Jost, C, Walker,
P, Bett, B, Poole,
J, Azar, M,
Murahman, J,
Daju, D, McLaws,
M, Schoonman,
L, Unger, F,
Mariner, J
USING A PARTICIPATORY
APPROACH TO
CHARACTERIZE HPAI
OUTBREAKS IN
INDONESIAN VILLAGE
POULTRY

Reproduction number (R)
The number of new individuals that will become infected from
a single infected individual
TRANSMISSIBILITY

Risk factors
Variables associated with an increased risk for infection
Relative risk
The probability of infection occurring in an exposed group
versus a non-exposed group
RISK

Mass vaccination efficacy
study:
One-year mass vaccination
program
Control neighborhoods
Sampling:
16 districts on Java
All H5N1 outbreaks diagnosed
by VS
1-3 randomly selected
outbreaks
Infection tree reconstruction
Susceptible-infected-
recovered (SIR) model
METHODS

Affected Neighborhood (RT):
Focus group interview
Mapping
Transect walk
Geo-referencing
1-5 Affected Households:
Individual interview
Timeline
2 Adjacent Neighborhood
Transect walk
Rapid interviews
PE TOOLS

Epidemiological
relationships
Housing
Husbandry
Bird contacts
Risk factors
FOCUS GROUP INTERVIEWS

All households
Species of poultry
in each household
Households
affected
Species affected
in each household
Spread of the
outbreak
Timing of each
household
affected
MAPPING

Triangulation
interview info
Geo-
referencing
Index
household
Closest
unaffected
household
2nd household
affected
TRANSECT WALK AND GEO-REFERENCING

Morbidity,
mortality,
slaughter and
sale rates
Key outbreak
events
Husbandry
characteristics
TIMELINE

Commercial poultry
Present in the village in ½ of outbreaks
Involved in only 7.3% of outbreaks
Relative risk for presence in outbreak
household:
Muscovy ducks
Backyard chickens
Broilers
Geese
But not pigeons or ducks!
Top risk factor for introduction: New
bird entry into household flocks
(24.4%)
Top risk factor for spread: Bird
contact between households (73.2%)
RESULTS

Within Flock R*
Vaccinated areas: 2.23, 95% credible
interval (1.96-2.51)
Unvaccinated areas: 2.79, 95% CrI
(2.52-3.10)
Vaccination coverage: 11% (5%-19%)
Between Flock R
Vaccinated areas: 1.9, 95 % CrI
(1.59,2.26)
Unvaccinated areas: 2.07, 95% CrI
(1.82,2.35)
Vaccination coverage: 14% (5%-27%)
RESULTS
*decisive according to Jeffrey’s scale
of evidence (Bayes factor (BF)> 100)

Backyard poultry on Java provide the
necessary conditions for indefinite
transmission
Level of population immunity necessary to
interrupt transmission:
64.2% (+60.3-67.7%) of birds in household
flocks
51.7% (+41.5-57.4%) of households in
neighborhood
Incidence study: moderate levels of flock
protection reduced HPAI-compatible
disease incidence by 46%
Cost > 1 million USD
PE is a cost effective and simple tool for
assessing the epidemiological impact of
disease control measures
Cost ~ 90,000 USD
LESSONS LEARNT

MoA Indonesia
District VS
Imperial College London
USAID and the World Bank
ACKNOWLEDGEMENTS