Brussels, 26 Apr 2004
UK and German researchers have discovered that a common cold virus that causes bronchitis in children has the ability to survive in the body for months, rather than days, as was previously thought.
Respiratory syncytial virus (RSV) is very common, infecting most children during their first year of life, and can lead to bronchitis. Around a third of those infants who develop bronchitis as a result of RSV infection go on to suffer from childhood asthma and a recurring wheeze.
The research was carried out by scientists from Imperial College London and St. Mary's Hospital in the UK, and the Ruhr University in Bochum, Germany, and was supported by grants from the Wellcome Trust and the German Ministry for Education and Research.
UK author Professor Peter Openshaw said: '[Our] studies show that RSV is a 'hit and hide' virus, rather like HIV, herpes or some hepatitis viruses. The symptoms seem to go away but the virus is just hiding, waiting for a chance to re-emerge and begin infecting other people.'
In carrying out the study, the team infected mice with the human strain of RSV, and found that after 14 days the virus could no longer be detected in samples taken from the airways. However, traces of the virus's genetic material (viral RNA) were found lying dormant in lung tissue over 100 days later.
The researchers believe that RSV may well behave in the same way in the human body, lying dormant long after symptoms such as coughs and sneezes have disappeared. They even speculate that the recurrent wheezing that affects children who have suffered from bronchitis could be due to the hidden presence of the RSV virus in the lung.
Professor Openshaw speculated that: 'Some people may be 'carriers', able to act as a source of new outbreaks in children. If RSV is a 'hit and hide' virus, this could explain where the virus goes in the summer and where it comes from each winter.
'If the virus is able to lie dormant in previously infected individuals, it could re-emerge when the conditions are right and cause the outbreaks that fill our children's wards each winter,' he concluded.
The research was published in the American Journal of Respiratory and Critical Care Medicine.