Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


New research helps explain why bird flu has not caused a pandemic

Bird flu viruses would have to make at least two simultaneous genetic mutations before they could be transmitted readily from human to human, according to research published today in PLoS ONE.

The authors of the new study, from Imperial College London, the University of Reading and the University of North Carolina, USA, argue that it is very unlikely that two genetic mutations would occur at the same time.

Today's new study adds to our understanding of why avian influenza has not yet caused a pandemic. Earlier this year, the Imperial researchers also showed that avian influenza viruses do not thrive in humans because, at 32 degrees Celsius, the temperature inside a person's nose is too low.

H5 strains of influenza are widespread in bird populations around the world. The viruses occasionally infect humans and the H5N1 strain has infected more than 400 people since 2003.

H5N1 has a high mortality rate in humans, at around 60 per cent, but to date there has been no sustained human to human transmission of the virus, which would need to happen in order for a pandemic to occur.

Today's study suggests that one reason why H5N1 has not yet caused a pandemic is that two genetic mutations would need to happen to the virus at the same time in order to enable it to infect the right cells and become transmissible. At present, H5 viruses can only infect one of the two main types of cell in the mouth and nose, a type of cell known as a ciliated cell. In order for H5 to transmit from human to human, it would need to be able to infect the other, non-ciliated type of cell as well.

To infect a cell, the influenza virus uses a protein called HA to attach itself to a receptor molecule on the cell's surface. However, it can only do this if the HA protein fits that particular receptor. Today's research shows that H5 would only be able to make this kind of adaptation and fit the receptor on the cells that are important for virus transmission if it went through two simultaneous genetic mutations.

Professor Wendy Barclay, corresponding author of the study from the Division of Investigative Science at Imperial College London, said: "H5N1 is a particularly nasty virus, so when humans started to get infected with bird flu, people started to panic. An H5N1 pandemic would be devastating for global health. Thankfully, we haven't yet had a major outbreak, and this has led some people to ask, what happened to bird flu? We wanted to know why the virus hasn't been able to jump from human to human easily.

"Our new research suggests that it is less likely than we thought that H5N1 will cause a pandemic, because it's far harder for it to infect the right cells. The odds of it undergoing the kind of double mutation that would be needed are extremely low. However, viruses mutate all the time, so we shouldn't be complacent. Our new findings do not mean that this kind of pandemic could never happen. It's important that scientists keep working on vaccines so that people can be protected if such an event occurs," added Professor Barclay.

Professor Ian Jones, leader of the collaborating group at the University of Reading, added: "It would have been impossible to do this research using mutation of the real H5N1 virus as we could have been creating the very strain we fear. However, our novel recombinant approach has allowed us to safely address the question of H5 adaptation and provide the answer that it is very unlikely."

In addition to explaining why bird flu's ability to transmit between humans is limited, the new research also gives scientists a better understanding of the virus. They believe that this could help the development of a better vaccine against bird flu, in the unlikely event that one was needed in the future.

The researchers used a realistic model of the inside of a human airway to study H5 binding to human cells. They made genetic changes to the H5 HA protein to change its shape, to see if they could make the virus recognise and infect the right types of cells. Results showed that the virus would need two genetic changes occurring at once in its genome before it could infect these cells.

The researchers then investigated intermediate forms of the virus, with one or the other mutation, to see if the change could occur gradually. They found that intermediate versions of the virus could not infect human cells, so would die out before they could be transmitted. The researchers say this means the two genetic mutations would need to occur simultaneously.

Lucy Goodchild | EurekAlert!
Further information:

More articles from Health and Medicine:

nachricht Indian roadside refuse fires produce toxic rainbow
26.10.2016 | Duke University

nachricht Inflammation Triggers Unsustainable Immune Response to Chronic Viral Infection
24.10.2016 | Universität Basel

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: Etching Microstructures with Lasers

Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.

This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

3-D-printed structures shrink when heated

26.10.2016 | Materials Sciences

Indian roadside refuse fires produce toxic rainbow

26.10.2016 | Health and Medicine

First results of NSTX-U research operations

26.10.2016 | Physics and Astronomy

More VideoLinks >>>