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The Viruses
Published in Julius P. Kreier, Infection, Resistance, and Immunity, 2022
The etiologic agent of smallpox is the variola virus, a large and complex DNA virus (Poxviridae, Table 16.1). It naturally infects man and can also be transmitted to some higher primates. Two distinct forms of the disease occur in man: variola major, with twenty-five to fifty percent mortality, and variola minor (classical smallpox), which has less than one percent mortality. Smallpox is a highly contagious disease spread mainly by inhalation of virus. The virus also infects through breaks in the skin either from contact with pock fluids or contaminated clothing and bedding. Poxviruses survive in the environment because the virion has a protective fibrous protein outer coat.
Prevention, Screening, and Treatment of Sexually Transmitted Infections
Published in James M. Rippe, Lifestyle Medicine, 2019
Molluscum contagiosum is a skin infection caused by a Pox virus in the Poxviridae family. It can be transmitted by skin-to-skin contact and thus is commonly seen in school-aged children. Vaccination against smallpox is not protective. The incubation period is between two weeks and six months. Lesions are generally asymptomatic aside from cosmetic complaints of clusters of lesions 2–5 mm in diameter, with a pearl appearance and central umbilication. The lesions avoid the palms and soles. The papules of molluscum contagiosum may become red, inflamed, and swollen. No therapy has proven beneficial for this self-limited infection. Lesions generally clear spontaneously in six to twelve months in those with a healthy immune system.49
Vulvar therapies
Published in Miranda A. Farage, Howard I. Maibach, The Vulva, 2017
Natalie Moulton-Levy, Howard I. Maibach
Currently, cidofovir is being used for treating molluscum contagiosum (113), as are they are for other Poxviridae (114). Studies show promising results of treating HIV-infected patients with advanced molluscum contagiosum with topical and intravenous cidofovir (115). Any added benefit in this population may be due to antiviral effects.
Gender trend of monkeypox virus infection
Published in Expert Review of Anti-infective Therapy, 2023
Aliya Orassay, Ansal Diassova, Alan Berdigaliyev, Dongsheng Liu, Zhandaulet Makhmutova, Amr Amin, Yingqiu Xie
Poxviruses target host innate response pathways mediated by interferons and chemokines. They have the ability to inhibit the production of pro-inflammatory cytokines that regulate major histocompatibility complex (MHC) expression. Several studies revealed the role of steroid hormones in the virulence of poxviridae which the MPXV belongs to. One study by Reading et al. (2003) showed that the Poxvirus A44L gene (which encodes the 3β-HSD enzyme) is responsible for steroid hormone production corresponding to the immunosuppression and associating with the virulence of the virus [19]. The deletion of this gene may elevate the levels of IFN-γ [19]. It is known that interferons activate the innate and adaptive immune response that would combat the viral infection. However, according to Harris et al. (2018), poxviruses have evolved to encode interferon-binding proteins that neutralize secreted interferon after binding, which prevents INFs from association with cell-surface IFNAR1, and IFNAR2 receptors [20].
Mpox: epidemiology, clinical manifestations and recent developments in treatment and prevention
Published in Expert Review of Anti-infective Therapy, 2023
Nikil Selvaraj, Shreya Shyam, Puvin Dhurairaj, Kaviarasan Thiruselvan, Akil Thiruselvan, Yochana Kancherla, Pritika Kandamaran
Double-stranded deoxyribonucleic acid viruses belonging to the Poxviridae family infect a variety of species, including birds, reptiles, insects, and mammals [5]. The family is divided into two subfamilies: Entomopoxvirinae and Chordopoxvirinae, which together contain 52 species and 18 genera (with 4 genera and 30 species). The Chordopoxvirinae subfamily of the Poxviridae family, which includes the genus Orthopoxvirus, is where Mpox originates [5]. Variola (smallpox), cowpox, Mpox, vaccinia, camelpox, alaskapox, yaba monkey tumor virus, tanapox virus, orf virus, pseudocowpox virus, bovine papular stomatitis virus, buffalopox, and molluscum contagiosum are some of the poxvirus species that have been linked to human diseases [5]. Variola and molluscum contagiosum viruses are reservoir hosts in humans (Figure 1). As the Mpox virus (MPXV) can infect a broad variety of creatures, it circulates in wild animals while sporadically infecting humans through spillover episodes [6]. It is important to remember that infection with any one virus of a genus has shown to offer some protection against infections with any other viruses within the same genus [5].
The roles of epidermal growth factor receptor in viral infections
Published in Growth Factors, 2022
Vaccinia virus (VACV) is the prototype of family Poxviridae. It is a large, enveloped virus with linear, double stranded DNA genome that is closely related to variola virus (VARV), the causative pathogen of smallpox disease. VACV was employed as smallpox vaccine for the eradication of the disease. Several members of family Poxviridae, including VACV and VARV encode homologs of cellular EGF and TGFα (Smith 2008). Previous studies have revealed that treatment of EGFR inhibitors, gefitinib and 324674 blocked the uptake of the two distinct forms of VACV infectious particles, mature virion (MVs) and extracellular virions (EVs) into HeLa cells. This suggested that VACV utilises vaccinia growth factor (VGF) to stimulate EGFR and its downstream signalling cascade involving P21-activated kinase 1 (PAK1) and actin dynamics to facilitate the macropinocytosis of virions (Figure 2(k)). However, CHO cells that lack of EGFR are susceptible to VACV infection, indicating EGFR mediates macropinocytosis of VACV in a cell-type-specific manner (Mercer et al. 2010; Schmidt et al. 2011).