In a group of travelers leaving the Netherlands, researchers reported that the attack rate for confirmed influenza infection in the tropical and subtropical countries they briefly visited was 7% and the incidence was 8.9 per 100 person-months. Reporting in Emerging Infectious Diseases, the investigators said infections imported from these regions probably are a major factor in the epidemiology of influenza.
In the study, they enrolled 1190 individuals who visited the travel clinic of the Public Health Service in Amsterdam from October 2006 to October 2007. All planned travel in any of 6 regions: South America; Central America and the Caribbean; central, western, and northern Africa; southern and eastern Africa; southeastern and eastern Asia; and south-central and western Asia.
Brief Travel to Subtropical Areas Imports Flu, Researchers Say. JAMA. 2013;310(4):363. doi:10.1001/jama.2013.8507