Molecular epidemiology of seasonal and pandemic influenza a (H1N1) in Hawai'i

Influenza is a viral infection causing seasonal outbreaks, periodic epidemics and global pandemics in humans, the latest being the 2009 pandemic. The State of Hawai‘i is particularly vulnerable to the spread of influenza due to its unique geographic position in the Pacific Ocean with heavily trafficked passenger and freight patterns. By combining epidemiological data on case occurrences with their laboratory-derived viral sequences, we are able to trace viral strain origins based on phylogenetic relationships between isolates.;In collaboration with the Hawai‘i Department of Health State Laboratories Division, we present a study in which seasonal, or pandemic, H1N1 influenza A viral isolates collected from infected individuals in Hawai‘i were extracted, hemagglutinin and neuraminidase genes were amplified and sequenced, and examined for evolutionary relationships and spatio-temporal patterns. Implications of molecular data are also supported by epidemiologic information and statistical support of summary transmission data. Phylogenetic analysis suggests that Hawai‘i acts as both a source and sink population for type A influenza virus: in some instances Hawai‘i isolates represented the earliest instance of a strain subsequently seen elsewhere; in other instances Hawai‘i isolates clustered with strains observed earlier in other countries or geographic regions.;Through the continued usage of molecular methods, we hope to develop an improved understanding of influenza dynamics in Hawai‘i. Targeting an area of geographic importance additionally assists in depicting how location and population distribution play a role in the spread of infectious disease. Enhanced comprehension as a result of these analyses may help to improve efficiency and effectiveness of preparation and response efforts, and reduce the impact of influenza on Hawai‘i and the continental United States.