久久亚洲国产成人影院-久久亚洲国产的中文-久久亚洲国产高清-久久亚洲国产精品-亚洲图片偷拍自拍-亚洲图色视频

Global EditionASIA 中文雙語Fran?ais
China
Home / China / Innovation

Scientists discover how H5N1 virus invades cattle

By Zhao Yimeng | China Daily | Updated: 2025-07-08 09:32
Share
Share - WeChat

Chinese scientists say they have uncovered how the H5N1 virus initially invades the mammary glands of dairy cattle, potentially triggering last year's outbreak of bird flu across more than 1,000 dairy farms in the United States.

The study, published recently in the journal National Science Review, was conducted by the Harbin Veterinary Research Institute of the Chinese Academy of Agricultural Sciences in Heilongjiang province. Researchers found that tissues in the mouths of cattle support H5N1 virus binding and replication, allowing the virus to spread to the mammary glands during suckling.

Chen Hualan, an academician with the Chinese Academy of Sciences and a chief scientist at the institute, and her team also confirmed that vaccination provides full protection against the virus in dairy cows. The study suggests that targeted control of milk-stealing behavior and immunization could help curb H5N1 outbreaks among cattle.

Highly pathogenic bird flu subtype H5N1 is a major zoonotic disease, transmissible from animals to humans under natural conditions. Since 2021, a new strain has caused tens of thousands of outbreaks among poultry and wild birds worldwide.

In March last year, the virus began infecting dairy cows in the US. As of June 7 this year, infections have been reported on more than 1,070 dairy farms across 17 states, with cow-to-cow transmission suspected during milking, according to the study.

The outbreaks have resulted in a cow mortality rate of up to 10 percent and infected at least 41 farmworkers, raising concerns about dairy production and public health.

Previous research found that H5N1 can damage cows' mammary glands and contaminate milk, with about one-fourth of retail milk samples in the US testing positive for the virus. However, it was unclear how the virus initially entered the mammary glands, and no effective control measures were available.

The new findings shed light on the virus' transmission routes in cattle, Chen said. The study revealed that cows' oral tissues are rich in sialic acid receptors, which are key binding sites for H5N1, making cattle vulnerable to infection through contaminated feed and water. The virus can replicate and remain in the mouth for several days. Behaviors such as self-suckling and cross-suckling from other cows can enable oral-to-udder transmission of the virus, the study found.

Vaccination has been central to controlling highly pathogenic bird flu in China since 2004, with anti-genically well-matched vaccines providing complete protection in poultry. Applying this approach to cattle could be an effective and economical way to halt H5N1 transmission and reduce its threat to public health, Chen said.

"We found that either an inactivated H5 vaccine or a hemagglutinin-based DNA vaccine could induce sterilizing immunity in cows against challenges from multiple H5N1 virus strains," she said.

Inactivated and DNA vaccines could prevent both naturally occurring H5N1 infections in cattle and mammary gland infections caused by high-dose virus exposure during milking, Chen said.

Top
BACK TO THE TOP
English
Copyright 1995 - . All rights reserved. The content (including but not limited to text, photo, multimedia information, etc) published in this site belongs to China Daily Information Co (CDIC). Without written authorization from CDIC, such content shall not be republished or used in any form. Note: Browsers with 1024*768 or higher resolution are suggested for this site.
License for publishing multimedia online 0108263

Registration Number: 130349
FOLLOW US
 
主站蜘蛛池模板: 久久一日本道色综合久 | 91香蕉国产线在线观看免费 | 欧美毛片在线 | 加勒比毛片 | 99国产欧美久久精品 | 欧美一级视屏 | 成人福利在线 | 日韩一级高清 | aaa在线观看 | 永久天堂| 日韩视频免费一区二区三区 | 欧美一区二区三区久久久人妖 | japanese乱子另类 | 亚洲午夜久久 | 欧美日韩精品一区二区三区视频播放 | 成年人网站黄 | 欧美成人性色大片在线观看 | 91视频免费播放 | 美女在线网站免费的 | 久久精品视频网 | 亚洲综合自拍 | 俄罗斯美女在线观看一区 | 亚洲精品国产拍拍拍拍拍 | 香蕉久久综合精品首页 | 自拍小视频在线观看 | 亚洲精品综合一区二区三区 | 亚洲一区二区三区视频 | 久久久久久久久毛片精品 | 国产精品日韩 | chinese农村野战videos | 国产精品密蕾丝视频 | 亚洲美女性视频 | 欧美一级视频在线观看 | 一级毛片在线完整免费观看 | 久久久久久国产精品免费免 | 国产aⅴ精品一区二区三区久久 | 久久综合婷婷香五月 | 久久草在线观看 | 国产精品一级香蕉一区 | 男人亚洲天堂 | 亚洲欧美男人天堂 |