Asymptomatic rhinovirus infection outnumbers symptomatic infection 4 to 1 among university students

The common cold virus may be more common than previously thought in university students not reporting any symptoms. Rhinovirus, the virus responsible for the common cold was found at some point during an 8-week study period in an estimated 60% of university students that were asymptomatic. Researchers from Canada report their findings at the 2012 General Meeting of the American Society for Microbiology.

"A high occurrence of asymptomatic infections indicates that can spread infections to , or individuals in the community without knowing they are infected," says Andrea Granados of McMaster University in Hamilton, Ontario, a researcher on the study. The study was conducted at McMaster University and St. Joseph's Healthcare in Hamilton, Ontario, Canada as part of the McFlu2 COLD3 clinical trial by Granados and colleagues Emma Goodall, Marek Smieja and James Mahony.

Rhinovirus, best known for causing the common cold can also cause bronchitis and trigger .

Granados and her colleagues recruited 545 McMaster University undergraduates over two years (September-October 2010, and September-October 2011) 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. One hundred and sixty-seven cold-like illnesses were reported over two years. Using DNA-based (PCR) 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 collected during the 8 study weeks each year from students that did not report feeling sick. Twenty-five swabs were randomly selected 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 estimate that as many as 60.5% of the asymptomatic student population was infected at some time with rhinovirus over an eight week study period.

They also used PCR 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, says Granados, however, 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 4 the number of infected students with symptoms. 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," says Granados.

add to favorites email to friend print save as pdf

Related Stories

Common cold may send some young children to the hospital

Feb 21, 2007

New evidence supports the link between a cause of the common cold and more severe respiratory infections such as pneumonia and acute bronchitis. The study is published in the March 15 issue of The Journal of Infectious Di ...

How colds cause coughs and wheezes

Mar 27, 2012

Cold-like infections make 'cough receptors' in the airways more sensitive, making asthmatics more prone to bouts of coughing and wheezing, reveal scientists presenting their findings at the Society for General Microbiology's ...

Recommended for you

Filipino tests negative for Middle East virus

8 hours ago

A Filipino nurse who tested positive for the Middle East virus has been found free of infection in a subsequent examination after he returned home, Philippine health officials said Saturday.

US orders farms to report pig virus infections

Apr 18, 2014

The U.S. government is starting a new program to help monitor and possibly control the spread of a virus that has killed millions of pigs since showing up in the country last year.

Foreigner dies of MERS in Saudi

Apr 18, 2014

A foreigner has died after she contracted MERS in the Saudi capital, the health ministry said on announced Friday, bringing the nationwide death toll to 73.

Vietnam battles fatal measles outbreak

Apr 18, 2014

Vietnam is scrambling to contain a deadly outbreak of measles that has killed more than 100 people, mostly young children, and infected thousands more this year, the government said Friday.

New clues on tissue scarring in scleroderma

Apr 18, 2014

A discovery by Northwestern Medicine scientists could lead to potential new treatments for breaking the cycle of tissue scarring in people with scleroderma.

User comments