title: Effect of travel on influenza epidemiology.
abstract: To assess the attack and incidence rates for influenza virus infections, during October 2006-October 2007 we prospectively studied 1,190 adult short-term travelers from the Netherlands to tropical and subtropical countries. Participants donated blood samples before and after travel and kept a travel diary. The samples were serologically tested for the epidemic strains during the study period. The attack rate for all infections was 7% (86 travelers) and for influenza-like illness (ILI), 0.8%. The incidence rate for all infections was 8.9 per 100 person-months and for ILI, 0.9%. Risk factors for infection were birth in a non-Western country, age 55-64 years, and ILI. In 15 travelers with fever or ILI, influenza virus infection was serologically confirmed; 7 of these travelers were considered contagious or incubating the infection while traveling home. Given the large number of travelers to (sub)tropical countries, travel-related infection most likely contributes to importation and further influenza spread worldwide.
authors.affiliation: Department of Infectious Diseases, Public Health Service, Amsterdam, the Netherlands. sbelderok@ggd.amsterdam.nl
authors.forename: Sanne-Meike
authors.initials: SM
authors.lastname: Belderok
authors.forename: Guus F
authors.initials: GF
authors.lastname: Rimmelzwaan
authors.forename: Anneke
authors.initials: A
authors.lastname: van den Hoek
authors.forename: Gerard J B
authors.initials: GJ
authors.lastname: Sonder
mesh_terms: D000328:Adult; D000914:Antibodies, Viral / Q000276:immunology; D005260:Female; D006801:Humans; D015994:Incidence; D009980:Influenza A virus / Q000276:immunology; D007251:Influenza, Human / Q000175:diagnosis / Q000453:epidemiology* / Q000276:immunology; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012307:Risk Factors; D014195:Travel; D055815:Young Adult
chemical_list: D000914:Antibodies, Viral
keywords: Influenza; attack rate; epidemiology; incidence; prospective study; travel; viruses