Spatial-temporal and phylogenetic analyses of epidemiologic data to help understand the modes of transmission of endemic typhoid fever in Samoa
Fig 1
Map of Samoa with census regions, roads, and health facilities.
Samoa is comprised of two primary islands, Upolu to the east and Savaii to the west. About three quarters of the population and the capital town of Apia are located on Upolu. The black lines indicate roads associated with populated areas, which are predominantly located around the periphery of the islands except for the urban areas where inland settlements are increasing. The islands are subdivided into four statistical census regions, 43 political districts (outlined in light grey), and >300 villages (not depicted). The four colored geographic areas differentiate the four census regions: Apia Urban Area (AUA), North West Upolu (NWU), Rest of Upolu (ROU), and Savaii (SAV). AUA is most dense with ~25% of the total population. Apia is the capital seat of government and includes the Ministry of Health headquarters, Samoa Typhoid Fever Public Health Laboratory, and Tupua Tamasese Meaole (TTM) national hospital, which processes the blood cultures for Upolu (insert). NWU is mixed peri-urban and rural in population density and separates Apia from the inter-island ferry (navy dashed line) and adjacent international airport (not shown). The Malietoa Tanumafili II (MT2) hospital processes blood cultures for Savaii. The health facility icons indicate the two central hospitals with clinical microbiology laboratories, TTM and MT2, and the 6 district hospitals and 4 peripheral health centers. Base layer map available from https://planet.openstreetmap.org.