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The Pathogenesis and Pathology of the Hemorrhagic State in Viral and Rickettsial Infections
Published in James H. S. Gear, CRC Handbook of Viral and Rickettsial Hemorrhagic Fevers, 2019
Among the hundreds of togaviruses that have been isolated, only a few have been considered to cause hemorrhagic fevers. These agents are dengue viruses 1 to 4, yellow fever virus, Kyasanur Forest disease virus, Omsk hemorrhagic fever virus, and Chikungunya virus. Except for the last, an alphavirus, they are all flaviviruses. Only yellow fever and dengue hemorrhagic fever will be considered in detail.
Viruses
Published in Loretta A. Cormier, Pauline E. Jolly, The Primate Zoonoses, 2017
Loretta A. Cormier, Pauline E. Jolly
Kyasanur Forest disease virus is a vector-borne infection occurring in southwest India (Hensgens and Kuijper 2013). It is spread through the bite of Haemaphysalis species of ticks (Mourya et al. 2014). Symptoms include high fever, severe myalgia, and bleeding from the nasal cavity, throat, and gingivae, and hemorrhagic pulmonary edema in 40% of the cases (Thomas et al. 2015). The case fatality rate is 2–10% (Thomas et al. 2015). Although a vaccine is available, approximately 100–500 people are infected each year (Hensgens and Kuijper 2013). Rodents or related species are believed to be the natural hosts, since neutralizing antibodies have been found in a number of species of rodents, as well as squirrels and bats (Pattnaik 2006). Epizootic outbreaks have been documented in macaques (Macaca radiata) and langurs (Semnopithecus entellus), which also experience severe febrile illness (Hensgens and Kuijper 2013). The primary means through which humans become infected is likely through contact with infected monkeys. The first documented outbreak of the disease occurred in 1956, when there was a simultaneous outbreak in forest monkeys and local villagers (Work and Trapido 1957). The most recent human outbreak in 2013 occurred in workers in the Bandipur National Reserve in India who were caring for sick langurs (Hensgens and Kuijper 2013).
Tick-Borne Encephalitis
Published in Sunit K. Singh, Daniel Růžek, Neuroviral Infections, 2013
Daniel Růžek, Bartosz Bilski, Göran Günther
TBEV is the most medically important member of the tick-borne serocomplex group of the genus Flavivirus, family Flaviviridae. The TBE serocomplex includes Langat virus, louping-ill virus, Negishi virus, Kyasanur Forest disease virus, Omsk hemorrhagic fever virus, Powassan virus, and others. TBE virus is subdivided into three antigenic subtypes corresponding to three genotypes: European (previously Central European encephalitis; with Neudoerfl strain as prototype), Far Eastern (previously Russian spring—summer encephalitis; prototype strain Sofjin), and Siberian (previously Western Siberian encephalitis; prototype strains Zausaev and Vasilchenko) (Ecker et al. 1999). However, based on antigenic properties, the European TBEV strains are more closely related rather to Louping ill virus than to the Far Eastern and Siberian strains (Hubálek et al. 1995).
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].
Role of structural disorder in the multi-functionality of flavivirus proteins
Published in Expert Review of Proteomics, 2022
Shivani Krishna Kapuganti, Aparna Bhardwaj, Prateek Kumar, Taniya Bhardwaj, Namyashree Nayak, Vladimir N. Uversky, Rajanish Giri
These were the common examples of flaviviruses associated with a substantial fraction of outbreaks responsible for flavivirus infections. However, there are few lesser known examples that, though obscure now, may follow trend and lead to sudden epidemics. The Usutsu (USUV), Ilheus (ILHV), and Rocio (ROCV) flaviviruses belong to the JEV serocomplex [2]. In terms of vectors and intermediate hosts, USUV is closely related to WNV. It was initially isolated from South Africa in 1959, however, during 2014–2015, it was detected in different parts of Europe and was associated with avian mortality. Reports of encephalitis, febrile disease and paralysis caused by USUV exist. It shares around 76% sequence identity with WNV indicating that it may emerge like WNV [58]. ILHV was identified in Brazil in 1944. However, now it circulates widely in South America and can cause febrile disease leading to encephalitis [59]. ROCV was associated with an encephalitis epidemic in Brazil in 1975 where it lead to 13% case fatality. Some of the survivors had developed neurological complications. These viruses use Aedes and Culex mosquitoes as vectors [60]. Tick-borne encephalitis virus (TBEV) include examples such as Omsk haemorrhagic fever virus, Powassan virus, Kyasanur forest disease virus, Karshi virus, Alkhurma haemorrhagic fever virus, etc. Some of these viruses can cause vascular leakage and severe neuroinvasive diseases. The geographical coverage of TBEVs is increasing due to changing climate and human activities [61]. The Spondweni virus is closely related to ZIKV. It has around 75% sequence similarity to ZIKV. In 2016, it was detected in Culex mosquitoes. It can cause vascular shock and neurological complications in severe infections [62,63]. Regardless, looking into the molecular level would raise the understanding of viral mechanism and shed light on how to inhibit the functionality of the viruses.