The feasibility of canine rabies elimination in Africa: dispelling doubts with data

<p><b>Background:</b> Canine rabies causes many thousands of human deaths every year in Africa, and continues to increase throughout much of the continent.</p> <p><b>Methodology/Principal Findings:</b> This paper identifies four common reasons given for the lack of effective canine rabies control in Africa: (a) a low priority given for disease control as a result of lack of awareness of the rabies burden; (b) epidemiological constraints such as uncertainties about the required levels of vaccination coverage and the possibility of sustained cycles of infection in wildlife; (c) operational constraints including accessibility of dogs for vaccination and insufficient knowledge of dog population sizes for planning of vaccination campaigns; and (d) limited resources for implementation of rabies surveillance and control. We address each of these issues in turn, presenting data from field studies and modelling approaches used in Tanzania, including burden of disease evaluations, detailed epidemiological studies, operational data from vaccination campaigns in different demographic and ecological settings, and economic analyses of the cost-effectiveness of dog vaccination for human rabies prevention.</p> <p><b>Conclusions/Significance:</b> We conclude that there are no insurmountable problems to canine rabies control in most of Africa; that elimination of canine rabies is epidemiologically and practically feasible through mass vaccination of domestic dogs; and that domestic dog vaccination provides a cost-effective approach to the prevention and elimination of human rabies deaths.</p&gt

Assessing anti-rabies baiting – what happens on the ground?

BACKGROUND: Rabies is one of the most hazardous zoonoses in the world. Oral mass vaccination has developed into the most effective management method to control fox rabies. The future need to control the disease in large countries (i.e. Eastern Europe and the Americas) forces cost-benefit discussions. The 'Increase bait density' option refers to the usual management assumption that more baits per km(2 )could compensate for high fox abundance and override the imperfect supply of bait pieces to the individual fox. METHODS: We use a spatial simulation, which combines explicitly fox space use (tessellation polygons) and aeroplane flight lines (straight lines). The number of baits actually falling into each polygon is measured. The manager's strategic options are converted into changes of the resulting bait distribution on the ground. The comparison enables the rating of the options with respect to the management aim (i.e. accessibility of baits). RESULTS: Above 5% (approx. 10%) of all fox groups without any bait (at most 5 baits) relate to the baiting strategy applied in the field (1 km spaced parallel flight lines, 20 baits per km(2 )distributed) under habitat conditions comparable to middle and western Europe (fox group home-range 1 km(2), 2.5 adults; reference strategy). Increasing the bait density on the same flight-line pattern neither reduces the number of under-baited fox group home-ranges, nor improves the management outcome and hence wastes resources. However, reducing the flight line distance provides a more even bait distribution and thus compensates for missed fox groups or extra high fox density. The reference strategy's bait density can be reduced when accounting for the missed fox groups. The management result with the proper strategy is likely the same but with reduced costs. CONCLUSION: There is no overall optimal strategy for the bait distribution in large areas. For major parts of the landscape, the reference strategy will be more competitive. In situations where set backs are attributed to non-homogeneous bait accessibility the distribution scheme has to be refined zone-based (i.e. increase of the flight line length per unit area). However, increase in bait density above the reference strategy appears inappropriate at least for non-urban abundance conditions of the red fox

Chemistry Central Journal Poster presentation Web-based computational chemistry

© 2009 Entzian et al; licensee BioMed Central Ltd. With the establishment of web applications and user-generated content under the concept of Web 2.0, the data stream increases in the direction to the Internet. The possibility of not having to collect and store data locally anymore, but to work centralized on the web offers a remarkable amount of new applications and teamwork in science. To use software and data on a server, reduces the need for local installation and administration. Another aspect is the possibility to use the efforts of collaborative work optimally. Platforms for the aggregation of knowledge, so called Wikis, are the future. Thus in computer chemistry the arrangement of input-data, the calculations and the graphical representation and interpretation of the results can be done on a server

GENERALIZED REPRESENTATION OF GRAIN BOUNDARY SELF-DIFFUSION DATA

Les résultats d'autodiffusion pour des joints de forte désorientation relatifs aux métaux FCC, HCP, et BCC, sont présentés dans un diagramme d'Arrhenius en utilisant une échelle de température réduite Tm/T où Tm est la température de fusion. Les résultats disponibles dans la littérature montrent un comportement unique du graphe d'Arrhenius pour chaque type de structure et pour ce type de joints. Les coefficients de diffusion intergranulaire sont de même ordre de grandeur au point de fusion (10-9 m2/s en supposant une épaisseur de joint de 1 nm) mais ils sont assez différents aux basses températures. Cette représentation d'Arrhenius pour chaque structure est utile pour estimer rapidement avec une relative bonne précision des données de diffusion intergranulaire. Pour de nombreux et importants processus industriels tels que le futtage, le fluage et le transport de matière, des estimations de ce type sont utiles et souvent la seule possibilité pour obtenir des coefficients de diffusion intergranulaires.The self-diffusion data for large-angle grain boundaries in FCC, HCP and BCC metals are presented in an Arrhenius diagram employing a reduced reciprocal temperature scale Tm/T, where Tm is the melting temperature. The data available from the literature show a generalized Arrhenius behavior for these types of grain boundaries. The grain boundary diffusion coefficients are of the same order of magnitude at the melting temperature (ca 10-9 m2/s assuming a boundary thickness of 1 nm), but they are quite different at low temperatures. The generalized Arrhenius representation is useful for estimating grain boundary diffusion data quickly and relatively accurately. For many commercially important processes such as sintering, creep and material transport estimates of this type are helpful and frequently the only way to obtain grain boundary diffusivities