Phlebovirus
Introduction
Member genus Phlebovirus is the only genus of the Phenuiviridae family that has over 60 viruses that cause disease in humans, such as Rift Valley Fever Virus (RVFV) can cause hemorrhagic fever syndrome. Creative Biolabs is dedicated to developing a series of anti-Phlebovirus antibody products to meet our clients’ needs.
Genome and Structure
The phlebovirus (order Bunyavirales, family Phenuiviridae) is a negative-sense single-stranded RNA virus. Phlebovirus consists of three RNA segments, including large (L) segment (6.4kb), which encodes an RNA-dependent RNA polymerase; medium (M) segment (3.2kb), which encodes a precursor polypeptide for the two envelope glycoproteins Gn and Gc, and non-structural components; and small (S) segment (1.7kb), which encodes for the nucleoprotein (N) and a non-structural protein (NSs). Phleboviruses possess an enveloped spherical virion approximately 100 nm in diameter. The surface of virions has two glycoprotein projections (Gn and Gc) that are embedded in a bilayered lipid envelope.
Fig.1 Prototypic phlebovirus virion and genome organization. (Wuerth, 2016)
Epidemiology
Phleboviruses are transmitted by mosquitos and ticks to humans. Direct human-to-human or parenteral transmission has not been demonstrated to date. Phleboviruses have a broad distribution and further surveillance is warranted. The phlebovirus Toscana was first isolated in 1971 in Italy. Then the increasing number of outbreaks was reported in Spain, south of France, Italy, and Greece. RVFV was discovered in the Great Rift Valley, Kenya, in 1930 and has since spread across Africa and beyond in the 1970s to reach Madagascar and, more recently, Saudi Arabia and Turkey. Severe fever with thrombocytopenia syndrome virus (SFTSV) was found in China, South Korea, and Japan.
SFTSV Pathogenesis
Several mechanisms of SFTSV may be attributed to:
- Invading pathogen impairs host immune response.
- The virus goes to the systemic circulation.
- Immune cells are over-stimulated causing cytokine storm and severe inflammatory response syndrome (SIRS).
- Endothelial damage from severe systemic inflammation increases consumption of peripheral platelets.
Fig.2 Probable mechanism of SFTSV pathogenesis. (Casel, 2021)
Symptoms
Phleboviruses can cause to humans an asymptomatic or mild infection, such as chills, joint pain, myalgia, and malaise. Some patients appear thrombocytopenia, leukocytopenia, and some hemorrhagic manifestations. For example, humans exposed to RVFV can present febrile illness, but in 1% to 2% of the cases it can progress to retinitis with persisting visual impairment, meningoencephalitis, or hemorrhagic fever.
Prevention and Treatment
No special vaccines or treatments against phenuivirus are currently approved for human use. The treatment of phlebovirus infections is mainly symptomatic and hepatotoxic medications as well as aspirin. Insecticide spraying is the most effective measure for protecting humans against virus transmission. It is necessary to develop a strategy for the prevention and antiviral therapy.
What Creative Biolabs offers
As a leading global provider of custom antibody products, now Creative Biolabs extends expertise to the specific virology area. We can provide anti-RVFV antibody products, SFTSV pseudovirus packaging services, etc. Please reach out to our scientists for antibody discovery services and customized services. Please feel free to contact us for further information.
References
- Wuerth, J.D.; Weber, F. Phleboviruses and the type I interferon response. Viruses, 2016, 8(6): 174.
- Casel, M.A.; et al. Severe fever with thrombocytopenia syndrome virus: emerging novel phlebovirus and their control strategy. Experimental & Molecular Medicine, 2021, 53(5): 713-722.
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