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Classification of Hemorrhagic Fevers
Published in James H. S. Gear, CRC Handbook of Viral and Rickettsial Hemorrhagic Fevers, 2019
The family Bunyaviridae comprises over 200 viruses (serotypes, subtypes, and varieties) that infect vertebrates and/or invertebrates.3 Four genera of viruses have been defined, namely Bunyavirus, Nairovirus, Phlebovirus, and Ukuvirus. The virions are mostly uniformly spherical, 80 to 110 nm in diameter, and possess a unit membrane envelope from which protrude polypeptide spikes 5 to 10 nm long. They have three helical nucleocapsids, often in the form of supercoiled circles, each consisting of a single species of single-stranded RNA, a major nucleocapsid polypeptide N, and in some cases a large polypeptide which may be a transcriptase component. The genome is composed of three species of RNA, L large, M medium, and S small, organized in end-hydrogen bonded structures. The viruses appear to mature primarily at smooth membrane surfaces and accumulate in Golgi vesicles and saccules. It has been shown that transovarial, venereal, and transstadial transmission in arthropods occurs in some members of the family.
Chemical and Biological Threats to Public Safety
Published in Frank A. Barile, Barile’s Clinical Toxicology, 2019
Viral hemorrhagic fevers (VHF) are a clinically related group of viral diseases with a diverse etiology. The family of Filoviridae includes the Marburg and Ebola viruses. Similarly, the family of Bunyaviridae includes the hantavirus and bunyavirus (which primarily causes encephalitis in humans). All are RNA viruses endemic in Africa and with the exception of the bunyavirus, cause severe or fatal hemorrhagic fevers. The condition is characterized by acute onset of fever, headache, generalized myalgia, conjunctivitis, and severe prostration, followed by various hemorrhagic symptoms. The organism facilitates the destruction of endothelial cells, leading to vascular injury and increased capillary permeability, leukopenia, and thrombocytopenia. Antiviral therapy has not been shown to be clinically useful.
Viral Haemorrhagic Fever
Published in Meera Chand, John Holton, Case Studies in Infection Control, 2018
CCHF is an arbovirus member of the Nairovirus genus (family Bunyaviridae), and is a single-stranded, enveloped, negative-sense RNA virus. There are over 300 species of Bunyaviridae within five genera: Orthobunyavirus, Hantavirus, Phelbovirus, Nairovirus, and Tospovirus. All Nairoviruses are thought to be transmitted by either the hard ixodid or soft argasid ticks, with Hyalomma ticks most responsible for CCHF transmission. Three species cause human illness, with CCHF by far the most important. Dugbe virus causes a mild febrile illness with thrombocytopenia, and Nairobi sheep disease virus causes fever, joint aches, and general malaise. Virions are 100 nm, spherical, with a lipid bilayer envelope derived from host cells through which virus-encoded glycoprotein spikes protrude. These spikes are responsible for virion binding to cellular receptors. The virus replicates in the host cell cytoplasm and virus particles are released from the infected cells by exocytosis.
Clinical and biochemical differences between hantavirus infection and leptospirosis: a retrospective analysis of a patient series in Belgium
Published in Acta Clinica Belgica, 2020
Emma Bakelants, Willy Peetermans, Katrien Lagrou, Wouter Meersseman
Hantaviruses belong to the family of Bunyaviridae. In Europe there are five different species; Puumala (PUUV), Dobrava (DOBV), Saaremaa (SAAV), Tula (TULV), and Seoul virus (SEOV). Each virus has a specific rodent as vector, for PUUV this is the bank vole (Myodes glareolus). In this article, we will focus on PUUV since the southern part of Belgium, a forested area, is an endemic region. The other species are not prevalent in Belgium [1–3]. PUUV is named after a little village in Finland, where it was first noticed. Nowadays Finland still has the largest disease burden in Europe, with 1000 cases per year [1]. Incidence in Belgium differs yearly, ranging from 10 to 100 cases per year with higher incidence within so called tree mast years of oak and beech [4,5]. In those years, trees tend to have more seed production which indicates more food and better breeding conditions for the bank vole. Tree seed production itself is influenced by climate changes, especially warm and dry conditions in summer and autumn. There is disease notification duty in Brussels and since 2017 also in Wallonia [4].
Characterization of clinical features and outcome for human-to-human transmitted severe fever with thrombocytopenia syndrome
Published in Infectious Diseases, 2018
Bei Jia, Weihua Wu, Rui Huang, Guiyang Wang, Peixin Song, Yang Li, Yong Liu, Yali Xiong, Xiaomin Yan, Yingying Hao, Juan Xia, Zhaoping Zhang, Yuxin Chen, Chao Wu
Severe fever with thrombocytopenia syndrome (SFTS) is an emerging hemorrhagic fever-like illness, first identified in central and northeast China in 2009 and later in Japan and Korea in 2012 [1–3]. In 2013, a similar disease was reported in United States [4]. The cause of this potential life-threatening disease was further identified as SFTS bunyavirus (SFTSV), a new member of family Bunyaviridae. SFTSV infection leads to a wide variety of clinical manifestations that range from asymptomatic infection to various grades of severe disease. Severe SFTS is characterized by fever, thrombocytopenia, gastrointestinal symptoms and multi-organ dysfunction syndrome (MODS). The average case fatality of SFTSV infection is about 12%, ranging from 6.3% to 30.0% [5,6]. SFTSV has been widely isolated and identified from tick species (Haemaphysalis longicornis and Rhipicephalus microplus) in mountain-hill area. Further, poultry and livestock are also the reservoirs for SFTSV, as SFTSV-specific antibodies were present in domestic animals. Therefore, it is considered that most cases acquired infection via tick bites and livestock [5]. However, there is a small percentage of patients who denied the presence of tick bite or livestock contact before illness onset.
Comparative genome analysis of Alkhumra hemorrhagic fever virus with Kyasanur forest disease and tick-borne encephalitis viruses by the in silico approach
Published in Pathogens and Global Health, 2018
Navaneethan Palanisamy, Dario Akaberi, Johan Lennerstrand, Åke Lundkvist
Alkhumra hemorrhagic fever virus (AHFV), or Alkhurma, belongs to the Flavivirus genus of the Flaviviridae family. This Flavivirus genus comprises over 70 viruses, nearly half of which are reported to cause infections in humans [1]. Other well-known examples of human pathogenic viruses within this genus include Zika virus (ZIKV), dengue virus (DENV), Japanese encephalitis virus (JEV), West Nile virus (WNV) and yellow fever virus (YFV). AHFV is a relatively new virus discovered only 23 years ago [2]. This virus was initially isolated from a butcher in the Al-Khumra district of the Jeddah metropolitan in Saudi Arabia [2]. The patient was originally misdiagnosed as infected with the Crimean-Congo hemorrhagic fever virus (CCHFV) (Bunyaviridae family); however, Dr. Zaki and his colleagues were later able to establish that it was a novel virus [2]. By performing phylogenetic studies using the NS5 sequence, they showed that the virus clustered within the tick-borne encephalitis virus serocomplex. It closely resembled, yet is distinct from the Kyasanur forest disease virus (KFDV), another tick-borne virus, which was discovered in the late 1950’s in Karnataka, India [2].