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Order Martellivirales: Togaviridae
Published in Paul Pumpens, Peter Pushko, Philippe Le Mercier, Virus-Like Particles, 2022
Paul Pumpens, Peter Pushko, Philippe Le Mercier
The Alphavirus members are mosquito-borne viruses. Most alphaviruses are cytopathic to vertebrates such as humans, nonhuman primates, equids, birds, amphibians, reptiles, rodents, and pigs and cause in humans a short febrile illness that can lead to prolonged arthritis or encephalitis but is rarely fatal. There are two aquatic alphaviruses, southern elephant seal virus and salmon pancreas disease virus, often referred to as salmonid alphavirus (SAV), infecting sea mammals and fish, respectively.
Determination of Antiviral Activity
Published in Adorjan Aszalos, Modern Analysis of Antibiotics, 2020
Viruses of primary importance to this chapter that are included in the Togaviridae family are those of Alpha virus and Flavivirus genera, also known as arboviruses group A and B. The arboviruses are the causal agents of encephalitis, an often fatal disease that can occur in epidemic proportions throughout the world. In the United States, the case rate has been determined to be as high as 1.8 in 100,000 population [274]. The Alphaviruses are the 20 mosquito-transmitted group A arboviruses described by Casals and Brown [275]. Most studied of these are eastern, western, and Venezuelan equine encephalomyelitis, Sindbis virus, and Chikungungya virus. The Flaviviruses comprise more than 30 group B arboviruses [276], the more recognized being St. Louis encephalitis, West Nile, Japanese B encephalitis, Murray Valley encephalitis, yellow fever, dengue, and tick-borne encephalitis viruses. Most of these viruses are associated with particular geographic areas where they are often a major public health problem. A number of effective vaccines are available for most of these viral diseases, but the lack of widespread use of those vaccines often hampers their effectiveness. No clinically effective antiviral drugs are available for any of these encepahlitis diseases.
Encephalitis and Its Mimics in the Critical Care Unit
Published in Cheston B. Cunha, Burke A. Cunha, Infectious Diseases and Antimicrobial Stewardship in Critical Care Medicine, 2020
Chikungunya similarly remains very rare in the United States but is widely prevalent elsewhere in the Americas. Unlike most of the other viruses discussed, most patients infected with this alphavirus are symptomatic [35]. Most are febrile with severe, widespread arthralgias symmetrically affecting multiple joints. While neurologic involvement occurs in only about 10%–15% of cases, primarily affecting individuals above the age of 60, encephalitis is a relatively common nervous system manifestation. Specific details remain unclear, particularly since encephalopathy is very common in these patients and encephalitis and encephalopathy have not always been clearly distinguished in reported series.
Chikungunya Virus Infection Outcome: A Systematic Review of Host Genetics
Published in Immunological Investigations, 2021
Jean Moisés Ferreira, Leandro Douglas Silva Santos, Susana Paiva Oliveira, Bárbara Rayssa Correia dos Santos, Ana Caroline Melo dos Santos, Edilson Leite de Moura, Elaine Virginia Martins de Souza, José Luiz de Lima Filho
After the initial returns, duplicate studies were excluded from this review. The PICOS approach (da Costa Santos, de Mattos Pimenta, and Nobre 2007) was used, the descriptors to assess eligibility were the participants (P): were the patients with symptomatic Chikungunya virus infection; the intervention (I): identification of genetic variations (polymorphisms); in comparison to the control groups (C): absence of Chikungunya virus infection or asymptomatic patients; and outcome (O): presence or absence of polymorphisms in the group of patients with Chikungunya virus infection; Study design (S): genetic association study. Using PICOS strategy, the titles and abstracts were carefully evaluated by two authors (LDSS and SPO) to determine inclusion and select all genetic studies. The discrepancies were resolved by consensus. In addition, references were also identified manually to find other relevant studies. Review articles, annals, abstracts, patents, in vitro or in vivo studies, letters, case reports and content on other alphaviruses were excluded.
Semliki Forest virus-based immunotherapy for cancer
Published in Expert Opinion on Biological Therapy, 2020
Alphaviruses belong to the family of Togaviridae and hold a single-stranded RNA (ssRNA) genome surrounded by a protein capsid structure and spike membrane proteins [9]. The alphavirus lifecycle is characterized by a large host range due to recognition of several cell surface receptors, direct RNA replication in the host cell cytoplasm and release of progeny by budding [10]. Alphaviruses have been associated with epidemics in different parts of the world resulting in fever, severe persistent headache, myalgia and arthralgia [11,12]. Moreover, recent outbreaks of Chikungunya virus (CHIK) have occurred presenting clinical symptoms such as polyarthralgia, rash, high fever and severe headaches, which have been characterized by rapid spread and high morbidity [13]. For this reason, alphavirus expression systems based on attenuated or avirulent strains and replication-deficient viruses have been engineered for immunization approaches demonstrating no harm to humans. In this context, alphavirus vectors have been frequently used for recombinant protein expression in cell lines [14], in primary cells [15], and in vivo[16]. Furthermore, alphavirus vectors have been applied for numerous immunization studies in animal models [8]. The aim of the review is to give an overview of the current status of alphavirus-based cancer immunotherapy by a description of alphavirus vector and expression systems and their applications in preclinical animal models and some clinical trials.
Antiviral therapeutics for chikungunya virus
Published in Expert Opinion on Therapeutic Patents, 2020
Alphaviruses are subdivided into two groups according to clinical prospective; one type is linked with encephalitis (New World viruses) and the other is associated with arthritis and rash (Old World viruses). CHIKV falls in the second group as its symptoms include arthralgia, rash, fever. CHIKV infection is transmitted by the bite of infected Ae. aegypti or Ae. albopictus [13]. Replication of virus takes place in the midgut of infected mosquitoes. Once infected in the human host, the virus does replicate in both lymphoid and myeloid originated cells [14]. CHIKV enters the host cell via clathrin-mediated endocytosis and induces cytopathic effects [10]. During the first few days of infection, the elevated titers of virus in the blood can be detected by amplification of viral protein via PCR method. During acute phase of the infection, virus disseminates through the blood and after the incubation period of 3 days there is a sudden onset of symptoms [1]. Simon and coworkers reported that during the late stage of CHIKV infection, the sinusoidal endothelium of the liver and macrophages act as main cellular reservoirs for virus. The symptoms can include high fever, arthralgia, myalgia and rash whereas about 15% of the infected patients were asymptomatic [1,6]. During the acute phase, the infection lasts from a few days to few weeks and in the chronic phase the symptoms of recurrent arthralgia, inflammation, and morning stiffness can be prolonged up to 3 years in CHIKV infected patients [3].