Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Source identification of H7N9 influenza virus causing human infections

25.04.2013
In March 2013, a novel H7N9 influenza virus was identified in China as the etiological agent of a flu-like disease in humans, resulting in some deaths.

A group of scientists, led by Professor Chen Hualan (National Avian Influenza Reference Laboratory, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences) have investigated the origins of this novel H7N9 influenza virus (Shi et al., 2013).

Following analysis of H7N9 influenza viruses collected from live poultry markets, it was found that these viruses circulating among birds were responsible for human infections. These novel H7N9 viruses are reassortants in which the six internal genes were derived from avian H9N2 viruses; however the origins of their hemagglutinin (HA) and neuraminidase (NA) genes were unclear.

A total of 970 samples were collected from live poultry markets and poultry farms located in Shanghai and Anhui Province. Samples analyzed included drinking water, feces, contaminated soil, and cloacal and tracheal swabs. Of these samples, 20 were positive for the presence of H7N9 influenza viruses. All of the positive samples originated from live poultry markets in Shanghai. Of these 20 positive samples, 10 were isolated from chickens, 3 from pigeons, and 7 were from environmental samples.

The complete genome of three H7N9 isolates, from a chicken, pigeon, and environmental sample, was sequenced and deposited into the GISAID database. Genetic analysis of these isolates revealed high homology across all eight gene segments. Phylogenetic analysis of these novel H7N9 influenza virus isolates showed that that the six internal genes were derived from avian H9N2 viruses, but the ancestor of their HA and NA genes is unknown. According to the GenBank database, the HA genes of the novel isolated viruses were most similar to those from duck H7N3 influenza viruses, sharing 95.2.8% homology at the nucleotide level. The NA gene of the novel H7N9 virus isolates shared highest homology (97.3.9%) with NA genes from H4N9 or H11N9 influenza viruses isolated from ducks, and environmental samples from duck farms, located in the Dongting Lake region. It is clear that the novel H7N9 viruses are the product of gene reassortment, with the internal genes from one donor, and HA and NA genes from one or several other donors.

HA receptor-binding specificity is a major molecular determinant for the host range of influenza viruses. Amino acids at positions 226 and 228 of HA are critical for specificity of receptor-binding in influenza viruses. Within the HA protein of novel H7N9 viruses, there was a leucine residue at position 226, which is characteristic of the HA gene in human influenza viruses. This finding implies that H7N9 viruses have partially acquired human receptor-binding specificity. All of the H7N9 human isolates examined contained a lysine residue at position 627 in the PB2 protein. It is well known that this lysine residue contributes to the replication and transmission of avian influenza viruses in mammalian hosts. It is likely that the acquisition of this lysine in H7N9 viruses during their replication in human hosts has significantly contributed to their virulence and lethality in humans.

Tracing the source of these novel H7N9 influenza viruses, and their subsequent characterization, was a collaborative effort involving researchers from the National Avian Influenza Reference Laboratory at the Harbin Veterinary Research Institute, and Shanghai Animal Disease Control Center. This research project was partially supported by the National Basic Research Program of China (2011CB505000), the China Agriculture Research System (CARS-42-G08), and the National Science and Technology Major Project (2012ZX10004214). We suggest that strong measures, such as continued surveillance of avian and human hosts, control of animal movement, shutdown of live poultry markets, and culling of poultry in affected areas, should be taken during this initial stage of virus prevalence to prevent a possible pandemic. Additionally, it is also imperative to evaluate the pathogenicity and transmissibility of these H7N9 viruses, and to develop effective vaccines and antiviral drugs against so as to reduce their adverse effects upon human health.

corresponding author:

CHEN HuaLan
hlchen1@yahoo.com
Reference:
Shi J Z, Deng G H, Liu P H, et al. Isolation and characterization of H7N9 viruses from live poultry markets—Implication of the source of current H7N9 infection in humans. Chin Sci Bull, 2013, 58, doi:10.1007/s11434-013-5873-4.

http://link.springer.com/article/10.1007/s11434-013-5873-4
Science China Press Co., Ltd. (SCP) is a scientific journal publishing company of the Chinese Academy of Sciences (CAS). For 50 years, SCP takes its mission to present to the world the best achievements by Chinese scientists on various fields of natural sciences researches.

YAN Bei | EurekAlert!
Further information:
http://www.scichina.org

More articles from Health and Medicine:

nachricht How cancer metastasis happens: Researchers reveal a key mechanism
19.01.2018 | Weill Cornell Medicine

nachricht Researchers identify new way to unmask melanoma cells to the immune system
17.01.2018 | Duke University Medical Center

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Artificial agent designs quantum experiments

On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.

We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...

Im Focus: Scientists decipher key principle behind reaction of metalloenzymes

So-called pre-distorted states accelerate photochemical reactions too

What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...

Im Focus: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

Im Focus: Room-temperature multiferroic thin films and their properties

Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.

Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

 
Latest News

Let the good tubes roll

19.01.2018 | Materials Sciences

How cancer metastasis happens: Researchers reveal a key mechanism

19.01.2018 | Health and Medicine

Meteoritic stardust unlocks timing of supernova dust formation

19.01.2018 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>