Estimating the Magnitude and Direction of Altered Arbovirus Transmission Due to Viral Phenotype

Vectorial capacity is a measure of the transmission potential of a vector borne pathogen within a susceptible population. Vector competence, a component of the vectorial capacity equation, is the ability of an arthropod to transmit an infectious agent following exposure to that agent. Comparisons of arbovirus strain-specific vector competence estimates have been used to support observed or hypothesized differences in transmission capability. Typically, such comparisons are made at a single time point during the extrinsic incubation period, the time in days it takes for the virus to replicate and disseminate to the salivary glands. However, vectorial capacity includes crucial parameters needed to effectively evaluate transmission capability, though often this is based on the discrete vector competence values. Utilization of the rate of change of vector competence over a range of days gives a more accurate measurement of the transmission potential. Accordingly, we investigated the rate of change in vector competence of dengue virus in Aedes aegypti mosquitoes and the resulting vectorial capacity curves. The areas under the curves represent the effective vector competence and the cumulative transmission potentials of arboviruses within a population of mosquitoes. We used the calculated area under the curve for each virus strain and the corresponding variance estimates to test for differences in cumulative transmission potentials between strains of dengue virus based on our dynamic model. To further characterize differences between dengue strains, we devised a displacement index interpreted as the capability of a newly introduced strain to displace the established, dominant circulating strain. The displacement index can be used to better understand the transmission dynamics in systems where multiple strains/serotypes circulate or even multiple arbovirus species. The use of a rate of a rate of change based model of vectorial capacity and the informative calculations of the displacement index will lead to better measurements of the differences in transmission potential of arboviruses

Energy Governance in Spain

Spain is lagging behind in the transition to a sustainable energy system compared to other EU member states. Its unique position as an energy island, coupled with errors in energy planning inherited from previous government regimes, constitute a legacy that makes changes in the system difficult to achieve. Current political instability adds to the difficulties, under a governance framework characterised by lack of coordination and supremacy of the central government in the decision making process, in an environment where traditional energy companies still exert lobby power. The continuous changes in the regulatory framework of the energy sector have hindered investments in low carbon sources of energy due to perceived uncertainty. Small changes in the right direction are being observed though, with a more prominent role expected from the local levels of government. But many measures still originate on requirements linked to EU commitments and more initiatives at the national level need to be seen

Population structure of Aedes albopictus from La Réunion Island (Indian Ocean) with respect to susceptibility to a dengue virus.

International audienceTen F1 Aedes albopictus samples collected from Réunion Island in the Indian Ocean were tested for oral susceptibility to dengue 2 virus and 20 were analysed for genetic polymorphism by starch gel electrophoresis. Data from infection rates defined two distinct geographical areas: east coast vs. west coast. Genetic differentiation was found to be dependent on ecological factors and the biological characteristics of Ae. albopictus. These results have implications for the vector ecology and pattern of migration, and have importance in the understanding of dengue transmission