Poxviruses: smallpox vaccine, its complications and chemotherapy

Abstract

The threat of bioterrorism in the recent years has once again posed to mankind the unresolved problems of contagious diseases, well forgotten in the past. Smallpox (variola) is among the most dangerous and highly contagious viral infections affecting humans. The last natural case in Somalia marked the end of a successful World Health Organization campaign for smallpox eradication by vaccination on worldwide scale. Smallpox virus still exists today in some laboratories, specially designated for that purpose. The contemporary response in the treatment of the post-vaccine complications, which would occur upon enforcing new programs for mass-scale smallpox immunization, includes application of effective chemotherapeutics and their combinations. The goals are to provide the highest possible level of protection and safety of the population in case of eventual terrorist attack. This review describes the characteristic features of the poxviruses, smallpox vaccination, its adverse reactions, and poxvirus chemotherapy.

Monkeypox Virus in Nigeria: Infection Biology, Epidemiology, and Evolution

“…All the proteins required for viral DNA replication, transcription, virion assembly, and egress are encoded by the MPXV genome. The genes encoding for housekeeping functions are highly conserved among OPVs and are present in the central region of the genome while those that encode for the virus-host interactions are less conserved and are located in the termini region [1,[15][16][17][19][20][21][22][23]. In VACV (and most in likely MPXV) intracellular mature virus (IMV) and extracellular-enveloped virus (EEV) are two forms of infectious virions produced in poxvirus-infected cells.…”

“…IMV is released on cell lysis, while EEV is released from cells via interaction with actin tails, and this is said to be the cause of rapid long distance spread of the virus within the infected host. Although the aforementioned features are for VACV, it is likely that these features are common to all OPVs [22]. However, cell-associated virions (CEVs) are formed following the microtubule-mediated transport of intracellular enveloped virus (IEV) to the cell periphery, in which the outer membrane of IEV fuses with the plasma membrane and remains attached to the cell surface.…”

Monkeypox: A Comprehensive Review

“…Typical of orthopoxviruses, sequence conservation is high in the central region of the MPXV genome but decreases toward the terminal ITRs. Here, the genes responsible for housekeeping are located in the central region and thus are highly conserved among orthopoxviruses, while genes encoding proteins that interact with host factors have lower sequence identity and are located further toward the termini regions [ 30 , 31 ]. The latter coding genes are aptly named virulence factors, as most seem to be dispensable for in vitro replication in cell culture, but their absence attenuates in vivo pathogenesis [ 32 ].…”

The monkeypox diagnosis, treatments and prevention: A review

“…Housekeeping function genes are preserved across Orthopoxvirus (OPVs) and found in the genome’s central area. In contrast, virus-host interaction genes are less conserved and located in the termini area ( Cho and Wenner, 1973 ; Esposito and Knight, 1985 ; Takemura, 2001 ; Jahrling et al., 2007 ; Boyle and Traktman, 2009 ; Remichkova, 2010 ). Intracellular mature virus (IVM) and extracellular-enveloped virus (EEV) are the two kinds of infective virions formed by Vaccinia Virus (VACV) (and most likely MPXV).…”