Outbreak Notice
Outbreak of Influenza A Infection --
Alaska and the Yukon Territory, June-July 1998
Since July 26, CDC and Health Canada, in cooperation with
local public
health authorities, have been investigating reports of febrile
respiratory
illness and associated pneumonia among persons traveling on land
and sea,
both independently and on tour packages, in Alaska and the Yukon
Territory.
Commonly reported symptoms include fever and cough, and laboratory
evidence
suggests that influenza A infection may be a cause of many of the
illnesses. Summertime outbreaks of Influenza A have previously been
reported among tourists in the United States and Canada (1,2). No
evidence
suggests increased respiratory illness activity among residents of
these
areas.
From June 5 through August 4, 1998, a total of 419 cases of
acute
respiratory infection (ARI), including 20 cases of pneumonia during
June-July, have been reported to the investigation team in
Anchorage. No
deaths have been reported. The median age of persons with ARI is 63
years
(range: 3-88 years); the median age of persons with pneumonia is 74
years
(range: 61-88 years). Many cases have occurred in clusters,
particularly
among groups of 40-50 passengers sharing common transportation and
accommodation packages on overland tours between Anchorage and
Skagway or
Anchorage and Seward during June-July. Affected passengers have
traveled on
several different tours from different companies. Information from
case
reports suggests that after touring inland, ill persons are
boarding cruise
ships, possibly resulting in further spread. In some instances,
travelers
are becoming ill and seeking medical attention for their
respiratory
illnesses only after returning home.
During June-September, approximately 70,000 overland tour and
cruise
ship passengers visit Alaska and the Yukon Territory each week.
Most do not
experience febrile respiratory illness. No special prevention
measures are
recommended at this time for travelers in good health.
Systematic surveillance for febrile respiratory illness and
pneumonia
is being initiated by CDC, Health Canada, and other public health
officials
in the region to better define the scope of the outbreak.
Health-care
providers who see patients with febrile respiratory illness and/or
pneumonia should obtain a travel history and consider influenza A
in the
differential diagnosis for those with recent travel to Alaska or
the Yukon
Territory. Additional cases should be reported to CDC's Special
Investigation Team; telephone (907) 729-3431; fax (907) 729-3429;
or
e-mail, SITEAM@cdc.gov.
Reported by: Alaska Dept of Health and Social Svcs; Bur of
Infectious
Diseases and Office of Special Health Initiatives, Laboratory
Center for
Disease Control, Occupational Health and Safety Agency, Health
Canada,
Ottawa. Arctic Investigations Program, Div of Viral and Rickettsial
Diseases and Div of Quarantine, National Center for Infectious
Diseases;
and EIS officers, CDC.
References
CDC. Outbreak of influenza-like illness in a tour group,
Alaska. MMWR
1987;36;697-8,704.
Miller J, Tam T, Afif C, et al. Influenza A outbreak on a
cruiseship.
Canada Communicable Disease Report 1998;24:9-11.
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