Molecular Epidemiology of Influenza A (H1N1) in Hawaii

Influenza is a high impact viral infection causing seasonal outbreaks as well as periodic epidemics and pandemics throughout the world. The state of Hawai‘i is vulnerable to the spread of type A influenza due to its unique geographic positioning and heavily trafficked travel patterns.

Through the usage of epidemiological research in conjunction with laboratory methods, we are able to trace viral origins and show phylogenetic relationships. In collaboration with the Hawai‘i Department of Health State Laboratory and Disease Outbreak Control Divisions, we present a pilot study in which viral isolates collected from individuals in Hawai‘i infected with H1N1 influenza are extracted, amplified, cleaned and sequenced for the hemagglutinin gene to show evolutionary relationships and circulatory patterns. Implications of molecular data are supported by epidemiologic information. Phylogenetic analysis suggests that Hawai‘i acts as both a source population 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 regions.

Through the usage of molecular methods, we hope to develop an improved understanding of influenza dynamics in Hawai‘i. Targeting an area of geographic importance, such as Hawai‘i, assists in providing a depiction of how location and the distribution of populations play a role in the spread of infectious disease. Enhanced understanding may help to improve efficiency and effectiveness of public health related preparation and response efforts, and reduce the impact of influenza on the state and it's visitors.