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 poultr y

Present in the village in ½ of outbreaks

Involved in only 7.3% of outbreaks

Relative r isk for presence in outbreak household:

Muscovy ducks

Backyard chickens

Broilers

Geese

But not pigeons or ducks!

Top r isk factor for introduction: New bird entry into household flocks (24.4%)

Top r isk 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 poultr y on Java provide the necessary condit ions 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 f lock protection reduced HPAI-compatible disease incidence by 46%

Cost > 1 million USD

PE is a cost ef fective 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