Spatiotemporal spread of chikungunya virus in Sarawak, Malaysia

Abstract Background We studied the spatiotemporal spread of a chikungunya virus (CHIKV) outbreak in Sarawak state, Malaysia, during 2009–2010. Methods The residential addresses of 3054 notified CHIKV cases in 2009–2010 were georeferenced onto a base map of Sarawak with spatial data of rivers and roads using R software. The spatiotemporal spread was determined and clusters were detected using the space-time scan statistic with SaTScan. Results Overall CHIKV incidence was 127 per 100 000 population (range, 0–1125 within districts). The average speed of spread was 70.1 km/wk, with a peak of 228 cases/wk and the basic reproduction number (R0) was 3.1. The highest age-specific incidence rate was 228 per 100 000 in adults aged 50–54 y. Significantly more cases (79.4%) lived in rural areas compared with the general population (46.2%, p