Presentation by Tabitha Kimani, Esther Schelling, Margaret Ngigi and Thomas Randolph at the 13th conference of the International Society for Veterinary Epidemiology and Economics, Maastricht, the Netherlands, 20-24 August 2012.

1. Economic analysis of Rift Valley fever
prevention and control options from a multi-
sectoral perspective in Kenya
T. Kimani1,4, E. Schelling2, M. Ngigi3, T. Randolph1
1 International Livestock Research Institute, Kenya
2 Swiss Tropical and Public Health Institute, Basel
3 Egerton University, Kenya
4 Food and Agriculture Organization of the United Nations, Kenya
Presented at the 13th conference of the International Society of
Veterinary Epidemiology and Economics (ISVEE), Maastricht,
Netherlands, 20-24 August 2012

2. Introduction: Rift Valley fever
• Mosquito borne viral zoonosis, Africa and Middle East
• Epizootics, every 3-15 years
• Last two outbreaks in Eastern Africa: 1997-98, 2006-07
• Higher than normal rainfall, prolonged flooding, after a prolonged
drought
• Mosquito to animals
• Infected animal and animal products to people
• Impacts: economy wide
• Livestock
• Mortality; morbidity; trade bans, control costs
• Public health
• Mortality, morbidity and control costs
13th ISVEE- Maastricht, Netherlands

3. Objective: CBA (livestock sector) and CEA (public health) of RVF control
options, period: 2006-2015, assumed outbreak in 2014/2015
Approach: Step 3: Identification of
Step 1: alternate prevention
Transmission (SEIR) Model: strategies, simulation, by
(poster 08.74, MSc, Fuhrimann ) farming systems, for high
risk areas (20.2/65 million
Livestock animals)
demography
Step 4: CBA & CEA:
RVF impact •Mortality (RVF and other)
Control •Milk loss (drought,
mesures RVF(abortions and
reductions),other abortions
Step 2: •RVF Market effects, control
Asses public health costs and costs, 2014/2015 DALYs
DALYs of 2006/2007 RVF- •Pastoral system
(MSc Thesis- A. Bitek) (13.5 m animals)
13th ISVEE- Maastricht, Netherlands

4. Selected AH Strategies
Based on current and past practices , involved technical consultations- closer to
reality
1=Enhanced 1= Use of
1 =Pour-on insecticides for
Inter-epidemic Surveillance insecticides for
animal treatment
vaccination schemes (+ vector) Larval
0= Baseline,
0 = none 0 = none
Strategy 9 sentinel herds
S1-
Baseline 0 0 0 0
S2 1 1 1 1
S3 2 1 1 1
S4 0 1 0 1
S5 1 1 0 1
S6 2 1 0 1
S7 1 1 0 0
S8 2 0 0 0
S9 0 0 0 1
S10 0 1 1 1
S11 0 1 0 0
13th ISVEE- Maastricht, Netherlands

5. Strategies
• Vaccination Schemes
• Baseline = 2008 – 2014, coverage 4-7% sheep and goats
only,
• Option 1 = 2 mass vaccinations 2012 (41-51%); 2013 (28-
33%); 4 species; ear tag & monitor 3 years
• Option 2 = 1 mass vaccination 2012 (41-51%); annual
vaccination of young animals only ( 6-11%); 4 species; ear
tag
• Enhanced surveillance from 2012, shorter reaction time (delay of 3
weeks from 6 weeks in 2007)
• Larvicidal –limited application; reduce infection pressure by 7.5%
• Pour-on treatments; 10% of susceptible animals (without ear tags);
3 applications; delay of 4 weeks; 6 weeks protection
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6. Results: Simulated Infected Proportions
0.250
Proportion infected
0.200
0.150
0.100
0.050
-
Prevention and Control Strategy
Cattle Sheep Goats Camels
None of the evaluated measures and assumed levels of application
would stop an RVF epidemic
13th ISVEE- Maastricht, Netherlands

7. • 24 month Livestock producer losses-2006-07
US$ 225 Million RVF Milk loss Drought and
3% other abortions
Drought and milk loss
baseline 10%
mortality
82% RVF Direct
mortality
5%
RVF Market effects ( US$ 9.3 million)
RVF Outbreak containment (US$ 5.23million)
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8. Estimated RVF Impacts 2014/2015
90,000,000
80,000,000
70,000,000
60,000,000
Million US$
50,000,000
40,000,000
30,000,000
20,000,000
10,000,000
-
S1 S2 S3 S4 S5 S6 S7 S8 S9 S10 S11
Prevention and Control Strategy
Losses Control costs
13th ISVEE- Maastricht, Netherlands

9. Average annual impacts 2008 - 2015
60.00
50.00
40.00
Million US$
30.00
20.00
10.00
-
S1 S2 S3 S4 S5 S6 S7 S8 S9 S10 S11
Prevention and Control Strategy
PV RVF losses PV other losses
• 8 years:1 RVF outbreak, 3 droughts & 3 normal years
• RVF impacts are relatively lower,
• Likely to be overlooked in the on going resilience building livestock
development activities
13th ISVEE- Maastricht, Netherlands

10. Livestock sector: Incremental Benefits & Costs compared
7.00
6.00
5.00
US$ (Million)
4.00
3.00
2.00
1.00
-
S2 S3 S4 S5 S6 S7 S8 S9 S10 S11
Prevention and Control Strategy
Incremental benefits (Saved losses) Incremental costs
Strategy S2 S3 S4 S5 S6 S7 S8 S9 S10 S11
BCR 2.2 3.3 0.4 2.0 3.2 3.7 5.2 1.5 1.0 -
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11. Public Health Costs and CEA -on going
•4,035.6 DALYs
estimated for 06/07
outbreak
•Next step
•Adjust DALYs for
underreporting
•Quantify the human
RVF transmission
from a known number
of infected animals
•Estimate costs/DALY
Human RVF risk sources
averted
13th ISVEE- Maastricht, Netherlands

12. Additional analysis
• The other two farming systems
• Sensitivity analysis
• Apply Social Accounting Matrix to estimate
economy wide impacts of RVF under
different control strategies
13th ISVEE- Maastricht, Netherlands

13. Conclusions
• This analysis more or less show that unless control measures are
stepped up, the next RVF epizootic is likely to have devastating
impacts.
• The current baseline vaccination of 4-7% of small ruminants
would barely have any impacts on reducing magnitude
• Increasing vaccination coverage for all species would yield
significant reductions in outbreak magnitude
• RVF epidemics have significant impacts, but higher impacts are
attributed to other causes.
• Need for tools to address market level impacts e.g. food safety
credibility and safe slaughter systems.
13th ISVEE- Maastricht, Netherlands

14. Acknowledgements
Funding from the International Development Research Centre
(IDRC) via the Agriculture and Health Research Platform of CGIAR
CDC Kenya and the Kenya Medical Research Institute
Thank you for listening
13th ISVEE- Maastricht, Netherlands