Dengue is a mosquito-borne disease that has gone from isolated sylvatic spill-overs to a pathogen of global public health importance in less than a century. Surveillance and control efforts have continually lagged behind contemporary needs and this thesis investigates the pressing need to reassess the current geographic limits and case burden of dengue including how these are measured. First, the global distribution of reported dengue infections was mapped. In many areas dengue reporting is sparse as it can be asymptomatic or clinically similar to other diseases. The maps identified surveillance gaps, particularly in Africa and the Middle East, where targeted efforts are needed to reliably measure the contemporary global extent of dengue transmission. Second, the global case burden of dengue was estimated by pairing risk maps with longitudinal cohort study data. This gave the first cartographic estimate of dengue cases and at 390 million per year (95% CI: 284-528) was over three times the World Health Organization official estimate. Reconciling these estimates with reported case data allowed an assessment of existing national surveillance strategies. Third, existing methods for outbreak identification were compared. High burden dengue outbreaks are preventable if timely and appropriate measures are applied. This analysis suggested, however, that commonly used outbreak definitions are not consistent, which could have an adverse effect on outbreak response. An alternative framework for outbreak identification based on healthcare capacities is thus outlined. Fourth, an analysis was undertaken that quantified how mosquito vectors place geographic and seasonal limits on dengue transmission. This involved updating estimates of mosquito longevity which were integrated with temperature-dependent dynamic transmission models to produce global maps. These suggested that while temperature places strong limits on the distribution of dengue in some settings, mosquito ecology may be more important in others. Finally, these findings are discussed in the context of global dengue surveillance gaps, with recommendations of how these can be addressed at a time when providing an evidence base for deployment of new control strategies will be critical.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:711867 |
| Date | January 2015 |
| Creators | Brady, Oliver Jerome |
| Contributors | Hay, Simon |
| Publisher | University of Oxford |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | https://ora.ox.ac.uk/objects/uuid:b5bc9f32-cb41-421e-8f14-7d7b1fe2b133 |
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