Researchers at Queen Mary, University of London have identified the genes which allow some viruses to survive better in the human body than others, and then go on to affect other individuals. The research is published today (18 December, 2006) in the Proceeding of the National Academy of Science (USA).
The Queen Mary team - led by Professors Judy Breuer and Richard Nichols - working in collaboration with scientists from the University of Columbia, studied the chicken pox virus as it evolved within the human body over the course of a few weeks. They exploited a US run vaccination campaign against the virus.
The vaccine is a live virus, although cultured in such a way that it has become less virulent than normal chicken pox. This weakened, or attenuated, vaccine virus is made up of a mixture of genetically different viral strains. Consequently, the millions of vaccine doses administered in the vaccination campaign introduced the same mixture into each patient - thereby starting an evolutionary competition between them within every patient's body. Occasionally the viruses from the vaccine are so successful that they actually cause an unwanted rash resembling mild chicken pox.
Collaborators at Columbia University had collected samples from the lesions (spots) of these rashes, and the Queen Mary team determined which of the viruses in the original mixture had succeeded in the evolutionary competition to form the rash. Rashes are a key stage in the viruses' life cycle because when scratched, the virus is released into the air, and may go on to infect other individuals. As most of us can remember, rashes also cause considerable human discomfort.
The analysis of the successful viruses has identified genetic changes that seem to make the viruses most virulent in forming rashes. Richard Nichols, Professor of Evolutionary Genetics and Queen Mary, University of London said; "Not only does this result help us understand the evolution of virulence, it may also help us to improve the vaccine. It may be possible to remove these genetic variants from the vaccine mixture, and reduce the frequency of the vaccine rash."
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Queen Mary, University of London
Queen Mary is one of the leading colleges in the federal University of London, with over 11,000 undergraduate and postgraduate students, and an academic and support staff of around 2,600.
Queen Mary is a research university, with over 80 per cent of research staff working in departments where research is of international or national excellence (RAE 2001). It has a strong international reputation, with around 20 per cent of students coming from over 100 countries.
The College has 21 academic departments and institutes organised into three sectors: Science and Engineering; Humanities, Social Sciences and Laws; and the School of Medicine and Dentistry.
It has an annual turnover of £200 million, research income worth £43 million, and it generates employment and output worth nearly £500 million to the UK economy each year.
Queen Mary's roots lie in four historic colleges: Queen Mary College, Westfield College, St Bartholomew's Hospital Medical College and the London Hospital Medical College.