Quantifying the roles of host movement and vector dispersal in the transmission of vector-borne diseases of livestock

Sumner, T., Orton, R. J. , Green, D. M., Kao, R. R. and Gubbins, S. (2017) Quantifying the roles of host movement and vector dispersal in the transmission of vector-borne diseases of livestock. PLoS Computational Biology, 13(4), e1005470. (doi: 10.1371/journal.pcbi.1005470) (PMID:28369082) (PMCID:PMC5393902)

Abstract

The role of host movement in the spread of vector-borne diseases of livestock has been little studied. Here we develop a mathematical framework that allows us to disentangle and quantify the roles of vector dispersal and livestock movement in transmission between farms. We apply this framework to outbreaks of bluetongue virus (BTV) and Schmallenberg virus (SBV) in Great Britain, both of which are spread by Culicoides biting midges and have recently emerged in northern Europe. For BTV we estimate parameters by fitting the model to outbreak data using approximate Bayesian computation, while for SBV we use previously derived estimates. We find that around 90% of transmission of BTV between farms is a result of vector dispersal, while for SBV this proportion is 98%. This difference is a consequence of higher vector competence and shorter duration of viraemia for SBV compared with BTV. For both viruses we estimate that the mean number of secondary infections per infected farm is greater than one for vector dispersal, but below one for livestock movements. Although livestock movements account for a small proportion of transmission and cannot sustain an outbreak on their own, they play an important role in establishing new foci of infection. However, the impact of restricting livestock movements on the spread of both viruses depends critically on assumptions made about the distances over which vector dispersal occurs. If vector dispersal occurs primarily at a local scale (99% of transmission occurs <25 km), movement restrictions are predicted to be effective at reducing spread, but if dispersal occurs frequently over longer distances (99% of transmission occurs <50 km) they are not.

• Item Type: Articles
• Additional Information: This work was funded by the Department for Environment, Food and Rural Affairs (project SE4209).
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Orton, Dr Richard and Kao, Professor Rowland
• Authors: Sumner, T., Orton, R. J., Green, D. M., Kao, R. R., and Gubbins, S.
• College/School: College of Medical Veterinary and Life Sciences > School of Infection & Immunity; College of Medical Veterinary and Life Sciences > School of Infection & Immunity > Centre for Virus Research; College of Medical Veterinary and Life Sciences > School of Biodiversity, One Health & Veterinary Medicine
• Journal Name: PLoS Computational Biology
• Publisher: Public Library of Science
• ISSN: 1553-734X
• ISSN (Online): 1553-7358
• Copyright Holders: Copyright © 2017 Sumner et al.
• First Published: First published in PLoS Computational Biology 13(4):e1005470
• Publisher Policy: Reproduced under a Creative Commons License