Research

I am fascinated by data that can tell a story, the larger and messier, the better. My two main research themes are:

Ecology & control of vector-borne diseases

Vector-borne diseases are a globally important cause of human and animal disease that are particularly challenging to understand and manage because of their complex ecology. Moreover, resistance threatens to reverse progress made towards the control of multiple vector-borne diseases.

  • Malaria: I dedicate a lot of my time to malaria vector control. Vector control remains the most efficient strategy against malaria, however, we currently know exceptionally little about how exactly these vector control tools impact on the natural mechanisms of mosquito population regulation, and this impedes the rational and effective deployment of control efforts. I have been addressing this challenge by combining ecological and population modelling with surveillance data from multiple studies, including laboratory studies, mesocosmos experiments and clinical trials. For example, see Viana et al. 2016.
    Main collaborators: Heather Ferguson, Jason Matthiopoulos and Hilary Ranson.
  • Other projects: include collaborations with Poppy Lamberton and Christina Faust to quantify the effects of drug treatments on life-history traits and trade-offs of drug-resistant Schistosoma mansoni (Viana et al 2017); and with Roman Biek and Caroline Millins on ecological community thresholds for tick-borne disease emergence, such as Lyme disease.

Disease reservoirs & cross-species transmission

Many important human, wildlife and livestock diseases infect multiple host species; however, in most cases only a subset of the hosts that can be infected are important for long-term pathogen persistence at the population level (i.e. the ‘reservoir’). Failure to understand which hosts constitute the infection reservoirs greatly undermines control strategies (Viana et al 2014). I’m particularly interested in finding ways to identify disease reservoirs, quantify cross-species transmission and their drivers, and determining the role of interventions on the disease dynamics. I’ve been addressing these questions by using serology data with Bayesian state-space models in a range of different systems:

  • Canine distemper virus (CDV): Truly a multi-host pathogen with unpredictable dynamics and burden. Perhaps one of my favourite viruses. I have been involved in projects to investigate the CDV cross-species transmission dynamics between domestic dogs and African lions in the Serengeti ecosystem, Tanzania (Viana et al. 2016), and between bears and wolves in the Yellowstone National Park, USA. Currently we are exploring the co-infection dynamics of CDV with canine parvovirus in domestic dogs. Main collaborators: Sarah Cleaveland, Tiziana Lembo, Daniel Haydon, Abdelkader Behdenna and Paul Cross [wolves/bears].
  • Vampire bat viruses in Peru: Vampire bats are widespread throughout Latin America and their range continues to expand due to intensification of livestock rearing, which provides a novel and abundant food resource. Their unique diet creates many opportunities for pathogen transmission from bats to livestock and humans. As a consequence, vampire bats are culled across much of Latin America, but the effects of culling on bat-associated pathogens are impossible to predict without better understanding of their natural transmission dynamics. I am collaborating with the Streicker group on this system in Peru to develop approaches to determine the impact of bat culling on the dynamics of vampire bat rabies virus as well as exploring the transmission ecology of recently found bat influenza H17N10 and H18N11.
  • Brucellosis in Tanzania: Brucellosis is a bacterial zoonosis that has a worldwide distribution but human incidence is higher in low and mid-income countries. We have been trying to understand the origins of human Brucella infections in Tanzania (Viana et al 2016).
    Main collaborators: Jo Halliday

Other miscellaneous projects
Identifying the ecological determinants of bacterial virulence, applying social evolution theory to fisheries management, drivers of ecological stability, intensification of the hydrological cycle, water level fluctuations in lakes due to global climatic drivers and diversity dynamics in the fossil record.

Previous life as a fisheries modeller
Although I now focus on infectious diseases, I did my PhD on fisheries modelling. Fishing is central to the livelihood and food security of millions of people around the world. However, the removal of organisms from the marine ecosystem can greatly impact the biodiversity, stability and productivity of the ecosystems. I am interested in understanding these impacts and finding ways to maintain fishing sustainable.

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