美国疾病控制和预防中心Joanna A. Pulit-Penaloza等研究人员报道了，人类分离的2.3.4.4b亚型A（H5N1）病毒在雪貂中的传播。相关论文于2024年10月28日在线发表在《自然》杂志上。

研究人员采用雪貂模型，以评估从德克萨斯州一名乳农工人分离的A/Texas/37/2024（TX/37）A(H5N1)病毒。这是一种经过充分表征的物种，允许同时研究病毒的致病性和传播性。

研究人员发现该病毒在雪貂中具有显著的系统性感染能力，导致高水平的病毒排泄和传播至未感染的接触者。

接种TX/37的雪貂迅速出现严重和致命的感染，表现为病毒血症和肺外传播。该病毒在直接接触环境中有效传播，并能够通过污染物进行间接传播。

通过检测到感染动物排放到空气中的传染性病毒，研究人员证实了气溶胶传播，尽管与高度传播的人类季节性和猪源H1亚型病毒株相比，其水平较低。

这些结果表明，尽管TX/37保持了鸟类样的受体结合特异性，但相较于2024年牛疫情前分离的其他2.3.4.4b亚型病毒，TX/37表现出更高的毒力、传播性和气溶胶排泄，进而强调了持续公共卫生警惕的必要性。

据了解，自2020年以来，高致病性禽流感A（H5N1）在野生鸟类种群中的传播空前广泛，波及多种哺乳动物并偶尔感染人类。在2024年3月，2.3.4.4b亚型A（H5N1）病毒首次在美国乳牛中被检测到，随后在多个州发现，导致十多例确认的人类病例。

附：英文原文

Title: Transmission of a human isolate of clade 2.3.4.4b A(H5N1) virus in ferrets

Author: Pulit-Penaloza, Joanna A., Belser, Jessica A., Brock, Nicole, Kieran, Troy J., Sun, Xiangjie, Pappas, Claudia, Zeng, Hui, Carney, Paul, Chang, Jessie, Bradley-Ferrell, Brandon, Stevens, James, De La Cruz, Juan A., Hatta, Yasuko, Di, Han, Davis, C. Todd, Tumpey, Terrence M., Maines, Taronna R.

Issue&Volume: 2024-10-28

Abstract: Since 2020, there has been unprecedented global spread of highly pathogenic avian influenza A(H5N1) in wild bird populations with spillover into a variety of mammalian species and sporadically humans1. In March 2024, clade 2.3.4.4b A(H5N1) virus was first detected in dairy cattle in the U.S., with subsequent detection in numerous states2, leading to over a dozen confirmed human cases3,4. In this study, we employed the ferret model, a well-characterized species that permits concurrent investigation of viral pathogenicity and transmissibility5 in the evaluation of A/Texas/37/2024 (TX/37) A(H5N1) virus isolated from a dairy farm worker in Texas6. Here, we show that the virus has a remarkable ability for robust systemic infection in ferrets, leading to high levels of virus shedding and spread to nave contacts. Ferrets inoculated with TX/37 rapidly exhibited a severe and fatal infection, characterized by viremia and extrapulmonary spread. The virus efficiently transmitted in a direct contact setting and was capable of indirect transmission via fomites. Airborne transmission was corroborated by the detection of infectious virus shed into the air by infected animals, albeit at lower levels compared to the highly transmissible human seasonal and swine-origin H1 subtype strains. Our results show that despite maintaining an avian-like receptor binding specificity, TX/37 displays heightened virulence, transmissibility, and airborne shedding relative to other clade 2.3.4.4b virus isolated prior to the 2024 cattle outbreaks7, underscoring the need for continued public health vigilance.

DOI: 10.1038/s41586-024-08246-7

Source: https://www.nature.com/articles/s41586-024-08246-7