Molecular Evidence of Human Monkeypox Virus Infection, Sierra Leone

The Peculiar Emergence of Mpox (Monkeypox): Directions for the Search for the Natural Reservoir and Vaccination Strategies

Background/Objectives: Mpox (monkeypox) is a zoonosis with origins in a currently unknown African reservoir. The first epidemiological accounts of mpox date back to the early 1980s, yet mpox only emerged as a pandemic threat in 2022-2023, more than 40 years later. This scenario is very different from those of other emerging diseases such as HIV and SARS, which immediately spread globally, in fully susceptible populations, starting from patients zero. Methods: We use mathematical modeling to illustrate the dynamics of mpox herd immunity in small communities in touch with the mpox natural reservoir. In particular, we employ an SEIR stochastic model. Results: The peculiar emergence of mpox can be explained by its relationship with smallpox, which was eradicated through universal mass vaccination in 1980. Mpox first emerged in small rural communities in touch with mpox's animal reservoir and then spread globally. The relative isolation of these communities and their herd-immunity dynamics against mpox worked to delay the introduction of mpox in large urban centers. Conclusions: Mathematical modeling suggests that the search for the mpox animal reservoir would be most fruitful in communities with high mpox seroprevalence and small outbreaks. These are communities is tight contact with the mpox natural reservoir. We propose vaccinating individuals in communities in these communities to severely reduce the importation of cases elsewhere.

A comprehensive review of monkeypox virus and mpox characteristics

Monkeypox virus (MPXV) is the etiological agent of monkeypox (mpox), a zoonotic disease. MPXV is endemic in the forested regions of West and Central Africa, but the virus has recently spread globally, causing outbreaks in multiple non-endemic countries. In this paper, we review the characteristics of the virus, including its ecology, genomics, infection biology, and evolution. We estimate by phylogenomic molecular clock that the B.1 lineage responsible for the 2022 mpox outbreaks has been in circulation since 2016. We interrogate the host-virus interactions that modulate the virus infection biology, signal transduction, pathogenesis, and host immune responses. We highlight the changing pathophysiology and epidemiology of MPXV and summarize recent advances in the prevention and treatment of mpox. In addition, this review identifies knowledge gaps with respect to the virus and the disease, suggests future research directions to address the knowledge gaps, and proposes a One Health approach as an effective strategy to prevent current and future epidemics of mpox.

Monkeypox: Past, Present, and Future

Monkeypox (Mpox) is a zoonotic disease caused by a virus (monkeypox virus-MPV) belonging to the Poxviridae family. In humans, the disease has an incubation period of 5-21 days and then progresses in two phases, the prodromal phase and the rash phase. The prodromal phase is characterized by non-specific symptoms such as fever, muscle pain, malaise, lymphadenopathy, headache, and chills. Skin lesions appear in the rash phase of the disease. These lesions progress through different stages (macules, papules, vesicles, and pustules). In May 2022, WHO reported an outbreak of human Mpox in several countries which were previously Mpox-free. As per the CDC report of March 01, 2023, a total of 86,231 confirmed cases of Mpox and 105 deaths have been reported from 110 countries and territories across the globe. Notably, more than 90% of these countries were reporting Mpox for the first time. The phylogenetic analysis revealed that this outbreak was associated with the virus from the West African clade. However, most of the cases in this outbreak had no evidence of travel histories to MPV-endemic countries in Central or West Africa. This outbreak was primarily driven by the transmission of the virus via intimate contact in men who have sex with men (MSM). The changing epidemiology of Mpox raised concerns about the increasing spread of the disease in non-endemic countries and the urgent need to control and prevent it. In this chapter, we present all the documented cases of Mpox from 1970 to 2023 and discuss the past, present, and future of MPV.

Pathogenicity and virulence of monkeypox at the human-animal-ecology interface

Monkeypox (Mpox) was mostly limited to Central and Western Africa, but recently it has been reported globally. The current review presents an update on the virus, including ecology and evolution, possible drivers of transmission, clinical features and management, knowledge gaps, and research priorities to reduce the disease transmission. The origin, reservoir(s) and the sylvatic cycle of the virus in the natural ecosystem are yet to be confirmed. Humans acquire the infection through contact with infected animals, humans, and natural hosts. The major drivers of disease transmission include trapping, hunting, bushmeat consumption, animal trade, and travel to endemic countries. However, in the 2022 epidemic, the majority of the infected humans in non-endemic countries had a history of direct contact with clinical or asymptomatic persons through sexual activity. The prevention and control strategies should include deterring misinformation and stigma, promoting appropriate social and behavioural changes, including healthy life practices, instituting contact tracing and management, and using the smallpox vaccine for high-risk people. Additionally, longer-term preparedness should be emphasized using the One Health approach, such as systems strengthening, surveillance and detection of the virus across regions, early case detection, and integrating measures to mitigate the socio-economic effects of outbreaks.

An Updated Review on Monkeypox Viral Disease: Emphasis on Genomic Diversity

Monkeypox virus has remained the most virulent poxvirus since the elimination of smallpox approximately 41 years ago, with distribution mostly in Central and West Africa. Monkeypox (Mpox) in humans is a zoonotically transferred disease that results in a smallpox-like disease. It was first diagnosed in 1970 in the Democratic Republic of the Congo (DRC), and the disease has spread over West and Central Africa. The purpose of this review was to give an up-to-date, thorough, and timely overview on the genomic diversity and evolution of a re-emerging infectious disease. The genetic profile of Mpox may also be helpful in targeting new therapeutic options based on genes, mutations, and phylogeny. Mpox has become a major threat to global health security, necessitating a quick response by virologists, veterinarians, public health professionals, doctors, and researchers to create high-efficiency diagnostic tests, vaccinations, antivirals, and other infection control techniques. The emergence of epidemics outside of Africa emphasizes the disease's global significance. Increased monitoring and identification of Mpox cases are critical tools for obtaining a better knowledge of the ever-changing epidemiology of this disease.

Overview of Diagnostic Methods, Disease Prevalence and Transmission of Mpox (Formerly Monkeypox) in Humans and Animal Reservoirs

Mpox-formerly monkeypox-is a re-emerging zoonotic virus disease, with large numbers of human cases reported during multi-country outbreaks in 2022. The close similarities in clinical symptoms that Mpox shares with many orthopoxvirus (OPXV) diseases make its diagnosis challenging, requiring laboratory testing for confirmation. This review focuses on the diagnostic methods used for Mpox detection in naturally infected humans and animal reservoirs, disease prevalence and transmission, clinical symptoms and signs, and currently known host ranges. Using specific search terms, up to 2 September 2022, we identified 104 relevant original research articles and case reports from NCBI-PubMed and Google Scholar databases for inclusion in the study. Our analyses observed that molecular identification techniques are overwhelmingly being used in current diagnoses, especially real-time PCR (3982/7059 cases; n = 41 studies) and conventional PCR (430/1830 cases; n = 30 studies) approaches being most-frequently-used to diagnose Mpox cases in humans. Additionally, detection of Mpox genomes, using qPCR and/or conventional PCR coupled to genome sequencing methods, offered both reliable detection and epidemiological analyses of evolving Mpox strains; identified the emergence and transmission of a novel clade 'hMPXV-1A' lineage B.1 during 2022 outbreaks globally. While a few current serologic assays, such as ELISA, reported on the detection of OPXV- and Mpox-specific IgG (891/2801 cases; n = 17 studies) and IgM antibodies (241/2688 cases; n = 11 studies), hemagglutination inhibition (HI) detected Mpox antibodies in human samples (88/430 cases; n = 6 studies), most other serologic and immunographic assays used were OPXV-specific. Interestingly, virus isolation (228/1259 cases; n = 24 studies), electron microscopy (216/1226 cases; n = 18 studies), and immunohistochemistry (28/40; n = 7 studies) remain useful methods of Mpox detection in humans in select instances using clinical and tissue samples. In animals, OPXV- and Mpox-DNA and antibodies were detected in various species of nonhuman primates, rodents, shrews, opossums, a dog, and a pig. With evolving transmission dynamics of Mpox, information on reliable and rapid detection methods and clinical symptoms of disease is critical for disease management.

Demographic, Epidemiologic, and Clinical Characteristics of Human Monkeypox Disease Pre- and Post-2022 Outbreaks: A Systematic Review and Meta-Analysis

(1) Background: In early May 2022, an increasing number of human monkeypox (mpox) cases were reported in non-endemic disparate regions of the world, which raised concerns. Here, we provide a systematic review and meta-analysis of mpox-confirmed patients presented in peer-reviewed publications over the 10 years before and during the 2022 outbreak from demographic, epidemiological, and clinical perspectives. (2) Methods: A systematic search was performed for relevant studies published in Pubmed/Medline, Embase, Scopus, and Google Scholar from 1 January 2012 up to 15 February 2023. Pooled frequencies with 95% confidence intervals (CIs) were assessed using the random or fixed effect model due to the estimated heterogeneity of the true effect sizes. (3) Results: Out of 10,163 articles, 67 met the inclusion criteria, and 31 cross-sectional studies were included for meta-analysis. Animal-to-human transmission was dominant in pre-2022 cases (61.64%), but almost all post-2022 reported cases had a history of human contact, especially sexual contact. The pooled frequency of MSM individuals was 93.5% (95% CI 91.0-95.4, I2: 86.60%) and was reported only in post-2022 included studies. The male gender was predominant in both pre- and post-2022 outbreaks, and the mean age of confirmed cases was 29.92 years (5.77-41, SD: 9.38). The most common clinical manifestations were rash, fever, lymphadenopathy, and malaise/fatigue. Proctalgia/proctitis (16.6%, 95% CI 10.3-25.6, I2: 97.76) and anal/perianal lesions (39.8%, 95% CI 30.4-49.9, I2: 98.10) were the unprecedented clinical manifestations during the 2022 outbreak, which were not described before. Genitalia involvement was more common in post-2022 mpox patients (55.6%, 95% CI 51.7-59.4, I2: 88.11). (4) Conclusions: There are speculations about the possibility of changes in the pathogenic properties of the virus. It seems that post-2022 mpox cases experience a milder disease with fewer rashes and lower mortality rates. Moreover, the vast majority of post-2022 cases are managed on an outpatient basis. Our study could serve as a basis for ongoing investigations to identify the different aspects of previous mpox outbreaks and compare them with the current ones.

Identifying the Most Probable Mammal Reservoir Hosts for Monkeypox Virus Based on Ecological Niche Comparisons

Previous human cases or epidemics have suggested that Monkeypox virus (MPXV) can be transmitted through contact with animals of African rainforests. Although MPXV has been identified in many mammal species, most are likely secondary hosts, and the reservoir host has yet to be discovered. In this study, we provide the full list of African mammal genera (and species) in which MPXV was previously detected, and predict the geographic distributions of all species of these genera based on museum specimens and an ecological niche modelling (ENM) method. Then, we reconstruct the ecological niche of MPXV using georeferenced data on animal MPXV sequences and human index cases, and conduct overlap analyses with the ecological niches inferred for 99 mammal species, in order to identify the most probable animal reservoir. Our results show that the MPXV niche covers three African rainforests: the Congo Basin, and Upper and Lower Guinean forests. The four mammal species showing the best niche overlap with MPXV are all arboreal rodents, including three squirrels: Funisciurus anerythrus, Funisciurus pyrropus, Heliosciurus rufobrachium, and Graphiurus lorraineus. We conclude that the most probable MPXV reservoir is F. anerythrus based on two niche overlap metrics, the areas of higher probabilities of occurrence, and available data on MPXV detection.

Temporal dynamic characteristics of human monkeypox epidemic in 2022 around the world under the COVID-19 pandemic background

Background

The reemergence of the monkeypox epidemic has aroused great concern internationally. Concurrently, the COVID-19 epidemic is still ongoing. It is essential to understand the temporal dynamics of the monkeypox epidemic in 2022 and its relationship with the dynamics of the COVID-19 epidemic. In this study, we aimed to explore the temporal dynamic characteristics of the human monkeypox epidemic in 2022 and its relationship with those of the COVID-19 epidemic.

Methods

We used publicly available data of cumulative monkeypox cases and COVID-19 in 2022 and COVID-19 at the beginning of 2020 for model validation and further analyses. The time series data were fitted with a descriptive model using the sigmoid function. Two important indices (logistic growth rate and semi-saturation period) could be obtained from the model to evaluate the temporal characteristics of the epidemic.

Results

As for the monkeypox epidemic, the growth rate of infection and semi-saturation period showed a negative correlation (r = 0.47, p = 0.034). The growth rate also showed a significant relationship with the locations of the country in which it occurs [latitude (r = -0.45, p = 0.038)]. The development of the monkeypox epidemic did not show significant correlation compared with the that of COVID-19 in 2020 and 2022. When comparing the COVID-19 epidemic with that of monkeypox, a significantly longer semi-saturation period was observed for monkeypox, while a significant larger growth rate was found in COVID-19 in 2020.

Conclusions

This novel study investigates the temporal dynamics of the human monkeypox epidemic and its relationship with the ongoing COVID-19 epidemic, which could provide more appropriate guidance for local governments to plan and implement further fit-for-purpose epidemic prevention policies.

Risk of Monkeypox virus (MPXV) transmission through the handling and consumption of food

Monkeypox (MPX) is a zoonotic infectious disease caused by Monkeypox virus (MPXV), an enveloped DNA virus belonging to the Poxviridae family and the Orthopoxvirus genus. Since early May 2022, a growing number of human cases of Monkeypox have been reported in non-endemic countries, with no history of contact with animals imported from endemic and enzootic areas, or travel to an area where the virus usually circulated before May 2022. This qualitative risk assessment aimed to investigate the probability that MPXV transmission occurs through food during its handling and consumption. The risk assessment used "top-down" (based on epidemiological data) and "bottom-up" (following the agent through the food chain to assess the risk of foodborne transmission to human) approaches, which were combined. The "top-down" approach first concluded that bushmeat was the only food suspected as a source of contamination in recorded cases of MPXV, by contact or ingestion. The "bottom-up" approach then evaluated the chain of events required for a human to become ill after handling or consuming food. This approach involves several conditions: (i) the food must be contaminated with MPXV (naturally, by an infected handler or after contact with a contaminated surface); (ii) the food must contain viable virus when it reaches the handler or consumer; (iii) the person must be exposed to the virus and; (iv) the person must be infected after exposure. Throughout the risk assessment, some data gaps were identified and highlighted. The conclusions of the top-down and bottom-up approaches are consistent and suggest that the risk of transmission of MPXV through food is hypothetical and that such an occurrence was never reported. In case of contamination, cooking (e.g., 12 min at 70°C) could be considered effective in inactivating Poxviridae in foods. Recommendations for risk management are proposed. To our knowledge, this is the first risk assessment performed on foodborne transmission of MPXV.

Monkeypox: A Contemporary Review for Healthcare Professionals

The ongoing 2022 multicountry outbreak of monkeypox is the largest in history to occur outside of Africa. Monkeypox is an emerging zoonotic disease that for decades has been viewed as an infectious disease with significant epidemic potential because of the increasing occurrence of human outbreaks in recent years. As public health entities work to contain the current outbreak, healthcare professionals globally are aiming to become familiar with the various clinical presentations and management of this infection. We present in this review an updated overview of monkeypox for healthcare professionals in the context of the ongoing outbreaks around the world.

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.

Genomic history of human monkey pox infections in the Central African Republic between 2001 and 2018

Monkeypox is an emerging infectious disease, which has a clinical presentation similar to smallpox. In the two past decades, Central Africa has seen an increase in the frequency of cases, with many monkeypox virus (MPXV) isolates detected in the Democratic Republic of Congo (DRC) and the Central African Republic (CAR). To date, no complete MPXV viral genome has been published from the human cases identified in the CAR. The objective of this study was to sequence the full genome of 10 MPXV isolates collected during the CAR epidemics between 2001 and 2018 in order to determine their phylogenetic relationships among MPXV lineages previously described in Central Africa and West Africa. Our phylogenetic results indicate that the 10 CAR isolates belong to three lineages closely related to those found in DRC. The phylogenetic pattern shows that all of them emerged in the rainforest block of the Congo Basin. Since most human index cases in CAR occurred at the northern edge of western and eastern rainforests, transmissions from wild animals living in the rainforest is the most probable hypothesis. In addition, molecular dating estimates suggest that periods of intense political instability resulting in population movements within the country often associated also with increased poverty may have led to more frequent contact with host wild animals. The CAR socio-economic situation, armed conflicts and ecological disturbances will likely incite populations to interact more and more with wild animals and thus increase the risk of zoonotic spillover.

Pharmacokinetics and Efficacy of a Potential Smallpox Therapeutic, Brincidofovir, in a Lethal Monkeypox Virus Animal Model

Smallpox, caused by Variola virus (VARV), was eradicated in 1980; however, VARV bioterrorist threats still exist, necessitating readily available therapeutics. Current preparedness activities recognize the importance of oral antivirals and recommend therapeutics with different mechanisms of action. Monkeypox virus (MPXV) is closely related to VARV, causing a highly similar clinical human disease, and can be used as a surrogate for smallpox antiviral testing. The prairie dog MPXV model has been characterized and used to study the efficacy of antipoxvirus therapeutics, including recently approved TPOXX (tecovirimat). Brincidofovir (BCV; CMX001) has shown antiviral activity against double-stranded DNA viruses, including poxviruses. To determine the exposure of BCV following oral administration to prairie dogs, a pharmacokinetics (PK) study was performed. Analysis of BCV plasma concentrations indicated variability, conceivably due to the outbred nature of the animals. To determine BCV efficacy in the MPXV prairie dog model, groups of animals were intranasally challenged with 9 × 105 plaque-forming units (PFU; 90% lethal dose [LD90]) of MPXV on inoculation day 0 (ID0). Animals were divided into groups based on the first day of BCV treatment relative to inoculation day (ID-1, ID0, or ID1). A trend in efficacy was noted dependent upon treatment initiation (57% on ID-1, 43% on ID0, and 29% on ID1) but was lower than demonstrated in other animal models. Analysis of the PK data indicated that BCV plasma exposure (maximum concentration [Cmax]) and the time of the last quantifiable concentration (AUClast) were lower than in other animal models administered the same doses, indicating that suboptimal BCV exposure may explain the lower protective effect on survival.IMPORTANCE Preparedness activities against highly transmissible viruses with high mortality rates have been highlighted during the ongoing coronavirus disease 2019 (COVID-19) pandemic. Smallpox, caused by variola virus (VARV) infection, is highly transmissible, with an estimated 30% mortality. Through an intensive vaccination campaign, smallpox was declared eradicated in 1980, and routine smallpox vaccination of individuals ceased. Today's current population has little/no immunity against VARV. If smallpox were to reemerge, the worldwide results would be devastating. Recent FDA approval of one smallpox antiviral (tecovirimat) was a successful step in biothreat preparedness; however, orthopoxviruses can become resistant to treatment, suggesting the need for multiple therapeutics. Our paper details the efficacy of the investigational smallpox drug brincidofovir in a monkeypox virus (MPXV) animal model. Since brincidofovir has not been tested in vivo against smallpox, studies with the related virus MPXV are critical in understanding whether it would be protective in the event of a smallpox outbreak.

[B virus]

B virus is a herpes virus that natutaly infects macaque monkeys. It is extremely neuropathogenic when infection occurs in humans. B virus infection has been reported only in laboratory workers and breeders of macaque monkeys in North America and the United Kingdom, and it is therefore recognized as a rare infectious disease. The first cases of B virus disease were reported in Japan in 2019 and in China in 2021, although no cases had been reported since 1997. Although B virus disease has not been reported for more than 20 years, the potential threat has always existed. The viral factors responsible for the strong neuropathogenicity of B virus to humans has not been identified. There are no reports of infection by contact with wild macaque monkeys, but the possibility can not been ruled out. In this paper, we describe its virological properties, findings from B virus disease from patient-reported cases, and the genotype of B virus.