Space-time epidemiology of Crimean-Congo hemorrhagic fever (CCHF) in Iran.

Iran, as an endemic country of Crimean-Congo hemorrhagic fever (CCHF), has been suffering from severe health issues and substantial economic burdens imposed by the disease. We analyzed monthly and yearly spatial and temporal distributions of CCHF to better understand the epidemiology of the disease in Iran. A cross-sectional survey was performed on 1027 recorded cases between 2000 and 2014. Global Moran's I analysis was applied to statistically evaluate the spatial pattern of the disease. Additionally, spatial and space-time scan statistics were used to study the presence of possible spatial and space-time hotspots. Global Moran's I analysis proved that the incidence of the disease is strongly clustered in Iran (p<0.01). Purely spatial scan statistics identified that there were three clusters in the eastern, southern and western parts of the country. Through space-time analysis, we found that the highest incidence of CCHF occurred in the eastern parts of the country between 2006 and 2012. Monthly clusters, which include cities with lower (average) temperatures, had been occurring in relatively short periods. The distribution of CCHF incidence in this country is spatially and temporally clustered. The majority of the clusters emerged during the critical years of 2009 and 2013. Summer is the predominant period for the formation of CCHF clusters.