Factors driving the circulation and possible expansion of Crimean–Congo haemorrhagic fever virus in the western Palearctic
Article first published online: 7 NOV 2012
© 2012 The Society for Applied Microbiology
Journal of Applied Microbiology
Volume 114, Issue 1, pages 278–286, January 2013
How to Cite
Estrada-Peña, A., Ruiz-Fons, F., Acevedo, P., Gortazar, C. and de la Fuente, J. (2013), Factors driving the circulation and possible expansion of Crimean–Congo haemorrhagic fever virus in the western Palearctic. Journal of Applied Microbiology, 114: 278–286. doi: 10.1111/jam.12039
- Issue published online: 12 DEC 2012
- Article first published online: 7 NOV 2012
- Accepted manuscript online: 13 OCT 2012 08:45AM EST
- Manuscript Accepted: 4 OCT 2012
- Manuscript Revised: 12 SEP 2012
- Manuscript Received: 14 JUN 2012
- EU FP7. Grant Number: 278976
- Spanish Ministry for the Economy and Competitiveness
- Comissionat per a Universitats i Recerca del Departament d'Innovació
- Universitats i Empresa' of the Generalitat de Catalunya
- Crimean–Congo haemorrhagic fever;
- next-generation matrix;
- process-driven model;
To produce a spatial risk map regarding spread of Crimean-Congo haemorrhagic fever virus (CCHFV) in the western Palearctic by linking a process-driven model of the main tick vector, Hyalomma marginatum, to a Next Generation Matrix.
Methods and Results
Process-driven model was composed of deterministic equations that simulate developmental and mortality rates of different tick stages by using temperature and atmospheric water vapour data. The model used climate data at 10-day intervals at a spatial resolution of 10 min over western Palearctic. The model estimated the basic reproduction number, R0, for CCHFV transmission by H. marginatum ticks and evaluated how changes in temperature and biological parameters may alter the geographical range of CCHFV. In particular, variation in the rate of transovarial transmission of CCHFV in the tick produced the greatest change in CCHFV circulation in the tick population. Parameters affecting the rates of tick bite, non-systemic transmission and efficiency of tick-to-tick transmission had little effect on R0. Temperature changes that affect tick development, survival and activity rates increased the suitable area for CCHFV transmission at higher latitudes in the western Palearctic.
Non-systemic transmission had little impact on virus transmission under all scenarios. In the area studied, increase of temperature has no impact on the routes of transmission of CCHFV. However, climate conditions favouring tick survival, which increase infected adult tick populations, together with large numbers of hosts for adults were predicted as the most likely scenario for the spread of the virus in the studied area.
Significance and Impact of the Study
The proposed framework is able to capture the dynamics and the relative contribution of the different routes (hosts, ticks) in the transmission and spread of an important pathogen affecting human health. The high contribution of the transovarial transmission route makes the process highly dependent upon suitable hosts for adult ticks, like large domestic and wild ungulates. Climate seems to have a very reduced effect on such spread.