Genetic and biological characteristics of the globally circulating H5N8 avian influenza viruses and the protective efficacy offered by the poultry vaccine currently used in China.

The H5N8 avian influenza viruses have been widely circulating in wild birds and are responsible for the loss of over 33 million domestic poultry in Europe, Russia, Middle East, and Asia since January 2020. To monitor the invasion and spread of the H5N8 virus in China, we performed active surveillance by analyzing 317 wild bird samples and swab samples collected from 41,172 poultry all over the country. We isolated 22 H5N8 viruses from wild birds and 14 H5N8 viruses from waterfowls. Genetic analysis indicated that the 36 viruses formed two different genotypes: one genotype viruses were widely detected from different wild birds and domestic waterfowls; the other genotype was isolated from a whopper swan. We further revealed the origin and spatiotemporal spread of these two distinct H5N8 virus genotypes in 2020 and 2021. Animal studies indicated that the H5N8 isolates are highly pathogenic to chickens, mildly pathogenic in ducks, but have distinct pathotypes in mice. Moreover, we found that vaccinated poultry in China could be completely protected against H5N8 virus challenge. Given that the H5N8 viruses are likely to continue to spread in wild birds, vaccination of poultry is highly recommended in high-risk countries to prevent H5N8 avian influenza.

Genetic and biological properties of H7N9 avian influenza viruses detected after application of the H7N9 poultry vaccine in China.

The H7N9 avian influenza virus (AIV) that emerged in China have caused five waves of human infection. Further human cases have been successfully prevented since September 2017 through the use of an H7N9 vaccine in poultry. However, the H7N9 AIV has not been eradicated from poultry in China, and its evolution remains largely unexplored. In this study, we isolated 19 H7N9 AIVs during surveillance and diagnosis from February 2018 to December 2019, and genetic analysis showed that these viruses have formed two different genotypes. Animal studies indicated that the H7N9 viruses are highly lethal to chicken, cause mild infection in ducks, but have distinct pathotypes in mice. The viruses bound to avian-type receptors with high affinity, but gradually lost their ability to bind to human-type receptors. Importantly, we found that H7N9 AIVs isolated in 2019 were antigenically different from the H7N9 vaccine strain that was used for H7N9 influenza control in poultry, and that replication of these viruses cannot, therefore, be completely prevented in vaccinated chickens. We further revealed that two amino acid mutations at positions 135 and 160 in the HA protein added two glycosylation sites and facilitated the escape of the H7N9 viruses from the vaccine-induced immunity. Our study provides important insights into H7N9 virus evolution and control.

Extensive removal of thallium by graphene oxide functionalized with aza-crown ether.

Thallium (Tl) is a highly toxic heavy metal, and its pollution and remediation in aquatic environments has attracted considerable attention. To reduce or remove Tl pollution in the environment, various strategies have been applied. Graphene oxide (GO) has abundant oxygen-containing functional groups, indicating its high application potential for pollution remediation via methods involving binding to metal ions or positively charged organic molecules or electrostatic interaction and coordination. However, the adsorption of Tl to GO occurs via physical adsorption, for which the adsorption efficiency is low. Therefore, herein, we report a new method to effectively remove Tl pollution in water. We combined GO with aza-crown ether, which enhanced the electronegativity and ability to bind metal ions. The functionalized graphene oxide (FGO) demonstrated high efficiency through a wide pH gradient of 5-10, with a dominant Tl(i) adsorption capacity (112.21 mg g-1) based on the Langmuir model (pH 9.0, adsorbent concentration of 0.8 g L-1). The adsorption of Tl(i) during removal fit a pseudo-second-order kinetic model well. The mechanisms of Tl removal involve physical and chemical adsorption. In summary, our study provides a new method for the detection and treatment of Tl-containing wastewater by using FGO.