Orthonairovirus

Introduction

Orthonairovirus is a genus of viruses in the family Nairoviridae of the order Bunyavirales. The genus Orthonairovirus is classified into 15 species. The most momentous genus member is Crimean-Congo Hemorrhagic Fever Virus (CCHFV) causing severe hemorrhagic fever in humans. The first recognized outbreak of Crimean-Congo Hemorrhagic Fever (CCHF) took place in the summer of 1944. CCHFV can cause severe viral hemorrhagic fever outbreaks. To better understand and study the CCHFV, Creative Biolabs provides anti-CCHFV antibodies for hot targets to meet the needs of customers.

Structure

The orthonairovirus genome consists of three single-stranded, negative-sense RNA molecules, termed small (S, 1-3kb), medium (M, 3.9-4.2kb), and large (L, 6.8-12 kb) segment. The S gene encodes the nucleocapsid protein (NP); the M gene encodes for glycoproteins Gn and Gc; the L gene encodes the viral polymerase. The virion is enveloped, spherical, 80 to 120nm in diameter.

CCHFV is spherical in shape, approximately 100nm in diameter with a dense core (capsid) surrounded by a lipid envelope, through which glycoprotein spikes, 5-10 mm in length. The viral genome is segmented, comprising three circular, single strands of negative-sense RNA. The small (S) segment (approximately 1.7 Kb) encodes NP, the medium (M) segment (approximately 5Kb) encodes a glycoprotein precursor, which is cleaved into mature glycoproteins, Gn and Gc, and the large (L) segment encodes RNA polymerase.

Fig.1 The virus structure. (Ergonul, 2006)

Pathogenesis of CCHF

CCHF pathogenesis is likely derived from a complex interaction between the virus and host cells, especially hepatic endothelial cells. The endothelium can be activated directly by the virus and/or indirectly by virus-induced soluble mediators. Endothelial damage contributes to hemostatic failure by stimulating platelet aggregation and degranulation, with consequent activation of the intrinsic coagulation cascade, which ultimately leads to diminished platelet numbers or function. Therefore, endothelial damage may lead to hemostatic failure and characteristic skin rash. In addition, the virus also has many different ways to block the immune response permitting uncontrolled viral replication.

Fig.2 Pathogenesis of CCHF. (Akinci, 2013)

Epidemiology

CCHF is a zoonotic disease and its vector is ixodid (hard) ticks. Humans are infected by tick bite, crushing it on an open wound, contact with blood, body fluids, or tissues of a viremic animal or human, and possibly through sexual transmission. CCHF virus is widely distributed in different regions of the world and is endemic in the Balkans, including Bulgaria, the former Yugoslavia.

Symptom

The incubation period of the infection lasts from 3-7 days. The onset of CCHF is sudden, with initial signs and symptoms including headache, high fever, back pain, joint pain, stomach pain, and vomiting. There may be nausea, dizziness, and sore throat early on, accompanied by diarrhea and abdominal pain. Other clinical signs include tachycardia and enlarged lymph nodes. Severe symptoms start appearing including petechiae (red spots on the skin), ecchymosis (extravasation of blood), epistaxis (nose bleeding), gum bleeding, and emesis. As the illness progresses into the hemorrhagic phase, large areas of severe bruising, and uncontrolled bleeding can be seen, that can be fatal if not treated.

Prevention and Treatment

There is currently no safe and effective CCHF vaccine widely available for human use. A formalin-inactivated mouse-brain CCHF vaccine was developed in the Soviet Union and approved for use in 1970.

The treatment for CCHF viral infection mainly depends on the severity and symptoms of the disease. Treatment of the disease consists essentially of supportive and replacement therapy with blood products. Currently, there is no antiviral drug against CCHFV.

Anti-CCHFV Products and Services

Creative Biolabs provides antibody products and customized antibody development services against CCHFV targeting Gn and N protein. Our services include ViroAntibody Neutralization Assays, ViroAntibody Discovery Services, ViroAntibody Engineering Services, ViroAntibody Customized Services to help you produce specific antibodies, and maximize the success of the project. If you are interested in any details in ViroAntibody products and services, please feel free to contact us for further information.

References

1. Ergonul, O. Crimean-Congo haemorrhagic fever. Lancet Infectious Diseases. 2006, 6(4): 203-214.
2. Akinci, E.; et al. Pathogenesis of Crimean-Congo hemorrhagic fever. Vector Borne Zoonotic Dis. 2013, 13(7): 429-437.

All products and services are intended for Research Use Only, and NOT to be used in diagnostic or therapeutic procedures.