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Order Picornavirales
Published in Paul Pumpens, Peter Pushko, Philippe Le Mercier, Virus-Like Particles, 2022
Paul Pumpens, Peter Pushko, Philippe Le Mercier
The impressive Picornaviridae family currently includes 68 genera and 158 species, where the following genera are of primary interest for the VLP techniques: Aphthovirus with foot-and-mouth disease virus (FMDV); Cardiovirus with Mengo virus (MV) and porcine encephalomyocarditis virus (EMCV); Enterovirus with coxsackievirus B (CVB3), enterovirus 71 (EV71), and poliovirus (PV); and Hepatovirus with hepatitis A virus (HAV; Zell et al. 2017; ICTV 2020). Most of the known picornaviruses infect mammals and birds, but some have also been detected in reptiles, amphibians, and fish. Many picornaviruses are important human and veterinary pathogens and may cause diseases of the central nervous system, heart, liver, skin, gastrointestinal tract, or upper respiratory tract. Most picornaviruses are transmitted by the fecal-oral or respiratory routes (Zell et al. 2017).
Enteroviruses
Published in Avindra Nath, Joseph R. Berger, Clinical Neurovirology, 2020
Karen Straube-West, Burk Jubelt
Enteroviruses are one of the five subfamilies (genera) in the family Picornaviridae. They are found in humans (human enteroviruses) and many animals and are species specific. The Picornaviridae are small RNA viruses, thus the term “picornavirus” was derived from “pico,” meaning very small, and “RNA” for the type of genomic nucleic acid. There are over 100 recognized enterovirus serotypes specific for humans (Table 17.1). The enteroviruses share a number of characteristics. They replicate at 37°C, lack a lipid envelope, and are stable at acid pH, which allows them to survive and replicate in the gastrointestinal tract. The virion is composed of a positive single strand of RNA of approximately 7400 nucleotides and a 3′ poly-A tail [1]. The polyprotein is translated into one long single protein, which is then cleaved to form all the individual viral proteins [2]. The capsid is an icosahedron (spheroidal) that is 22–30 nm in diameter and composed of four proteins. Three of them, VP1, VP2, and VP3, are each repeated 60 times and compose the external surface of the capsid. Once the virus completes the replication cycle it is generally released from the host cell via cell lysis, thus killing the infected cell. However, recent studies suggest that a solely lytic infection is not always the case in that the virus or at least viral RNA may persist for months or years after the acute infection [3].
Autoimmunity and Immune Pathological Aspects of Virus Disease
Published in Irun R. Cohen, Perspectives on Autoimmunity, 2020
H. Wege, R. Dörries, P. Massa, R. Watanabe
These agents are typical picornaviruses with a small infectious RNA genome wrapped into an icosahedral protein capsid. Under natural conditions Theiler viruses cause asymptomatic enteric infections in mice. Two groups of viruses which differ markedly in virulence have been isolated. The TO strains (Theiler’s original viruses) have the tendency to cause persistent infections of the CNS which can lead to chronic inflammatory demyelinating disease.27 Another group of Theiler viruses (the GDVII and FA strains), is highly virulent for mice and causes acute disease.
The potential of plant-made vaccines to fight picornavirus
Published in Expert Review of Vaccines, 2020
Omayra C. Bolaños-Martínez, Sergio Rosales-Mendoza
Picornaviridae is one of the largest viral families, which according to the International Committee on Taxonomy of Viruses (ICTV) comprise 35 genera enclosing 80 viral species; many other are on the list to be classified. All members are ~30-32 nm in diameter with an icosahedral structure composed of 60 identical units (protomers) [1]. The members of this family have a genome composed of a single-stranded, positive-sense, and non-segmented RNA; with a length ranging 6.7–10.1 kb. The ORF is flanked by two untranslated regions (UTR); with the 5´end containing diverse RNA secondary structures implicated in replication and associated with the VPg protein that plays an important role in translation. The 3´UTR contains a poly (A) tail that mimics mRNA from the host providing genome stability (Figure 1). Picornaviruses possess four capsid proteins having b-barrel folding and code for a polyprotein that is processed by virus-encoded cysteine proteinases; their replication is performed by an RNA-dependent RNA polymerase containing the YGDD sequence motif. Picornaviruses are transmitted through the oral-fecal or aerial routes and many of them affect humans and animals; causing subclinical infections, mild febrile illness, and mild diseases in the gastrointestinal or respiratory tracts; as well as severe heart, liver, and central nervous system diseases. Picornaviruses of the genera Cardiovirus, Cosavirus, Enterovirus, Hepatovirus, Kobuvirus, Parechovirus, and Salivirus infect humans [2].
The platelets’ perspective to pathogen reduction technologies
Published in Platelets, 2018
Abdimajid Osman, Walter E. Hitzler, Patrick Provost
The most important limitation of PRT is that they cannot prevent 100% of infections. It has been shown that PRT cannot inactivate HEV, WNV, some bacteria and Prions [66]. HEV is very common in the population, and therefore also in blood donors: 1 of 1250 (0.08%) donors in Germany [67] and 1 of 2848 (0.04%) in Great Britain [68]. In Spain, the rate of HEV RNA positivity was 1 per 3333 donations (0.03%) [69]. In Canada, almost all platelet products are whole blood-derived PCs pooled from 4 to 6 different donors (pooled PCs), which increases the risks by as many fold compared to apheresis PCs. The susceptibility of non-enveloped viruses to PRT varies significantly between viruses. Good efficacy can be seen with Adenovirus and Bluetongue virus, intermediate efficacy with Parvovirus B19 and low efficacy with Picornaviruses. Hepatitis A virus and Poliovirus are resistant to Intercept, whereas HEV cannot be inactivated by PR [70].
Enteroviruses and coronaviruses: similarities and therapeutic targets
Published in Expert Opinion on Therapeutic Targets, 2021
Varpu Marjomäki, Kerttu Kalander, Maarit Hellman, Perttu Permi
Several high-throughput screens have provided novel drugs to inhibit 3 C proteases. Kuo et al. [52] performed a high-throughput screening containing 6800 small-molecule-compounds. One candidate inhibited picornaviruses and CoV equally: a compound containing dihydropyrazole ring with three substituents, two phenyl groups and N-butyl-benzimidazolylamino-toluene. Also, analogues of this showed good potency against picornaviruses and coronaviruses. These are competitive inhibitors indicating that they bind to the active site. Several other molecules based on this hit were searched from other libraries and tested. This testing revealed several drugs inhibiting both SARS-CoV, HCov-229, Coxsackievirus B3, enterovirus-A71, and human rhinovirus 14 with low µM concentration.