This PhD opportunity is being offered as part of the LSTM and Lancaster University Doctoral Training Partnership. Find out more about the studentships and how to apply.
| Abstract | Dengue virus (DENV) is transmitted by Aedes mosquitoes and the disease it causes in humans is now endemic in >100 countries. Cases of dengue reported to the World Health Organisation have increased substantially in the last two decades, from 505 430 in 2000 to 5.2 million in 2019. So far this year, there have been >7 million suspected cases globally. This year is also the first year an outbreak of DENV was reported in Ghana. Recent studies in Ghana have provided evidence of DENV serotype-2 antibodies in people suspected to have malaria or visiting the hospital with acute fever symptoms (Narkwa et al., 2016; Ofosu-Appiah et al., 2018, Manu et al. 2019). Also, a recent study in Accra (Amoako et al., (2018)) detected DENV-2 viral RNA among two children which was closely related with DENV-2 involved in a 2016 outbreak in Burkina Faso. There is a need for increased understanding of drivers of transmission risk in Ghana. Despite research toward a vaccine, reducing Aedes populations remains the main strategy for DENV control. In some countries, Ae. aegypti-infected Wolbachia have been released to successfully reduce DENV incidence, but this relies on this species being necessary and sufficient for transmission. Therefore, it is essential to confirm the relative contribution of Ae. aegypti, Ae. albopictus and potentially other Aedes species to transmission in a given ecological context to enable targeted surveillance and control. More generally, vector control efforts are rarely applied evenly across a region and therefore locations of highest transmission risk also need to be identified. Cross-sectional household surveys quantifying immature or adult Aedes abundance are often used by researchers and control practitioners to implicate species and guide where to focus control efforts. Cromwell et al. (2017) however showed that even adult Aedes abundance was not a sufficient proxy for human DENV infection risk. This is likely in part because human factors, including movement and behaviour, also influence contact between susceptible humans and infectious mosquitoes and vice versa. This project will quantify DENV transmission risk across an urban-rural continuum in the Eastern region of Ghana. Data will be collected on: i) adult Aedes abundance using Prokopack aspirators and odour-baited traps – including trial of a heat trap that is as effective as a human-landing catch but without the inherent risks to the collector; ii) Aedes blood-feeding behaviour; and iii) the proportion of adult mosquitoes infected with DENV using RT-qPCR and sequence diversity using nanopore long-read sequencing. These data will be used, in combination with human population data and vector competence to quantify the relative transmission risk associated with location and species using computational modelling. Designing surveillance strategies informed by DENV transmission dynamics and greater focus on drivers of variation in the transmission process would improve the subsequent targeting of vector control which could be assessed using resulting models. We envisage the project would be suitable for a student familiar with the Ghanian context. |
| Where does this project lie in the translational pathway? | T1 - Basic Research,T4 - Practice to Policy/Population |
| Expected Outputs | This project will produce high quality REF returnable 3*/ 4* papers reporting the field data results and potentially vector competence experiments and then bringing these results together in a paper using modelling to determine the relative contribution of vector species and location to transmission risk. This project will also generate data to be used in collaborative applications to MRC for further Aedes-borne virus research in Ghana. |
| Training Opportunities | The student will receive a unique combination of skills in: i) medical entomology; ii) nanopore sequencing and bioinformatics; iii) working at CL3/ arthropod infections and with support will gain exposure to the application of mathematical modelling in infectious disease epidemiology. In general we will encourage the student to identify internal/external training of interest and support attendance. |
| Skills Required | Basic knowledge of and strong interest in vector biology and arbovirus epidemiology Molecular biology/ sequencing Experience of working in Ghana |
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Key Publications associated with this project |
Longbottom et al. (2023) Aedes albopictus invasion across Africa: the time is now for cross-country collaboration and control |