Pandemic Gallery

Haemagglutinin from bird flu virus

Haemagglutinin from bird flu virus, molecular model. This protein, H5, is found on the surface of the bird flu virus H5N1. It is responsible for binding the virus to the cell membrane before it enters the cell. All influenza viruses contain haemagglutinin, but the shape of the protein determines which species the virus will infect. H5N1 cannot infect humans because H5 cannot bind to human cells; normally, only flu viruses with H1, H2 or H3 haemagglutinins can infect humans. In this model, solid colours represent the secondary structure of the protein (spiral ribbons are alpha helices; arrows are beta sheets), and the faded tubular structure behind represents the individual atoms and bonds

© LAGUNA DESIGN/SCIENCE PHOTO LIBRARY

Flu virus particle, artwork F008/3245

Flu virus particle, computer artwork. In the virus envelope are two types of protein spike, haemagglutinin (H, pink) and neuraminidase (N, orange), which determine the strain of virus. These are used for recognising and binding to the host cell

© ROGER HARRIS/SCIENCE PHOTO LIBRARY

Artwork, Bacteriology, Biological, Biology, Blue Background, Disease, Disorder, Flu, Haemagglutinin, Health, Healthcare, Illness, Illustration, Influenza, Influenza Virus, Medical Illustration, Microbe, Microbiological, Microbiology, Microorganism, Neuraminidase, Protein, Research, Spike, Strain, Viral, Virion, Virology, Virus, Virus Particle

Avian influenza virus, TEM

Avian influenza virus, type A strain H5N1, coloured transmission electron micrograph (TEM). This virus was isolated in Vietnam, during the avian flu outbreak in early 2004. The virus consists of ribonucleic acid (RNA), surrounded by a nucleocapsid and a lipid envelope (orange). In the envelope are two types of protein spike, haemagglutinin (H) and neuraminidase (N), which determine the strain of virus. The natural hosts of this virus are wild birds, which show few symptoms, however infected domestic birds suffer a 90-100% mortality rate. Humans that have contact with infected birds can become infected, but no human to human transmission has yet been recorded

© NIBSC/SCIENCE PHOTO LIBRARY