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

Abstract

Most Chinese provinces have a daily‐updated database of live animal movements; however, the data are not efficiently utilized to support interventions to control H7N9 and other avian influenzas. Based on official records, this study assessed the spatio‐temporal patterns of live broilers moved out of and within Guangxi in 2017. The yearly and monthly networks were analyzed for inter‐ and intra‐provincial movements, respectively. Approximately 200,000 movements occurred in 2017, involving the transport of 200 million live broilers from Guangxi. Although Guangxi exported to 24 out of 32 provinces of China, 95% of inter‐provincial movements occurred with three bordering provinces. Within Guangxi, counties were highly connected through the live broiler movements, creating conditions for rapid virus spreading throughout the province. Interestingly, a peak in movements during the Chinese Lunar New Year celebrations, late January in 2017, was not observed in this study, likely due to H7N9‐related control measures constraining live bird trading. Both intra‐ and inter‐provincial movements in March 2017 were significantly higher than in other months of that year, suggesting that dramatic price changes may influence the movement's network and reshape the risk pathways. However, despite these variations, the same small proportion of counties (less than 20%) exporting/importing more than 90% of inter‐ and intra‐provincial movements remains the same throughout the year. Interventions, particularly surveillance and improving biosecurity, targeted to those counties are thus likely to be more effective for avian influenza risk mitigation than implemented indiscriminately. Additionally, simulations further demonstrated that targeting counties according to their degree or betweenness in the movement network would be the most efficient way to limit disease transmission via broiler movements. The study findings provide evidence to support the design of risk‐based control interventions for H7N9 and all other avian influenza viruses in broiler value chains in Guangxi.

A dataset of a proxy variable for the poultry trade flows in China

“…Therefore, understanding the trade patterns is of great help to develop avian influenza control strategies. Unfortunately, poultry trade flows in China have rarely been reported, except for a few local surveys 2 , 4 , 5 .…”

“…First, we compare our estimation with the movements of live broilers out of and within Guangxi in 2017 analyzed by Tang et al . 5 . According to their analysis of the movements out of Guangxi, Guangdong Province received the most movements (77.5%), followed by Guizhou (9.9%) and Hunan (8.6%).…”

“…What we need to do is to find a balance between keeping more flows and ensuring accuracy. Since a few sources contributed most of the poultry trade volumes 5 , we can use the contribution rates as threshold values to obtain the main sources for each city. Figure 4 shows the trade flows that cumulatively contributed to more than 90% of the total volumes for each city.…”

“…Since very few investigations on the poultry trade flows in 2015 are available, we compare some statistical results in the years around 2015 with our estimation. First, we compare our estimation with the movements of live broilers out of and within Guangxi in 2017 analyzed by Tang et al 5 . According to their analysis of the movements out of Guangxi, Guangdong Province received the most movements (77.5%), followed by Guizhou (9.9%) and Hunan (8.6%).…”

Bayesian phylodynamics reveals the transmission dynamics of avian influenza A(H7N9) virus at the human–live bird market interface in China

“…The majority of species sold in LBMs are indigenous yellow-feather broilers, followed by spent hens and waterfowl ( 10 ). There are two types of LBMs: retail LBMs serve as a major source of food for both urban and rural populations, while wholesale LBMs play a specialized role in the distribution of poultry in their areas and others ( 10 , 12 ). However, the size and characteristics of each LBM, as well as the types of bird species sold, can vary greatly and lead to variations in the trade patterns and movements of poultry ( 12 , 13 ).…”