declining and fish species composition of the lake is also changing, threatening the fisheries sustainability. Hence the Lake’s fisheries management system should be addressed for the sustainability.

English

This study aimed to show impacts of land use and land cover change (LULCC) and climate on waterbird community structure of Lake Zeway and the surrounding areas. Purposive sampling techniques were used to collect primary data. Based on the purposive sampling techniques, 12 key informants and 12 focus group discussants were selected. A semi-structured questionnaire prepared in English and translated into Afan Oromo was used to interview the focus groups. The key informants participated in the interview under close inspection of the researcher. Field observations and literatures searches were also carried out on the impacts of LULCC, climate changes, lake hydrodynamics and biodiversity. Most (92%) of the discussants indicated decreases in the level and width of Lake Zeway during the last 3-4 decades. The lake water withdrawal for irrigated agricultural activities in the surrounding areas was the main reason for decreases. Eleven groups (92%) reported temperature increases and lower and unpredictable rainfall patterns as cause for the decreases. These changes reportedly resulted in decreased waterbird species diversity and abundance and changed distribution patterns across the lake and the surrounding areas. The FGD identified fish production and irrigated farm and bird habitat as the three most important values of the lake. The discussants also reported the combination of land-use and climate, or climate changes, as important drivers that altered the lake water level, wetland habitats and bird community structure. Urgent conservation measures that could reduce the impacts are needed to conserve the bird species at the lake. Key words: Bird community, climate, changes, impacts, irrigated agriculture, land use.

Microbiological and Chemical Changes of Nile Tilapia (<em>Oreochromis niloticus</em> L.) Fillet during Ice Storage: Effect of Age and Sex

Fish is one of the most highly perishable food products. The aim of this study was to investigate microbiological and chemical changes of Nile tilapia fillet during ice storage. Nile tilapia samples were collected from Lake Zeway, Ethiopia. The fillet was stored at 0°C for 30 days on ice. Total plate count, total and fecal coliform, total volatile base nitrogen and pH was measured at the interval of four days. Regardless of age and sex, Total plate count varied between 4 to 11.74 log cfu/g. Total coliform counts fluctuated between 1100 MPN/g. However fecal coliform changed between 23 to <3 MPN/g. Total volatile base- Nitrogen has increased from 7.5 to 42.0 mg N/100 g. Similarly, pH has increased from 6.1 to 7.6 during the ice storage period. The eventual increase observed in mean total plate count could be due to multiplication of organisms favored at the storage condition. The increased total coliforms may be attributed to fillet quality and temperature fluctuations. The increment in TVB-N during ice storage is associated with activity of micro-organisms during later stages of deterioration. The increase in pH values is due to the formation of basic decomposition products. Finally, Post mortem change of Nile tilapia fillet was noticed and bacterial metabolites like Total volatile base-nitrogen, Total plate count and pH were invariably increased throughout the storage time indicating that they are good parameters to predict shelf life.

Economic costs of epidemic malaria to households in rural Ethiopia

To estimate the direct and indirect costs of malaria morbidity among communities in an epidemic area in rural Southcentral Ethiopia. Community-based cross-sectional study of 2195 households in Adami Tulu district from October to November 2003. Treatment-seeking behaviour, expenditure on treatment and transportation, interruption of normal activities, time lost from working and household expenditure on preventive methods were ascertained through interview. Of 12,225 surveyed individuals, 1748 (14.3%) reported perceived malaria during the preceding 2 weeks. 77.1% sought any form of care and 70% had recovered at the time of interview. The average treatment cost per patient at private clinics was Birr 24.00 ($2.76) and Birr 12.50 ($1.44) at public facilities. The average estimated direct cost of malaria per patient was Birr 14.00 ($1.60); the average indirect cost, Birr 35.26 ($4.08). Only 5% of all households reported any preventive expenditure in the preceding month, with a mean of Birr 0.76 ($0.09). Malaria poses a significant economic burden on rural households and individuals both through out-of-pocket payment and person-days lost. The promotion and implementation of insecticide-treated nets would alleviate the economic consequences of the disease.