Ecology and Transmission of Buruli Ulcer Disease: A Systematic Review

Buruli ulcer is a neglected emerging disease that has recently been reported in some countries as the second most frequent mycobacterial disease in humans after tuberculosis. Cases have been reported from at least 32 countries in Africa (mainly west), Australia, Southeast Asia, China, Central and South America, and the Western Pacific. Large lesions often result in scarring, contractual deformities, amputations, and disabilities, and in Africa, most cases of the disease occur in children between the ages of 4–15 years. This environmental mycobacterium, Mycobacterium ulcerans, is found in communities associated with rivers, swamps, wetlands, and human-linked changes in the aquatic environment, particularly those created as a result of environmental disturbance such as deforestation, dam construction, and agriculture. Buruli ulcer disease is often referred to as the “mysterious disease” because the mode of transmission remains unclear, although several hypotheses have been proposed. The above review reveals that various routes of transmission may occur, varying amongst epidemiological setting and geographic region, and that there may be some role for living agents as reservoirs and as vectors of M. ulcerans, in particular aquatic insects, adult mosquitoes or other biting arthropods. We discuss traditional and non-traditional methods for indicting the roles of living agents as biologically significant reservoirs and/or vectors of pathogens, and suggest an intellectual framework for establishing criteria for transmission. The application of these criteria to the transmission of M. ulcerans presents a significant challenge

Sucrose acceptance, discrimination and proboscis responses of honey bees (Apis mellifera L.) in the field and the laboratory

Mujagic S, Erber J. Sucrose acceptance, discrimination and proboscis responses of honey bees (Apis mellifera L.) in the field and te laboratory. Journal of Comparative Physiology A. 2009;195(4):325-339.Laboratory studies in honey bees have shown positive correlations between sucrose responsiveness, division of labour and learning. We tested the relationships between sucrose acceptance and discrimination in the field and responsiveness in the laboratory. Based on acceptance in the field three groups of bees were differentiated: (1) bees that accept sucrose concentrations >10%, (2) bees that accept some but not all of the sucrose concentrations <10% and water, and (3) bees that accept water and all offered sucrose concentrations. Sucrose acceptance can be described in a model in which sucrose- and water-dependent responses interact additively. Responsiveness to sucrose was tested in the same bees in the laboratory by measuring the proboscis extension response (PER). The experiments demonstrated that PER responsiveness is lower than acceptance in the field and that it is not possible to infer from the PER measurements in the laboratory those concentrations the respective bees accepted in the field. Discrimination between sucrose concentrations was tested in three groups of free-flying bees collecting low, intermediate or high concentrations of sucrose. The experiments demonstrated that bees can discriminate between concentrations differences down to 0.2 relative log units. There exist only partial correlations between discrimination, acceptance and PER responsiveness