Vaccine and Infectious Disease Division

Dissociating bocavirus from respiratory disease

Human bocavirus was first discovered in 2005, but it is unclear if it causes disease in humans.  Studies have shown the presence of bocavirus DNA in patients with cold-like illnesses, leading many researchers to believe it causes respiratory disease.  However, some of these studies lacked the appropriate controls; that is, samples were only taken from patients with respiratory symptoms, and samples from healthy patients were not used as a comparison.  To explore whether human bocavirus is really a causative agent of respiratory disease, researchers led by Dr. Emily Martin, post-doctoral fellow at Seattle Children’s, along with VIDI affiliate investigators Drs. Danielle Zerr, Anna Wald and Janet Englund and VIDI joint assistant member Dr. Amalia Magaret, looked for bocavirus in 119 daycare-aged children with and without respiratory symptoms.

The researchers looked at children aged 6 weeks to 2 years attending day care at the Fort Lewis Army Base near Tacoma, Wash.  They took nasal swab samples from each child at the start of the study, and then took more swabs if the study participants showed signs of respiratory illness through the course of the 2-year study.  The scientists then looked for the presence of various respiratory viruses, including bocavirus, by using PCR to detect viral DNA.  They found bocavirus in 59 percent of children with respiratory symptoms, but also in 44 percent of swabs from children with no symptoms when they enrolled in the study.  The researchers did find bocavirus more often in samples from children with more severe illness, but the presence of the virus in so many healthy children calls into question the virus’ role as a cause of respiratory disease.

Frequent and prolonged shedding of bocavirus in young children attending daycare.  Martin ET, Fairchok MP, Kuypers J, Magaret A, Zerr DM, Wald A, Englund JA.  J Infect Dis. 2010 Jun 1;201(11):1625-32.