Guam's influenza epidemic(s) of 2009

Abstract

Objective: To characterize syndromic and laboratory surveillance for influenza on Guam during 2009, including the relation of cases to the timing of swine flu-related stories published in a local newspaper.

Methods: Data utilized in the study included clinical diagnoses of acute respiratory infection (ARI) in the Emergency Department log of Guam's only civilian hospital (syndromic surveillance) and laboratory confirmed cases of Influenza A (rapid test) and novel 2009 H1N1 influenza virus (RT-PCR subtyping) from both civilian and military sources. In addition, the number of "swine flu" stories appearing weekly in a local paper were tallied.

Results: What initially appeared to be an epidemic occurring in 2 distinct waves was shown to be separate epidemics of "seasonal flu" and "swine flu." There was a strong correlation between the timing of "swine flu" stories appearing in local media and the diagnosis of ARI.

Conclusion: Syndromic surveillance is useful for the early detection of disease outbreaks but laboratory results may be necessary in order to gain a clear epidemiologic picture of a disease incident.

Figure 1

Cases of syndromic ARI seen in the GMH-ER during the first 41 weeks in 2009.

Figure 2

Comparison of confirmed H1N1 and “other” influenza A cases, Guam, 2009.

Figure 3

Comparison of number of published “swine flu” news articles and hospital Emergency Room ARI data by week, Guam, 2009.