Modeling the effect of improved diagnostics and antibiotic treatment on the dynamics of Contagious Bovine Pleuropneumonia (CBPP)
Modeling the effect of improved diagnostics
and antibiotic treatment on the dynamics of
Contagious Bovine Pleuropneumonia (CBPP)
Amos Ssematimba* and Jeffrey Mariner
Epidemics 4 conference, 2013, Amsterdam, The Netherlands, 19-22 November 2013
Methods II: modeling details
CBPP is a livestock disease that has continuously
devastated the industry in the sub-Saharan
Control intervention is mainly through
vaccination but seems unsuccessful due to
vaccine- and management-specific factors.
Currently, uninformed use of antibiotics is
rampant in the field; much as it is against OIE
• studies to unravel the “myths” about their use
are in place with hope to guide reconsideration
of the OIE position.
Above: Reported CBPP cases (red) 2010-2013; Below left: Cow
standing legs apart and extended neck, a sign of CBPP; Below
right: A typical encapsulation in the lungs of a CBPP “recovered”
Methods I: The model
Currently, better diagnostic tools are being
sought and antibiotic efficacies being assessed. •
Given the current CBPP research interests,
there is need for predictive tools to guide
field implementation of the improved
• Assumed a gamma-distributed waning of
vaccine induced immunity (i.e. method
of steps); protection=8months.
• A seasonally forced transmission rate:
𝛽 𝑡 = 𝛽0 1 + 𝐴sin 2𝜋𝑡 with 𝛽0 =0.5.
• Effects of pulse vaccination or treatment
scenarios are explored in isolated herd.
• Six year period is simulated in a herd of
500 (S=205, E=10, I=10, R=275) heads.
• Treated animals are assumed 50% less
• New recruits are all susceptible to CBPP
and for clarity, between herd mixing is
ignored in the comparison.
Sample graphical results
SVEIRQT compartmental model
implemented stochastically using
Gillespie direct algorithm.
incorporates vaccination and
The aim here is to develop mathematical
models to assess how effectively antibiotics
can be used in the field as supplements to
Conclusions and next steps
Simulation outcomes for the different interventions
Antibiotic treatment can provide the much wanted
supplement to the current vaccination campaigns and should
Synchronizing intervention at regional level is paramount due
to the cross-boarder animal movements.
Cheaper diagnostic tools should be availed to aid CBPP
identification and better antibiotics with higher cure rate are
Next step: obtain field data to calibrate the models .
Cure rate/ detected
fraction/ vaccination chance
a) Annual pulse
b) Treatment (default
different cure rates
1/7 per week
1/2 per week
c) Treatment (default cure 20%
rate = 1/4.5 per week):
different detected fraction 90%
number of CBPPinduced deaths
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This project was funded by BBSRC and partly by BMZ
This document is licensed for use under a Creative Commons Attribution –Non commercial-Share Alike 3.0
Unported License November 2013