Aerosol exposure of live bird market workers to viable influenza A/H5N1 and A/H9N2 viruses, Cambodia

Abstract

Live bird markets (LBMs) have been identified as key factors in the spread, persistence and evolution of avian influenza viruses (AIVs). In addition, these settings have been associated with human infections with AIVs of pandemic concern. Exposure to aerosolised AIVs by workers in a Cambodian LBM was assessed using aerosol impact samplers. LBM vendors were asked to wear an air sampler for 30 min per day for 1 week while continuing their usual activities in the LBM during a period of high AIV circulation (February) and a period of low circulation (May). During the period of high circulation, AIV RNA was detected from 100% of the air samplers using molecular methods and viable AIV (A/H5N1 and/or A/H9N2) was isolated from 50% of air samplers following inoculation into embryonated chicken eggs. In contrast, AIV was not detected by molecular methods or successfully isolated during the period of low circulation. This study demonstrates the increased risk of aerosol exposure of LBM workers to AIVs during periods of high circulation and highlights the need for interventions during these high-risk periods. Novel approaches, such as environmental sampling, should be further explored at key high-risk interfaces as a potentially costeffective alternative for monitoring pandemic threats.

Advancements in Airborne Viral Nucleic Acid Detection with Wearable Devices

“…Active air samplers function by using mechanical means, such as internal fans, blowers, or pumps to force air into a collection apparatus at various flow rates. [58,61] Typical flow rates range from 3.5 to 500 L min −1 (Table 1). For reference, humans breathe at a rate of 6 L min −1 .…”

“…(2.371-4.217 μm) Horwood et al [58] Sioutas 86 mm (H) × 55 mm (∅) [69] 30 min 9 -Linde et al [38] Conical Inhalable Sampler (JS Holdings) with Gilian…”

“…Instead, studies typically only tested the performance of one sampler and differed in the target analyzed, detection method, and whether real or artificially generated air samples were collected. [38,54,58,61,63,67] One recent study that carried out a direct comparison of different sampler types did so in a nursing home setting. In this study by Linde et al, [38] aerosol samples were collected from confirmed COVID-19 patients rooms using an impingement-based sampler, a two-stage cyclone-based sampler, and a filtration-based sampler.…”

Editorial: Global Surveillance of Highly Pathogenic Avian Influenza Viruses in Poultry, Wild Birds, and Mammals to Prevent a Human Influenza Pandemic

“…Mutations in the virus may have increased the ability to replicate and infect a broader range of species of birds [ 10 ]. A recent concern is that this strain has begun to infect mammals, including mink [ 11 ]. Currently, there is no evidence that A(H5N1) spreads between mammals, but this scenario is possible.…”

“…The risk of infection has been assessed as low for the general population in the EU/EEA and as low to medium for those occupationally exposed to poultry [ 10 ]. Within the past month, Horwood and colleagues have reported that live bird markets in Cambodia have been identified as a source of airborne spread of avian influenza viruses [ 11 ]. The authors have identified viral spread and persistence in market workers during a period of high viral circulation, which supports the possibility of the evolution of avian influenza viruses in live bird markets [ 11 ].…”