Reemergence of Human Monkeypox and Declining Population Immunity in the Context of Urbanization, Nigeria, 2017-2020

Epidemiology-based analysis of the risks and elimination strategies of the monkeypox outbreak in 2022

Human monkeypox, caused by monkeypox virus, has spread unprecedentedly to more than 100 countries since May 2022. Here we summarized the epidemiology of monkeypox through a literature review and elucidated the risks and elimination strategies of this outbreak mainly based on the summarized epidemiology. We demonstrated that monkeypox virus became more contagious and less virulent in 2022, which could result from the fact that the virus entered a special transmission network favoring close contacts (i.e., sexual behaviors of men who have sex with men outside Africa) and the possibility that the virus accumulated a few adaptive mutations. We gave the reasons to investigate whether cattle, goats, sheep, and pigs are susceptible to monkeypox virus and whether infection with monkeypox virus could be latent in some primates. We listed six potential scenarios for the future of the outbreak (e.g., the outbreak could lead to endemicity outside Africa with increased transmissibility or virulence). We also listed multiple factors aiding or impeding the elimination of the outbreak. We showed that the control measures strengthened worldwide after the World Health Organization declared the outbreak a public health emergency of international concern (PHEIC) could eliminate the outbreak in 2022. We clarified eight strategies, i.e., publicity and education, case isolation, vaccine stockpiling, risk-based vaccination or ring vaccination, importation quarantine, international collaboration, and laboratory management, for the elimination of the outbreak.

Estimation of anti-orthopoxvirus immunity in Moscow residents and potential risks of spreading Monkeypox virus

WHO has declared the outbreak of monkeypox as a public health emergency of international concern. In less than three months, monkeypox was detected in more than 30 000 people and spread to more than 80 countries around the world. It is believed that the immunity formed to smallpox vaccine can protect from monkeypox infection with high efficiency. The widespread use of Vaccinia virus has not been carried out since the 1980s, which raises the question of the level of residual immunity among the population and the identification of groups requiring priority vaccination. We conducted a cross-sectional serological study of remaining immunity among Moscow residents. To do this, a collection of blood serum samples of age group over 30 years old was formed, an in-house ELISA test system was developed, and a virus neutralization protocol was set up. Serum samples were examined for the presence of IgG antibodies against Vaccinia virus (n=2908), as well as for the ability to neutralize plaque formation with a Vaccinia virus MNIIVP-10 strain (n=299). The results indicate the presence of neutralizing antibody titer of 1/20 or more in 33.3 to 53.2% of people older than 45 years. Among people 30-45 years old who probably have not been vaccinated, the proportion with virus neutralizing antibodies ranged from 3.2 to 6.7%. Despite the higher level of antibodies in age group older than 66 years, the proportion of positive samples in this group was slightly lower than in people aged 46-65 years. The results indicate the priority of vaccination in groups younger than 45, and possibly older than 66 years to ensure the protection of the population in case of spread of monkeypox among Moscow residents. The herd immunity level needed to stop the circulation of the virus should be at least 50.25 - 65.28%.

Monkeypox: Clinical Considerations, Epidemiology, and Laboratory Diagnostics

Monkeypox virus (MPXV) has garnered recent attention as outbreaks are continually reported outside historic regions of endemicity in Africa. Consequently, MPXV is becoming routinely included in the differential diagnosis of rash illnesses, requiring clinicians and laboratorians alike to quickly adapt to a new public health emergency. This review discusses the epidemiology, clinical presentation, and laboratory testing of MPXV in the context of recent outbreaks.

Monkeypox Mysteries of the New Outbreak in Non-Endemic Areas

Monkeypox virus (MPXV) was declared by the World Health Organization (WHO) in mid-2022 to be a public health emergency of international concern, following its spread around the world after circulating in Western and Central Africa. This new outbreak is concentrated in men who have sex with men (MSM). Moreover, beyond the epidemiological change, compared with endemic countries, differences in clinical features and many other aspects have also been detected. These and other characteristics are unusual and still unclear. Based on the available data, the authors try to help to clarify some of the current major gaps in monkeypox knowledge to strengthen the outbreak response.

Strengthening monkeypox diagnostics and healthcare amidst Covid-19 realities: A call to action

Monkeypox virus is a zoonotic DNA virus related to the virus that causes smallpox. It was first isolated and identified in 1958 but its first confirmed human case was in 1970 when the virus was isolated from a child in the Democratic Republic of Congo. Since then, several cases have been reported within the African continent and globally. Despite its spread, Monkey pox disease has continued to suffer neglect in terms of research and funding due to its reported inefficiency in transmitting from Man to man as its transmission was reportedly limited to its endemic regions in Africa. Poor health data management, inadequate capacities in terms of testing infrastructure and health care workers and weak surveillance systems are some of the challenges faced by African countries. Multisectoral collaboration in breaking the transmission cycle of monkeypox infection and other preventive measures must be improved upon. Community advocacies and education play integral roles in infection spread preparedness, as well as in strengthening the healthcare system.

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Monkeypox virus infection remains a challenging health threat in sub-Saharan Africa, and the world at large.

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Research, monitoring, supporting, and sharing information among countries affected by monkeypox should be improved.

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Research priorities towards monkeypox virus vaccine production should be prioritised.

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Sensitization toward the populations at risk must be invested into.

Reemergence of monkeypox: prevention and management

INTRODUCTION

The reemergence of monkeypox virus in the twenty-first century, calls for an urgency in its control and preventive measures. There is a long-standing concern that the reemergence of monkeypox across countries could lead to another epidemic like the COVID-19 pandemic. Understanding the disease ecology, preventing its transmission could help curbing its spread. The established treatment protocols along with development of new antiviral agents and vaccines could play a pivotal role in controlling its transmission.

AREAS COVERED

In this review, we summarize the different modes of transmission of this disease, the associated symptoms, the standard protocol of treatment, the available vaccines and use of alternative treatments. We have collated recent research on novel entities that could potentially treat monkeypox infection.

EXPERT OPINION

The One Health approach fostered by the World Health Organization (WHO) for emergent and reemerging zoonotic diseases has to be implemented with a view to curb their transmission. The growing global population and increased inter-country travel has led to rapid spread of transmissible pathogens. Stigmatization, associated with lack of knowledge can be prevented by enhancing awareness campaigns. Vaccines need to be administered to high-risk individuals, and drug discovery efforts need to be intensified to combat such diseases.

Early estimates of the incidence trend and the reproductive number of the monkeypox epidemic in Brazil

BACKGROUND

We aimed to calculate the weekly growth of the incidence and the effective reproductive number (Rt) of the 2022 Monkeypox epidemic during its introduction in Brazil.

METHOD

We described the case distribution in the country and calculated the incidence trend and the Rt in the four geographical states with the highest case reports. By using two regression approaches, count model and the Prais-Winsten, we calculated the relative incidence increase. Moreover, we estimated the Rt for the period between the 24th and the 50th days after the first official report, using a serial interval reported in another population and two alternative values (± 3 days).

RESULTS

Up to August 22, 3.896 Monkeypox cases were confirmed in Brazil. The weekly incidence increases were between 37.5% (95% CI: 20.7% - 56,6%) and 82.1% (95% CI: 59.5%-107.8%), and all estimates of Rt were significantly higher than 1 in the four states analyzed.

CONCLUSIONS

The Monkeypox outbreak in Brazil is a significant public health emergency that requires coordinated public health strategies such as testing, contact tracing, and vaccination.

On nonlinear dynamics of a fractional order monkeypox virus model

In this work, we examine a fractional-order model for simulating the spread of the monkeypox virus in the human host and rodent populations. The employment of the fractional form of the model gives a better insight into the dynamics and spread of the virus, which will help in providing some new control measures. The model is formulated into eight mutually exclusive compartments and the form of a nonlinear system of differential equations. The reproduction number for the present epidemic system is found. In addition, the equilibrium points of the model are investigated and the associated stability analysis is carried out. The influences of key parameters in the model and the ways to control the monkeypox epidemic have been thoroughly examined for the fractional model. To ensure that the model accurately simulates the nonlinear phenomenon, we adapt an efficient numerical technique to solve the presented model, and the acquired results reveal the dynamic behaviors of the model. It is observed that when memory influences are considered for the present model, through Caputo fractional-order derivatives, they affect the speed and time taken by solution trajectories towards steady-state equilibria.

Strategy of developing nucleic acid-based universal monkeypox vaccine candidates

Until May 2022, zoonotic infectious disease monkeypox (MPX) caused by the monkeypox virus (MPXV) was one of the forgotten viruses considered to be geographically limited in African countries even though few cases outside of Africa were identified. Central and West African countries are known to be endemic for MPXV. However, since the number of human MPX cases has rapidly increased outside of Africa the global interest in this virus has markedly grown. The majority of infected people with MPXV have never been vaccinated against smallpox virus. Noteworthily, the MPXV spreads fast in men who have sex with men (MSM). Preventive measures against MPXV are essential to be taken, indeed, vaccination is the key. Due to the antigenic similarities, the smallpox vaccine is efficient against MPXV. Nevertheless, there is no specific MPXV vaccine until now. Nucleic acid vaccines deserve special attention since the emergency approval of two messenger RNA (mRNA)-based coronavirus disease 2019 (COVID-19) vaccines in 2020. This milestone in vaccinology has opened a new platform for developing more mRNA- or DNA-based vaccines. Certainly, this type of vaccine has a number of advantages including time- and cost-effectiveness over conventional vaccines. The platform of nucleic acid-based vaccines gives humankind a huge opportunity. Ultimately, there is a strong need for developing a universal vaccine against MPXV. This review will shed the light on the strategies for developing nucleic acid vaccines against MPXV in a timely manner. Consequently, developing nucleic acid-based vaccines may alleviate the global threat against MPXV.

Smallpox vaccination discontinuation and monkeypox incidence in an African endemic region: a reanalysis on the relationship between the withdrawal of smallpox vaccine and subsequent morbidity

BACKGROUND

Monkey pox has expanded across Europe as a result of the widespread outbreak, creating a severe public health risk. Monkey pox is an uncommon pox infection that has reappeared due to zoonosis. Monkey pox has spread over Europe and North America, posing a serious public health risk. The regular smallpox vaccine has been shown to be effective against monkeypox. The suspension of smallpox immunization is currently being debated due to the possibility of a connection with the current monkeypox outbreak. In clinical immunology, the link between a desire for smallpox vaccination, low population immunity, and a higher incidence of monkeypox is an intriguing topic.

METHODS

This is a descriptive analysis done in the past. The writers investigate the situation in West Africa in this research. The available data on monkeypox incidence in an African endemic area was reassessed.

RESULTS

Based on a recent analysis of epidemiological data from an endemic area, there is no indication of a yearly ongoing increase in monkeypox incidence following the discontinuation of the smallpox vaccine, and incidence varies.

CONCLUSION

There is no evidence of an annual increase in monkeypox incidence following the withdrawal of smallpox immunization.

Infection-competent monkeypox virus contamination identified in domestic settings following an imported case of monkeypox into the UK

An imported case of monkeypox was diagnosed in December 2019 in a traveller returning from Nigeria to the UK. Subsequently, environmental sampling was performed at two adjoining single-room residences occupied by the patient and their sibling. Monkeypox virus DNA was identified in multiple locations throughout both properties, and monkeypox virus was isolated from several samples 3 days after the patient was last in these locations. Positive samples were identified following the use of both vacuum and surface sampling techniques; these methodologies allowed for environmental analysis of potentially contaminated porous and non-porous surfaces via real-time quantitative reverse transcriptase PCR analysis in addition to viral isolation to confirm the presence of infection-competent virus. This report confirms the potential for infection-competent monkeypox virus to be recovered in environmental settings associated with known positive cases and the necessity for rapid environmental assessment to reduce potential exposure to close contacts and the general public. The methods adopted in this investigation may be used for future confirmed cases of monkeypox in order to establish levels of contamination, confirm the presence of infection-competent material and to identify locations requiring additional cleaning.

Monkeypox: From A Neglected Tropical Disease to a Public Health Threat

Since the first case of human monkeypox was diagnosed in 1970, the disease remained endemic in several countries in West and Central Africa. In 1996, there was a sudden increase in cases in the Democratic Republic of Congo (DRC), and since 2017 an ongoing outbreak in Nigeria took place, probably related to the population growth, human invasion of MPXV animal habitat reservoirs, and the waning of the cross-protection offered from smallpox immunization, later ending in 1980. Since May 2022, an unprecedented outbreak of human monkeypox has rapidly spread around the world, outside endemic regions of Africa, through new modes of transmission, showing differences in clinical features compared with previous reports. The 2022 MPXV strain belongs to the clade of West Africa but diverges from the original strain, making the virus more transmissible. The authors review the main milestones in more than 50 years of history of human monkeypox, from a rare viral zoonotic infection to a public health emergency.

[Treatment and prevention of monkeypox]

Monkeypox is a zoonosis that is spread mainly through direct contact with fluids and skin lesions of infected people with vesicles still active. Although the virus was isolated for the first time in 1958 and the first human case was identified in a child in 1970, in the Democratic Republic of the Congo, the disease has progressively increased its incidence in Africa reaching in May 2022 sustained transmission outside this continent. As it is a newly introduced virus in our health system, it is necessary to learn the epidemiological pattern in a different environment from that of traditionally endemic areas and to know the available antiviral treatments, as well as the prophylactic measures that could be considered, knowing that as a virus emerging in our regions, scientific evidence is still limited. There are antivirals that have been shown, in animal models, to effectively combat the disease with very good clinical tolerance. This disease has also forced us to review the characteristics of smallpox vaccines, because they have shown a protective effect against monkeypox. For this reason, it is important to have a document that compiles all the scientific information published in this regard.

Evaluating the risk of transfusion and transplant-transmitted monkeypox infections

The recent emergence of monkeypox virus (MPXV) in the UK and elsewhere is of urgent public health concern. Several aspects of MPXV epidemiology and pathogenesis, including its systemic spread and viraemia during acute infection, furthermore represent an important potential threat to the safety of blood transfusion and organ transplantation. Reported infections in the UK have been exponentially increasing over the last 2 months, with 1552 reported cases in the UK by 7th July 2022. This is likely to be considerable underestimate given current limitations in diagnostic capacity and clinical diagnoses hampered by its similar disease presentations to other causes of rash and genitourinary disease. While MPXV infections are currently most widespread in gay, bisexual or other men who have sex with men, wider spread of MPXV outside defined risk groups for infection may prevent identification of infection risk in donors. While typically mild disease outcomes have been reported in UK cases, case fatality rates ranging from 1% to over 10% are reported for different MPXV strains in its source area in sub-Saharan Africa. Recipients of blood components and organs transplant, especially those who are immunosuppressed, may reproduce the greater systemic spread and morbidity of those infected through percutaneous routes. There is a potential risk of MPXV transmission and severe disease outcomes in blood and transplant recipients. In addition to current risk assessments performed in the UK and exclusion of donors with recent MPXV exposure, determining viraemia frequencies in donors and directly evaluating transmission risk would be of considerable value in assessing whether MPXV nucleic acid screening should be implemented.

[Diagnosis and treatment of human monkeypox]

The guideline for the diagnosis and treatment of monkeypox (2022 edition) issued by National Health Commission of the People's Republic of China introduces the key knowledge of the diagnosis and treatment of human monkeypox (HMPX) and does not systematically introduce the sampling methods and requirements of specimens for HMPX etiology testing and the discrepancy in diagnostic criteria between China and overseas. However, the doctors who are not engaged in dermatology lack understanding of the sampling methods and requirements of specimens for laboratory diagnosis of HMPX, and there are few relevant references available. This article collects the information on the diagnosis and treatment of HMPX, so as to provide a reference for learning, understanding, and application of this guideline.

Monkeypox Virus Infections in Southern Italy: Is There a Risk for Community Spread?

The ongoing outbreak of the Monkeypox virus (MPXV) is characterized by sustained human-to-human transmission, particularly among men who have sex with men (MSM). The aim of the study was to describe the characteristics of the MPXV infection identified in Southern Italy. Clinical samples for each suspected case identified from 1 June to 1 August 2022 were tested for MPXV, and whole-genome sequencing (WGS) was performed on two strains. Ten cases were identified: eight were young adult males, including six MSMs, and two were female. Nine subjects reported recent sexual exposure. One female subject without sexual exposure only reported attendance at a social gathering. Overall, 7 of 10 skin lesion samples had a high viral load of MPXV DNA, and 6/9 whole blood samples and 6/8 nasopharyngeal swab samples also tested positive. The analyzed sequences belonged to Clade 3, lineage B.1, and B.1.5, respectively. Despite this recent multinational outbreak of MPXV cases having revealed a high proportion of cases occurring among MSM, the identification of cases among heterosexual subjects and in a female subject without sexual risk factors should raise awareness among clinicians about the possible spread of MPXV in the general population.

Atypical and Unique Transmission of Monkeypox Virus during the 2022 Outbreak: An Overview of the Current State of Knowledge

An ongoing monkeypox outbreak in non-endemic countries has resulted in the declaration of a public health emergency of international concern by the World Health Organization (WHO). Though monkeypox has long been endemic in regions of sub-Saharan Africa, relatively little is known about its ecology, epidemiology, and transmission. Here, we consider the relevant research on both monkeypox and smallpox, a close relative, to make inferences about the current outbreak. Undetected circulation combined with atypical transmission and case presentation, including mild and asymptomatic disease, have facilitated the spread of monkeypox in non-endemic regions. A broader availability of diagnostics, enhanced surveillance, and targeted education, combined with a better understanding of the routes of transmission, are critical to identify at-risk populations and design science-based countermeasures to control the current outbreak.

Human monkeypox disease (MPX)

Monkeypox is a rare viral infection, endemic in many central and western African countries. The last international outbreak of monkeypox reported outside Africa occurred back in 2003. However, monkeypox has reemerged at a global scale with numerous confirmed cases across the globe in 2022. The rapid spread of cases through different countries has raised serious concerns among public health officials worldwide prompting accelerated investigations aimed to identify the origins and cause of the rapid expansion of cases. The current situation is reminiscent of the very early stages of the still ongoing COVID-19 pandemic. Overlapping features between these, two seemingly alike viral entities include the possibility for airborne transmission and the currently unexplained and rapid spread across borders. Early recognition of cases and timely intervention of potential transmission chains are necessary to contain further outbreaks. Measures should include rapid and accurate diagnosis of cases meeting case definitions, active surveillance efforts, and appropriate containment of confirmed cases. Governments and health policymakers must apply lessons learned from previous outbreaks and start taking active steps toward limiting the recent global spread of monkeypox. Herein, we discuss the status of the current monkeypox outbreaks worldwide, the epidemiological and public health situation at a global scale and what can be done to keep at bay its further expansion and future global implications.

Increased outbreaks of monkeypox highlight gaps in actual disease burden in Sub-Saharan Africa and in animal reservoirs

We explain research gaps on Monkeypox (MPX) virus epidemiology in endemic countries and present hypotheses for the recent increase of MPX cases in West Africa as a possible explanation for the current epidemic in Europe, America, and Australia. The detection of >400 MPX cases in less than a month in May 2022, across many countries underscores the epidemic potential of MPX in humans and demonstrates several important research gaps. First, the true burden of MPX in West and Central Africa is poorly understood, although it is critical for prevention and control of future outbreaks. Second, the diversity and extent of the animal reservoir remain unknown. We hypothesize that the synanthropic rodent population has increased in recent years in Africa leading to more human-rodent interactions and thus increased transmission of MPXV. We further hypothesise that nearly 45 years after the end of routine smallpox vaccination, the larger and more interconnected immune-naïve population has crossed a threshold resulting in more sustainable human-to-human transmission of MPXV. The current epidemic in the Western World is possibly a consequence of increased local transmission of MPXV in Africa. A new estimation of the basic and effective reproduction rate (R0 and Re) in different populations is required. National, regional, and international collaborations are needed to address research gaps related to MPX outbreaks.

Comparison of Transcriptomic Signatures between Monkeypox-Infected Monkey and Human Cell Lines

Monkeypox virus (MPV) is a smallpox-like virus belonging to the genus Orthopoxvirus of the family Poxviridae. Unlike smallpox with no animal reservoir identified and patients suffering from milder symptoms with less mortality, several animals were confirmed to serve as natural hosts of MPV. The reemergence of a recently reported monkeypox epidemic outbreak in nonendemic countries has raised concerns about a global outburst. Since the underlying mechanism of animal-to-human transmission remains largely unknown, comprehensive analyses to discover principal differences in gene signatures during disease progression have become ever more critical. In this study, two MPV-infected in vitro models, including human immortal epithelial cancer (HeLa) cells and rhesus monkey (Macaca mulatta) kidney epithelial (MK2) cells, were chosen as the two subjects to identify alterations in gene expression profiles, together with co-regulated genes and pathways that are affected during monkeypox disease progression. Using Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and MetaCore analyses, we discovered that elevated expression of genes associated with interleukins (ILs), G protein-coupled receptors (GPCRs), heat shock proteins (HSPs), Toll-like receptors (TLRs), and metabolic-related pathways play major roles in disease progression of both monkeypox-infected monkey MK2 and human HeLa cell lines. Interestingly, our analytical results also revealed that a cluster of differentiation 40 (CD40), plasmin, and histamine served as major regulators in the monkeypox-infected monkey MK2 cell line model, while interferons (IFNs), macrophages, and neutrophil-related signaling pathways dominated the monkeypox-infected human HeLa cell line model. Among immune pathways of interest, apart from traditional monkeypox-regulated signaling pathways such as nuclear factor- (NF-κB), mitogen-activated protein kinases (MAPKs), and tumor necrosis factors (TNFs), we also identified highly significantly expressed genes in both monkey and human models that played pivotal roles during the progression of monkeypox infection, including CXCL1, TNFAIP3, BIRC3, IL6, CCL2, ZC3H12A, IL11, CSF2, LIF, PTX3, IER3, EGR1, ADORA2A, and DUOX1, together with several epigenetic regulators, such as histone cluster family gene members, HIST1H3D, HIST1H2BJ, etc. These findings might contribute to specific underlying mechanisms related to the pathophysiology and provide suggestions regarding modes of transmission, post-infectious sequelae, and vaccine development for monkeypox in the future.

Human Monkeypox: A Comprehensive Narrative Review and Analysis of the Public Health Implications

Recently, numerous cases of monkeypox were reported from several non-endemic countries in Europe, North America, and Oceania, suggesting an unusual and alarming public health issue, particularly considering that the disease is not directly related to human or animal travels. Attention is currently being drawn to this phenomenon since more than 70% of the global population is no longer vaccinated against smallpox. Indeed, the smallpox vaccination also confers some indirect degree of protection against other poxviruses, including monkeypox. We performed a narrative review to describe the existing literature with regard to monkeypox using the MEDLINE, EMBASE, and Scopus databases. This review aims to provide updated evidence of findings on the epidemiology, clinical features, diagnosis, management, and prevention of monkeypox, also considering the concurrent zoonotic pandemic caused by the COVID-19 coronavirus, SARS-CoV-2.

The presumed receptivity and susceptibility to monkeypox of European animal species

The Monkeypox virus belongs to the Orthopoxvius genus, as does the specifically human smallpox virus. It is zoonotic and had never previously been considered as capable of human-to-human transmission over more than nine viral generation cycles. While relevant animal reservoirs have yet to be identified, non-human primates (NHP) are only accidental hosts. The potentially high number of current human shedders during the clinical phase (3 weeks maximum) raises the question of a risk in our countries of animals being contaminated by infected humans (reverse zoonosis). Cats as well as cows are susceptible to the Cowpox virus, another zoonotic Orthopoxvirus, which they transmit to humans. Dogs are much less susceptible to this virus and seem only receptive to Vaccinia virus (also belonging to the Orthopoxvirus genus). On the other hand, one study has demonstrated the pronounced susceptibility of the adult albino rabbit and of young animals of several rodent species to Monkeypox virus (MPXV). Given the susceptibility to MPXV of prairie dogs, which are American Sciuridae, the potential for infection of European squirrels cannot be ruled out.

Monkeypox virus: a re-emergent threat to humans

Human monkeypox (MPX) is a rare zoonotic infection characterized by smallpox-like signs and symptoms. It is caused by monkeypox virus (MPXV), a double stranded DNA virus belonging to the genus Orthopoxvirus. MPX was first identified in 1970 and mostly prevailed in the rural rainforests of Central and West Africa in the past. Outside Africa, MPX was reported in the United Kingdom, the USA, Israel, and Singapore. In 2022, the resurgence of MPX in Europe and elsewhere posed a potential threat to humans. MPXV was transmitted by the animals-human or human-human pathway, and the symptoms of MPXV infection are similar to that of smallpox, but in a milder form and with lower mortality (1%-10%). Although the smallpox vaccination has been shown to provide 85% protection against MPXV infection, and two anti-smallpox virus drugs have been approved to treat MPXV, there are still no specific vaccines and drugs against MPXV infection. Therefore it is urgent to take active measures including the adoption of novel anti-MPXV strategies to control the spread of MPXV and prevent MPX epidemic. In this review, we summarize the biological features, epidemiology, pathogenicity, laboratory diagnosis, and prevention and treatment strategies on MPXV. This review provides the basic knowledge for prevention and control of future outbreaks of this emerging infection.

Tecovirimat for the treatment of human monkeypox: an initial series from Massachusetts, United States

A large, ongoing multicountry outbreak of human monkeypox has the potential to cause considerable morbidity and mortality. Therapeutics for the treatment of smallpox, a related Orthopoxvirus, may be used and affect the natural history of monkeypox. We present 3 patients from our hospitals treated with tecovirimat, a pan-Orthopoxvirus inhibitor currently available under an expanded access investigational new drug protocol for monkeypox.

[Learning from the past: the history of human monkeypox and the atypical multi-country outbreak in 2022]

In 2022, the outbreak of human monkeypox (HMPX) occurred in many non-endemic countries. World Health Organization (WHO) assesses that this outbreak is "atypical". The history of monkeypox and HMPX must be reviewed to clearly recognize the "typical" outbreaks to fully understand this comment. Therefore, this paper reviews the epidemiological history of monkeypox, especially HMPX, and discusses and analyzes the atypical manifestations and the possible causes of the present outbreak based on the recent views of WHO, other organizations/institutions, and experts. The text describes the thought-provoking history of the interaction between the monkeypox virus and the human being in the past 64 years, and provides various information and views on the outbreak of HMPX, which is helpful to understand risk assessment and the potential impact of this outbreak on clinical and public health in future.

When a Neglected Tropical Disease Goes Global: Knowledge, Attitudes and Practices of Italian Physicians towards Monkeypox, Preliminary Results

Monkeypox (MPX) has been regarded as a neglected tropic disease of Western and Central Africa since the early 70s. However, during May 2022, an unprecedent outbreak of MPX has involved most of European Countries, as well as North and South America. While the actual extent of this outbreak is being assessed by health authorities, we performed a pilot study on specific knowledge, attitudes, and practices (KAP) in a sample of Italian medical professionals (24-30 May 2022; 10,293 potential recipients), focusing on Occupational Physicians (OP), Public Health Professionals (PH), and General Practitioners (GP), i.e., medical professionals more likely involved in the early management of incident cases. More specifically, we inquired into their attitude on the use of variola vaccine in order to prevent MPX infection. From a total of 566 questionnaire (response rate of 5.5%), 163 participants were included in the final analyses. Knowledge status was quite unsatisfying, with substantial knowledge gaps on all aspect of MPX. In turn, analysis of risk perception suggested a substantial overlooking of MPX as a pathogen, particularly when compared to SARS-CoV-2, TB, HIV, and HBV. Overall, 58.6% of respondents were somehow favorable to implement variola vaccination in order to prevent MPX, and the main effectors of this attitude were identified in having been previously vaccinated against seasonal influenza (adjusted Odds Ratio [aOR] 6.443, 95% Confidence Interval [95%CI] 1.798-23.093), and being favorable to receive variola vaccine (aOR 21.416; 95%CI 7.290-62.914). In summary, the significant extent of knowledge gaps and the erratic risk perception, associated collectively stress the importance of appropriate information campaigns among first-line medical professionals.

Frequent detection of monkeypox virus DNA in saliva, semen, and other clinical samples from 12 patients, Barcelona, Spain, May to June 2022

A monkeypox (MPX) outbreak has expanded worldwide since May 2022. We tested 147 clinical samples collected at different time points from 12 patients by real-time PCR. MPX DNA was detected in saliva from all cases, sometimes with high viral loads. Other samples were frequently positive: rectal swab (11/12 cases), nasopharyngeal swab (10/12 cases), semen (7/9 cases), urine (9/12 cases) and faeces (8/12 cases). These results improve knowledge on virus shedding and the possible role of bodily fluids in disease transmission.

Frequent detection of monkeypox virus DNA in saliva, semen, and other clinical samples from 12 patients, Barcelona, Spain, May to June 2022

A monkeypox (MPX) outbreak has expanded worldwide since May 2022. We tested 147 clinical samples collected at different time points from 12 patients by real-time PCR. MPX DNA was detected in saliva from all cases, sometimes with high viral loads. Other samples were frequently positive: rectal swab (11/12 cases), nasopharyngeal swab (10/12 cases), semen (7/9 cases), urine (9/12 cases) and faeces (8/12 cases). These results improve knowledge on virus shedding and the possible role of bodily fluids in disease transmission.

The outbreak of monkeypox 2022: An overview

On May 6, 2022 an outbreak of monkeypox (MPX) was confirmed in the United Kingdom, originating from a British resident who had travelled to Nigeria. As of May 21, 2022, 92 cases have been confirmed worldwide, from 13 countries where monkeypox virus (MPXV) is not endemic. Reported cases thus far have mainly but not exclusively been identified among gay and bisexual men aged 20–50. MPXV is a viral zoonosis transmitted to humans via contacting or eating an infected animal, and direct connect with natural host's blood and body fluids. In addition to contacting with a patient's respiratory droplets, lesions, body fluids and polluted personal objects. Symptoms including shivers, headaches, fainting, backaches, and myodynia do not have any specific characteristics making it difficult to establish a proper diagnosis. Nevertheless, lymphatic hyperplasia, one of the most common symptoms of monkeypox, can be useful for diagnosing the disease. Clinical symptoms help establish the suspicion of monkeypox. However, in the absence of confirmed diagnostic tests it is very difficult to verify the disease and determine its cause based on clinical symptoms alone. There are numerous methods for detecting MPX, involving genetic, phenotypic, immunological methods, and electron microscopy. These tests require modern equipment and expert hands, which may not be available in developing countries where this disease is prevalent. Currently, there is no definite treatment for MPX. CDC recommends administering the smallpox vaccine within 4 days of exposure which may prevent the disease from happening, and within 2 weeks to reduce symptoms severity. To promptly identify patients and prevent further spreading, physicians should be aware of the travel or contact history of the patient with compatible symptoms.

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On May 6, 2022 an outbreak of monkeypox (MPX) was confirmed in the United Kingdom, originating from a British resident who had travelled to Nigeria.

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As of May 21, 2022, 92 cases have been confirmed worldwide, from 13 countries where monkeypox virus (MPXV) is not endemic.

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MPXV is a viral zoonosis transmitted to humans via contacting or eating an infected animal, and direct connect with natural host's blood and body fluids. In addition to contacting with a patient's respiratory droplets, lesions, body fluids and polluted personal objects.

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Symptoms do not have any specific characteristics. Nevertheless, lymphatic hyperplasia, one of the most common symptoms of monkeypox, can be useful for diagnosing the disease.

Enhancing the Immunogenicity of Vaccinia Virus

The conventional live smallpox vaccine based on the vaccinia virus (VACV) cannot be widely used today because it is highly reactogenic. Therefore, there is a demand for designing VACV variants possessing enhanced immunogenicity, making it possible to reduce the vaccine dose and, therefore, significantly eliminate the pathogenic effect of the VACV on the body. In this study, we analyzed the development of the humoral and T cell-mediated immune responses elicited by immunizing mice with low-dose VACV variants carrying the mutant A34R gene (which increases production of extracellular virions) or the deleted A35R gene (whose protein product inhibits antigen presentation by the major histocompatibility complex class II). The VACV LIVP strain, which is used as a smallpox vaccine in Russia, and its recombinant variants LIVP-A34R*, LIVP-dA35R, and LIVP-A34R*-dA35R, were compared upon intradermal immunization of BALB/c mice at a dose of 10⁴ pfu/animal. The strongest T cell-mediated immunity was detected in mice infected with the LIVP-A34R*-dA35R virus. The parental LIVP strain induced a significantly lower antibody level compared to the strains carrying the modified A34R and A35R genes. Simultaneous modification of the A34R gene and deletion of the A35R gene in VACV LIVP synergistically enhanced the immunogenic properties of the LIVP-A34R*-dA35R virus.

Preparedness for a monkeypox outbreak

In light of the ongoing COVID-19 pandemic, the unexpected outbreak and worldwide spread of monkeypox has gained global attention. As of June 22, 2022, there were 3340 confirmed cases of monkeypox globally, which is the largest and most widespread monkeypox epidemic outside Africa. Monkeypox virus (MPXV) is transmitted from human-to-human through direct contact with infectious skin or mucosal skin lesions, respiratory droplets, or indirect contact with contaminated objects or materials, as well as mother-to-child vertical transmission. It is also possibly sexually transmitted through semen/vaginal fluid, and the possibility of community transmission cannot be ruled out. Monkeypox is a viral zoonotic disease caused by MPXV, which is an enveloped, linear, double-stranded DNA virus belonging to the Orthopoxvirus genus, of the Chordopoxvirinae subfamily, within the Poxviridae family. Monkeypox is usually a self-limiting infection, with symptoms lasting 2-4 weeks, and has a fatality rate that has historically fluctuated from 0% to 11%. Symptoms of monkeypox include intense headaches, fever, lesions, and lymphadenopathy. Although there is no specific treatment or vaccine for MPXV infection, antiviral drugs and vaccines for smallpox have been approved for use in several countries in response to the monkeypox outbreak. Before the virus can be allowed to establish efficient person-to-person transmission, rapid action must be taken to contain the local spread and, by extension, the multi-country outbreak of monkeypox.

Monkeypox in a Traveler Returning from Nigeria - Dallas, Texas, July 2021

Monkeypox is a rare, sometimes life-threatening zoonotic infection that occurs in west and central Africa. It is caused by Monkeypox virus, an orthopoxvirus similar to Variola virus (the causative agent of smallpox) and Vaccinia virus (the live virus component of orthopoxvirus vaccines) and can spread to humans. After 39 years without detection of human disease in Nigeria, an outbreak involving 118 confirmed cases was identified during 2017-2018 (1); sporadic cases continue to occur. During September 2018-May 2021, six unrelated persons traveling from Nigeria received diagnoses of monkeypox in non-African countries: four in the United Kingdom and one each in Israel and Singapore. In July 2021, a man who traveled from Lagos, Nigeria, to Dallas, Texas, became the seventh traveler to a non-African country with diagnosed monkeypox. Among 194 monitored contacts, 144 (74%) were flight contacts. The patient received tecovirimat, an antiviral for treatment of orthopoxvirus infections, and his home required large-scale decontamination. Whole genome sequencing showed that the virus was consistent with a strain of Monkeypox virus known to circulate in Nigeria, but the specific source of the patient's infection was not identified. No epidemiologically linked cases were reported in Nigeria; no contact received postexposure prophylaxis (PEP) with the orthopoxvirus vaccine ACAM2000.

The changing epidemiology of human monkeypox-A potential threat? A systematic review

Monkeypox, a zoonotic disease caused by an orthopoxvirus, results in a smallpox-like disease in humans. Since monkeypox in humans was initially diagnosed in 1970 in the Democratic Republic of the Congo (DRC), it has spread to other regions of Africa (primarily West and Central), and cases outside Africa have emerged in recent years. We conducted a systematic review of peer-reviewed and grey literature on how monkeypox epidemiology has evolved, with particular emphasis on the number of confirmed, probable, and/or possible cases, age at presentation, mortality, and geographical spread. The review is registered with PROSPERO (CRD42020208269). We identified 48 peer-reviewed articles and 18 grey literature sources for data extraction. The number of human monkeypox cases has been on the rise since the 1970s, with the most dramatic increases occurring in the DRC. The median age at presentation has increased from 4 (1970s) to 21 years (2010-2019). There was an overall case fatality rate of 8.7%, with a significant difference between clades-Central African 10.6% (95% CI: 8.4%- 13.3%) vs. West African 3.6% (95% CI: 1.7%- 6.8%). Since 2003, import- and travel-related spread outside of Africa has occasionally resulted in outbreaks. Interactions/activities with infected animals or individuals are risk behaviors associated with acquiring monkeypox. Our review shows an escalation of monkeypox cases, especially in the highly endemic DRC, a spread to other countries, and a growing median age from young children to young adults. These findings may be related to the cessation of smallpox vaccination, which provided some cross-protection against monkeypox, leading to increased human-to-human transmission. The appearance of outbreaks beyond Africa highlights the global relevance of the disease. Increased surveillance and detection of monkeypox cases are essential tools for understanding the continuously changing epidemiology of this resurging disease.

The Past, Present, and Future of Monkeypox: A Rapid Review Regarding Prevalence and Prevention

While monkeypox virus (MPXV) remained endemic in central and western African countries, a sudden unusual spike of global cases among non-endemic countries is an enigma for scientists. With 257 cases reported as of 26th May 2021, a multi-country outbreak of monkeypox has been declared in countries including the UK, EU/EEA states, and North America. Even though the likelihood of transmissibility of MPXV is limited compared to COVID-19, yet a coordinated multidisciplinary effort is required to prevent any further global expansion. Few appropriate responsive approaches to contain the infection could be; limiting the contact with potential animal reservoirs, isolation of confirmed cases, using PPEs to prevent human-human transmission, awareness activities, and administration of pre and post prophylactic vaccination. In this review, we have discussed the previous and current outbreaks of MPXV along with the abrupt actions that are needed to address the situation.

A narrative review of pox: smallpox vs monkeypox

The famed variola (smallpox) virus and the monkeypox virus (MPXV) are closely related, and MPXV causes a milder form of febrile rash disease in people. Human monkeypox was mostly an uncommon zoonotic illness that was restricted to West and Central African wooded areas in the twentieth century. The global population’s smallpox vaccine-induced immunity, however, has started to decrease as the number of cases and the geographic breadth have both increased significantly in this century. Several countries have seen human monkeypox outbreaks since May 2022. A possible shift in the monkeypox transmission pattern that might represent a bigger worldwide danger is raised by the atypical nature of these outbreaks, which are characterized by their high-case numbers and absence of ties to endemic countries. Here, we explore a wide range of MPXV biology topics.

Transmission dynamics of Monkeypox virus: a mathematical modelling approach

Monkeypox (MPX), similar to both smallpox and cowpox, is caused by the monkeypox virus (MPXV). It occurs mostly in remote Central and West African communities, close to tropical rain forests. It is caused by the monkeypox virus in the Poxviridae family, which belongs to the genus Orthopoxvirus. We develop and analyse a deterministic mathematical model for the monkeypox virus. Both local and global asymptotic stability conditions for disease-free and endemic equilibria are determined. It is shown that the model undergo backward bifurcation, where the locally stable disease-free equilibrium co-exists with an endemic equilibrium. Furthermore, we determine conditions under which the disease-free equilibrium of the model is globally asymptotically stable. Finally, numerical simulations to demonstrate our findings and brief discussions are provided. The findings indicate that isolation of infected individuals in the human population helps to reduce disease transmission.

Family cluster of three cases of monkeypox imported from Nigeria to the United Kingdom, May 2021

Most reported cases of human monkeypox occur in Central and West Africa, where the causing virus is endemic. We describe the identification and public health response to an imported case of West African monkeypox from Nigeria to the United Kingdom (UK) in May 2021. Secondary transmission from the index case occurred within the family to another adult and a toddler. Concurrent COVID-19-related control measures upon arrival and at the hospital, facilitated detection and limited the number of potential contacts.