Risk-based surveillance of PPR featuring spatial qualitative risk analysis R. Lancelot, C. Coste, C. Squarzoni-Diaw CIRAD, Unit ASTRE June 2018 1
Outline 1 Qualitative risk analysis and risk mapping Overview Risk of disease introduction Risk of disease spread 2 Risk-based surveillance: Rift Valley fever in Senegal The epidemiology of Rift Valley fever Spatial qualitative risk analysis Risk-based surveillance and disease management 3 Conclusion: take-home message 2
Outline 1 Qualitative risk analysis and risk mapping Overview Risk of disease introduction Risk of disease spread 2 Risk-based surveillance: Rift Valley fever in Senegal The epidemiology of Rift Valley fever Spatial qualitative risk analysis Risk-based surveillance and disease management 3 Conclusion: take-home message 3
Outline 1 Qualitative risk analysis and risk mapping Overview Risk of disease introduction Risk of disease spread 2 Risk-based surveillance: Rift Valley fever in Senegal The epidemiology of Rift Valley fever Spatial qualitative risk analysis Risk-based surveillance and disease management 3 Conclusion: take-home message 4
Overview Identification and ranking of risk factors for disease introduction and spread Data collection: scientific papers, international databases and specific national data (outbreaks, markets...) integrative mapping (QGIS, R...) collective expertise for validation Qualitative risk assessment for disease introduction and spread At the finest administrative unit level Risk categorization into 4 classes = risk strata Risk of occurrence = combination of risks of (1) introduction and (2) spread 5
Outline 1 Qualitative risk analysis and risk mapping Overview Risk of disease introduction Risk of disease spread 2 Risk-based surveillance: Rift Valley fever in Senegal The epidemiology of Rift Valley fever Spatial qualitative risk analysis Risk-based surveillance and disease management 3 Conclusion: take-home message 6
Risk of disease introduction Two main components 1 Border permeability to animal movements: Di Nardo et al. (2011) 7
Risk of disease introduction Two main components 1 Border permeability to animal movements: Natural or artificial border (accessibility) 7
Risk of disease introduction Two main components 1 Border permeability to animal movements: Natural or artificial border (accessibility) Intensity of transboundary animal movements (social analysis network - SNA) 7
Risk of disease introduction Two main components 1 Border permeability to animal movements: Natural or artificial border (accessibility) Intensity of transboundary animal movements (social analysis network - SNA) 2 Risk of disease introduction from other countries 7
Risk of disease introduction Two main components 1 Border permeability to animal movements: Natural or artificial border (accessibility) Intensity of transboundary animal movements (social analysis network - SNA) 2 Risk of disease introduction from other countries Epidemiological situation in these countries 7
Risk of disease introduction Two main components 1 Border permeability to animal movements: Natural or artificial border (accessibility) Intensity of transboundary animal movements (social analysis network - SNA) 2 Risk of disease introduction from other countries Epidemiological situation in these countries Existence of surveillance / control measures Metwally et al. (2015) 7
Risk of disease introduction Two main components 1 Border permeability to animal movements: Natural or artificial border (accessibility) Intensity of transboundary animal movements (social analysis network - SNA) 2 Risk of disease introduction from other countries Epidemiological situation in these countries Existence of surveillance / control measures Existence of animal movements: trade, transhumance, wildlife 7
Combination of risk factors for introduction Stratum Label Rule 4 Very high Intro > 1 AND [ Highest Accessibility OR Highest TB SNA ] 3 High Intro > 1 AND [ High accessibility OR High TB SNA ] 2 Low Intro > 1 AND [ Low national accessibility OR Low TB SNA ] 1 Negligeable Anything else 8
Outline 1 Qualitative risk analysis and risk mapping Overview Risk of disease introduction Risk of disease spread 2 Risk-based surveillance: Rift Valley fever in Senegal The epidemiology of Rift Valley fever Spatial qualitative risk analysis Risk-based surveillance and disease management 3 Conclusion: take-home message 9
Risk of disease spread Animal densities Mass gathering (markets, feedlots, Watering) National spread (national SNA data, Accessibility) Risk of disease spread 4 Very high 3 High 2 Low 1 Negligible 10
Combination of risk factors for spread 11
Outline 1 Qualitative risk analysis and risk mapping Overview Risk of disease introduction Risk of disease spread 2 Risk-based surveillance: Rift Valley fever in Senegal The epidemiology of Rift Valley fever Spatial qualitative risk analysis Risk-based surveillance and disease management 3 Conclusion: take-home message 12
Outline 1 Qualitative risk analysis and risk mapping Overview Risk of disease introduction Risk of disease spread 2 Risk-based surveillance: Rift Valley fever in Senegal The epidemiology of Rift Valley fever Spatial qualitative risk analysis Risk-based surveillance and disease management 3 Conclusion: take-home message 13
The epidemiology of Rift Valley fever Primary foci: flooding of Aedes breeding sites Aedes mosquito 1a Culex, Mansonia, Anopheles mosquitoes 5a Viraemic animals Aedes eggs Temporary pond 2a Larva Pupa Adult emerges RVFV infected animal 3a 4a Transport by road, rain or boat of viraemic animals from primary foci to secondary foci Géraldine Laveissiere Cirad-Astre, 2017 from http://www.who.int/mediacentre/factsheets/fs207/en/ 14
The epidemiology of Rift Valley fever Secondary foci:: introduction in irrigated crop areas viraemic animals from primary foci to secondary foci 1b RVFV infected animal Culex, Mansonia, Anopheles mosquitoes Irrigation channel 2b Culex, Mansonia, Anopheles mosquitoes 3b Irrigation channel Indirect contact Direct contact 4b Géraldine Laveissiere Cirad-Astre, 2017 from: http://www.who.int/mediacentre/factsheets/fs207/en/ 14
Outline 1 Qualitative risk analysis and risk mapping Overview Risk of disease introduction Risk of disease spread 2 Risk-based surveillance: Rift Valley fever in Senegal The epidemiology of Rift Valley fever Spatial qualitative risk analysis Risk-based surveillance and disease management 3 Conclusion: take-home message 15
Risk mapping Risk of introduction Risk of occurrence Risk of spread 70% of declared outbreaks (Empres-I) occurred in high or very-high risk areas 16
Outline 1 Qualitative risk analysis and risk mapping Overview Risk of disease introduction Risk of disease spread 2 Risk-based surveillance: Rift Valley fever in Senegal The epidemiology of Rift Valley fever Spatial qualitative risk analysis Risk-based surveillance and disease management 3 Conclusion: take-home message 17
Consequences for disease surveillance Changes in the location of veterinary posts 18
Consequences for disease surveillance Changes in the location of veterinary posts Changes in the allocation of human resources (field veterinary officers) 18
Consequences for disease surveillance Changes in the location of veterinary posts Changes in the allocation of human resources (field veterinary officers) New implementation of sentinel herds to detect low-noise virus circulation 18
Consequences for disease surveillance Changes in the location of veterinary posts Changes in the allocation of human resources (field veterinary officers) New implementation of sentinel herds to detect low-noise virus circulation Allows designing stratified sampling frames of epidemiological surveys 16 N 15 N 14 N 13 N Predicted sero-prevalence of RVF antibodies in ruminants after a national survey, 2015 17 W 16 W 15 W 14 W 13 W 12 W 0.1 0.2 0.3 0.4 0.5 0.6 0.7 Predicted seroprevalence rate Directorate of Veterinary Services, Dakar, unpublished data 18
Consequences for disease surveillance Changes in the location of veterinary posts Changes in the allocation of human resources (field veterinary officers) New implementation of sentinel herds to detect low-noise virus circulation Allows designing stratified sampling frames of epidemiological surveys Use of RVF risk maps in One Health activities (RVF, Ebola, avian influenza ) Distribution of Ebola cases, 2016 Breakwell et al. (2016) 18
Road map July 2018: revise risk map according to improved data (e.g. add markets) and work flow (better spatial queries, factor weights...) December 2018 Define the RVF surveillance protocol according to the RVF risk strata Define a set of performance indicators to monitor and assess the surveillance system Revise the risk map according to new data December 2019 The new risk-based surveillance protocol is implemented including a new national serological survey First assessment of the RVF surveillance system using the performance indicators 19
Outline 1 Qualitative risk analysis and risk mapping Overview Risk of disease introduction Risk of disease spread 2 Risk-based surveillance: Rift Valley fever in Senegal The epidemiology of Rift Valley fever Spatial qualitative risk analysis Risk-based surveillance and disease management 3 Conclusion: take-home message 20
Conclusion Combination of collective, qualitative risk analysis with a thorough analysis of animal mobility Accounts for actual surveillance activities and uncontrolled animal movements National experts can be trained for a full autonomy (capacity building) and implementation in different contexts, including zoonotic diseases Continuous process and collective work 21
Contributions A. Apolloni, A. Bataille, F. Bouyer, D. Chavernac, C. Coste, A. Diallo, P. Hammami, O. Kwiatek, T. Lefranois, M. Lesnoff, G. Libeau, M. Peyre, H. Salami (Cirad, C. Squarzoni-Diaw, OIE/FAO World Reference Laboratory and Collaborating center) G. Mignangou, L. Ouattara, J. Savadogo (Burkina Faso) J. Avuma, S. Ockling (Ghana) L. Kaba (Guinea) A.S. El Arbi, B. El Mamy, K. Isselmou (Mauritania) M. Diop, K. Tounkara (Mali) M. Diop, M. Lo, R. Maboudou, I. Mall, I. Seck, M.T. Seck, D.A. Sow (Senegal) K. Tounkara, D. Bourzat, J. Domenech, A. Dehove (OIE) F. Njeumi, B. Diop, J.J. Soula (FAO) 22
References Breakwell, L., Gerber, A. R., Greiner, A. L., Hastings, D. L., Mirkovic, K., Paczkowski, M. M., Sidibe, S., Banaski, J., Walker, C. L., Brooks, J. C., Caceres, V. M., Arthur, R. R., and Angulo, F. J. (2016). Early Identification and Prevention of the Spread of Ebola in High-Risk African Countries. MMWR supplements, 65:21 27. Di Nardo, A., Knowles, N. J., and Paton, D. J. (2011). Combining livestock trade patterns with phylogenetics to help understand the spread of foot and mouth disease in sub-saharan africa, the middle east and southeast asia. Revue scientifique et technique (International Office of Epizootics), 30:63 85. Metwally, S., Weber-Wintzel, L., Raizman, E., Kreindel, S., Leboucq, N., and Torres, G. (2015). Update on the implemrntation of the global strategy. In First West Africa FMD roadmap meeting. 23