Journal of Clinical Virology 35 (2006) 154–159 Evaluation of a Crimean-Congo hemorrhagic fever virus recombinant antigen expressed by Semliki Forest suicide virus for IgM and IgG antibody detection in human and animal sera collected in Iran S. Garcia a,d , S. Chinikar b , D. Coudrier a , A. Billecocq a , B. Hooshmand c , J.M. Crance d , D. Garin d , M. Bouloy a,∗ a Unit´ e de g´ en´ etique mol´ eculaire des Bunyavirid´ es, Institut Pasteur, 25 rue du Dr Roux, 75724 Paris Cedex 15, France b Arboviruses and Hemorrhagic Fever National Laboratory, Institut Pasteur, Tehran, Iran c Center for Disease Control, Ministry of Health, Iran d Laboratoire de virologie, CRSSA Emile Pard´ e, Grenoble, France Received 22 July 2004; received in revised form 1 October 2004; accepted 1 February 2005 Abstract Crimean-Congo hemorrhagic fever virus (CCHFV) is transmitted to humans by ticks or by direct contact with infected blood. It causes severe, often fatal, hemorrhagic diseases in humans but infection in animals is asymptomatic. CCHFV can spread from person to person and has caused many nosocomial outbreaks. Because the virus is very pathogenic for humans it must be manipulated in a biosafety level 4 (BSL4) laboratory, rendering the production of antigen for serological diagnosis difficult. To replace the native antigen, we produced a recombinant nucleoprotein expressed in mammalian cells via the recombinant Semliki Forest alphavirus replicon and developed an indirect immunofluorescence assay (IFA) as well as an enzyme-linked immunosorbent assay (ELISA) by immunocapture to detect IgM and IgG in human and animal serum. Using these methods, we analyzed clinical samples from human patients and sera from domestic animals collected in Iran and we show that this novel antigen provides a novel, sensitive and specific tool for CCHF diagnosis. © 2005 Elsevier B.V. All rights reserved. Keywords: Diagnosis; ELISA; IgM and IgG; Indirect immunofluorescence 1. Introduction Crimean-Congo hemorrhagic fever virus (CCHFV) is a tick-transmitted member of the Bunyaviridae family (Nairovirus genus) that causes severe hemorrhagic diseases in humans, with a mortality rate as high as 30–40% (Elliott et al., 2000; Hoogstraal, 1979). This is a potential agent of bioterrorism. Humans become infected with CCHFV either through bites of infected ticks, which maintain a life-long infection and are competent reservoirs, or by direct con- tact with virus-contaminated tissues or blood. Shepherds, campers, agricultural workers, veterinarians, abattoir work- ers and other persons in close contact with livestock and ticks ∗ Corresponding author. Tel.: +33 140 613157; fax: +33 140 613151. E-mail address: mbouloy@pasteur.fr (M. Bouloy). are at risk for infection (Chapman et al., 1991; Swanepoel et al., 1985a,b). In addition to zoonotic transmission, CCHFV can spread from person to person and is one of the rare hem- orrhagic fever viruses able to cause nosocomial outbreaks in high hygiene standard hospitals (Suleiman et al., 1980; van Eeden et al., 1985). CCHFV is prevalent from Africa through the western part of China, including Eastern European and Middle Eastern countries and human cases have been reported in Africa, the Balkans, Russia, the Central Asian Republics, western China and the Middle East (Drosten et al., 2002b; Hoogstraal, 1979; Khan et al., 1997; Papa et al., 2002a,b). In Iran, detection of antibodies showed that the virus circulated already in 1975 in the regions bordering the Caspian Sea and in East Azerbaijan (Saidi et al., 1975) and CCHFV was first isolated in 1978 from ticks (Sureau et al., 1980). In 2000, CCHF was recognized as 1386-6532/$ – see front matter © 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.jcv.2005.02.016