Malaria transmission in the vicinity of impounded water: evidence from the Koka Reservoir, Ethiopia

Malaria / Waterborne diseases / Disease vectors / Habitats / Disease control / Entomology / Epidemiology / Surveys / Dams / Reservoirs / Villages / Case studies / Africa / Ethiopia / Koka Reservoir / Rift Valley / Awash River Basin

Bacteriological and physico-chemical quality of drinking water sources in a rural community of Ethiopia

Background: Accesses to safe water is a universal need however, many of the world’s population lack access to adequate and safe water. Consumption of water contaminated causes health risk to the public and the situation is serous in rural areas.Objectives: To assess the bacteriological and physico-chemical quality of drinking water sources in a rural community of Ethiopia.Methods: Water samples were collected from tap, open springs, open dug wells and protected springs for bacteriological analysis of total coliforms and thermotolerant coliforms. The turbidity, pH and temperature were measured immediately after collection.Results: Most drinking water sources were found to have coliform counts above the recommended national and international guidelines and had high sanitary risk scores. There was a statistically significant difference among water sources with respect to TC and TTC (p < 0.05) and there was a statistically significant positive correlation between coliform counts and sanitary risk scores (p < 0.01). Most water sources didn’t satisfy the turbidity values recommended by WHO.Conclusion: The water sources were heavily contaminated which suggested poor protection and sanitation practice in the water sources. Source protection strategies as well as monitoring are recommend for this community.Keywords: Coliforms; physico-chemical; rural community; water qualityAfrican Health Sciences 2013; 13(4): 1156- 116

Bone repair and regenerative biomaterials: Towards recapitulating the microenvironment

© 2019 by the authors. Biomaterials and tissue engineering scaffolds play a central role to repair bone defects. Although ceramic derivatives have been historically used to repair bone, hybrid materials have emerged as viable alternatives. The rationale for hybrid bone biomaterials is to recapitulate the native bone composition to which these materials are intended to replace. In addition to the mechanical and dimensional stability, bone repair scaffolds are needed to provide suitable microenvironments for cells. Therefore, scaffolds serve more than a mere structural template suggesting a need for better and interactive biomaterials. In this review article, we aim to provide a summary of the current materials used in bone tissue engineering. Due to the ever-increasing scientific publications on this topic, this review cannot be exhaustive; however, we attempted to provide readers with the latest advance without being redundant. Furthermore, every attempt is made to ensure that seminal works and significant research findings are included, with minimal bias. After a concise review of crystalline calcium phosphates and non-crystalline bioactive glasses, the remaining sections of the manuscript are focused on organic-inorganic hybrid materials

Sol-gel derived tertiary bioactive glass–ceramic nanorods prepared via hydrothermal process and their composites with poly(Vinylpyrrolidone-Co-Vinylsilane)

© 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). Bioactive glass (BG) nanoparticles have wide applications in bone repair due to their bone-bonding and biodegradable nature. In this work, nanometric rod-shaped ternary SiO2-CaO-P2O5 bioactive glass particles were prepared through sol-gel chemistry followed by a base-induced hydrothermal process at 130 ◦C and 170 ◦C for various times up to 36 h. This facile, low-temperature and surfactant-free hydrothermal process has shown to be capable of producing uniform nanorods and nanowires. One-dimensional growth of nanorods and the characteristics of siloxane bridging networks were dependent on the hydrothermal temperature and time. Hardened bioactive composites were prepared from BG nanorods and cryo-milled poly(vinylpyrrolidone-co-triethoxyvinylsilane) in the presence of ammonium phosphate as potential bone graft biomaterials. Covalent crosslinking has been observed between the organic and inorganic components within these composites. The ultimate compressive strength and modulus values increased with increasing co-polymer content, reaching 27 MPa and 500 MPa respectively with 30% co-polymer incorporation. The materials degraded in a controlled non-linear manner when incubated in phosphate-buffered saline from 6 h to 14 days. Fibroblast cell attachment and spreading on the composite were not as good as the positive control surfaces and suggested that they may require protein coating in order to promote favorable cell interactions

Fabrication and In-Situ Cross-linking of Carboxylic Acid-Functionalized Poly(ester amide) Scaffolds for Tissue Engineering

Three-dimensional (3D) scaffolds are important tools for tissue engineering, and should ideally provide both biochemical cues and biomechanical support for cells. Poly(ester amide)s (PEAs) have emerged as promising materials for the preparation of tissue engineering scaffolds and the pendant side chains of residues such as ʟ-lysine and ʟ-aspartic acid can provide sites for the conjugation of biochemical signals. However, it has been challenging to combine scaffold morphological stability with the presentation of reactive groups on PEA scaffolds. We describe here a new approach involving the functionalization of a ʟ-lysine-containing PEA with maleic anhydride to simultaneously introduce cross-linkable alkenes and carboxylic acid conjugation sites. Maleic-acid-functionalized PEA was processed to form 3D scaffolds using a salt leaching method and the scaffolds were cross-linked in situ using a poly(ethylene glycol) dimethacrylate cross-linking agent by thermal free radical curing. Micro-computed tomography analysis indicated that the cross-linked scaffolds had higher polymer volume fraction, lower porosity, and smaller pore size than the non-cross-linked scaffolds, but both scaffolds exhibited high morphological stability and negligible mass loss upon incubation in phosphate buffered saline for 5 days. The Young’s moduli of the cross-linked and non-cross-linked scaffolds were 28 and 9 kPa respectively. Fluorescein-labeled bovine serum albumin was successfully conjugated to the scaffolds using a carbodiimide-based coupling. Finally, it was shown that the scaffolds supported the attachment and proliferation of mouse embryonic mesenchymal multipotent cells, showing their promise as platforms for tissue engineering applications

Seismicity and crustal structure of the southern main Ethiopian rift: new evidence from Lake Abaya

The Main Ethiopian Rift (MER) has developed during the 18 Ma-Recent separation of the Nubian and Somalian plates. Extension in its central and northern sectors is associated with seismic activity and active magma intrusion, primarily within the rift, where shallow (urn:x-wiley:15252027:media:ggge22586:ggge22586-math-00015 km) seismicity along magmatic centers is commonly caused by fluid flow through open fractures in hydrothermal systems. However, the extent to which similar magmatic rifting persists into the southern MER is unknown. Using data from a temporary network of five seismograph stations, we analyze patterns of seismicity and crustal structure in the Abaya region of the southern MER. Magnitudes range from 0.9 to 4.0; earthquake depths are 0–30 km. urn:x-wiley:15252027:media:ggge22586:ggge22586-math-0002 ratios of urn:x-wiley:15252027:media:ggge22586:ggge22586-math-00031.69, estimated from Wadati diagram analysis, corroborate bulk-crustal urn:x-wiley:15252027:media:ggge22586:ggge22586-math-0004 ratios determined via teleseismic P-to-S receiver function H-urn:x-wiley:15252027:media:ggge22586:ggge22586-math-0005 stacking and reveal a relative lack of mafic intrusion compared to the MER rift sectors to the north. There is a clear association of seismicity with the western border fault system of the MER everywhere in our study area, but earthquake depths are shallow near Duguna volcano, implying a shallowed geothermal gradient associated with rift valley silicic magmatism. This part of the MER is thus interpreted best as a young magmatic system that locally impacts the geothermal gradient but that has not yet significantly modified continental crustal composition via rift-axial magmatic rifting

The effect of physical water quality and water level changes on the occurrence and density of <i>Anopheles</i> mosquito larvae around the shoreline of the Koka reservoir, central Ethiopia

Entomological studies to determine the effect of the physical characteristics of mosquito larval breeding water bodies and reservoir water level changes on the occurrence of Anopheles mosquito larvae were conducted in two villages at Koka reservoir in central Ethiopia between August and December 2007. Of the two study villages, Ejersa is located close to the reservoir, and Kuma is 5 km away from it. Data on the type, number and physical characteristics of Anopheles larval breeding habitat, species composition and densities of anopheles mosquitoes in and around the study villages were investigated and recorded. Meteorological and reservoir water level data were compared with availability of Anopheles larval breeding sites and densities. Entomological data, derived from weekly larval collections, showed that Anopheles pharoensis Theobald, Anopheles gambiae s.l. Giles, Anopheles coustani Laveran and Anopheles squamosus Theobald were breeding in the study area. The mean larval density of An. gambiae s.l. in this study was higher in slightly turbid and shallow aquatic habitat than in turbid and relatively deep aquatic habitat. The density of An. pharoensis in habitat with floating vegetation and with relatively shady conditions was significantly higher than that of less shaded aquatic habitat and greater emergent vegetation. There was also a positive correlation between the occurrence of Anopheles larvae with the water and daily minimum atmospheric temperature. Similarly at Ejersa, over the sampling period, there was a positive correlation between falling reservoir water levels and the number of positive breeding habitats. These results confirm that physical characteristics of the water bodies play an important role in the species composition, total Anopheles larval count, and the density of Anopheles mosquitoes. Suitable breeding habitat in the vicinity of the reservoir village was strongly associated with the reservoir. This is particularly important for An. pharoensis and An. gambiae s.l. which are important vectors of malaria in the area

Mortality rate among HIV-positive children on ART in Northwest Ethiopia: a historical cohort study.

BackgroundThough highly active antiretroviral therapy (HAART) has been available for more than a decade in Ethiopia, information regarding mortality rates of human immunodeficiency virus (HIV)-positive children after antiretroviral therapy antiretroviral therapy (ART) initiation is very scarce. Thus, this study intends to determine the predictors of mortality among HIV-positive children receiving ART in Amhara Region.MethodsA multicenter facility-based historical cohort study was conducted in 538 HIV-positive children on ART from January 2012 to February 2017. We employed a standardized data extraction tool, adapted from ART entry and follow-up forms. Descriptive analyses were summarized using the Kaplan-Meier survival curve and log rank test. Then, the Cox-proportional hazard regression model was employed to estimate the hazard of death up to five-years after ART initiation. Variables with p-values ≤0.25 in bivariable analysis were candidates to the multivariable analysis. Finally, variables with p-values ResultsThe cohort contributed a total follow-up time of 14,600 child-months, with an overall mortality rate of 3.2 (95% CI: 2.3, 4.3) per 100 child-years. This study also indicated that HIV-infected children presenting with opportunistic infections (OIs) (AHR: 2.5, 95% CI: 1.04, 5.9), anemia (AHR: 3.1, 95% CI: 1.4, 6.7), severe immunodeficiency (AHR: 4.4, 95% CI: 1.7, 11.7), severe stunting (AHR: 3.3, 95% CI: 1.4, 8.0), severe wasting (AHR: 3.1, 95% CI: 1.3, 7.3), and advanced disease staging (III and IV) (AHR: 3.0, 95% CI: 1.2, 7.1) were at higher risk of mortality.ConclusionA higher rate of mortality was observed in our study as compared to previous Ethiopian studies. HIV-positive children presenting with anemia, OIs, severe immunodeficiency, advanced disease staging (III and IV), severe stunting, and severe wasting were at higher risk of mortality