Browsing by Author "Dugassa, Sisay (PhD)"

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    Assessment of Pesticide Use and Disposal in Gida Ayana District, Western Oromia, Ethiopia
    (Addis Ababa University, 2019-08-08) Olani, Dugassa; Dugassa, Sisay (PhD)
    Pesticides are poisonous chemicals used to kill insects, fungus, bacteria and other organisms that affect crops and transmit diseases to the public. They also have veterinary importance – they kill ticks that affect livestock health. The chemicals destroy herbs (weeds) and animals causing harm to the health of the livestock. The Ethiopian agricultural sector has the potential to drive the country’s economic development. It ensures food security of its people and brings about industrial transformation. Agriculture is major source of income and occupation in the study area. Promoting sustainability of the sector requires using improved agricultural technologies. Pesticides are such technologies that enable farmers to control pest and weeds in order to increase agricultural yields, and thereby provide a number of benefits to the society. The study is done in Gida Ayana district, West Oromia, Ethiopia. Out of 27 Kebeles of the district, three Kebeles were purposively selected for study. The research design was survey research, and open and closed-ended questions were prepared and distributed to a total of 182 respondents. Of these 156 responded to the questionnaires. The response rate is 85.71%. Based on this comparative study was conducted on pesticides use taking the three Kebeles as units of analysis. The research findings indicated that pesticides are widely used in the study area. Most of these are used against anti-crop pests/insects and weeds in order to increase crop production. About 75.82% of the respondents use pesticides for different purposes. The study further indicated that Glyphosate, Glymax, Glycel, 2, 4-D, and Zura herbicides are largely used in the study area. Majority of the users have no adequate knowledge of the health effects of the pesticides. About 33.5% of the respondents indicated they dispose in the agricultural fields where the chemicals are used. The use of pesticides is not restricted to agricultural fields. They are also used in homes. Improper disposal of the chemicals causes health problems to the people themselves and their livestock. The chemicals also contaminate the environment. Proper disposal of the unwanted pesticides is one of the important tasks of responsible user. Improper disposal can lead to contamination of environment and pesticide users, it is necessary to encourage farmers to use alternative methods of cultivation. Every user of pesticides needs to know the benefits and risks of the chemicals.
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    Distribution of Tsetse fly and the Prevalence of Bovine Trypanosomasis, in Hawa Galan District Western Oromia, Ethiopia
    (Addis Ababa University, 2018-08-08) Alemayehu, Temesgen; Dugassa, Sisay (PhD)
    Livestock farming is a major part of African agricultural sector and plays an important role in food and economic security though provision of a variety of products and services including hides, skins, milk, meat, drought power, manure fiber and energy and capital accumulation. Trypanosomiasis is distributed in natural herds particularly in Africa where tsetse flies are present. Ethiopia is one of the countries which are affected by trypanosomiasis. A cross sectional study was conducted in Hawa Gelan district of Kellem Wollega Zone, Oromia Regnal State western Ethiopia from September 2017 to July 2018 to study the distribution of tsetse flies and prevalence of Bovine trypanosomiasis. Simple random sampling was used to select 384 cattle from five peasant association for collection of blood sample and 50 traps (10/site) were deployed in this peasant association. Buff coat technique was used to determine prevalence of bovine trypanosomiasis in the study area. The blood sample was examined and it was found that 24 (6.25%) were parasite positive. The prevalence was significant in age group, sex and peasant association. The most common trypanosoma species identified, Trypanosoma conglense, was 16 (66.66%) higher than that of the prevalence of Trypanosoma vivax 7 (29.16%) and Trypanosoma brucie 1(4.16%). Adult animals were relatively more prone to high infection rate 6.94% than young animals 4.54% and higher prevalence of trypanosomiasis infection was observed in animals with poor body condition and low packed cell volueme (PCV) value animals. Out of 24 trypanosomiasis positive animals 75% had PCV< 24%, i.e., they were both infected and anemic. This clearly shows that, PCV value can be affected by trypanosomiasis. The mean PCV value of the present finding of parastemic (20.75) and was significantly lower than aparastemic animals (26.62). The trap was deployed before sun for 48 hours. 259 flies were caught during survey, acetone octanol and cow urine were used as attractants. Out of these flies 78 (35.13%) were the Glossina species and the rest 181 (69.86%) were biting flies. The major Glossina species identified were 65.3% (51/78) Glossina tachinoides and 34.6% (27/78) Glossina morrsitance sub moristans. The apparent densities of different flies during the study period 0.8fly/trap/day for tsetse species and 2.6 flies/trap/day. Finally, to minimize the disease vector tsetse implementing control method with integrated approach is essential for sustainable benefit from cattle.
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    Investigation of Factors that Affect Beekeeping and Honey Production Practices in Sayo District, Western Oromia, Ethiopia.
    (Addis Ababa University, 2018-09-09) Tesfa, Tizazu; Dugassa, Sisay (PhD)
    Beekeeping is a long-standing practice in the rural communities of Ethiopia and appears as ancient history of the country. Despite the long tradition of beekeeping in Ethiopia and having potential for beekeeping, the beekeepers in particular and the country in general are not well benefited from the sub-sector. Moreover, the study area is covered with natural vegetations, shrubs and man-made forest, annual and perennial crops which create conducive environment for beekeeping. However, beekeeping activities are still at low level and could not exploit the existing potential. The main objective of this research was to assess the factors that affect development of beekeeping and honey production in the study area. Household survey and key informant interview were used to collect primary data. To conduct the household survey structured questionnaire was prepared in English language first and translated to mother tongue. In order to collect primary data multiple stage technique of sampling was employed. Accordingly, three sample kebeles were selected purposively and 90 sample beekeepers were selected using simple random sampling technique. Households‟ survey data was analyzed using descriptive statistics; percentages, frequencies. It was found that shortages of bee forages, application of pesticides and herbicides, pests and predators, previously unknown and recently emerged red color flower, farmers inclination to traditional beekeeping method, lack of extension services, expensiveness of improved hives and lack of allocation of budget for beekeeping activities, absence of man-power who have specialized in apiculture are the major factors that hindered the development of beekeeping in the study area. Based on the findings of the study the researcher recommends: Education for beekeepers how to prevent enemies of bees, mobilizing the community to destroy the recently arriving poisonous plant, an arrangement to make improved hives, strong extension services, sustainable awareness creation activities among the farmers with respect to beekeeping activities, recruitment of man-power specialized in beekeeping, budget allocation specific to beekeeping activities, attention in producing professionals who have specialized in apiculture and adoption of policy specific to beekeeping sub-sector.
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    Isolation and Identification of Microflora From the Midgut and Salivary Glands of Laboratory Reared and Field Collected Anopheles Species from Some Malaria Endemic Areas of Ethiopia
    (Addis Ababa University, 2018-04-01) Berhanu, Abib; Tekie, Habte (PhD); Dugassa, Sisay (PhD)
    Anopheles mosquitoes are of great importance to human health. They transmit pathogens including malaria parasites, filarial worms, and O'nyong-nyong and rift valley viruses. The numbers of studies have shown that, midgut and salivary gland microflora have an impact on malaria parasite burden through colonization mechanisms, involving either direct Plasmodium microbiota interaction or bacterial mediated induction of mosquito immune response. The objective of this study was to isolate and identify the microflora from the midgut and salivary gland of laboratory reared and field collected Anopheles species in some malaria endemic areas of Ethiopia. A total of twenty pools of mosquitoes, ten per pool (insectary), and ten pools, thirty per pool (field collected) were anesthetized by chloroform and dissected. 70% of ethanol was used for surface sterilization of mosquitoes followed by washing of each pool four times by 1x PBS and the environment. Each pool of dissected midgut and salivary gland samples was transferred in 3ml phosphate buffer saline, squashed and incubated in water bath until enriched in tryptic soya broth for 24hrs at 35±2oc. After enrichment, a loopful of each sample was taken and inoculated on Blood, Chocolate, Mac Conkey and Sabouraud dextrose agar for 24 hrs. at 35±2oc. Finally, the microbiota was isolated based on their colony characteristics and identified by conventional biochemical tests and automated VITEK 2 Compact Analyzer. All identified microbiota was stored in 20% tryptic soya broth with glycerol at -80 oc. From all field collected and insectaries, Pseudomonas 38 (29%) was found to be the dominant microbiota from all species. Anopheles gambiae s.l 77 (50.33%) had got the largest number of microbiota identified and An. arabiensis had identified diversified types of microbiota from the rest species. From this report, 40 genera of microbiota were identified and can be a milestone for studying relationship between microbiota and mosquitoes and for the development of a new malaria control strategy.
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    Larvicidal and Adulticidal Effects of Some Selected Plant Extracts Against Anopheles Stephensi Liston (Culicidae: Diptera) Under Laboratory Condition
    (Addis Ababa University, 2021-09-21) Muhammed, Merdya; Gebresilassie, Araya (PhD); Dugassa, Sisay (PhD)
    Mosquitoes that belong to the genus Anopheles are among the major vectors of vector-borne diseases (VBDs). Among VBDs, malaria plays a crucial role in public health challenges worldwide. The use of synthetic insecticides to control malaria vectors causes resistance, environmental toxicity and kills non-target animals. Thus, it is imperative to seek a relatively safe and effective alternative tool to the currently available mosquitocidal products. Natural herbal products with insecticidal properties would play an important role in resolving this problem. Therefore, the current study aimed to assess the effects of crude leaf solvent extracts of Calpurnia aurea, Momordica foetida, and Zehneria scabra against the laboratory colony of larvae and adults of An. stephensi. Fresh leaves of test plants were collected, air dried, and then separately ground to powder. The powders were soaked in aqueous, hexane, and methanol solvents. The extracts were concentrated, and a stock solution was prepared to desired test concentration. For comparison, temephos (larvicide) and untreated solutions were used as the standard and negative controls, respectively. Mortality was observed after 24 hrs recovery period. The statistical analyses were performed using SPSS software (Kruskal-Wallis test), and R software (a generalized linear model was used to determine LC50 and LC90 values of the extracts). Larvicidal activity between treatments, negative control, and standard groups were significant differences (P < 0.05). Among the test extracts, the lowest LC50 and LC90 values were recorded in larvae treated with aqueous extract of M. foetida with 34.61 ppm and 57.61 ppm, respectively followed by Z. scabra (LC50 = 35.85 ppm; LC90 = 68.26 ppm) and C. aurea (LC50 = 38.69 ppm; LC90 = 108.28 ppm). Larval mortality was not observed from the hexane and control treatments, while the temephos achieved 100%. In addition, aqueous extract of Z. scabra showed the most effective adulticidal action in An. stephensi with LC50 and LC90 values of 176.20 ppm and 425.13 ppm, respectively. The results suggest that the leaf extracts of the three test plants have the potential of being used for the control of An. stephensi instead of synthetic mosquitocides. Further studies need to be conducted to identify the active ingredients and their mode of action.
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    Species Composition and Abundance of Mosquitoes in Selected Areas of Gobu Sayo District, West Oromia, Ethiopia.
    (Addis Ababa University, 2018-09-09) Dugasa, Mekonnen; Dugassa, Sisay (PhD)
    Prior to implementing vector control, it is always important to have baseline information about the species present and their densities. This study was conducted in selected areas of Gobu Sayo district East Wollega Zone, West Oromia, Ethiopia between September and August; 2018. It was intended to identify mosquito species present and estimate their abundance. Hand collection, spray sheet collection and hand net collection methods were used. It was investigated that Anopheles; Culex and Aedes mosquitoes are widely found in the study areas. The mosquitoes belong to Family Culicidae ;- ( subfamily anophelinae and culicinae). Those mosquitoes were morphologically identified by using identification key under compound microscope based on their morphological characteristics. Anopheles were 600, the most predominant in all the selected areas. The second most abundant was culicine mosquitoes 260 followed by Aedes 40. Generally, 900 individual adult mosquitoes were sampled from the three kebeles. The main rainy season usually extends from June to August and short rainy season occurs in March to May. The mosquitoes appear abundantly following the short rainy season (March to May) and the main rainy season (September to December). The principal malaria vectors, female Anopheles mosquitoes are abundant in the district.
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    Species Composition Distribution and Ecology of Anopheles Mosquitoes in Relation to Malaria Transmission and Control in Dembiya District Northwestern Ethiopia
    (Addis Ababa University, 2022-05-04) Tarekegn, Mihretu; Dugassa, Sisay (PhD)
    Malaria is an important vector borne disease transmitted by the infective bite of female Anopheles mosquitoes in malaria endemic areas in Ethiopia. Malaria vector control requires field and clinical data on malaria transmission and ecology of local vectors. A six-year retrospective malaria data set from health facilities was analyzed to determine trends in malaria prevalence in the two malaria-prone areas of Dembiya District, Northwestern Ethiopia. A cross-sectional parasitological study was conducted to determine the prevalence of malaria during the peak transmission season in the two Kebeles of Dembiya district. A longitudinal entomological study on the species composition and ecology of adult and immature Anopheles mosquitoes was conducted from June 2018 to May 2019. Larvae and pupae of Anopheles mosquitoeswere collected from different mosquito breeding habitats using a 350 ml standard dipper, and physicochemical characteristics of the larval breeding habitats were measured in conjunction with larval sampling. CDC light traps, pyrethrum spray catches (PSCs) and artificial pit shelters were used to collect host seeking and resting Anopheles mosquitoes from indoors and outdoors. Using morphological keys, collected Anopheles mosquitoes were identified to the species level and An. gambiae s.l (sensu lato) were further identified to sibling species using polymerase chain reaction (PCR). Enzyme-linked immunosorbent assay (ELISA) was used to examine the blood meal source of blood fed Anopheles mosquitoes, and to detect Plasmodium species using circum-sporozoite proteins (CSP). A WHO test tube bioassay was used to assess the susceptibility status of Anopheles arabiensis to four insecticides such as pyrethroids, deltamethrin, bendiocarb and fenitrothion. Malaria is endemic in the area according to retrospective malaria data from health facilities. Over the past six-years, the overall prevalence of malaria cases was 22.4% (484/2157). Plasmodium falciparum was responsible for 75.1 % (367/484) of the malaria cases in the study area, while P. vivax was responsible for 18.2% (88/484) the malaria cases. The remaining 5.9% (29/484) were mixed infections. Malaria parasites were found in 3.5% (26) of 735 blood smears stained with 3% geimsa and microscopically examined slides. Plasmodium falciparum and P. vivax were responsible for 65% (17) and 19% (5/26) of the malaria infection, respectively, with 15% (4/26) being mixed infections. Males (18/382; 4.7%) were 2.6 times more likely to be infected with malaria than females (8/353; 2.3%) (AOR = 2.6; 95% CI: 1.041- 6.412; p= 0.041). A total of 1,629 Anopheles larvae and 185 pupae were collected from different breeding habitats. Eight species of Anopheles mosquitoes were identified from female mosquitoes that emerged from field collected larvae and pupae, including Anopheles arabiensis, An. pharoensis, An. coustani, An. christyi, An. squamosus, An. demeilloni, An. danicalicus and An. cinereus. Anopheles arabiensis (59.2%) was the most common followed by An. pharoensis (35.3%). Anopheles mosquitoes belonging to 11 species were identified from 2,055 field collected adult specimens during this study: An. pharoensis, An. arabiensis, An. coustani, An. demeilloni, An. cinereus, An. funestus, An. ardensis, and An. squamosus were identified from both Guramba Bata and Arebiya study sites, whereas An. garnhami, An. christyi and An. nili were identified only from Guramba Bata. Anopheles pharoensis was the dominant species identified in both Arebiya and Guramba Bata study sites, accounting for 46.4% (953/2,055), while An. Arabiensis was also relatively dominant in both study sites (38.3%; 776/2055). Anopheles larvae were more abundant in drainage canals (14.7 ± 3.5 larvae/dip) than in other types of breeding habitats such as river side pools (2.0 ± 0.9), hoof prints (3.0 ± 1.2), swamps (3.8 ± 1.2), and puddles (2.7 ± 2.7) (F8,99 = 9.85; p<0.001). The presence or absence of Anopheles larvae was associated with physical characteristics of larval breeding habitats such as turbidity (mid turbid) (AOR = 66.03; 95% CI: 2.01-2168.24, p= 0.019) and presence of grass (AOR= 12.62; 95% CI: 1.29-122.78, p= 0.029). The mean outdoor density of Anopheles mosquitoes collected with a CDC light trap (4.8 ± 1.8 mosquitoes/trap/night) was slightly higher than mean indoor density of Anopheles mosquitoes (4.3 ± 1.7 mosquitoes/trap/night) in Arebiya study site. Similarly, in Guramba Bata, the mean density of outdoor Anopheles mosquito collected with CDC light trap (8.1 ± 2.6 mosquitoes/trap/night) was higher than indoor Anopheles mosquito density (5.5 ± 1.7 mosquitoes/trap/night). The human blood indices (HBI) of indoor and outdoor hosts seeking An. arabiensis were 17.4% and 15.3%, respectively. The overall sporozoite rate of An. arabiensis, An. pharoensis and An. coustani was 0.3%, 0.9% and 5.9%, respectively. Whereas, the annual Entomological inoculation rate (EIR) of outdoor hosts seeking An. arabiensiswas 4.7 infective bites/person/year. Anopheles arabiensis was resistant to deltamethrin and permethrin. In conclusion, the dominant Anopheles vector species in the study area were An. arabiensis and An. pharoensis.The season, and type and physicochemical characteristics of the breeding habitats, influenced the distribution of Anopheles mosquitoes. Anopheles arabiensis, An. pharoensis and An. coustani showed relatively strong exophilic, exophagic and zoophilic tendencies in the study area, which was likely influenced by decades of indoor malaria interventions with IRS and ITNs. Anopheles arabiensis has developed resistance to pyrethroids and deltamethrin that have been used over the years. As a result, malaria control and elimination programmes should target outdoor biting and resting Anopheles mosquitoes with appropriate resistance management measures.
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    Studies on the Spatial Ecology of Malaria and the Impact of Mass Trapping of Anopheles Mosquitoes on Malaria Transmission in Southern Ethiopia
    (Addis Ababa University, 2020-07-06) Debebe, Yared; Tekie, Habte (PhD); Ignell, Rickard (Professor); Rose, Sharon (PhD); Hopkins, Richard (Professor); Dugassa, Sisay (PhD)
    The sustainability of current indoor vector control methods is challenged by the emergence of insecticide resistance in malaria mosquito populations and the behavioural shift of vectors, resulting in increased outdoor biting activities. As a result, there is a dire need for novel vector control tools, which complement the existing strategies, particularly targeting the outdoor-active mosquitoes. Effective control of mosquitoes outdoors can be achieved through in-depth understandings of their spatial and behavioural ecology. The effect of landscape elements on the resting site selection of the outdoor Anopheles mosquito population was assessed. Fine-scale characterization of landscape factors within 10 m radius from resting clay pots was conducted and their association with the number of resting anophelines was determined. Canopy cover, distance from the nearest focal house, and land cover type significantly influenced the aggregation of resting mosquitoes. Canopy cover was the strongest predictor for both the number and presence of Anopheles mosquitoes in the clay pots. Female Anopheles were most frequently found resting in the pots placed within the banana plantations, and at sampling points that were ≥75 m from the focal house. To identify the factors underlying hotspots for higher vector densities and malaria incidence, and associated landscape features, monthly entomological monitoring, and fourstage repeated seasonal malaria prevalence surveys were conducted in two rural villages in southern Ethiopia. Moreover, characterization of the landscape features in and around every household of the study villages was conducted. Spatial analyses using Getis-Ord Gi* statistics were used to identify hotspots for malaria incidence, as well as malaria vector density and associated sporozoite prevalence. The result from the regression models revealed that household occupancy, location and housing conditions were the main iv predictors of vector density, entomological inoculation rate, and malaria incidence. The spatial analyses revealed that statistically significant hotspots for malaria vector densities and Plasmodium-infected individuals were identified at village edges. The impact of mass trapping of Anopheles mosquitoes using odour-baited traps was assessed in a controlled before-and-after study design in two rural villages of Southern Ethiopia. Baseline monthly entomological and seasonal cross-sectional malaria prevalence surveys were conducted in the two villages for a year. Then, mass trapping was implemented in one of the villages immediately before the beginning of the rainy season, while the monthly entomological monitoring and the seasonal malaria prevalence surveys continued in both villages for nine months, throughout the long and short rainy seasons. The impact of the mass trapping was then assessed by computing the relative reduction of entomological indices and malaria incidence in the intervention village in a seasonal comparison with the control village. The mass trapping resulted in a significant reduction in the population of the primary malaria vector in the area, An. arabiensis and the associated entomological indices (the human biting-, sporozoite-, and entomological inoculation rates) in the intervention compared to the control village. This resulted in a relative reduction of malaria incidence by 61 %, 44 %, and 49 % in the long rain, short rain, and dry seasons, respectively.
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    Study on Prevalence of White Mango Scale and their Management Options in Alge Sachi District of Illu Aba Bora Zone, Oromia Regional State, Ethiopia
    (Addis Ababa University, 2019-08-08) Ayana, Tsegaye; Dugassa, Sisay (PhD)
    Tropical and sub-tropical fruits make a significant direct contribution to the subsistence of small–scale farmers by providing locally generate nutritious food that is often available when other agricultural crops have not yet been harvested. Mango (Mangifera indica L) is the third most important fruit crop in the tropics and sub-tropics following Citrus and Banana. It is consumed as a fresh fruit and different form of preparations for its high contents of sugars, vitamins, minerals, protein and known to play a vital role in export and import business. Mango suffers from several diseases and insect pests and its trunk, branches, leaves, petiole, flower and fruit are attacked at all stages of its development It spread and has become a threat to mango production in almost all Oromia zones of the districs and the kebeles and affected economic benefits of mango farmers. The objectives of this study was to assess the status and prevalence of white mango scales infestation, distribution and the existing capacities to control the pest at Wayoseko kebele of AlgeSachi district of Illuababora zone of Oromia Regional State. From the current study, white mango scale was the crucial mango production limiting factor in Illuababora zone of AlgeSachi District because of its high rate of dispersal in all mango plantations in the vicinity. The data were collected randomly from January 10/5/2011 to June 10/10/2011 from the orchard of Green focus through observation, interview and Questionnaire which distributed for purposefully sampled population. The result of study showed that high population peaks of WMS was recorded and distributed from its original point with high and very high infestations across district and kebeles in km. Most mango grower farmers used cultural methods to control the pests. The current study concluded that WMS was spreading very fast across district and kebeles from it first locus, and it is recommended that the infestation on mango can be reduced by the use of farmer’s indigenous knowledge of pest management practice.