Human monkeypox: a study of 2,510 contacts of 214 patients

Human monkeypox: a comparison of the characteristics of the new epidemic to the endemic disease

In May 2022, a new global outbreak of mpox (formerly, human monkeypox) emerged that was declared a public health emergency of international concern by the World Health Organization on July 23, 2022. With new patterns of person-to-person spread within sexual networks in nonendemic countries and several differences from the classic disease course, we performed a comprehensive review of existing literature on human monkeypox to discuss epidemiology, modes of transmission, clinical presentation and asymptomatic infection, diagnostics, therapeutics, and vaccines with the primary aim to identify important areas for future research of this new epidemic form of the disease. A comprehensive literature search was performed of all published literature to August 15, 2022. Historically, in regions of monkeypox virus endemicity, human outbreaks have occurred related to discrete zoonotic events. The animal reservoir is unknown, but the virus has been isolated from rodents. Traditionally, transmission occurred by direct or indirect contact with an infected animal. In nonendemic countries affected in the 2022 outbreak, almost exclusive person-to-person spread has been observed, and most cases are connected to sexual networks of gay, bisexual, and other men who have sex with men. After an incubation period of approximately 13 days, in traditional human cases affected persons developed a febrile prodrome preceding a rash that started on the face and body, spread centrifugally to the palms and soles and healed monomorphically over two to four weeks. However, in the 2022 outbreak, the febrile illness is often absent or occurs after the onset of the rash. The rash presents primarily in the anogenital region and face before disseminating throughout the body, with lesions displaying regional pleomorphism. There is a paucity of data for the role of antiviral agents or vaccines. The epidemiology and clinical course of mpox has changed in the 2022 epidemic from that observed with the endemic disease. There is an urgent need to establish rapid and collaborative research platforms to diagnose, treat and prevent disease and inform important public health and other strategies to stop the spread of disease.

Global monkeypox case hospitalisation rates: A rapid systematic review and meta-analysis

BACKGROUND

Estimates of the case hospitalization rate and case fatality rate when hospital care is available for monkeypox (MPX) infections have not been well defined. This rapid systematic review and meta-analysis aimed to estimate the case hospitalisation rate and case fatality rate where hospital care is available.

METHODS

We systematically searched PubMed, Embase, the Lancet Preprints, and MedRxiv for studies published between Jan 1, 1950 and Aug 2, 2022. We included documents which contained both the number of cases and associated hospitalisations of MPX infections. From eligible studies we extracted the country, the year of the study, the study design type, the clade of MPX, the participant characteristics, transmission type, any treatments used, number of cases (including suspected, probable, or laboratory confirmed diagnosis), number of hospitalizations, hospitalized patient outcomes, and case definition. Case hospitalization rate (CHR) was defined as the proportion of cases that were admitted to hospital care while case fatality rate (CFR) was defined as the proportion of cases that died. CHR and CFR were analysed in a fully Bayesian meta-analytic framework using random effects models, including sub-group analysis with heterogeneity assessed using I².

FINDINGS

Of the 259 unique documents identified, 19 studies were eligible for inclusion. Included studies represented 7553 reported cases among which there were 555 hospitalizations. Of the 7540 cases for which outcomes were available, there were 15 recorded deaths. The median age of cases was 35 years (interquartile range 28-38, n = 2010) and primarily male (7339/7489, 98%) in studies where age or sex were available. Combined CHR was estimated to be 14.1% (95% credible interval, 7.5-25.0, I² 97.4%), with a high degree of heterogeneity. Further analysis by outbreak period indicates CHRs of 49.8% (28.2-74.0, I² 81.4%), 21.7% (7.2-52.1, I² 57.7%), and 5.8% (3.2-9.4, I² 92.4%) during the pre-2017, 2017-2021, and 2022 outbreaks, respectively, again with high levels of heterogeneity. CFR was estimated to be 0.03% (0.0-0.44, I² 99.9%), with evidence of large heterogeneity between the studies.

INTERPRETATION

There is limited data for MPX hospitalization rates in countries where MPX has been traditionally non-endemic until the current outbreak. Due to substantial heterogeneity, caution is needed when interpreting these findings. Health care organizations should be cognizant of the potential increase in healthcare utilization. Rapid identification of infection and use of appropriate therapies such as antivirals play a role reducing the CHR and associated CFR.

FUNDING

None.

Evolution, epidemiology, geographical distribution, and mutational landscape of newly emerging monkeypox virus

Recent monkeypox (MPX) outbreaks are major ones in non-endemic countries. The present study analyzed molecular phylogenetics, divergence, epidemiology, the geographical distribution, entropy diversity of genome, mutational landscape, and evolution of the monkeypox virus (MPXV) genome and the current MPXV is entitled "hMPXV1." We used different in-silico and statistical methods to study our objectives. The developed phylogram from molecular phylogenetics describes the origin and evolution of hMPXV1 of A, A.1, A.1.1, A.2, and B.1 lineages. The microevolution of B.1 lineage shows its evolution from May to August 2022. B.1 lineage is further adapting and showing more mutation and sub-lineages. The scatter plot of all lineages shows the clustering pattern of lineages and the divergence. We also developed two statistical models of confirmed cases and a diagram of the age-related pattern of infected cases to illustrate the epidemiology of the MPX outbreaks. The entropy diversity and mutational landscape of the hMPXV1 genome were analyzed in nucleotide and codon contexts. Our study has shown the in-depth evolution pattern of different lineages of the hMPXV1. We found B.1 lineage is associated with the current outbreaks. The mutational landscape informs about the slow mutation of the virus. Finally, the study might assists the new therapeutic development considering all the above points and would help the researcher to set up their future research directions.

Global Research Trends on Monkeypox Virus: A Bibliometric and Visualized Study

Monkeypox is a zoonotic viral disease that has recently emerged as another global infection disease. A double-stranded enveloped deoxyribonucleic acid virus the cause of this disease. Since monkeypox is an evolving field of study with a growing interest in public health, it is crucial to study the scientific trend and research activities. This study provides an essential insight into the research response to scientific trends of monkeypox using the bibliometric analysis technique. A literature search for published articles on LSD from 2001 to 2021 was conducted in Scopus on 24 July 2022. Visualization analysis was performed using R statistical software. The growth and trend of documents, country-level distribution of publications and collaborations, and the relationship between authors and co-authors were analyzed. Findings revealed a significant increase in the research conducted, mainly from the United States (US). The top 12 institutions published papers on the monkeypox virus, accounting for 33.09 percent of the articles. The US was the most productive nation, producing 275 documents (54.34%), or one-third of all publications in this sector worldwide. Centers for Disease Control and Prevention in Georgia in the United States were the organization that produced the most (365 publications). The Journal of Virology garnered the most citations, with an h-index of 18. In the last year, there has been an increase in the publication of monkeypox virus-related studies. The importance of the monkeypox virus highlights the necessity for continued research to help international health organizations identify areas that require prompt action to implement suitable solutions. This study also provides scaling-up analysis, evidence dissemination on the monkeypox virus, emerging hotspots, and perceptive remarks on the technological advances in this field.

Serological responses to the MVA-based JYNNEOS monkeypox vaccine in a cohort of participants from the Democratic Republic of Congo

The current worldwide monkepox outbreak has reaffirmed the continued threat monkeypox virus (MPXV) poses to public health. JYNNEOS, a Modified Vaccinia Ankara (MVA)-based live, non-replicating vaccine, was recently approved for monkeypox prevention for adults at high risk of MPXV infection in the United States. Although the safety and immunogenicity of JYNNEOS have been examined previously, the clinical cohorts studied largely derive from regions where MPXV does not typically circulate. In this study, we assess the quality and longevity of serological responses to two doses of JYNNEOS vaccine in a large cohort of healthcare workers from the Democratic Republic of Congo (DRC). We show that JYNNEOS elicits a strong orthopoxvirus (OPXV)-specific antibody response in participants that peaks around day 42, or 2 weeks after the second vaccine dose. Participants with no prior history of smallpox vaccination or exposure have lower baseline antibody levels, but experience a similar fold-rise in antibody titers by day 42 as those with a prior history of vaccination. Both previously naïve and vaccinated participants generate vaccinia virus and MPXV-neutralizing antibody in response to JYNNEOS vaccination. Finally, even though total OPXV-specific IgG titers and neutralizing antibody titers declined from their peak and returned close to baseline levels by the 2-year mark, most participants remain IgG seropositive at the 2-year timepoint. Taken together, our data demonstrates that JYNNEOS vaccination triggers potent OPXV neutralizing antibody responses in a cohort of healthcare workers in DRC, a monkeypox-endemic region. MPXV vaccination with JYNNEOS may help ameliorate the disease and economic burden associated with monkeypox and combat potential outbreaks in areas with active virus circulation.

Monkeypox: epidemiology, pathogenesis, treatment and prevention

Monkeypox is a zoonotic disease that was once endemic in west and central Africa caused by monkeypox virus. However, cases recently have been confirmed in many nonendemic countries outside of Africa. WHO declared the ongoing monkeypox outbreak to be a public health emergency of international concern on July 23, 2022, in the context of the COVID-19 pandemic. The rapidly increasing number of confirmed cases could pose a threat to the international community. Here, we review the epidemiology of monkeypox, monkeypox virus reservoirs, novel transmission patterns, mutations and mechanisms of viral infection, clinical characteristics, laboratory diagnosis and treatment measures. In addition, strategies for the prevention, such as vaccination of smallpox vaccine, is also included. Current epidemiological data indicate that high frequency of human-to-human transmission could lead to further outbreaks, especially among men who have sex with men. The development of antiviral drugs and vaccines against monkeypox virus is urgently needed, despite some therapeutic effects of currently used drugs in the clinic. We provide useful information to improve the understanding of monkeypox virus and give guidance for the government and relative agency to prevent and control the further spread of monkeypox virus.

The re-emerging monkeypox disease

BACKGROUND

On 7th May 2022, human monkeypox was identified in the United Kingdom, a non-endemic zone, with subsequent multi-country outbreaks. About 6 weeks later, the European Centre for Disease Prevention and Control reported 1158 confirmed cases in non-endemic countries scattered within the European Economic Area (EEA), and a total of 1882 cases confirmed worldwide, inclusive of the EEA. These numbers are expected to increase with high alert and amplified surveillance established in non-endemic regions. In light of a looming epidemic, current understanding of the virus, and identification of gaps in the literature remain critical hence warranting a scoping review of available literature.

METHODS

Literature searches were performed through PubMed, SCOPUS, ScienceDirect and Hinari to identify studies eligible for inclusion in accordance with PRISMA guidelines.

RESULTS

Seventy-seven articles were included in the review. Majority of the cases were from the Central African clade (n = 29,905) versus the West African clade (n = 252). 6/16 articles that reported vaccination status stated that none of the cases were vaccinated. In the remaining articles, approximately 80%-96% cases were unvaccinated. It was noted that 4%-21% of the vaccinated individuals got infected. The secondary attack rate ranged from 0% to 10.2%, while the calculated pooled estimated case fatality rate was 8.7%.

CONCLUSION

This scoping review provides an extensive look at our current understanding on monkeypox disease. Further studies are needed to better understand its risk factors, genetics and natural history, in order for public health strategists to generate prevention strategies and management decisions.

Global Outbreak of Human Monkeypox in 2022: Update of Epidemiology

Background: Human monkeypox was a neglected zoonotic disease considered endemic to rainforests of rural parts of Central and Western Africa, until a global outbreak in May 2022. Methods: This review describes the epidemiological characteristics of human monkeypox. Results: Since the first confirmed case in the United Kingdom on 13 May 2022, and up until 19 September, more than 62,000 cases of human monkeypox were reported in 104 countries in the world (among them 97 countries where the monkeypox virus was not endemic). Up to today, 20 persons have died in this global outbreak. This outbreak predominantly affects men self-identifying as gay or bisexual or other men who have sex with men, and for now, there is no sign of continuous transmission of the disease in other populations. Today, the monkeypox outbreak is increasing alarmingly in many countries and presents a new challenge and a large issue for public health worldwide. The World Health Organization declared the global monkeypox outbreak a public health emergency of international concern on 24 July 2022. Before this outbreak, health professionals in many countries had a knowledge gap and a lack of experience in the management of monkeypox. Conclusions: Advances in the comprehension of the epidemiology of human monkeypox are necessary for effective prevention and outbreak response.

Monkeypox 2022 outbreak in non-endemic countries: Open questions relevant for public health, nonpharmacological intervention and literature review

Starting from mid-May 2022, cases of human monkeypox started to rise in several non-endemic countries. By mid-July, more than 17000 confirmed/suspect cases have been reported by at least 82 countries worldwide, with a regular incremental trend. In order to contain the disease diffusion, risk evaluation is crucial to undertake informed decisions and effective communication campaigns. However, since orthopoxvirus infections so far have attracted low attention, due to the eradication of smallpox 40 years ago, and to the confinement of human monkeypox almost exclusively to endemic areas, several unresolved issues concerning natural history, ecology and pathogenesis remain. To this respect, we identified some open questions and reviewed the relevant literature on monkeypoxvirus and/or related orthopoxviruses. The results will be discussed in the perspective of their relevance to public health decisions, particularly those related to non-pharmacological interventions.

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.

Vaccinia-Virus-Based Vaccines Are Expected to Elicit Highly Cross-Reactive Immunity to the 2022 Monkeypox Virus

Beginning in May 2022, a novel cluster of monkeypox virus infections was detected in humans. This virus has spread rapidly to non-endemic countries, sparking global concern. Specific vaccines based on the vaccinia virus (VACV) have demonstrated high efficacy against monkeypox viruses in the past and are considered an important outbreak control measure. Viruses observed in the current outbreak carry distinct genetic variations that have the potential to affect vaccine-induced immune recognition. Here, by investigating genetic variation with respect to orthologous immunogenic vaccinia-virus proteins, we report data that anticipates immune responses induced by VACV-based vaccines, including the currently available MVA-BN and ACAM2000 vaccines, to remain highly cross-reactive against the newly observed monkeypox viruses.

Human monkeypox virus: An updated review

The human monkeypox is an emerging zoonotic orthopoxvirus with a clinical presentation similar to that of smallpox. It is difficult to differentiate monkeypox from other orthopedic infections, and laboratory diagnosis is the primary component of disease identification and monitoring. However, current diagnostics are time-consuming, and new tests are needed for rapid and precise diagnosis. Most cases have been reported in Central Africa; however, an increasing number of cases have been reported in Europe, the United States of America (USA), Australia, and the United Arab Emirates. Although investigation of the current global outbreak is still ongoing, viral transmission seems to have occurred during crowded events in Spain and Belgium. New therapeutics and vaccines are being deployed for the treatment and prevention of monkeypox, and more research on the epidemiology, biology, and ecology of the virus in endemic areas is required to understand and prevent further global outbreaks.

New challenges in human monkeypox outside Africa: A review and case report from Italy

BACKGROUND

Human monkeypox (MPX) is a neglected zoonotic disease caused by the MPX virus a double-stranded DNA virus which belongs to the Poxviridae family genus Orthopoxvirus. It is endemic in the rural rainforests of Central and Western Africa where it is responsible of human sporadic cases and outbreaks since 1970. Outside Africa MPXV caused an outbreak in 2003 in the United States linked to importation of infected rodents from Ghana and a few travel-related cases in the USA, United Kingdom, Israel and Singapore. Actually, a worldwide outbreak with more than 1200 confirmed cases mainly concentrated among men who have sex with men is ongoing.

CASE REPORT

We present the case of an Italian man living in Portugal that was diagnosed with MPX at our clinic in Milan, Italy. Monkeypox virus infection was confirmed by a specific homemade Real-Time PCR. Samples obtained from different sites (pharynx, skin lesions, anal ulcer, seminal fluid) turned all positive with different viral load.

CONCLUSIONS

Our report illustrates the challenge of a disease that seems to present in a different way from classic description with possible human-to-human transmission through sexual contact.

Monkeypox: An international epidemic

Human monkeypox (MPX) is a viral zoonosis caused by the Monkeypox virus. For decades outbreaks exclusively occurred in the tropical rainforests of Africa, with a few imported cases and very limited human-to-human transmission outside Africa. Nevertheless, in the last years sustained outbreaks have emerged, peaking at 4600 cases in 2020 in the Democratic Republic of Congo. Since May 2022, an international epidemic originated at 2 events in Spain and Belgium led to sustained human-to-human transmission across multiple continents, mostly in males having sex with males subjects. We review here clinical presentation, epidemiology, viral evolution, vaccines, and therapeutics against human MPX.

Monkeypox, a Literature Review: What Is New and Where Does This concerning Virus Come From?

Among the Poxviridae family, orthopoxvirus is the most notorious genus. Several DNA viruses belonging to this group are known to produce human disease from the life-threatening variola virus (VARV) (the causative agent of smallpox), monkeypox virus (MPXV), cowpox virus (CPXV), and vaccinia virus (VACV). These orthopoxviruses still remain a public health concern as VACV or CPXV still cause emerging endemic threads, especially in developing countries. MPXV is able to cause sporadic human outbreaks of a smallpox-like zoonotic disease and, in May 2022, hundreds of cases related to MPXV have been reported from more than 30 countries around the globe. At the end of July, monkeypox (MPX) outbreak was even declared a global health emergency by the World Health Organization (WHO). Many aspects remain unclear regarding this outbreak and a deep understanding of orthopoxvirus might have crucial and evident implications. During the era in which people under 45 years old are not protected against VACV, the potential use of orthopoxviruses as a biological weapon raises global concern considering the rapid spreading of the current MPX outbreak in vulnerable populations. Hence, we review the most recent evidence about phylogenesis, pathogenesis, prevention, and treatment for this concerning disease.

The First Two Cases of Monkeypox Infection in MSM in Bahia, Brazil, and Viral Sequencing

Monkeypox infection is rapidly spreading across the world. Despite the increasing number of cases, only a few reports have been published, and most are on people living without HIV. We report here the first two cases of monkeypox infection in Bahia, Brazil, one of them in a person living with HIV, on stable treatment. Both cases had a similar evolution, with a limited number of lesions and mild symptoms, with a complete recovery after 7–10 days. The potential route of transmission was via oral sex for the first case and was undefined for the second one. Both cases were confirmed through detection of the viral genome by PCR, and the partial sequence of the first case indicates the infection was caused by the West African clade. These cases confirm that monkeypox infection is currently being transmitted in Brazil and that people living with HIV on stable treatment are not likely to present a more severe form of monkeypox.

A Review of the Recent Monkeypox Outbreak in 2022

The coincidence of the monkeypox outbreak with the coronavirus disease 2019 (COVID-19) pandemic raises a global concern about a potential new pandemic and the possible consequences. As the World Health Organization declared the international monkeypox outbreak a global emergency, there is apprehension about the complications and mortality of monkeypox infection.

The monkeypox virus is a zoonosis: a disease that is transmitted from animals to humans. It is an enveloped double-stranded DNA virus that belongs to the Orthopoxvirus genus. Human-to-human transmission occurs with close contact with respiratory secretions, sores on an infected person's skin, or contaminated items like clothing.

Monkeypox is endemic in regions of Africa, however, because of smallpox eradication and a decrease in vaccination efforts, this led to an outbreak in the United States of America in 2003 and a new world outbreak in 2022.

Most patients experience prodromal sickness with fever, malaise, and enlarged lymph nodes before developing a rash. In addition to skin lesions, individuals may also experience secondary skin and/or soft tissue infection, pneumonitis, ocular problems, and encephalitis. There is an increased risk of infection among men who have sex with men and human immunodeficiency virus infection (HIV) patients. The polymerase chain reaction is the gold standard for diagnosis. Management is usually supportive but some cases may require tecovirimat. This is a comprehensive review of monkeypox virus epidemiology, clinical features, and the most up-to-date, effective management and prevention.

Monkeypox: considerations for the understanding and containment of the current outbreak in non-endemic countries

The neglected and rare zoonotic disease caused by monkeypox virus (MPV) has recently spread widely, resulting in the largest known monkeypox outbreak outside of Africa, where it is endemic. MPV belongs to the Poxviridae family, genus Orthopoxvirus. At least two different clades have been identified, each having different fatality rates but recent cases are all phylogenetically related to the West African clade. MPV is transmitted directly by either person-to-person, -animal, or virus-contaminated fomite contact. The disease is often self-limited, and clinical symptoms include fever, skin lesions, and lymphadenopathies. At present, no deaths have been associated with the current outbreak. MPV DNA detection using molecular techniques is recommended for diagnosis. At least two approved drugs for antiviral therapy are available in the USA. Two different vaccines, including the vaccine used in the past for smallpox eradication and a new formulation more recently approved based on a live but non-replicating virus, are available that provide immunity to MPV. These and other clinical and public health considerations pertaining to the recent monkeypox outbreaks together with aspects of MPV biology are discussed in this article.

Monkeypox: A New Threat?

The global vaccination programme against smallpox led to its successful eradication and averted millions of deaths. Monkeypox virus (MPXV) is a close relative of the Variola (smallpox) virus. Due to antigenic similarity, smallpox vaccines cross-protect against MPXV. However, over 70% of people living today were never vaccinated against smallpox. Symptoms of monkeypox (MPX) include fever, head- and muscle ache, lymphadenopathy and a characteristic rash that develops into papules, vesicles and pustules which eventually scab over and heal. MPX is less often fatal (case fatality rates range from <1% to up to 11%) than smallpox (up to 30%). MPXV is endemic in sub-Saharan Africa, infecting wild animals and causing zoonotic outbreaks. Exotic animal trade and international travel, combined with the increasing susceptibility of the human population due to halted vaccination, facilitated the spread of MPXV to new areas. The ongoing outbreak, with >10,000 cases in >50 countries between May and July 2022, shows that MPXV can significantly spread between people and may thus become a serious threat to public health with global consequences. Here, we summarize the current knowledge about this re-emerging virus, discuss available strategies to limit its spread and pathogenicity and evaluate its risk to the human population.

Knowledge of Human Monkeypox and Its Relation to Conspiracy Beliefs among Students in Jordanian Health Schools: Filling the Knowledge Gap on Emerging Zoonotic Viruses

Background and Objective: The recent multi-country outbreak of human monkeypox (HMPX) in non-endemic regions poses an emerging public health concern. University students in health schools/faculties represent a core knowledgeable group that can be helpful to study from a public health point of view. As future healthcare workers, assessment of their knowledge and attitude towards emerging zoonotic viral infections can be helpful to assess their taught material and courses with potential improvement if gaps in knowledge were identified. Therefore, we aimed to evaluate the level of HMPX knowledge, conspiracy beliefs regarding emerging virus infections, as well as their associated determinants among university students studying Medicine, Nursing, Dentistry, Pharmacy, Medical Laboratory Sciences, and Rehabilitation in Jordanian health schools/faculties. In addition, we sought to evaluate the correlation between HMPX knowledge and the extent of holding conspiracy beliefs regarding emerging viral infection. Materials and Methods: A convenient sample of university students was obtained through an electronic survey distributed in late May 2022 using the chain-referral approach. Assessment of HMPX knowledge and general attitude towards emerging virus infections was based on survey items adopted from previously published literature. Results: The study sample comprised 615 students with a mean age of 20 years and a majority of females (432, 70.2%) and medical students (n = 351, 57.1%). Out of eleven monkeypox knowledge items, three were identified correctly by >70% of the respondents. Only 26.2% of the respondents (n = 161) knew that vaccination to prevent monkeypox is available. Age was significantly associated with better HMPX knowledge for a majority of items. Older age, females, and affiliation to non-medical schools/faculties were associated with harboring higher levels of conspiracy beliefs regarding emerging virus infections. Our data also indicate that lower levels of HMPX knowledge were associated with higher levels of conspiracy beliefs. Conclusion: The current study pointed to generally unsatisfactory levels of knowledge regarding the emerging HMPX among university students in Jordanian health schools/faculties. Conspiracy beliefs regarding emerging virus infections were widely prevalent, and its potential detrimental impact on health behavior should be evaluated in future studies.

New p35 (H3L) Epitope Involved in Vaccinia Virus Neutralization and Its Deimmunization

Vaccinia virus (VACV) is a promising oncolytic agent because it exhibits many characteristic features of an oncolytic virus. However, its effectiveness is limited by the strong antiviral immune response induced by this virus. One possible approach to overcome this limitation is to develop deimmunized recombinant VACV. It is known that VACV p35 is a major protein for B- and T-cell immune response. Despite the relevance of p35, its epitope structure remains insufficiently studied. To determine neutralizing epitopes, a panel of recombinant p35 variants was designed, expressed, and used for mice immunization. Plaque-reduction neutralization tests demonstrated that VACV was only neutralized by sera from mice that were immunized with variants containing both N- and C- terminal regions of p35. This result was confirmed by the depletion of anti-p35 mice sera with recombinant p35 variants. At least nine amino acid residues affecting the immunogenic profile of p35 were identified. Substitutions of seven residues led to disruption of B-cell epitopes, whereas substitutions of two residues resulted in the recognition of the mutant p35 solely by non-neutralizing antibodies.

Retrospective detection of asymptomatic monkeypox virus infections among male sexual health clinic attendees in Belgium

The magnitude of the 2022 multi-country monkeypox virus (MPXV) outbreak has surpassed any preceding outbreak. It is unclear whether asymptomatic or otherwise undiagnosed infections are fuelling this epidemic. In this study, we aimed to assess whether undiagnosed infections occurred among men attending a Belgian sexual health clinic in May 2022. We retrospectively screened 224 samples collected for gonorrhea and chlamydia testing using an MPXV PCR assay and identified MPXV-DNA-positive samples from four men. At the time of sampling, one man had a painful rash, and three men had reported no symptoms. Upon clinical examination 21-37 days later, these three men were free of clinical signs, and they reported not having experienced any symptoms. Serology confirmed MPXV exposure in all three men, and MPXV was cultured from two cases. These findings show that certain cases of monkeypox remain undiagnosed and suggest that testing and quarantining of individuals reporting symptoms may not suffice to contain the outbreak.

Monkeypox Rash Severity and Animal Exposures in the Democratic Republic of the Congo

Experimental studies have suggested a larger inoculum of monkeypox virus may be associated with increased rash severity; however, little data are available on the relationship between specific animal exposures and rash severity in endemic regions. Using cross-sectional data from an active surveillance program conducted between 2005 and 2007 in the Sankuru Province of the Democratic Republic of the Congo, we explored the possible relationship between rash severity and exposures to rodents and non-human primates among confirmed MPX cases. Among the 223 PCR-confirmed MPX cases identified during active surveillance, the majority of cases (n = 149) presented with mild rash (5-100 lesions) and 33% had a more serious presentation (> 100 lesions). No association between exposure to rodents and rash severity was found in the multivariable analysis. Those that self-reported hunting NHP 3 weeks prior to onset of MPX symptoms had 2.78 times the odds of severe rash than those that did not report such exposure (95% CI: 1.18, 6.58). This study provides a preliminary step in understanding the association between animal exposure and rash severity and demonstrates correlation with exposure to NHPs and human MPX presentation. Additional research exploring the relationship between rash severity and NHPs is warranted.

A systematic review of the epidemiology of human monkeypox outbreaks and implications for outbreak strategy

Monkeypox is a vesicular-pustular illness that carries a secondary attack rate in the order of 10% in contacts unvaccinated against smallpox. Case fatality rates range from 1 to 11%, but scarring and other sequelae are common in survivors. It continues to cause outbreaks in remote populations in Central and West Africa, in areas with poor access and weakened or disrupted surveillance capacity and information networks. Recent outbreaks in Nigeria (2017-18) and Cameroon (2018) have occurred where monkeypox has not been reported for over 20 years. This has prompted concerns over whether there have been changes in the biology and epidemiology of the disease that may in turn have implications for how outbreaks and cases should best be managed. A systematic review was carried out to examine reported data on human monkeypox outbreaks over time, and to identify if and how epidemiology has changed. Published and grey literature were critically analysed, and data extracted to inform recommendations on outbreak response, use of case definitions and public health advice. The level of detail, validity of data, geographical coverage and consistency of reporting varied considerably across the 71 monkeypox outbreak documents obtained. An increase in cases reported over time was supported by literature from the Democratic Republic of Congo (DRC). Data were insufficient to measure trends in secondary attack rates and case fatality rates. Phylogenetic analyses consistently identify two strains of the virus without evidence of emergence of a new strain. Understanding of monkeypox virulence with regard to clinical presentation by strain is minimal, with infrequent sample collection and laboratory analysis. A variety of clinical and surveillance case definitions are described in the literature: two definitions have been formally evaluated and showed high sensitivity but low specificity. These were specific to a Congo-Basin (CB) strain-affected area of the DRC where they were used. Evidence on use of antibiotics for prophylaxis against secondary cutaneous infection is anecdotal and limited. Current evidence suggests there has been an increase in total monkeypox cases reported by year in the DRC irrespective of advancements in the national Integrated Disease Surveillance and Response (IDSR) system. There has been a marked increase in number of individual monkeypox outbreak reports, from outside the DRC in between 2010 and 2018, particularly in the Central African Republic (CAR) although this does not necessarily indicate an increase in annual cases over time in these areas. The geographical pattern reported in the Nigeria outbreak suggests a possible new and widespread zoonotic reservoir requiring further investigation and research. With regards to outbreak response, increased attention is warranted for high-risk patient groups, and nosocomial transmission risks. The animal reservoir remains unknown and there is a dearth of literature informing case management and successful outbreak response strategies. Up-to-date complete, consistent and longer-term research is sorely needed to inform and guide evidence-based response and management of monkeypox outbreaks.

Epidemiologic and Ecologic Investigations of Monkeypox, Likouala Department, Republic of the Congo, 2017

Monkeypox, caused by a zoonotic orthopoxvirus, is endemic in Central and West Africa. Monkeypox has been sporadically reported in the Republic of the Congo. During March 22-April 5, 2017, we investigated 43 suspected human monkeypox cases. We interviewed suspected case-patients and collected dried blood strips and vesicular and crust specimens (active lesions), which we tested for orthopoxvirus antibodies by ELISA and monkeypox virus and varicella zoster virus DNA by PCR. An ecologic investigation was conducted around Manfouété, and specimens from 105 small mammals were tested for anti-orthopoxvirus antibodies or DNA. Among the suspected human cases, 22 met the confirmed, probable, and possible case definitions. Only 18 patients had available dried blood strips; 100% were IgG positive, and 88.9% (16/18) were IgM positive. Among animals, only specimens from Cricetomys giant pouched rats showed presence of orthopoxvirus antibodies, adding evidence to this species' involvement in the transmission and maintenance of monkeypox virus in nature.

Monkeypox re-emergence in Africa: a call to expand the concept and practice of One Health

INTRODUCTION

Monkeypox is a re-emerging viral zoonosis that occurs naturally in heavily forested regions of West and Central Africa. Inter-human transmission of monkeypox virus, although limited, drives outbreaks, particularly in household and health-care settings. But the available evidence suggests that without repeated zoonotic introductions, human infections would eventually cease to occur. Therefore, interrupting virus transmission from animals to humans is key to combating this disease. Areas covered: Herein we review laboratory and field studies examining the susceptibility of various animal taxa to monkeypox virus infection, and note the competence of various species to serve as reservoirs or transmission hosts. In addition, we discuss early socio-ecologic theories of monkeypox virus transmission in rural settings and review current modes of ecologic investigation - including ecologic niche modeling, and ecologic sampling - in light of their potential to identify specific animal species and features of the environment that are associated with heightened risk for human disease. Expert opinion: The role of disease ecology and scientific research in ongoing disease prevention efforts should be reinforced, particularly for wildlife-associated zoonoses such as monkeypox. Such efforts alongside those aimed at nurturing 'One Health' collaborations may ultimately hold the greatest promise for reducing human infections with this pathogen.

Investigation of an outbreak of monkeypox in an area occupied by armed groups, Central African Republic

BACKGROUND

Monkeypox is a zoonosis caused by an Orthopoxvirus of the Poxviridae family. Human infections are often severe and are a public health problem.

PATIENTS AND METHOD

We conducted a monkeypox outbreak investigation of suspected case patients in five villages of the Alindao-Mingala Health District following blood sample confirmation of the virus by the Institut Pasteur in Bangui. We aimed to determine disease characteristics, to describe the context and the risk factors, and to measure the incidence and case fatality. Patients were reported in the villages of Rehou 4, 5, Dalakere 1, Kongbo, and Pavika from August to October 2016. Data was collected on individual records when interviewing patients or parents.

RESULTS

A total of 26 patients were identified. The˂10 years and 21-30 years age groups were the most affected. The overall attack rate was 5 per 1000 inhabitants and the case fatality was 7.7%. Young age and the absence of smallpox vaccination were associated with severe presentations in 87.5% of cases.

CONCLUSION

The annual number of monkeypox outbreaks increases in the Central African Republic with severe presentations and a high case fatality especially in children. Reinforcing the surveillance and characterization of circulating strains will provide information on the need for vaccine production.

A Single Vaccination of Nonhuman Primates with Highly Attenuated Smallpox Vaccine, LC16m8, Provides Long-term Protection against Monkeypox

Monkeypox virus (MPXV) causes human monkeypox (human MPX), which is a similar disease to smallpox in humans. A previous study showed that a single vaccination of monkeys with LC16m8, a highly attenuated smallpox vaccine, protected them from MPX from 4-5 weeks post-vaccination. In this study, we evaluated the long-term efficacy of a single vaccination with LC16m8 in a nonhuman primate model of MPXV infection. The monkeys were inoculated with either LC16m8, Lister (parental strain of LC16m8), or a mock-up vaccine, and then challenged with MPXV via a subcutaneous route, at 6 and 12 months after vaccination, which we compared with either Lister or the mock-up vaccination. The LC16m8 monkeys exhibited almost no MPX-associated symptoms, whereas most of the naïve monkeys died. LC16m8 generated the protective memory immune response against MPXV, as suggested by the immediate viremia reduction and the response of the IgG antibody. The results demonstrated that the vaccination of monkeys with a single dose of LC16m8 provided durable protection against MPXV for longer than one year after immunization. The results suggest that the vaccination of humans with LC16m8 could induce long-term protection against MPXV infection.

Human Monkeypox: Current State of Knowledge and Implications for the Future

The zoonosis human monkeypox (MPX) was discovered in 1970, twelve years after the discovery of monkeypox virus (MPXV) in a Danish laboratory in 1958. Historically confined to West Africa (WA) and the Congo basin (CB), new epidemics in Sudan and the United States of America (USA) have fuelled new research highlighting environmental factors contributing to the expanded geographical spread of monkeypox virus (MPXV). A systematic literature review was conducted in MEDLINE^® (Ovid), MEDLINE^® (PubMed) and Google Scholar databases using the search terms: monkeypox, MPXV and “human monkeypox”. The literature revealed MPX has classic prodromal symptoms followed by a total body rash. The sole distinguishing clinical characteristic from other pox-like illnesses is the profound lymphadenopathy. Laboratory diagnosis of MPX is essential, a suitable test for endemic areas is under development but not yet available. For the time being anti-poxvirus antibodies in an unvaccinated individual with a history of severe illness and rash can suggest MPX infection. The reservoir host remains elusive yet the rope squirrel and Gambian pouched rat appear to be the most likely candidates. Transmission includes fomite, droplet, direct contact with infected humans or animals and consumption of infected meat. Though smallpox vaccination is protective against MPXV, new non-immune generations contribute to increasing incidence. Environmental factors are increasing the frequency of contact with potential hosts, thus increasing the risk of animal-to-human transmission. Increased risk of transmission through globalisation, conflict and environmental influences makes MPX a more realistic threat to previously unaffected countries. Health worker training and further development and accessibility of suitable diagnostic tests, vaccinations and anti-viral treatment is becoming increasingly necessary.

[Twelve cases of monkeypox virus outbreak in Bangassou District (Central African Republic) in December 2015]

An outbreak of monkeypox occurred in the district of Bangassou in 2015. The monkeypox is a re-emerging zoonosis of viral origin highly contagious. It is an eruptive fever which evolves in an epidemic manner. An investigation was held December 10, 2015, to February 10, 2016 in the focus of the epidemic. Its objective was to describe the epidemic according to the time, places and people and to determine the incidence and lethality of the disease. This was a descriptive study. The data collection was made by interview and using a linear plug composed of several sections. All suspected cases were taken into account. The interview was done with patients or the parents of sick children. The blood and the contents of the lesions were collected and sent to the laboratory of the Institut Pasteur in Bangui for confirmation. Our data were analyzed with Epi info7. In total 12 patients had been registered including 9 secondary cases. Patients aged 31 to 40 years and less than 10 years were most affected. In addition, adults were most affected by the disease (8/12). The average age was 25 years with extremes at 15 months and 41 years. The sex male/female ratio was 1. The overall attack rate of disease and lethality were 0.2 per 1000 inhabitants and 25% respectively. The fatality was 67% among children less than 10 years. Fever and rash were the main symptoms of the disease. Lymphadenopathy was present in 54.5%. Ten of the 12 patients were hospitalized (83%). The average duration of hospitalization was 13 days with the extremes 6 and 28 days. The monkeypox like smallpox remains a serious and fatal disease in children. A survey of animal reservoirs complained to identify strains of the virus is essential. During an outbreak, good communication and isolation of patients may break the chain of transmission. Other measures to limit their contact with the forest or virus reservoirs are to be encouraged.

A phylogeographic investigation of African monkeypox

Monkeypox is a zoonotic disease caused by a virus member of the genus Orthopoxvirus and is endemic to Central and Western African countries. Previous work has identified two geographically disjuct clades of monkeypox virus based on the analysis of a few genomes coupled with epidemiological and clinical analyses; however, environmental and geographic causes of this differentiation have not been explored. Here, we expand previous phylogenetic studies by analyzing a larger set of monkeypox virus genomes originating throughout Sub-Saharan Africa to identify possible biogeographic barriers associated with genetic differentiation; and projected ecological niche models onto environmental conditions at three periods in the past to explore the potential role of climate oscillations in the evolution of the two primary clades. Analyses supported the separation of the Congo Basin and West Africa clades; the Congo Basin clade shows much shorter branches, which likely indicate a more recent diversification of isolates within this clade. The area between the Sanaga and Cross Rivers divides the two clades and the Dahomey Gap seems to have also served as a barrier within the West African clade. Contraction of areas with suitable environments for monkeypox virus during the Last Glacial Maximum, suggests that the Congo Basin clade of monkeypox virus experienced a severe bottleneck and has since expanded its geographic range.

Enhancing health care worker ability to detect and care for patients with monkeypox in the Democratic Republic of the Congo

BACKGROUND

Monkeypox (MPX) is an endemic disease of public health importance in the Democratic Republic of the Congo (DRC). In 2010, the DRC Ministry of Health joined with external partners to improve MPX surveillance in the Tshuapa Health District of DRC. A pivotal component of the program is training of health zone personnel in surveillance methods and patient care. In this report we evaluate outcomes of the training program.

METHODS

Health care worker knowledge of key concepts in the MPX training curriculum was assessed using an anonymous self-administered survey. Additionally, evaluators collected feedback about the capacity of participants to perform the surveillance tasks. Training impacts were determined by assessing various surveillance performance metrics.

RESULTS

Correct trainee responses to questions about MPX symptoms and patient care increased significantly upon completion of training events. During the 12 months after the initial training, the proportion of suspected cases investigated increased significantly (from 6.7 to 37.3%), as compared to the 5 months prior. However, the proportion of reported cases that were ultimately confirmed remained unchanged, 20.1% (5/24) vs 23.3% (60/257).

CONCLUSIONS

We have demonstrated that the MPX curriculum developed for this initiative was effective in transferring knowledge and was associated with improved detection of human MPX cases.

CAN CULLING TO PREVENT MONKEYPOX INFECTION BE COUNTER-PRODUCTIVE? SCENARIOS FROM A THEORETICAL MODEL

In the last two decades, monkeypox outbreaks in human populations in Africa and North America have reminded us that smallpox is not the only poxvirus with potential to cause harm in human populations. Monkeypox transmission is sustained in animal reservoirs, and animal–human contacts are responsible for sporadic outbreaks in humans. Here, we develop and analyze a deterministic epizootic (animal-based) transmission model capturing disease dynamics in an animal population, disease dynamics in an age-structured human population, and their coupling through animal–human contacts. We develop a single-patch model as well as a two-patch meta-population extension. We derive mathematical expressions for the basic reproduction number, which governs the likelihood of a large outbreak. We also investigate the effectiveness of culling strategies and the impact of changes in the animal–human contact rate. Numerical analysis of the model suggests that, for some parameter values, culling can actually have the counter-productive outcome of increasing monkeypox infection in children, if animal reproduction is a density-dependent process. The likelihood of this happening, as well as the prevalence of monkeypox in humans, depends sensitively on the animal–human contact rate. We also find that ignoring age structure in human populations can lead to overestimating the transmissibility of monkeypox in humans. The effectiveness of monkeypox control strategies such as culling can strongly depend on the details of demography and epidemiology in the animal reservoirs that sustain it. Therefore, to better understand how to prevent and control monkeypox outbreaks in humans, better empirical data from wild animal populations where monkeypox is endemic must be collected, and these data must be incorporated into highly structured theoretical models.

Modelling HIV/AIDS and monkeypox co-infection

During the last two decades, reports on emerging human monkeypox outbreaks in Africa and North America have reminded us that beside the eradicated smallpox there are other pox viruses that have great potential to harm people. A deterministic model for the co-infection of HIV/AIDS and monkeypox is formulated and analysed. The endemic equilibria are shown to be locally and globally asymptotically stable using the Centre Manifold theory and the Lyapunov function approach, respectively. Analysis of the basic reproduction numbers and numerical simulations suggest that an increase in the number of monkeypox in the animal species results in an increase of the number of people having monkeypox. Threshold conditions that determine the competitive outcomes of the two diseases are provided. Furthermore, numerical simulations using a set of reasonable parameter values support the claim that HIV infection greatly enhances monkeypox infection and vice versa.

Optimization of peptide-based ELISA for serological diagnostics: a retrospective study of human monkeypox infection

Although smallpox has been eradicated, other diseases caused by virulent orthopoxviruses such as monkeypox virus (MPV) remain endemic in remote areas of western and central sub-Saharan Africa, and represent a potential biothreat due to international travel and/or inadvertent exposure. Unfortunately, extensive antigenic cross-reactivity among orthopoxviruses presents a challenge to serological diagnosis. We previously reported a 20mer peptide-based ELISA that identified recent MPV infection with >90% sensitivity and >90% specificity. However, the sensitivity of this approach was not determined with samples obtained at later time points after antibody titers had declined from their peak levels. To improve assay sensitivity for detecting MPV-specific antibodies at later time points, we compared diagnostic 20mer peptides to 30mer peptides. In addition, optimal 30mer peptides were tested in combination or after conjugating selected peptides to a carrier protein (bovine serum albumin) to further improve assay performance. An optimized combination of four unconjugated 30mer peptides provided 100% sensitivity for detecting MPV infection at 2-6 months post-infection, 45% sensitivity for detecting MPV infection at >2 years post-infection, and 99% specificity. However, an optimized combination of two peptide conjugates provided 100% sensitivity for detecting MPV infection at 2-6 months post-infection, 90% sensitivity for detecting MPV infection at >2 years post-infection, and 97% specificity. Peptide-based ELISA tests provide a relatively simple approach for serological detection of MPV infection. Moreover, the systematic approach used here to optimize diagnostic peptide reagents is applicable to developing improved diagnostics to a broad range of other viruses, and may be particularly useful for distinguishing between closely-related viruses within the same genus or family.

Outbreaks of human monkeypox after cessation of smallpox vaccination

The recent observation of a surge in human monkeypox in the Democratic Republic of the Congo (DRC) prompts the question of whether cessation of smallpox vaccination is driving the phenomenon, and if so, why is re-emergence not universal throughout the historic geographic range of the virus? Research addressing the virus's mechanisms for immune evasion and induction, as well as that directed at elucidating the genes involved in pathogenesis in different viral lineages (West African vs Congo Basin), provide insights to help explain why emergence appears to be geographically limited. Novel vaccines offer one solution to curtail the spread of this disease.

Whither monkeypox vaccination

Monkeypox (MPX) is a virulent orthopoxvirus that is endemic in some regions of Central Africa. MPX incidence has been rising since the cessation of routine smallpox immunization. While it causes significant disease, there is limited person-to-person spread, the incidence is still relatively low, and cases are generally restricted to remote areas that are difficult to access. Therefore, initiating vaccine trials or implementing vaccination programs would be challenging. This paper considers the factors that may influence future decisions on whether MPX vaccination should be pursued.

A naturally occurring cowpox virus with an ectromelia virus A-type inclusion protein gene displays atypical A-type inclusions

Human orthopoxvirus (OPV) infections in Europe are usually caused by cowpox virus (CPXV). The genetic heterogeneity of CPXVs may in part be due to recombination with other OPV species. We describe the characterization of an atypical CPXV (CPXV-No-H2) isolated from a human patient in Norway. CPXV-No-H2 was characterized on the basis of A-type inclusion (ATI) phenotype as well as the DNA region containing the p4c and atip open reading frames. CPXV-No-H2 produced atypical V(+/) ATI, in which virions are on the surface of ATI but not within the ATI matrix. Phylogenetic analysis showed that the atip gene of CPXV-No-H2 clustered closely with that of ectromelia virus (ECTV) with a bootstrap support of 100% whereas its p4c gene is diverged compared to homologues in other OPV species. By recombination analysis we identified a putative crossover event at nucleotide 147, downstream the start of the atip gene. Our results suggest that CPXV-No-H2 originated from a recombination between CPXV and ECTV. Our findings are relevant to the evolution of OPVs.

Zoonotic vaccinia virus outbreaks in Brazil

The vaccinia virus (VACV) was used as a live vaccine during the WHO-led smallpox eradication campaign in the second half of the 20th century. The program culminated with the obliteration of the disease, one of the most important achievements in modern medicine. Interestingly, one of the key factors in the successful vaccination campaign – the VACV itself – is poorly understood in relation to its natural reservoirs, evolutionary history and origins, being frequently considered extinct as a naturally occurring virus. Nevertheless, orthopoxviruses other than variola virus have been known to circulate in Brazil since the early 1960s. More specifically, VACV has been associated with naturally acquired infections in humans, cattle and possibly other reservoirs since 1999, when bovine vaccinia outbreaks started to be consistently described year after year. In this article, we list and discuss the most important VACV outbreaks that have occurred in Brazil in the last 20 years. Phylogenetic issues are considered, as the latest studies point to large genetic variance among isolates. Clinical and epidemiological data, both published and new, are presented.

Zoonotic poxviruses

Poxviruses compromise a group of long known important pathogens including some zoonotic members affecting lifestock animals and humans. While whole genome sequence analysis started to shed light into the molecular mechanisms underlying host cell infection, viral replication as well as virulence, our understanding of poxvirus maintenance in nature and their transmission to humans is still poor. During the last two decades, reports on emerging human monkeypox outbreaks in Africa and North America, the increasing number of cowpox virus infections in cats, exotic animals and humans and cases of vaccinia virus infections in humans in South America and India reminded us that – beside the eradicated smallpox virus – there are other poxviruses that can cause harm to men. We start to learn that the host range of some poxviruses is way broader than initially thought and that mainly rodents seem to function as virus reservoir. The following review is aiming to provide an up-to-date overview on the epidemiology of zoonotic poxviruses, emphasizing orthopoxviruses. By outlining the current knowledge of poxvirus transmission, we hope to raise the awareness about modes of acquisition of infections and their proper diagnosis.