Current status of intestinal Schistosomiasis and soiltransmitted helminthiasis among primary school children in Adwa Town, Northern Ethiopia

Background: Epidemiological baseline information on the prevalence and intensity of parasitic infections in a given locality is a prerequisite for development and evaluation of sound control strategies.Objective: To determine the current status of schistosomiasis and soil-transmitted helminthiasis among primary school children in Adwa Town, northern Ethiopia.Methods: A cross-sectional epidemiological study was carried out in eight primary schools in Adwa Town between October and November 2007. Fecal samples of 386 school children in the age group 7-18 were collected andmicroscopically examined using the Kato-Katz and formol-ether concentration methods. A questionnaire was used to identify determinants for Schistosoma mansoni and soil-transmitted helminth infections.Results: The most prevalent intestinal parasitic infection among primary school children in Adwa Town as determined by Kato-Katz (58.7%) and formol ether concentration (60.6%) methods was intestinal schistosomiasis, with an overall intensity of 95.8 eggs per gram of stool. The prevalence of S. mansoni infection was higher in males (70.7%) than in females (57%), as determined by both methods. Less common parasites observed included Ascaris lumbricoides, hookworm species, Hymenolepis nana, Strongyloides stercoralis, and Entamoeba histolytica/dispar.Conclusion: The residents of Adwa Town represent a high-risk community with respect to intestinal schistosomiasis. Hence, mass praziquantel administration to school-age children and all adults considered to be at risk is required once a year until the level of infection falls below the level of public health importance. There is also a need to supplement chemotherapy with other measures such as environmental sanitation and health education to make the impact of chemotherapy sustainable

Microbial genomic taxonomy

A need for a genomic species definition is emerging from several independent studies worldwide. In this commentary paper, we discuss recent studies on the genomic taxonomy of diverse microbial groups and a unified species definition based on genomics. Accordingly, strains from the same microbial species share >95% Average Amino Acid Identity (AAI) and Average Nucleotide Identity (ANI), >95% identity based on multiple alignment genes, 70% in silico Genome-to-Genome Hybridization similarity (GGDH). Species of the same genus will form monophyletic groups on the basis of 16S rRNA gene sequences, Multilocus Sequence Analysis (MLSA) and supertree analysis. In addition to the established requirements for species descriptions, we propose that new taxa descriptions should also include at least a draft genome sequence of the type strain in order to obtain a clear outlook on the genomic landscape of the novel microbe. The application of the new genomic species definition put forward here will allow researchers to use genome sequences to define simultaneously coherent phenotypic and genomic groups

Origin of the reduced exchange bias in epitaxial FeNi(111)/CoO(111) bilayer

We have employed Soft and Hard X-ray Resonant Magnetic Scattering and Polarised Neutron Diffraction to study the magnetic interface and the bulk antiferromagnetic domain state of the archetypal epitaxial Ni$_{81}$Fe$_{19}$(111)/CoO(111) exchange biased bilayer. The combination of these scattering tools provides unprecedented detailed insights into the still incomplete understanding of some key manifestations of the exchange bias effect. We show that the several orders of magnitude difference between the expected and measured value of exchange bias field is caused by an almost anisotropic in-plane orientation of antiferromagnetic domains. Irreversible changes of their configuration lead to a training effect. This is directly seen as a change in the magnetic half order Bragg peaks after magnetization reversal. A 30 nm size of antiferromagnetic domains is extracted from the width the (1/2 1/2 1/2) antiferromagnetic magnetic peak measured both by neutron and x-ray scattering. A reduced blocking temperature as compared to the measured antiferromagnetic ordering temperature clearly corresponds to the blocking of antiferromagnetic domains. Moreover, an excellent correlation between the size of the antiferromagnetic domains, exchange bias field and frozen-in spin ratio is found, providing a comprehensive understanding of the origin of exchange bias in epitaxial systems.Comment: 8 pages, 5 figures, submitte

Performance of CareStart™ Malaria Pf/Pv Combo test for the diagnosis of Plasmodium falciparum and Plasmodium vivax infections in the Afar Region, North East Ethiopia

Background: CareStart™ Malaria Pf/Pv Combo test has shown encouraging results for the diagnosis of P. falciparum and P. vivax infections in Ethiopia. Nevertheless, the performance of the test could be affected by different factors like gene polymorphisms, excess heat and humidity. Hence, evaluation of the performance of the test in different settings in Ethiopia is vital for the routine diagnosis of malaria.Objective: To evaluate the diagnostic performance of CareStartTM Malaria Pf/Pv Combo test for the diagnosis of P. falciparum and P. vivax infections in the Afar Region, Northeast Ethiopia.Methods: Finger prick blood samples were collected from a total of 1092 patients who had malaria symptoms and visited three different health facilities in the Afar Region. Giemsa-stained thin and thick blood smears were prepared and microscopically examined under 100 × magnifications for Plasmodium species identification and determination of parasitaemia. CareStart Malaria Pf/Pv Combo test was also performed as per the manufacturer's instructions. The sensitivity and the specificity of the test was determined using microscopy as gold standard.Results: The sensitivity and specificity of the test were 98.5% and 98.0% respectively, with a positive predictive value (PPV) of 91.7% and a negative predictive value (NPV) of 99.7% for the diagnosis of P. falciparum infection. The corresponding sensitivity and specificity for the diagnosis of P. vivax infection were 100% and 99.6% respectively, with PPV and NPV of 86.2% and 100%, respectively.Conclusion: The results of this study revealed high sensitivity and specificity of CareStartTM Malaria Pf/Pv Combo test for the diagnosis of both P. falciparum and P. vivax infections in the study area, though additional study may be needed in the most peripheral hottest areas of the region. [Ethiop. J. Health Dev. 2011;25(3):206-211

Schistosomiasis mansoni and soil-transmitted helminthiasis in Bushulo village, southern Ethiopia

Background: Schistosomiasis mansoni and soil-transmitted helminthiasis (STHs) are considerable medical and public health problems in Ethiopia. However, information is limited on the epidemiology of these infections in different localities even though it is needed to plan effective prevention and control measures. Objective: This study was designed to determine the prevalence of Schistosoma mansoni and soil-transmitted helminth infections in school children and residents in Bushulo village near Lake Awassa (Hawassa), southern Ethiopia. Methods: Cross-sectional epidemiological and parasitological studies were conducted on schistosomiasis mansoni and STHs in Bushulo village in May and June 2007. A total of 419 participants (353 school children and 66 other residents) were included in the study. The principal investigator interviewed the study subjects about demographic status using structured questionnaires. Moreover, experienced nurse took history and conducted physical examination to assess symptoms and signs related to chronic S. mansoni infection. A single stool sample was collected from each participant and processed using the Kato-Katz technique. Experienced laboratory technician read all slides at Bushulo Health Center. Results: The overall infection rates of schistosomiasis mansoni, trichuriasis, ascariasis and hookworm infection were 73.7%, 41.5%, 37.2% and 28.4%, respectively. Other parasitic infections observed were caused by Hymenolepis nana (1.7%), Taenia species (1.4%), and Enterobius vermicularis (1.4%). Children in the age range 10-14 years and those attending at St. Paul’s School had higher rates of T. trichiura and S. mansoni, respectively. Intensity of infection was higher for A. lumbricoides in the age range 5-9 years. The overall prevalence of any STHs was 67.3%. The rates of single, dual, triple and quadruple infections were 29.6%, 32%, 20.3% and 7.4%, respectively. Conclusion: The high prevalence and intensity of schistosomiasis mansoni and soil-transmitted helminthiasis makes periodic deworming programme urgent to reduce morbidity and transmission of helminthiasis in the area. Provisions of sanitary facilities and clean water supply as well as health education are also critically needed to sustain the impact of chemotherapy

Structural motifs of pre-nucleation clusters

Structural motifs of pre-nucleation clusters prepared in single, optically levitated supersaturated aqueous aerosol microparticles containing CaBr2 as a model system are reported. Cluster formation is identified by means of X-ray absorption in the Br K-edge regime. The salt concentration beyond the saturation point is varied by controlling the humidity in the ambient atmosphere surrounding the 15–30 μm microdroplets. This leads to the formation of metastable supersaturated liquid particles. Distinct spectral shifts in near-edge spectra as a function of salt concentration are observed, in which the energy position of the Br K-edge is red-shifted by up to 7.1 ± 0.4 eV if the dilute solution is compared to the solid. The K-edge positions of supersaturated solutions are found between these limits. The changes in electronic structure are rationalized in terms of the formation of pre- nucleation clusters. This assumption is verified by spectral simulations using first-principle density functional theory and molecular dynamics calculations, in which structural motifs are considered, explaining the experimental results. These consist of solvated CaBr2 moieties, rather than building blocks forming calcium bromide hexahydrates, the crystal system that is formed by drying aqueous CaBr2 solutions

Hard x ray spectroscopy and imaging by a reflection zone plate in the presence of astigmatism

The feasibility of an off axis x ray reflection zone plate to perform wavelength dispersive spectroscopy, on axis point focusing, and two dimensional imaging is demonstrated by means of one and the same diffractive optical element DOE at a synchrotron radiation facility. The resolving power varies between 30 and 400 in the range of 7.6 keV to 9.0 keV, with its maximum at the design energy of 8.3 keV. This result is verified using an adjustable entrance slit, by which horizontal H and vertical V focusing to 0.85 amp; 956;m H and 1.29 amp; 956;m V is obtained near the sagittal focal plane of the astigmatic configuration. An angular and axial scan proves an accessible field of view of at least 0.6 arcmin 0.8 arcmin and a focal depth of plus minus 0.86 mm. Supported by the grating efficiency of around 17.5 and a very short pulse elongation, future precision x ray fluorescence and absorption studies of transition metals at their K edge on an ultrashort timescale could benefit from our finding