Large summertime influenza A outbreak among tourists in Alaska and the Yukon Territory.
We investigated a large summertime outbreak of acute respiratory illness during May-September 1998 in Alaska and the Yukon Territory, Canada. Surveillance for acute respiratory illness (ARI), influenza-like illness (ILI), and pneumonia conducted at 31 hospital, clinic, and cruise ship infirmary sites identified 5361 cases of ARI (including 2864 cases of ILI [53%] and 171 cases of pneumonia [3.2%]) occurring primarily in tourists and tourism workers (from 18 and 37 countries, respectively). Influenza A viruses were isolated from 41 of 210 patients with ILI at 8 of 14 land sites and 8 of 17 cruise ship infirmaries. Twenty-two influenza isolates were antigenically characterized, and all were influenza A/Sydney/05/97-like (H3N2) viruses. No other predominant pathogens were identified. We estimated that >33,000 cases of ARI might have occurred during this protracted outbreak, which was attributed primarily to influenza A/Sydney/05/97-like (H3N2) viruses. Modern travel patterns may facilitate similar outbreaks, indicating the need for increased awareness about influenza by health care providers and travelers and the desirability of year-round influenza surveillance in some regions.
Uyeki
Timothy M
TM
Influenza Branch, Division of Viral and Rickettsial Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA. tmu0@cdc.gov
Zane
Suzanne B
SB
Bodnar
Ulana R
UR
Fielding
Katherine L
KL
Buxton
Jane A
JA
Miller
Joy M
JM
Beller
Michael
M
Butler
Jay C
JC
Fukuda
Keiji
K
Maloney
Susan A
SA
Cetron
Martin S
MS
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000413:Alaska / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D004196:Disease Outbreaks; D006801:Humans; D007223:Infant; D009980:Influenza A virus / Q000302:isolation & purification*; D007251:Influenza, Human / Q000453:epidemiology*; D008875:Middle Aged; D011446:Prospective Studies; D012189:Retrospective Studies; D014195:Travel; D015874:Yukon Territory / Q000453:epidemiology