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Ticks
Published in Gail Miriam Moraru, Jerome Goddard, The Goddard Guide to Arthropods of Medical Importance, Seventh Edition, 2019
Gail Miriam Moraru, Jerome Goddard
Kyasanur forest disease (KFD), caused by a flavivirus, is a severe hemorrhagic disease of humans and other primates in the Karnataka State of India, where it causes hundreds of cases and dozens of deaths every year. A close relative of the agent of KFD, Alkahurma virus, occurs in Saudia Arabia.90 KFD is transmitted to humans by the tick, Haemaphysalis spinigera, primarily as people venture into forest fringes collecting firewood. In the winter of 2012–2013, the virus expanded over 400 km geographically and is now considered to be emerging.91
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).
Ticks
Published in Jerome Goddard, Public Health Entomology, 2022
Viruses associated with ticks. Tick-borne encephalitis (TBE) is a disease complex encompassing at least three syndromes caused by closely related viruses spanning from the British Isles (Louping ill), across Europe (Central European tick-borne encephalitis), to far-eastern Russia [Russian spring-summer encephalitis (RSSE)] (Figure 10.12). In Central Europe the typical case has a biphasic course with an early, viremic, flulike stage, followed about a week later by the appearance of signs of meningoencephalitis.15 Central nervous system (CNS) disease is relatively mild, but occasional severe motor dysfunction and permanent disability occur. Powassan encephalitis (POW)—also in the TBE subgroup—is a relatively rare infection of humans that mostly occurs in the northeastern United States and adjacent regions of Canada. Characteristically, there is sudden onset of fever with temperature up to 40°C along with convulsions. Also, accompanying encephalitis is usually severe, characterized by vomiting, respiratory distress, and prolonged, sustained fever. Cases of POW are still relatively rare in North America, although its reported incidence is increasing.4,16 There were 21 cases reported in 2018.4 Colorado tick fever is a moderate, self-limiting febrile tick-borne illness occurring in the Rocky Mountain region of the United States and Canada. The primary vector is Dermacentor andersoni. Small mammals such as ground squirrels and the ticks themselves serve as reservoirs of the virus. Crimean-Congo hemorrhagic fever is a rather serious tick-borne illness occurring in many countries in central and eastern Europe, Russia, China, India, Pakistan, the Middle East, and parts of Africa. Transmission is mainly by Hyalomma marginatum and other closely related species. Rabbits, cattle, and goats are believed to be the reservoir hosts. Kyasanur forest disease, transmitted primarily by Haemaphysalis spinigera and related species, occurs in southern India. The disease is believed to be contracted by people working in/near the Kyasanur forest or cattle grazing at the forest edge. In the last decade, several new tick-borne viruses have been identified. Heartland virus (a Phlebovirus) is associated with the Lone Star tick, Amblyomma americanum and has been recognized in Missouri, Oklahoma, Kentucky, and Tennessee.17,18 Only about 50 cases of Heartland virus have been identified. A couple of cases of a new Thogotovirus called Bourbon virus have been identified in the Midwest and southern United States with an unknown tick vector.19 Evidence suggests the lone star tick may be a potential vector.20
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.