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Abstract: Like many countries in Sub-Saharan Africa, Hepatitis B virus (HBV) is highly prevalent in Ghana. Using qualitative methods, this paper draws from the political ecology of health theoretical framework to examine perceptions and understandings of HBV in the Upper West Region of Ghana. The findings reveal that extremely low levels of knowledge and pervasive lay misconceptions about the disease within this geographic context are shaped by large scale structural influences. Furthermore, in this context there is essentially no access to HBV immunizations, testing or treatment services which reinforces potential routes for the spread of HBV. An explosive spread of HBV is brewing with the potential to diffuse across space and time while, within the institutional contexts, it is the HIV epidemic that is largely consuming both policy attention and intervention. [Copyright &y& Elsevier]

Reinfection by healthy replanted cocoa (Theobroma cacao) by swollen shoot disease, caused by a mealybug-transmitted virus, has been modeled. Much of the spread of disease in pandemically diseased areas such as the Eastern Region of Ghana does not follow a pattern of focus expansion; and disease gradient models are not directly applicable. Equations are derived for cases in which reinfection occurs by ‘radial spread’ of vectors, moving short distances from around the perimeter of the replanted area; and by ‘jump spread’ of windborne vectors into the replanted area. The effect of a cordon sanitaire separating the replanting from the surrounding diseased area is analysed. The impact of jump spread appears to be small by contrast to radial spread, but the absence of estimated of the frequency of its occurrence precludes definitive conclusion. A cordon sanitaire markedly delays reinfection and this, together with eradication of diseased plants, may provide effective control of the disease. Some problems raised by the simplistic assumptions made in the model are discussed in relation to the epidemiology of swollen shoot disease. [ABSTRACT FROM AUTHOR]