Online 8 December 2020

1. 1EuFMD | Open Session special edition | #OS20se
Modelling and predicting national and
regional animal mobility affecting
livestock’s diseases circulation. A
comparison from studies in North/West
Africa and South-East Asia
Andrea Apolloni, Alexis Delabouglise
CIRAD Montpellier, Unit ASTRE, AQCR team

2. 2
• Extensive system. Animals kept mobile because of
environmental conditions. Focus on small and large
ruminants
• NO animal identification system. Use aggregated
information collected by Vetrinary Services
• Network Analysis:
• A single large component in the mobility
network
• Heterogeneity in degree and volume
distribution
• Variation along the year due to religious
festivity
• Connectivity Analysis
Livestock’s in/out flows in administrative areas
change if we consider land use and probability of
passing
• Models capture existence/absence of links but fail
to estimate volumes
• Mobility complex phenomenon involving several
aspects form environmental to socio economical
factors
West/North Africa
(a) Connectivity (b) Network
Normalized Activity
[0,0.1]
]0.1,0.2]
]0.2,0.3]
]0.3,0.4]
]0.4,0.5]
]0.5,0.6]
]0.6,0.7]
]0.7,0.8]
]0.8,0.9]
]0.9,1]

3. 3
• Small scale commercial production system. Focus
on poultry
• Longitudinal survey of 53 poultry farms in
Mekong river valley for 20 months
• Information collected:
• Introduction and harvest of birds
• Mortality + symptoms
• Preventive measure
• Mixed-effect generalized additive models:
• Non-linear relationship age – likelihood of
trade
• Random farm effect (farmers’ individual
characteristics)
• Fixed effect: poultry population, introduction
of new flocks, vaccination status, disease
outbreaks
• Small scale farms:
• Small flocks sold at slower rate
• Trade adjusted to evolving conditions
• Trade as risk-copying strategy : outbreaks
followed by increased sale rate
Viet Nam Small-scale flocks
Large-scale flocks
Outbreaks with
sudden deaths
Outbreaks no sudden
death
No outbreaks

4. 4
Conclusions
• Network approach on aggregated data
• Mobility changes along the year
• Importance of festivities and social
events
• Landuse and environmental factors can
shape mobility pattern and change
locations activity
• What we miss:
• Harmonised data on production chain
could explain certain axes
• Individual choices toward certain
markets/locations
Vietnam
• Individual longitudinal surveys
• Explore individual motivations for
introducing and removing animals
• Sale rate and destination change in
response to events at individual level –
changes in stock size, disease outbreaks.
• In small-scale farms: slower sale rate and
adaptable to changing conditions
• What we miss:
• Response to changes in market prices
• Description of trade networks of infected
poultry
Need to combine large scale /national information with individual’s choices
West Africa