The geographic distribution of cases of Crimean-Congo hemorrhagic fever: Kastamonu, Turkey

Abstract

The purpose of this study was to analyze the epidemiological characteristics of cases diagnosed with Crimean-Congo Hemorrhagic Fever (CCHF) with the help of Geographic Information Systems (GIS) and to establish an epidemiological risk map. Data for 434 cases diagnosed with CCHF between 01.01.2004 and 31.12.2013 were subjected to statistical analysis SPSS 13.0 software. A digital map of Kastamonu was transferred onto ArcGIS 10.0 software in order to establish a risk map for CCHF. The highest cumulative incidence of CCHF is 41.29/10,000, and in people living at altitudes of 1001–1200 meters. ROC analysis of altitudes above sea level of residences with CCHF cases revealed an area under the curve of 74.5% (95% CI: 0.72-0.76, p < 0.05). At a cut-off point of 836.5 meters, sensitivity was 0.74 and specificity 0.76. Cumulative incidence of CCHF was significantly positively correlated with number of animals per head (r = 0.76) and area of agricultural land per head (r = 0.59) (p < 0.05). No significant correlation was determined between cumulative incidence and forested area percentages. This study reveals that both men and women living at more than 836.5 meters above sea level and working in agriculture and animal husbandry are at risk of CCHF between May and July. Detailed examination of the ecology of vector ticks is now needed in order to fully determine the epidemiology of the disease.