OS20 Online 8 December

1. 1EuFMD | Open Session special edition | #OS20se
G. Guyver-Fletcher, I. Keskin, A. Bulut, K. Shea, M. Ferrari, M. Huran, X.
Li, C. Jewell, E. Gorsich, M. Tildesley
A model exploration of carrier
transmission sufficient for maintenance
of endemic FMD

2. 2
• Aim: To explore how likely carrier transmission has to be to have an
effect on persistence of FMD in a region, using a mechanistic
mathematical model.
• How do different assumptions about disease parameters change this?

3. 3
• How does the likelihood of persistence change with the following
parameters?
• Population of farms
• Simulating shipments between farms
• Duration of immunity
• Duration of carrier phase
• Infectivity of carrier animals
• For each set of parameters: Simulate 5 years, 100 times
• Number of simulations where disease persists

4. 4
• It is theoretically possible for even very low carrier transmission rates to
contribute to the persistence of FMD
• Low rates of transmission are much less likely to have been observed in
experiments
• The most important factors for carriers contributing to persistence are
the durations of the carrier state, carrier infectiousness, and duration of
immunity
Conclusions

5. eufmdvirtual.com
8, 10, 15, 17 December 2020
EuFMD / Open Session