Top Chinese lab reveals H7N9 source

[tetano]

BEIJING, April 10 (Xinhua) -- A top Chinese biology lab has ascribed the H7N9 avian influenza to genetic reassortment of wild birds from east Asia and chickens from east China.

The researchers found that no genes in H7N9 were traceable to pigs, thus excluding pigs as intermediate hosts for the deadly new strain of bird flu, the Chinese Academy of Sciences' Key Laboratory of Pathogenic Microbiology and Immunology said on Wednesday.

According to the researchers, the genetic reassortment is likely to have occurred in east China's Yangtze River Delta areas covering Shanghai, Zhejiang and Jiangsu.

They found that a virus carried by wild birds from the Republic of Korea and other east Asian regions mingled with the avian influenza virus carried by ducks and chickens in the Yangtze River Delta during migration.

The lab's research shows the H7 and N9 gene segments in H7N9 are similar to those in avian influenza samples collected from wild birds from east Asia, while the other six genes are traceable to chickens in China's Shanghai, Zhejiang and Jiangsu.

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http://news.xinhuanet.com/english/china/2013-04/10/c_132299005.htm

[Vibrant62]

Re: Top Chinese lab reveals H7N9 source

The researchers found that no genes in H7N9 were traceable to pigs, thus excluding pigs as intermediate hosts for the deadly new strain of bird flu, the Chinese Academy of Sciences' Key Laboratory of Pathogenic Microbiology and Immunology said on Wednesday.

This really does not follow. N7N9 is infecting humans without a human gene acquisition...

[Shiloh]

Re: Top Chinese lab reveals H7N9 source

Source: http://www.kaixian.tv/R1/n1771837c7.shtml

H7N9 virus from bird virus gene reassortant
2013-04-11 04:21 Source: People's Daily Edit: the spider comment 0 7 people involved

Reporters learned from the Institute of Microbiology, Chinese Academy of Sciences, Key Laboratory of the Chinese Academy of pathogenic microorganisms and Immunology researchers after human infection with the H7N9 avian influenza virus gene analysis revealed the virus may be carried by migration from Eurasia to East Asia's wild birds The avian influenza virus and the avian influenza virus carried by ducks and chickens in Shanghai, Zhejiang, Jiangsu occurring gene reassortment. In addition, the virus genetic variation, especially the N9 gene fragments of abnormal, it may be a new type of the H7N9 avian influenza virus infection and cause high mortality.

Wild birds and chickens, ducks virus gene reassortant H7N9 virus


"Virus reassortment is a very common phenomenon in nature, different viruses can be exchanged by the contact between the host gene fragments., Deputy director of pathogenic microorganisms and Immunology, Institute of Microbiology, Chinese Academy of Sciences Key Laboratory Wenjun said.

Conducted by the laboratory of the China Disease Prevention and Control Center of the H7N9 avian influenza virus genetic data analysis showed that the eight gene segments of the H7N9 virus, avian influenza virus H7 isolated fragments with Zhejiang ducks, ducks Zhejiang virus in upward retroactive, the similarity with the genes of the avian influenza virus isolated in wild birds in East Asia; N9 fragments East Asia separation of the avian influenza virus in wild birds in. The remaining six gene segments (PB2, PB1, PA, NP, M, NS) is similar to the H9N2 avian influenza virus. The viral genome comparison and phylogenetic analysis of H9N2 avian influenza virus from China Shanghai, Zhejiang, Jiangsu and other places flocks.

"This outbreak occurs in the Yangtze River Delta region, probably because of wild birds the Eurasian continental migratory carry H subtypes (including H7N3 and H7N9 subtype avian influenza virus) in the natural migration process (via South Korea and other East Asian region) , and the Yangtze River Delta region of China, ducks, chickens carrying the H9N2 avian influenza virus genetic reassortment. "said Liu Di, a research associate in bioinformatics analysis.

Earlier media said the H7N9 virus is "China and South Korea mestizo Wenjun corrected me, wild birds is constant movement, can not be said that the H7N9 virus bilateral mestizo.

The team's results also show that the H7N9 avian influenza virus yet found traces the evolution of pigs, suggesting that the pigs in this viral gene reassortment did not play the role of intermediate host. The specific conclusions relevant departments have yet to be further confirmed.

H7N9 virus to infect humans, may be derived from the virus mutates

According to the traditional experience of the avian flu virus, regardless of the poultry is low pathogenic virus or high pathogenic virus, are more difficult to infect human cells, generally after the human respiratory tract Jibei prevent.

Reality and research revealed that the original virus circulating in poultry, or through an intermediate host pig gene reassortment infected person;, or directly from poultry to people. The H7N9 avian influenza virus, that is, directly from birds to people. This attenuated virus is rendered in the poultry body, and in the human body is highly destructive, viruses replicate in the lungs crazy, causing infection more than 30% mortality.

According to reports, as the name of the virus hemagglutinin prime (HA), neuraminidase (NA) gene fragment is very important, two on the surface of the influenza virus glycoprotein projections, which the virus with the hemagglutinin (HA) such key to open and the invasion of human or animal cells, neuraminidase (NA) can destroy the cell receptors, and the spread of virus in the host body freedom. Can be divided into 16 kinds of HA, NA can be divided into nine kinds. Different combinations between them, in reality, more than 130 species have been found.

"In accordance with the mechanism of virus structure, the process of the virus invades the human body like a teamwork combat is divided into three steps: hemagglutinin (HA) breakthrough who host restriction; neuraminidase (NA) to help destroy the virus-cell receptor and thus make a new copy of the synthesis of the spread of the virus, the remaining six gene fragments collaboration, the completion of the virus to copy a large number of cells in the body. "Liu Zhai said," three steps with the indispensable, and which one imbalance can be caused by viruses strength Weakening the killing effect on the human body is difficult to play, but unfortunately, these three steps, in a new type of H7N9 avian influenza virus highly efficient havoc with the human body. "

The laboratory researchers said, the new H7N9 avian influenza virus infection in humans, may be derived from the virus mutates. N9 variability observed gene fragment is shorter than the N9 gene fragments, but still I do not know a mutation leading to what specific consequences.

In the course of the study, the the H7 gene fragment and customary H7 has not changed much. However, in decision - Avian receptor binding specificity, the emergence of a critical amino acid changes. The human impact of this change pending further scientific assessment, because the previous H7 subtype of avian influenza virus infection cases had occurred.

Wenjun pointed out that, in order to come up with there are still difficulties for all types of influenza vaccines. Because the the flu mutation rate is very difficult to predict what will happen variability. The same time, the vaccine can not be abused, or may accelerate the speed of virus mutation.

For the next step of the research, Wenjun said, will continue to follow the study H7N9 infection mechanism, to provide a theoretical basis for further prevention and control work.

Of: Wuyue Hui Source People's Daily)