While Crimean-Congo hemorrhagic fever (CCHF) has a high mortality rate in humans, the associated virus (CCHFV) does not induce clinical symptoms in animals, but animals play an important role in disease transmission to humans. Our aim in this study was to examine the immunogenicity of the CCHFV glycoprotein when expressed in the root and leaf of transgenic plants via hairy roots and stable transformation of tobacco plants, respectively. After confirmatory analyses of transgenic plant lines and quantification of the expressed glycoprotein, mice were either fed with the transgenic leaves or roots, fed the transgenic plant material and injected subcutaneously with the plant-made CCHFV glycoprotein (fed/boosted), vaccinated with an attenuated CCHF vaccine (positive control), or received no treatment (negative control). All immunized groups had a consistent rise in anti-glycoprotein IgG and IgA antibodies in their serum and feces, respectively. The mice in the fed/boosted group showed a significant rise in specific IgG antibodies after a single boost. Our results imply that oral immunization of animals with edible materials from transgenic plants is feasible, and further assessments are under way. In addition, while the study of CCHF is challenging, our protocol should be further used to study CCHFV infection in the knockout mouse model and virus neutralization assays in biosafety level 4 laboratories.

Crimean-Congo hemorrhagic fever (CCHF) is viral hemorrhagic fever caused by CCHF virus, which belongs to the family Bunyaviridae and the genus Nairovirus. The virus is transmitted to humans via contact with blood and tissue from infected livestock, a tick bite, or contact with an infected person. Since 2000, we have shown the disease to be prevalent in 23 out of 30 provinces of Iran. Among those, Sistan-va-Baluchistan, Isfahan, Fars, Tehran, Khorasan, and Khuzestan demonstrated the highest infection, respectively. Notably, Sistan-va-Baluchistan province, southeast of Iran, has the highest prevalence of CCHF, and has shown to be present since at least 2000. Phylogenetic study of the CCHF virus genome isolated from Iranian patients showed a close relationship with the CCHF Matin strain (Pakistan). Our epidemiological data in the last decade have implied that the severity and fatality rate of the disease has ranged variably in different provinces of Iran. More pathogenesis and phylogenetic studies should therefore be investigated to clarify these differences.

Crimean-Congo haemorrhagic fever (CCHF) is a viral haemorrhagic fever caused by the CCHF virus. It is mainly transmitted to humans and animals by ticks. In recent y, large numbers of livestock have been transported across the border areas of Ardabil Province resulting in an outbreak of CCHF in the adjacent districts. A comprehensive study was carried out to assess the epidemiological aspects of the disease in this province. In the study area, 130 ticks were collected from randomly selected villages and classified into 9 species of hard tick and 2 species of soft tick. All ticks were analyzed for the presence of CCHF virus genome using gel-based and real-time reverse transcriptase polymerase chain reactions (RT-PCR). The results showed CCHF infection in almost 28% of ticks collectively. Also, of 56 livestock sera, around 39% were IgG-positive. The presence of anti-CCHF virus IgG antibodies and the CCHF virus genome in ticks points to a great hidden threat of an outbreak in these districts. Those in high-risk professions in this province should be informed and trained on the risk of CCHF with urgency.

Crimean-Congo haemorrhagic fever (CCHF) is a viral zoonotic disease with a high mortality rate in humans. The CCHF virus (CCHFV) is transmitted to humans through the bite of Ixodid ticks or by contact with blood or tissues of infected livestock. In addition to zoonotic transmission, CCHFV can be spread from person to person and is one of the rare haemorrhagic fever viruses able to cause nosocomial outbreaks in hospitals. Crimean-Congo haemorrhagic fever is a public health problem in many regions of the world such as Eastern Europe, Asia, the Middle East and Africa. In addition to clinical symptoms, the diagnosis of CCHF is based on the use of serological tests for the detection of immunoglobulin M and immunoglobulin G antibodies and on the use of molecular tools such as RT-PCR. From 1970 to 1978, serological and epidemiological studies were performed in humans and in livestock of Iran. After two decades and observations of CCHF in some provinces of Iran, a CCHF surveillance and detection system was established in 1999, leading to a dramatically decreased mortality rate from 20% (year 2000) to 2% (year 2007).