Ex ante impact of peste des petits ruminants control on
micro and macro socioeconomic indicators in Senegal
Joshua Aboah1, Andrea Apolloni2, Raphael Duboz2, Edward Okoth1 and Michel Dione1
1 International Livestock Research Institute
2 CIRAD, UMR ASTRE Montpellier, France
Introduction
Vaccination is espoused as the most reliable and effective control mechanism for the procedures outlined in the Global
Control and Eradication Strategy for peste des petits ruminants (PPR). However, extant studies assert that vaccination
can be expensive. Hence, the effectiveness of disease control may not necessarily translate to overall profit for
farmers. Also, the consequences of PPR control on socioeconomic indicators like food and nutrition security at a macro-
national level have been underexplored.
Pictures
§ Compared to a no-vaccination scenario, all the vaccination scenarios for both 26.5%
(prevailing vaccination coverage) and 70% (expected vaccination coverage) resulted in
statistically significant difference in the gross margin earnings and the potential per capita
consumption for the supply of mutton and goat meat.
§ At the prevailing vaccination coverage (with or without the provision of government
subsidies), farm households will earn on average $69.43 annually more than the no-
vaccination scenario, and the average per capita consumption for mutton and goat meat
will increase by 1.13kg/person/year.
§ When the vaccination coverage is increased to the prescribed threshold for PPR
eradication (i.e., 70%), with or without the provision of government subsidies, the
average gross margin earnings will be $72.23 annually and the per capita consumption
will increase by 1.23kg/person/year.
Method
A bi-level system dynamics model, compartmentalised into five modules consisting of
integrated production-epidemiological, economics, disease control, marketing, and policy
modules, was developed.
Simulation duration: 30 years at a weekly timestep.
Data sources: Household surveys from pastoral areas in Northern Senegal and FAOSTAT,
relevant official government data, and AfDB data.
Scenarios: Nine (9) vaccination scenarios were examined from three vaccination
dimensions (vaccination coverage, vaccine wastage [multiple vaccination], and the
provision of government subsidies).
Joshua Aboah
j.aboah@cgiar.org ● Box 30709 Nairobi Kenya ● +254 20 422 3000
Dakar Senegal● ilri.org
This project was funded by IFAD
December 2022
Aim
This study seeks to examine the ex-ante impact of PPR control (vaccination) strategies on
farm-level profitability and the socioeconomic consequences concerning food and nutrition
security at a national level in Senegal.
Economics
Module
Production-
Epidemiological
Module
Disease
Control
Module
Marketing
Module
Policy
Module
Adult
billy
recovered
Adult
billy
>12 months
vaccinated
Adult
billy
infected
Grower
billy
6 to 12 months
vaccinated
recovered
Grower
billy
6 to 12 months
recovered
Grower
billy
6 to 12 months
infected
Adult
billy
> 12 months
susceptible
Adult Buck
for breeding
Grower
billy
6 to 12 months
recovered
Number
stolen
goat
Time
to sell
adult
billy
Time
to gift
goat
Average billy
received
Mortality
rate
>young
SR
Mortality
rate
>young
SR
Frequency
of
gifting
Becoming
adult
vaccinated
unidentified
Time
for goat
to become
adult
Proportion
wrongly
identified
Proportion
wrongly
identified
HH billy
Consumption
rate
HH
consumption
billy
Billy reserve
breeding
rate
Reserved
billy for
breeding
Time stolen
Offtake
Rate
Adult
billy
Selling
Adult
billy
Adult billy
Dying
Time
for goat
to become
adult
Time
to sell
reserved
billy for breeding
Disease
Control
Module.Sero-conversion
rate
Contact
rate
Becoming
Adult billy
natural
recovered
Growers
billy
Dying
Average
PPR
illness
duration
Average
PPR
illness
duration
Contact
rate
Average
PPR
illness
duration
Young
billy
selling
'rate
Grower
billy
6 to 12 months
recovery
rate
Time
to receive
Adult animal
Adult
billy
> 12 months
infecting
Becoming
adult
billy
> 12 months
vaccinated
identified
Adult
billy
>12 months
vaccinating
Adult
billy
> 12 months
recovery rate
Adult
billy
vaccinated
becoming
recovered
Billy
received
from external
sources
Prevalence
Adult
goat
>12 months
Disease
Control
Module.Adult
billy
>12 months
vaccination
rate
Time
to sell
reserved
billy for breeding
Selling of
adult billy
reserved for
breeding
Billy
gift out
Average
billy gift
Offtake
Rate
Adult
billy
HH billy
Consumption
rate
Infected
contacts adult
goats
Susceptible
contacts with
infected adult
goat
Probability
of contact with
susceptible
adult goat
Population
of adult
goat
Infected
contacts
grower goats
Offtake
rate
reserved
adult billy
Becoming
adult
vaccinated
unidentified
Adult
billy
stolen
Marketing Module.Total mutton and goat meat supply per capita
Weeks
Kilograms/(Persons*Weeks)
0
0.04
0.08
1 391 781 1170 1560
Scenario 1 - 0%coverage + 0% wastage + No subsidy
Scenario 2 - 26.5% coverage + 0% wastage + Subsidy
Scenario 3 - 26.5% coverage + 0% wastage + Subsidy
Scenario 4 - 26.5% coverage +10% wastage + No subsidy
Scenario 5 - 26.5% coverage +10% wastage + Subsidy
Policy Module.Total Government Expenditure on PPR control
Weeks
USD/Weeks
0
15k
30k
1 391 781 1170 1560
Scenario 1 - 0%coverage + 0% wastage + No subsidy
Scenario 2 - 26.5% coverage + 0% wastage + Subsidy
Scenario 3 - 26.5% coverage + 0% wastage + Subsidy
Scenario 4 - 26.5% coverage +10% wastage + No subsidy
Scenario 5 - 26.5% coverage +10% wastage + Subsidy
Economics Module.Gross Margin
Weeks
USD
-5.5
-2
1.5
1 391 781 1170 1560
Scenario 1 - 0%coverage + 0% wastage + No subsidy
Scenario 2 - 26.5% coverage + 0% wastage + Subsidy
Scenario 3 - 26.5% coverage + 0% wastage + Subsidy
Scenario 4 - 26.5% coverage +10% wastage + No subsidy
Scenario 5 - 26.5% coverage +10% wastage + Subsidy
Economics Module.BCR
Weeks
Dimensionless
0
1
2
1 391 781 1170 1560
Scenario 1 - 0%coverage + 0% wastage + No subsidy
Scenario 2 - 26.5% coverage + 0% wastage + Subsidy
Scenario 3 - 26.5% coverage + 0% wastage + Subsidy
Scenario 4 - 26.5% coverage +10% wastage + No subsidy
Scenario 5 - 26.5% coverage +10% wastage + Subsidy
Findings
Conclusion
• There was no statistically significant difference in the gross margin earnings and the potential per capita
consumption when vaccination is performed with or without government subsidies
• This study’s findings offer an empirical justification for a sustainable approach to PPR eradication in Senegal.
The information on the socioeconomic benefits of vaccination can be promoted via sensitization
campaigns to stimulate farmers’ uptake of the practice.
• Additionally, this study provides the precursory grounding for the development of web-based simulation
interface that can serve as decision support tool for stakeholders (scan the QR code)
Figure 1 Modules in the model
Figure 2 Extracted stocks and flow diagram in the production-epidemiological module
Figure 3 Ex-ante impact assessment @ prevailing vaccination coverage
SCAN the QR code to access the
web-based simulation interface under
construction
https://exchange.iseesystems.com/public/jaboah/i-ecoppr
Peste des petits ruminants Global Research and Expertise Network (PPR-GREN) meeting
Montpellier, France,7-9 December 2022