Interventions in live poultry markets for the control of avian influenza: A systematic review

Offeddu, Vittoria; Cowling, Benjamin J.; Peiris, J.S. Malik

Although RRRs represent relatively comparable outcome measures of the intervention effects across publications, these values should be interpreted with care. Aside from the very different sampling schedules, with time windows ranging from b14 days [19, 23, 27] to year-long surveillance [20, 21, 26] , the studies actually assessed very distinct scenarios: the duration and frequency of interventions ranged between one weekly rest day [26] and a one-time two-week LPM closure [27] in different LPM systems. In addition, sample sizes were very variable [21, 26, 27] . Importantly, samples were usually collected from different markets, distinct market areas and from several bird species, but pre-and post-intervention data was not unequivocally matched [19] [20] [21] 23, 26, 27] . Moreover, some investigations assessed AIV-prevalence by virus isolation [19] [20] [21] 23, 27] , while others used RT-PCR [26, 27] . Positive RT-PCR results do not discriminate between viable infectious virus and inactivated virus and thus does not have the same biological implications as virus isolation does. Finally, some interventions had different impacts on AIV circulation in different bird species [20, 21] . This suggests distinct AIV-transmission dynamics across species or varying market practises, highlighting the importance to investigate different species separately.