Spatial epidemiological modelling of infection by Vibrio aestuarianus shows that connectivity and temperature control oyster mortality

Type Article
Date 2020
Language English
Author(s) Lupo Coralie1, Dutta Bhagat Lal1, Petton Sebastien2, Ezanno P3, Tourbiez Delphine1, Travers Marie-Agnes1, 4, Pernet Fabrice2, Bacher Cedric5
Affiliation(s) 1 : Ifremer, SG2M, F-17390 La Tremblade, France
2 : Université Brest, Ifremer, CNRS, IRD, LEMAR, 29840 Plouzané, France
3 : INRAE, Oniris, BIOEPAR, 44300 Nantes, France
4 : Université Montpellier, CNRS, Ifremer, UPVD, IHPE, 34000 Montpellier, France
5 : Ifremer, DYNECO, F-29580 Plouzané, France
Source Aquaculture Environment Interactions (1869-215X) (Inter-Research Science Center), 2020 , Vol. 12 , P. 511-527
DOI 10.3354/aei00379
Keyword(s) Basic reproduction number, Crassostrea gigas, Hydrodynamics, Oyster disease, Sensitivity analysis, Vibrio aestuarianus
Abstract

Vibrio aestuarianus infection in oyster populations causes massive mortality, resulting in losses for oyster farmers. Such dynamics result from host-pathogen interactions and contagion through water-borne transmission. To assess the spatiotemporal spread of V. aestuarianus infection and associated oyster mortality at a bay scale, we built a mathematical model informed by experimental infection data at 2 temperatures and spatially dependent marine connectivity of oyster farms. We applied the model to a real system and tested the importance of each factor using a number of modelling scenarios. Results suggest that introducing V. aestuarianus in a fully susceptible adult oyster population in the bay would lead to the mortality of all farmed oysters over 6 to 12 mo, depending on the location in which infection was initiated. The effect of temperature was captured by the basic reproduction number (R0), which was >1 at high seawater temperatures, as opposed to values <1 at low temperatures. At the ecosystem scale, simulations showed the existence of long-distance dispersal of free-living bacteria. The western part of the bay could be reached by bacteria originating from the eastern side, though the spread time was greatly increased. Further developments of the model, including the consideration of the anthropogenic movements of oysters and oyster-specific sensitivity factors, would allow the development of accurate maps of epidemiological risks and help define aquaculture zoning.

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How to cite 

Lupo Coralie, Dutta Bhagat Lal, Petton Sebastien, Ezanno P, Tourbiez Delphine, Travers Marie-Agnes, Pernet Fabrice, Bacher Cedric (2020). Spatial epidemiological modelling of infection by Vibrio aestuarianus shows that connectivity and temperature control oyster mortality. Aquaculture Environment Interactions, 12, 511-527. Publisher's official version : https://doi.org/10.3354/aei00379 , Open Access version : https://archimer.ifremer.fr/doc/00662/77459/