The common cold virus may be more common than previously thought in asymptomatic university students, according to a study.
Rhinovirus, the virus responsible for the common cold, bronchitis and some asthma attacks, was found at some point during an eight-week study period in an estimated 60% of university students who were asymptomatic.
"A high occurrence of asymptomatic infections indicates that university students can spread infections to classmates or individuals in the community without knowing they are infected," study investigator Andrea Granados of McMaster University in Ontario, Canada, said in a news release.
Granados and her colleagues recruited 545 McMaster University undergraduates over two years (September-October 2010, and September-October 2011) during the time when cold activity usually peaks and asked them to collect a nasal swab once weekly regardless of symptom occurrence. If cold-like symptoms were reported by the students, they were asked to provide daily nasal swabs for a period of seven days. The researchers received reports of 167 cold-like illnesses over two years. Using DNA-based polymerase chain reaction they detected rhinovirus in 54% of students reporting symptoms.
To determine how many students had rhinovirus but did not have any cold-like symptoms they selected a 10% sampling of all nasal swabs collected during the eight study weeks each year from students that did not report feeling sick. They randomly selected 25 swabs each week for a total of 400 swabs (200 in 2010 and 200 in 2011). Of the 400 swabs, 33 (8.25%) were found to have rhinovirus.
Based on these findings, the researchers estimated that as much as 60.5% of the asymptomatic student population was infected at some time with rhinovirus over an eight week study period.
They also used polymerase chain reaction to determine the viral load in symptomatic and asymptomatic students. Students with asymptomatic rhinovirus infections had significantly less virus than symptomatic infections. Decreased amounts of the virus may be responsible for the lack of symptoms, said Granados, although larger studies are necessary to confirm this finding.
"In this study, we found that university students with rhinovirus infections who lacked symptoms outnumbered by a factor of four the number of infected students with symptoms," Granados said. "The virus particles can be spread by aerosols or direct contact with an asymptomatic individual. There is no treatment for the common cold; therefore, frequent hand-washing is important to prevent the spread of the common cold, particularly in early fall."
The researchers reported their findings June 19 in San Francisco at the 2012 General Meeting of the American Society for Microbiology.
Rhinovirus, the virus responsible for the common cold, bronchitis and some asthma attacks, was found at some point during an eight-week study period in an estimated 60% of university students who were asymptomatic.
"A high occurrence of asymptomatic infections indicates that university students can spread infections to classmates or individuals in the community without knowing they are infected," study investigator Andrea Granados of McMaster University in Ontario, Canada, said in a news release.
Granados and her colleagues recruited 545 McMaster University undergraduates over two years (September-October 2010, and September-October 2011) during the time when cold activity usually peaks and asked them to collect a nasal swab once weekly regardless of symptom occurrence. If cold-like symptoms were reported by the students, they were asked to provide daily nasal swabs for a period of seven days. The researchers received reports of 167 cold-like illnesses over two years. Using DNA-based polymerase chain reaction they detected rhinovirus in 54% of students reporting symptoms.
To determine how many students had rhinovirus but did not have any cold-like symptoms they selected a 10% sampling of all nasal swabs collected during the eight study weeks each year from students that did not report feeling sick. They randomly selected 25 swabs each week for a total of 400 swabs (200 in 2010 and 200 in 2011). Of the 400 swabs, 33 (8.25%) were found to have rhinovirus.
Based on these findings, the researchers estimated that as much as 60.5% of the asymptomatic student population was infected at some time with rhinovirus over an eight week study period.
They also used polymerase chain reaction to determine the viral load in symptomatic and asymptomatic students. Students with asymptomatic rhinovirus infections had significantly less virus than symptomatic infections. Decreased amounts of the virus may be responsible for the lack of symptoms, said Granados, although larger studies are necessary to confirm this finding.
"In this study, we found that university students with rhinovirus infections who lacked symptoms outnumbered by a factor of four the number of infected students with symptoms," Granados said. "The virus particles can be spread by aerosols or direct contact with an asymptomatic individual. There is no treatment for the common cold; therefore, frequent hand-washing is important to prevent the spread of the common cold, particularly in early fall."
The researchers reported their findings June 19 in San Francisco at the 2012 General Meeting of the American Society for Microbiology.
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