Cambridge Richard Stutt University Nik Cunniffe Erik DeSimone Matt Castle Chris Gilligan RothamstedStephen Parnell ResearchFrank van den Bosch May 2012

 Model must integrate ◦ Location of hosts ◦ Environmental drivers ◦ Pathogen dispersal  Compartmental model

 250m x 250m resolution  Combine data on  Larch  Rhododendron  Vaccinium  NIWT (other tree hosts)  Weight host types by sporulation/susceptibility

 Pathogen responds to temperature/moisture  Model underlying suitability for each location  Statistical climate model then used to predict future fluctuations about this

 Dispersal kernel describes pathogen spread  Implicitly incorporates many mechanisms Positive Negative

 Spread in the absence of control  Effect of extent of control ◦ Felling infected stands ◦ Felling infected stands + proactive control  Surveying for P. Ramorum on heathland

Hazard map + known infections = sampling pattern

 Continuous model improvement (data driven)  Region specific control  Effect of non compliance  Transition strategies  User friendly models

 Forestry Commission ◦ Bruce Rothnie ◦ Joan Webber  FERA ◦ Keith Walters ◦ Phil Jennings ◦ Judith Turner ◦ Kate Somerwill  Funding from DEFRA, BBSRC and USDA

 Susceptible hosts in the landscape are divided into a metapopulation at a chosen resolution (250m)  UK Sudden Oak death landscape assembled from: ◦ National Inventory of Woodland Trees (NIWT) ◦ Forestry Commission commercial Larch data ◦ Maximum Entropy suitability models for Rhododendron and Vaccinium (FERA/JNCC)  Different hosts have different weightings for sporulation and susceptibility

Broadleaved Young TreesFelled Coniferous

 Identify favourable conditions for P. ramorum ◦ moisture ◦ temperature  Parameterise using experimental results Relative Sporulation Temperature

 Fit model using historic spread data  Used Maximum Likelihood to assess goodness of fit  Predicted probability of infection by 2010 given starting conditions in 2004 Survey Positive for P. ramorum Survey Negative for P. ramorum

Total Infection Symptomatic Symptomatic at time of Survey

Total Infection Symptomatic Symptomatic at time of Survey

Total Infection Symptomatic Symptomatic at time of Survey

Total Infection Symptomatic Symptomatic at time of Survey

Examine region of South Wales

Cull: no delay after survey 6 month delay

 Key Questions When Surveying for Disease: ◦ Where is the disease likely to be? ◦ Where is it likely to be most severe and spread most rapidly? ◦ How to optimise the sampling?

 Uses: Currently known outbreaks Predicted severity of outbreaks => Sampling weighting  Survey pattern formed => sampling from weightings  Map shows a weighting and a set of survey points (green)