Poxviruses have evolved a wide array of mechanisms to evade the immune response, and we provide an overview of the different immunomodulatory strategies. Poxviruses prevent the recognition of viral DNA that triggers the immune responses and inhibit signaling pathways within the infected cell. A unique feature of poxviruses is the production of secreted proteins that mimic cytokines and cytokine receptors, acting as decoy receptors to neutralize the activity of cytokines and chemokines. The capacity of these proteins to evade cellular immune responses by inhibiting cytokine activation is complemented by poxviruses\' strategies to block natural killer cells and cytotoxic T cells, often through interfering with antigen presentation pathways. Mechanisms that target complement activation are also encoded by poxviruses. Virus-encoded proteins that target immune molecules and pathways play a major role in immune modulation, and their contribution to viral pathogenesis, facilitating virus replication or preventing immunopathology, is discussed.

BACKGROUND: Poxviruses comprise a group of large double-stranded DNA viruses and are known to cause diseases in humans, livestock animals, and other animal species. The Mpox virus (MPXV; formerly Monkeypox), variola virus (VARV), and volepox virus (VPXV) are among the prevalent poxviruses of the Orthopoxviridae genera. The ongoing Mpox infectious disease pandemic caused by the Mpox virus has had a major impact on public health across the globe. To date, only limited repurposed antivirals and vaccines are available for the effective treatment of Mpox and other poxviruses that cause contagious diseases.
METHODS: The present study was conducted with the primary goal of formulating multi-epitope vaccines against three evolutionary closed poxviruses i.e., MPXV, VARV, and VPXV using an integrated immunoinformatics and molecular modeling approach. DNA-dependent RNA polymerase (DdRp), a potential vaccine target of poxviruses, has been used to determine immunodominant B and T-cell epitopes followed by interactions analysis with Toll-like receptor 2 at the atomic level.
RESULTS: Three multi-epitope vaccine constructs, namely DdRp_MPXV (V1), DdRp_VARV (V2), and DdRp_VPXV (V3) were designed. These vaccine constructs were found to be antigenic, non-allergenic, non-toxic, and soluble with desired physicochemical properties. Protein-protein docking and interaction profiling analysis depicts a strong binding pattern between the targeted immune receptor TLR2 and the structural models of the designed vaccine constructs, and manifested a number of biochemical bonds (hydrogen bonds, salt bridges, and non-bonded contacts). State-of-the-art all-atoms molecular dynamics simulations revealed highly stable interactions of vaccine constructs with TLR2 at the atomic level throughout the simulations on 300 nanoseconds. Additionally, the outcome of the immune simulation analysis suggested that designed vaccines have the potential to induce protective immunity against targeted poxviruses.
CONCLUSIONS: Taken together, formulated next-generation polyvalent vaccines were found to have good efficacy against closely related poxviruses (MPXV, VARV, and VPXV) as demonstrated by our extensive immunoinformatics and molecular modeling evaluations; however, further experimental investigations are still needed.

Mpox is a zoonotic disease that became epidemic in multiple countries in 2022. There is a lack of published systematic reviews on natural animal infection due to Mpox. We performed a systematic literature review with meta-analysis to assess animal Mpox prevalence. We performed a random-effects model meta-analysis to calculate the pooled prevalence and 95% confidence interval (95%CI) for prevalence studies. After the screening, 15 reports were selected for full-text assessment and included in qualitative and quantitative analyses. Ten reports assessed Mpox infection by molecular or serological tests (n = 2680), yielding a pooled prevalence of 16.0% (95%CI: 3.0-29.0%) for non-human primates; 8.0% (95%CI: 4.0-12.0%) for rodents and 1.0% (95%CI: 0.0-3.0%) for shrews. Further studies in other animals are required to define the extent and importance of natural infection due to Mpox. These findings have implications for public human and animal health. OneHealth approach is critical for prevention and control.

Historically, biological agents have been used to target various populations. One of the earliest examples could be the catastrophic effect of smallpox in Australia in the eighteenth century (as alleged by some historians). Modern biological techniques can be used to both create or provide protection against various agents of biological warfare. Any microorganism (viruses, bacteria, and fungi) or its toxins can be used as biological agents. Minnesota Department of Health has listed Smallpox (variola major) as a category A bioterrorism agent, even though it has been eradicated in 1980 through an extensive vaccination campaign. Category A agents are considered the highest risk to public health. Laboratory-associated outbreaks of poxviruses could cause unprecedented occupational hazards. Only two WHO-approved BSL-4 facilities in the United States and Russia are allowed to perform research on the variola virus. So, poxviruses present themselves as a classical case of a dual-use dilemma, since research with them can be used for both beneficial and harmful purposes. Although the importance of ethics in scientific research requires no further elaboration, ethical norms assume greater significance during experimentation with poxviruses. In this chapter, we will update the readers on the sensitive nature of conducting research with poxviruses, and how these viruses can be a source of potential biological weapons. Finally, specified ethical guidelines are explored to ensure safe research practices in virology.

Despite the significant advancement of new tools and technology in the field of medical biology and molecular biology, the challenges in the treatment of most cancer types remain constant with the problem of developing resistance toward drugs and no substantial enhancement in the overall survival rate of cancer patients. Immunotherapy has shown the most promising results in different clinical and preclinical trials in the treatment of various cancer due to its higher efficacy and minimum collateral damage in many cancer patients as compared to conventional chemotherapy and radiotherapy. An oncolytic virus is a new class of immunotherapy that can selectively replicate in tumor cells and destroy them by the process of cell lysis while exerting minimum or no effect on a normal cell. Besides this, it can also activate the host\'s innate immune system, which generates an anti-tumor immune response to eliminate the tumor cells. Several wild types and genetically modified viruses have been investigated to show oncolytic behavior. Vaccinia virus has been studied extensively and tested for its promising oncolytic nature on various model systems and clinical trials. Recently, several engineered vaccinia viruses have been developed that express the desired genes encoded for selective penetration in tumor cells and enhanced activation of the immune system for generating anti-tumor immunity. However, further investigation is required to prove their potential and enhance their therapeutic efficacy.

Poxviruses target innate immunity mediators such as tumor necrosis factors, interleukins, interferons, complement, and chemokines. It also targets adaptive immunity such as CD4+ T cells, CD4+ T cells, and B cells. Emerging of the recent epidemic of monkeypox virus (MPXV), a zoonotic disease native to Central and Western Africa, besides the lack of permitted treatments for poxviruses infections, encouraged researchers to identify effective inhibitors to help in preventing and treating poxviruses infections. Natural bioactive components, particularly polyphenolics, are promising for creating powerful antioxidants, anti-inflammatory, immune-stimulating, and antiviral agents. As a result, they are potentially effective therapies for preventing and treating viral diseases, such as infections caused by poxviruses including the recent pandemic MPXV. Polyphenolics: rosmarinic acid, caffeic acid, resveratrol, quercitrin, myricitrin, gingerol, gallotannin, and propolis-benzofuran A, as well as isoquinoline alkaloids: galanthamine and thalimonine represent prospective antiviral agents against MPXV, they can inhibit MPXV and other poxviruses via targeting different viral elements including DNA Topoisomerase I (TOP1), Thymidine Kinase (TK), serine/threonine protein kinase (Ser/Thr kinase), and protein A48R. The bioactive extracts of different traditional plants including Guiera senegalensis, Larrea tridentata, Sarracenia purpurea, Kalanchoe pinnata (Lam.) Pers., Zingiber officinale Roscoe, Quercus infectoria, Rhus chinensis, Prunella vulgaris L., Salvia rosmarinus, and Origanum vulgare also can inhibit the growth of different poxviruses including MPXV, vaccinia virus (VACV), variola virus, buffalopox virus, fowlpox virus, and cowpox virus. There is an urgent need for additional molecular studies to identify and confirm the anti-poxviruses properties of various natural bioactive components, especially those that showed potent antiviral activity against other viruses.

Poxviruses belong to the family of double-stranded DNA viruses, and it is pathogenic for humans and spread worldwide. These viruses cause infections and various diseases in human. So, it is required to develop new drugs for the treatment of smallpox or other poxvirus infections. Very few potential compounds for the treatment of poxvirus such as smallpox, chickenpox, and monkeypox have been reported. Most of the compounds has used as vaccines. Cidofovir is most commonly used as a vaccine for the treatment of poxviruses. There are no phytochemicals reported for the treatment of poxviruses. Very few phytochemicals are under investigation for the treatment of poxviruses.

Smallpox was a significant cause of mortality for over three thousand years, amounting to 10% of deaths yearly. Edward Jenner discovered smallpox vaccination in 1796, which rapidly became a smallpox infection preventive practice throughout the world and eradicated smallpox infection by 1980. After smallpox eradication, monkeypox vaccines have been used primarily in research and in outbreaks in Africa, where the disease is endemic. In the present, the vaccines are being used for people who work with animals or in high-risk areas, as well as for healthcare workers treating patients with monkeypox. Among all orthopoxviruses (OPXV), monkeypox viral (MPXV) infection occurs mainly in cynomolgus monkeys, natural reservoirs, and occasionally causes severe multi-organ infection in humans, who were the incidental hosts. The first case of the present epidemic of MXPV was identified on May 7, 2022, and rapidly increased the number of cases. In this regard, the WHO declared the outbreak, an international public health emergency on July 23, 2022. The first monkeypox vaccine was developed in the 1960s by the US Army and was based on the vaccinia virus, which is also used in smallpox vaccines. In recent years, newer monkeypox vaccines have been developed based on other viruses such as Modified Vaccinia Ankara (MVA). These newer vaccines are safer and can provide longer-lasting immunity with fewer side effects. For the future, there is ongoing research to improve the current vaccines and to develop new ones. One notable advance has been the development of a recombinant vaccine that uses a genetically modified vaccinia virus to express monkeypox antigens. This vaccine has shown promising results in pre-clinical trials and is currently undergoing further testing in clinical trials. Another recent development has been the use of a DNA vaccine, which delivers genetic material encoding monkeypox antigens directly into cells. This type of vaccine has shown effectiveness in animal studies and is also undergoing clinical testing in humans. Overall, these recent advances in monkeypox vaccine development hold promise for protecting individuals against this potentially serious disease.

Although WHO-led global efforts led to eradication of smallpox over four decades ago, other poxviruses, especially monkeypox, have re-emerged to occupy the ecological niche vacated by smallpox. Many of these viruses produce similar lesions thus mandating a prompt laboratory confirmation. There has been considerable evolution in the techniques available to diagnose these infections and differentiate between them. With the 2022 multi-country outbreak of monkeypox, significant efforts were made to apprise the laboratory diagnosis of the virus and numerous real-time-PCR-based assays were made commercially available. This chapter discusses the sample collection and biosafety aspects along with the repertoire of diagnostic modalities, both traditional and emerging, for poxviruses which a special focus on monkeypox. The advantages and disadvantages of each technique have been illustrated. We have also reflected upon the newer advances and the existing lacunae.

The family Poxviridae is a large family of viruses with a ubiquitous distribution, subdivided into two subfamilies: Chordopoxvirinae (poxviruses of vertebrates) and Entomopoxvirinae (poxviruses of insects). Only three species from the first subfamily, Orthopoxvirus (OPV), Molluscipoxvirus and Parapoxvirus, can infect the human being. In the paediatric population, viruses belonging to the first two subfamilies have the greatest importance. Following the eradication of smallpox in 1980, vaccination of the general population was discontinued after careful consideration of the risks and benefits. However, nearly all children and most of the world\'s population had little to no protection against OPV. The aim of this chapter is to review the current evidence on the aetiology, clinical manifestations, diagnosis and management of Poxviridae infections in children.