Phylogenetic analyses were carried out by distance method using neighbor joining algorithm with Treecon, version 1.3 b software . like CCHFV infection. Furthermore, this is the first report of AP92 like strain in Turkey. In the region, elderly males carry the highest risk for CCHFV infection. Background The first Crimean-Congo hemorrhagic fever (CCHF) case in Turkey Geranylgeranylacetone was reported five years ago . Slc4a1 The virus belongs to the genus em Nairovirus /em in the em Bunyaviridae /em family and causes severe diseases in humans, with a reported case fatality rate (CFR) of 3C30% . By the year 2008, nearly 3000 CCHF confirmed patients with CFR of 5% were Geranylgeranylacetone recorded at the Ministry of Health (MOH) of Turkey . All of the confirmed cases, except one were detected in Anatolian region of Turkey. The occurrence of CCHF closely approximates the known distribution of em Hyalomma /em spp. ticks. Humans become infected through the bites of ticks, by contact with a patient with CCHF during the acute phase of infection, or by contact with blood or tissues from viremic livestock . In a previous study, , all of the CCHF cases detected in Istanbul were imported cases, who had been infected out of Istanbul. Herein, we report a mild CCHF case from rural Balkanian part of Istanbul. Based upon this index case, we performed a serosurvey and field tick survey in the region, where the index case acquired the infection, and described the risk factors. In previous studies reported from Turkey, the CCHFV were belonged to the Europe-Turkey clade [4-6]. By this new report, we describe a newly emerged CCHFV strain in Turkey. Furthermore, this newly emerged strain that led to a mild case was not described as a human pathogen in the literature, previously . Methods Index case and the material A mild CCHF case was diagnosed in a community hospital in Istanbul in June 2007. His disease started 3 days after the tick bite, and he was hospitalized Geranylgeranylacetone 4 days after the tick bite. Serum sample was obtained 5 days after the tick bite was studied by RT-PCR for CCHFV RNA and by ELISA for IgG and IgM antibodies against CCHFV. After this case, a serosurvey and tick survey studies were performed in the region at the end of June 2007. The serosurveillance studies were performed in four major districts, which were depicted in figure ?figure1.1. Seven hundred forty one subjects, who live in the region were surveyed. In total 56 ticks were collected from cattle from the same residential areas, and were screened for CCHFV RNA. Open in a separate window Figure 1 Distribution of CCHF IgM positive individuals in the region. Serologic studies All the subjects were tested for IgM and IgG. A commercial variant of capture ELISA kit (vectorbest?, Russia) was used for detection of IgM antibodies against CCHFV. Immunoglobulin G antibodies were tested by ELISA kit of the same company (vectorbest?, Russia). The individuals, who were positive for IgM and/or IgG were prospectively surveyed, and four months later the second sera from these individuals were collected, and were studied for IgM and IgG. The initial sera were re-tested simultaneously with the second samples of sera. The informed consents from each individual were obtained. RNA extractions, PCR, and phylogenetic analysis RNA was extracted from 200 l whole blood using a commercial RNA extraction kit (High Pure Viral Nucleic Acid Kit, Roche Diagnostics?, Germany) and cDNA synthesized with Omniscript reverse transcription kit (Qiagen?, Germany) in accordance with the instructions of the manufacturer. For designing of primers used during the diagnostic screening for CCHFV RNA, all S segment sequences from Turkey and some selected from eastern european countries were downloaded from the GeneBank and aligned using Clustal Wallis  software program. The sites of the possible primers were selected visually and evaluated using Primer test option of Primer Express software (Applied Biosystems?, USA). After initial diagnostic PCR, the amplicon was sequenced and the obtained sequence closely matched with the sequence of AP92 strain. For amplification of exclusively AP92 strain RNA we designed.