OBJECTIVE: To determine whether healthy adult nasal carriers of Staphylococcus aureus can disperse S. aureus into the air after rhinovirus infection. DESIGN: We investigated the "cloud" phenomenon among adult nasal carriers of S. aureus experimentally infected with a rhinovirus. Eleven volunteers were studied for 16 days in an airtight chamber wearing street clothes, sterile garb, or sterile garb plus surgical mask; rhinovirus inoculation occurred on day 2. Daily quantitative air, nasal, and skin cultures for S. aureus; cold symptom assessment; and nasal rhinovirus cultures were performed. SETTING: Wake Forest University School of Medicine, Winston-Salem, North Carolina. PARTICIPANTS: Wake Forest University undergraduate or graduate students who had persistent nasal carriage of S. aureus for 4 or 8 weeks. RESULTS: After rhinovirus inoculation, dispersal of S. aureus into the air increased 2-fold with peak increases up to 34-fold. Independent predictors of S. aureus dispersal included the time period after rhinovirus infection and wearing street clothes (P < .05). Wearing barrier garb but not a mask decreased dispersal of S. aureus into the air (P < .05). CONCLUSION: Virus-induced dispersal of S. aureus into the air may have an important role in the transmission of S. aureus and other bacteria.