Risk analysis of H5N1 highly pathogenic avian influenza in poultry at the Poyang Lake area, China

Abstract

Migratory birds have been known to spread the highly pathogenic avian influenza virus (HPAIV) H5N1 over large distances. Moreover, previous studies have shown it to be widely circulated in live-bird markets. However, how live-bird markets in addition to wild birds affect the local persistence of avian influenza virus (AIV) remains uncertain. The abundance of fresh water and widely distributed wetlands make the Poyang lake area a suitable overwintering site for migratory birds. The intensive local poultry industry and poor biosecurity potentially increase the risk of interactions between the wild and domestic birds. These factors likely contributed to the spread and persistence of AIVs in the Poyang lake area in these years. Here, a cross-sectional survey together with sampling was conducted randomly in the Poyang lake area to investigate the local distribution of the H5N1 viruses. In total, 891 poultry isolates from 31 villages around the Poyang lake area were randomly sampled in poultry sectors and tested for the presence of avian influenza using RT-PCR assays. Environmental factors such as poultry density, road accessibility, and wild bird biodiversity together with breeding characteristics derived from these questionnaires were collected and utilized for risk analysis modelling. Our results revealed that distance to the nearest wetlands with a high number of birds and accessibility by road were the main risk factors for the occurrence HPAIV H5N1, suggesting that the high density of road networks may facilitate the transmission of this virus. Investigating the regional distribution characteristics of the virus is of great significance, therefore the general public would benefit from an early warning, prevention, and taking control measures in high-risk regions.

What evidence exists on the impact of specific ecosystem components and functions on infectious diseases? A systematic map

“…Group 3 (proximity to waterbodies): The three studies of this group had very close validity profiles and only differed in the effort of replication in the observations.. As in the previous group, the studies did not target the same habitats (lakes [52] vs. all types of permanent waterbodies [53,58]), which could be a factor of variability. Variability was also reported within two studies: the proximity to waterbodies was found to be a risk factor for poultry infection in three out of four study regions in Paul et al [53], and only in one site and during one out of two epidemic waves in Saksena et al [52].…”

“…Ten studies looked at the composition of the landscape around recorded cases and searched for a correlation between the proportion of various types of land-use and epidemiological data. Exposures included: proportion of riceland ( [50,[52][53][54]; group 1 in Additional file 5), proportion of waterbodies ([50-52, 50-52]; group 2), proximity to waterbodies ( [52,53,58]; group 3), and Normalized Difference Vegetation Index (NDVI), used as a proxy for vegetation cover or climate ( [54,[58][59][60]; group 4).…”

“…The results from the three studies with a medium validity are difficult to analyse. Indeed, in one of them [58], the spatial resolution of the vegetation data was quite low (1 km grid), while it was not mentioned in the two other studies [54,60]. The lack of robust studies with high quality data is the main limit to establish a potential link between avian influenza and vegetation cover.…”

Effects of the 2022 extreme droughts on avian influenza transmission risk in Poyang Lake

“…Climate change and extreme climate events (e.g., droughts, floods, heatwaves) have substantial negative impacts on landscapes, animals, and humans, which may further increase spillover and transmission risk of zoonotic infectious diseases. 1 For example, extreme droughts could result in a substantial loss of water-related habitats (open surface water bodies, natural wetlands, and rice paddies), which reduces the amount of food resources and shelters available to wild waterfowl, thus further affects migratory waterfowl in different ways (Figure 1A), including (1) weaker and less healthy wild waterfowl, (2) higher density of wild waterfowl in fewer and smaller patches of habitats, which increases contact rates, virus exchange, and transmission risk among waterfowl, 2 (3) movement of wild waterfowl to use other and nearby agricultural habitats, which increases contacts between poultry and waterfowl and spread of highly pathogenic avian influenza virus (AIV), 3,4 and (4) movement of wild waterfowl to other surface water bodies and natural wetlands beyond their normal ranges, which could potentially introduce AIV to new places.…”

Thematic Issue: Environment and Health in China—I

“…The issue also contains a comparison of environmental legislation approaches in China and USA concerning the sustainable development of coal industry (Dzonzi-Undi and Li 2015). Finally, risk of highly pathogenic avian influenza is analyzed on the basis of parameterizing health models by using research results of the environmental components, which will be mainly involved in the forthcoming Thematic Issue ''Environment and Health in China-II'' (Huang et al 2016). …”