Spatial analysis of Crimean Congo hemorrhagic fever in Iran

Abstract

Crimean Congo hemorrhagic fever (CCHF) is a viral zoonotic disease. During 1999-2011, 871 human cases of CCHF were diagnosed in Iran. A history of serologic conversion for CCHF virus was seen in 58.7% of 2,447 sheep samples, 25.0% of 1,091 cattle samples and 24.8% of 987 goat samples from different parts of Iran. Spatial analysis showed that the main foci of this disease in humans during these years were in eastern Iran (P < 0.01) and the second most common foci were in northeastern and central Iran. Two livestock foci were detected in the northeastern northwestern Iran. On the basis of the results of this study, infection likely entered Iran from eastern and western neighboring countries.

Figure 1.

Centroids and provinces of Iran.

Figure 2.

Number of laboratory-confirmed human cases of Crimean-Congo hemorrhagic fever (CCHF), Iran, 1999–2011.

Figure 3.

A, Hot spot map of human Crimean-Congo hemorrhagic fever (CCHF), Iran, 1999–2011. The counties of Zabol and Zahedan (shown in red) had significantly more reports of CCHF during these years (P < 0.01). B, Hot spot map of human CCHF cases, Iran, 1999–2011. To show the second foci of the disease, Zabol and Zahedan information was omitted and not entered into analysis. C, Choropleth map of CCHF serum antibody conversion in referred livestock samples, i.e. cattle, goats and sheep, during 1999–2011. The infection rate is based on the percentage of submitted samples that were seropositive for CCHF from that geographic location. D, Smoothed map of CCHF serum antibody conversion in livestock, Iran, 1999–2011. There are estimations in areas with no sampling.