| epidemiologic study of influenza infection in okinawa, japan, from 2001 to 2007: changing patterns of seasonality and prevalence of amantadine-resistant influenza a virus. | to clarify seasonal influenza patterns and the prevalence of amantadine-resistant influenza a viruses in okinawa, located at the southern extremity of japan in a subtropical climate, we conducted a laboratory-based study of influenza virus infections from 2001 to 2007. the annual outbreaks tended to show two peaks in okinawa, in summer and winter, although the main islands of japan, located in a temperate climate area, showed only winter influenza activity. epidemic types and subtypes in okinawa ... | 2009 | 19158265 |