Live Poultry Market Closure and Avian Influenza A (H7N9) infection in cities of China, 2013-2017: An ecological study

Abstract

Background Previous studies have proven that the closure of live poultry markets (LPMs) was an effective intervention to reduce human risk of avian influenza A (H7N9) infection, but evidence is limited on the impact of scale and duration of LPMs closure on the transmission of H7N9. Method Five cities (i.e., Shanghai, Suzhou, Shenzhen, Guangzhou and Hangzhou) with the largest number of H7N9 cases in mainland China from 2013-2017 were selected in this study. Data on laboratory-confirmed H7N9 human cases in those five cities were obtained from the Chinese National Influenza Centre. The detailed information of LPMs closure (i.e., area and duration) was obtained from the Ministry of Agriculture. We used a generalized linear model with a Poisson link to estimate the effect of LPMs closure, reported as relative risk reduction (RRR). We used classification and regression trees (CARTs) to select and quantify the dominant factor of H7N9 infection. Results All five cities implemented the LPMs closure, and the risk of H7N9 infection decreased significantly after LPMs closure with RRR ranging from 0.80-0.93. Respectively, a long-term LPMs closure for 10-13 weeks elicited a sustained and highly significant risk reduction of H7N9 infection (RRR = 0.98). Short-time LPMs closure with 2 weeks in every epidemic did not reduce the risk of H7N9 infection (p>0.05). Partially closed LPMs in some suburbs contributed only 35% for reduction rate (RRR=0.35). Shenzhen implemented partial closure for first 3 epidemics (p>0.05) and all closure in the latest 2 epidemic waves (RRR=0.64). Conclusion Our findings suggest that LPMs all closure in whole city can be a highly effective measure comparing with partial closure (i.e. only urban closure, suburb and country remain open). Extend the duration of closure and consider permanently closing the LPMs will help improve the control effect. The effect of LPMs closure is greater than that of meteorology on H7N9 transmission.

The Impact of the Closure of the Live Poultry Market due to COVID-19 on the Avian Influenza Virus in Nanchang, Jiangxi Province, China

“…In the past, it was generally closed for shorter periods of about 2 weeks. The results of our and previous studies 11 show that no matter whether it is a shortterm or long-term market closure, the effect on controlling the spread of AIV among live birds is not clear. However, from the perspective of human-to-human transmission of the AIV, in areas where the virus is found in live poultry or people, the rapid implementation of LPM closures has a relatively good control effect in the short term.…”

Analysis of the movement of live broilers in Guangxi, China and implications for avian influenza control

“…This study further confirmed that Guangxi, with a considerable amount of live broiler movements, faces substantial challenges in AI risk management. The findings indicate that the live broiler trade volume was still large and very active in southern China, despite the closure of LBMs since late 2016 in response to the dramatic increase of human infections with H7N9 (China News Service, 2017; Chen et al, 2020). The study findings further confirmed earlier observations that public consumption demand for live poultry remained high even during the H7N9 epidemics (Lin et al., 2017).…”