Following a screening period of up to 30 days, eligible consenting subjects will be admitted to the clinic on the morning of Day 1. Laninamivir octanoate will be administered on Day 1. Subjects will remain in the clinic until Day 3 and will return for subsequent outpatient visits on Day 5, Day 6 and Day 7. A final follow-up visit for safety evaluations will occur on Day 14 ± 1 (or at the time of premature discontinuation). Each subject will participate in the study for approximately 7 weeks.