Worku Legesse

Urban impact on ecological integrity of nearby rivers in developing countries: the Borkena River in highland Ethiopia

Accelerated pollution and eutrophication of rivers and streams because of human activity are a concern throughout the world and severe in Africa where Ethiopia is case in point. The objective of this study was to assess the urban impact on the ecological integrity of the Borkena River at the eastern escarpment of the central Ethiopian highlands. The water quality status and macroinvertebrate distribution and diversity of the river were assessed during the dry and wet seasons. Diversity indices revealed that a severe decline in the ecological integrity of the Borkena River downstream of Dessie and within Kombolcha towns in terms of macroinvertebrate abundance and composition. Clustering and ordination analysis clearly separated reference sites from urban impacted sites. At the urban-impacted sites, dissolved oxygen was also depleted to 0.5 mg/l and BOD5 values were reached to a level of above 1,000 mg/l, with extremely low biological diversity of pollution-sensitive taxa. These patterns are the result of a combination of rampant dumping of untreated wastes exacerbated by geologic, topographic, climatic and land use factors.

Physico-chemical and biological characterization of anopheline mosquito larval habitats (Diptera: Culicidae): implications for malaria control.

BackgroundA fundamental understanding of the spatial distribution and ecology of mosquito larvae is essential for effective vector control intervention strategies. In this study, data-driven decision tree models, generalized linear models and ordination analysis were used to identify the most important biotic and abiotic factors that affect the occurrence and abundance of mosquito larvae in Southwest Ethiopia.MethodsIn total, 220 samples were taken at 180 sampling locations during the years 2010 and 2012. Sampling sites were characterized based on physical, chemical and biological attributes. The predictive performance of decision tree models was evaluated based on correctly classified instances (CCI), Cohen’s kappa statistic (κ) and the determination coefficient (R2). A conditional analysis was performed on the regression tree models to test the relation between key environmental and biological parameters and the abundance of mosquito larvae.ResultsThe decision tree model developed for anopheline larvae showed a good model performance (CCI = 84 ± 2%, and κ = 0.66 ± 0.04), indicating that the genus has clear habitat requirements. Anopheline mosquito larvae showed a widespread distribution and especially occurred in small human-made aquatic habitats. Water temperature, canopy cover, emergent vegetation cover, and presence of predators and competitors were found to be the main variables determining the abundance and distribution of anopheline larvae. In contrast, anopheline mosquito larvae were found to be less prominently present in permanent larval habitats. This could be attributed to the high abundance and diversity of natural predators and competitors suppressing the mosquito population densities.ConclusionsThe findings of this study suggest that targeting smaller human-made aquatic habitats could result in effective larval control of anopheline mosquitoes in the study area. Controlling the occurrence of mosquito larvae via drainage of permanent wetlands may not be a good management strategy as it negatively affects the occurrence and abundance of mosquito predators and competitors and promotes an increase in anopheline population densities.

High load of multi-drug resistant nosocomial neonatal pathogens carried by cockroaches in a neonatal intensive care unit at Tikur Anbessa specialized hospital, Addis Ababa, Ethiopia

BackgroundCockroaches have been described as potential vectors for various pathogens for decades; although studies from neonatal intensive care units are scarce. This study assessed the vector potential of cockroaches (identified as Blatella germanica) in a neonatal intensive care unit setup in Tikur Anbessa Hospital, Addis Ababa, Ethiopia.MethodsA total of 400 Blatella germanica roaches were aseptically collected for five consecutive months. Standard laboratory procedures were used to process the samples.ResultsFrom the external and gut homogenates, Klebsiella oxytoca, Klebsiella pneumoniae, Citrobacter spp. Enterobacter cloacae, Citrobacter diversus, Pseudomonas aeruginosa, Providencia rettgeri, Klebsiella ozaenae, Enterobacter aeruginosa, Salmonella C1, Non Group A streptococcus, Staphylococcus aureus, Escherichia coli, Acinetobacter spp. and Shigella flexneri were isolated. Multi-drug resistance was seen in all organisms. Resistance to up to all the 12 antimicrobials tested was observed in different pathogens.ConclusionCockroaches could play a vector role for nosocomial infections in a neonatal intensive care unit and environmental control measures of these vectors is required to reduce the risk of infection. A high level of drug resistance pattern of the isolated pathogens was demonstrated.

Assessment of composition and generation rate of healthcare wastes in selected public and private hospitals of Ethiopia

In many developing countries, the inadequacy of data regarding the quantity and composition of healthcare waste is one of the major reasons for improper healthcare waste management. We investigated the generation rate and composition of healthcare wastes in six public and three private hospitals. We conducted healthcare waste composition and characterization measurements for seven consecutive days in the selected hospitals following the protocol described by the World Health Organization (WHO). The results revealed that the total generation rate of healthcare wastes of hospitals ranged from 0.25 to 2.77 kg/bed/day with a median value of 1.67 kg/bed/day for inpatients to 0.21–0.65 in kg/patient/day with a median value of 0.31 kg/patient/day for outpatients. The waste generation rate in private hospitals (median 3.9 kg/bed/day) was significantly greater (Kruskal–Wallis test, P < 0.05) than in government hospitals (median 1.5 kg/bed/day). The median values of percent hazardous waste estimated for private and government hospitals were 63.4% and 52.2%, respectively. These figures are about three times greater than the threshold values recommended by the WHO. This situation might be attributed to the improper practice of healthcare waste segregation by health professionals and auxiliary health workers due to inadequate risk perception and lack of enforced public health regulations. The study revealed that the generation rate and proportion of hazardous waste significantly varies between public and private hospitals and number of patients treated per day.

Solar disinfection: an approach for low-cost household water treatment technology in Southwestern Ethiopia

Disinfection of contaminated water using solar radiation (SODIS) is known to inactivate bacteria. Its inactivation efficiency depends on local conditions where the disinfection is made. This study was aiming to test the efficiency of solar disinfection using different water parameters as low-cost household water treatment technology. Inactivation of microbes was tested using fecal coliform as test organism. The SODIS experiment was carried out at turbidity 2NTU, pH 7, and various water temperature (38.1°C, 41.8°C, 45.6°Cand 51.1°C) and solar intensities, using clear and black plastic bottles filled to different depths. The results show that the rate of microbial inactivation in relation to depth of water, turbidity, container type, intensity of light and color of container was statistically significant (p < 0.05). However, bottle placement, exposure and water pH were unrelated to microbial inactivation. Bacterial re-growth was not observed after solar disinfection. By adjusting the parameters, complete and irreversible fecal coliform inactivation was achieved within an exposure time of less than four hours in the areas where the solar irradiance is about 3.99 kW/m2 and above. Our results indicate that application of SODIS could play a significant role in the provision of safe water in rural communities of developing countries where there is ample sunshine, specifically in sub-Saharan African countries.

A Neglected Resource in Community Development: Participation of Ethiopian Academics in the Development of their Communities

This article examines three community development projects initiated by university educated individuals in or near their places of birth with the aim of presenting evidence that academics can be instrumental in contributing to development in their communities. The three projects used different approaches and resources. The project in Arya Jawi Kebele was developed and managed by a church-linked family association that aimed at broadly based development of this rural district guided by the theological principles of an Ethiopian evangelical church. The project in Kersole Village was initiated and managed by six university educated brothers, four of whom are currently living in the United States. Their primary objective was to help their family and secondly to improve livelihoods in the community. The project in the small town of Azena, conceived and fostered by a professor at Addis Ababa University, focused on the construction of a bridge over a river and several schools, with financial support mainly from several international NGOs. The academics’ familiarity with the needs of and their acceptance by the communities facilitated interaction with local leaders, organizations and craftsmen during the planning and implementation processes and promoted community participation.