Rapid Detection of the Monkeypox Virus Genome and Antigen Proteins Based on Surface-Enhanced Raman Spectroscopy

The conventional detection methods cannot satisfy the need for early and rapid detection of monkeypox virus (MPXV) infection. This is due to complicated pretreatment, time consumption, and complex operation of the diagnostic tests. Based on surface-enhanced Raman spectroscopy (SERS), this study attempted to capture the characteristic fingerprints of the MPXV genome and multiple antigenic proteins without the need to design specific probes. The minimum detection limit of this method is 100 copies/mL, with good reproducibility and signal-to-noise ratio. Therefore, the relationship between characteristic peak intensity and the protein and nucleic acid concentration can be used to construct a concentration-dependent spectral line with a good linear relationship. Additionally, principal component analysis (PCA) could identify the SERS spectra of four different MPXV proteins in serum. Therefore, this rapid detection method in the current outbreak of monkeypox control and the future response to possible new outbreaks has broad application prospects.

Use of Mpox Multiplex Serology in the Identification of Cases and Outbreak Investigations in the Democratic Republic of the Congo (DRC)

Human Mpox cases are increasingly reported in Africa, with the highest burden in the Democratic Republic of Congo (DRC). While case reporting on a clinical basis can overestimate infection rates, laboratory confirmation by PCR can underestimate them, especially on suboptimal samples like blood, commonly used in DRC. Here we used a Luminex-based assay to evaluate whether antibody testing can be complementary to confirm cases and to identify human transmission chains during outbreak investigations. We used left-over blood samples from 463 patients, collected during 174 outbreaks between 2013 and 2022, with corresponding Mpox and VZV PCR results. In total, 157 (33.9%) samples were orthopox-PCR positive and classified as Mpox+; 124 (26.8%) had antibodies to at least one of the three Mpox peptides. The proportion of antibody positive samples was significantly higher in Mpox positive samples (36.9%) versus negative (21.6%) (p < 0.001). By combining PCR and serology, 66 additional patients were identified, leading to an Mpox infection rate of 48.2% (223/463) versus 33.9% when only PCR positivity is considered. Mpox infections were as such identified in 14 additional health zones and 23 additional outbreaks (111/174 (63.8%) versus 88/174 (50.6%)). Our findings highlight the urgent need of rapid on-site diagnostics to circumvent Mpox spread.

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.

Mimics of Monkeypox: Considerations for the emergency medicine clinician

INTRODUCTION

Mpox, formerly known as monkeypox, is a public health emergency most commonly presenting with a painful rash and several systemic findings. However, there are several conditions that may mimic its presentation.

OBJECTIVE

This narrative review provides a focused overview of mpox mimics for emergency clinicians.

DISCUSSION

Mpox is a global health emergency. The disease is primarily spread through contact, followed by the development of a centrifugally-spread rash that evolves from macules to papules to vesicles to pustules. This is often associated with lymphadenopathy and fever. As the rash is one of the most common presenting signs of the infection, patients mpox may present to the emergency department (ED) for further evaluation. There are a variety of mimics of mpox, including smallpox, varicella, primary and secondary syphilis, acute retroviral syndrome, and genital herpes simplex virus.

CONCLUSION

Knowledge of mpox and its mimics is vital for emergency clinicians to differentiate these conditions and ensure appropriate diagnosis and management.

Current Methods for the Detection of Antibodies of Varicella-Zoster Virus: A Review

Infection with the varicella-zoster virus (VZV) causes chickenpox and shingles, which lead to significant morbidity and mortality globally. The detection of serum VZV-specific antibodies is important for the clinical diagnosis and sero-epidemiological research of VZV infection, and for assessing the effect of VZV vaccine immunization. Over recent decades, a variety of methods for VZV antibody detection have been developed. This review summarizes and compares the current methods for detecting VZV antibodies, and discussed future directions for this field.

Monkeypox 2022 Outbreak: How Alarming Is the Situation? Epidemiological and Clinical Review

Monkeypox is a disease caused by Orthopoxvirus, which also includes the smallpox virus. Several endemics have been reported on the African continent, typically in the western and central regions. However, since 13 May 2022, there have been several cases reported from different member states; the number of confirmed cases in 1 month exceeded the total number of cases reported outside the African continent since the first case in 1970. The World Health Organization (WHO) and Centers for Disease Control (CDC) consider monkeypox as an important disease for global public health. The clinical manifestations and laboratory findings in patients with monkeypox remain unclear. In this brief review, we investigated and compared the different characteristics already reported in cases of monkeypox.

Rapid Detection of the Varicella-Zoster Virus Using a Recombinase-Aided Amplification-Lateral Flow System

Varicella-zoster virus (VZV) is the etiological agent of varicella (chickenpox) and herpes zoster (shingles). VZV infections are ubiquitous and highly contagious, and diagnosis is mostly based on the assessment of signs and symptoms. However, monkeypox, an emerging infectious disease caused by the monkeypox virus (MPXV), has clinical manifestations that are similar to those of VZV infections. With the recent monkeypox outbreak in non-endemic regions, VZV infections are likely to be misdiagnosed in the absence of laboratory testing. Considering the lack of accessible diagnostic tests that discriminate VZV from MPXV or other poxviruses, a handy and affordable detection system for VZV is crucial for rapid differential diagnosis. Here, we developed a new detection method for VZV using recombinase-aided amplification technology, combined with the lateral flow system (RAA-LF). Given the prevalence of VZV worldwide, this method can be applied not only to distinguish VZV from other viruses causing rash, but also to foster early detection, contributing substantially to disease control.

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.

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.

Enhanced surveillance of monkeypox in Bas-Uélé, Democratic Republic of Congo: the limitations of symptom-based case definitions

BACKGROUND

Following an outbreak of cases of vesicular-pustular rash with fever, evocative of human monkeypox, in Bas-Uélé province, Democratic Republic of Congo, surveillance was strengthened.

METHODS

Households with at least one active generalized vesicular-pustular rash case were visited, and contact and clinical history information were collected from all household members. Whenever possible, skin lesions were screened by polymerase chain reaction for the monkeypox virus, followed by the varicella-zoster virus, when negative for the former.

RESULTS

Polymerase chain reaction results were obtained for 77 suspected cases, distributed in 138 households, of which 27.3% were positive for monkeypox, 58.4% positive for chickenpox, and 14.3% negative for both. Confirmed monkeypox cases presented more often with monomorphic skin lesions on the palms of the hands and on the soles of the feet. Integrating these three features into the case definition raised the specificity to 85% but would miss 50% of true monkeypox cases. A predictive model fit on patient demographics and symptoms had 97% specificity and 80% sensitivity but only 80% and 33% in predicting out-of-sample cases.

CONCLUSION

Few discriminating features were identified and the performance of clinical case definitions was suboptimal. Rapid field diagnostics are needed to optimize worldwide early detection and surveillance of monkeypox.

Monkeypox: A clinical update for paediatricians

The global spread of human monkeypox disease, a zoonotic infection related to smallpox and endemic to West and Central Africa, presents serious challenges for health systems. As of July 2022, 14 533 cases have been reported world-wide, leading to designation as a Public Health Emergency of International Concern. Monkeypox disease is spread from animals to humans through infected lesions or fluids; human-human transmission occurs through fomites, droplets or direct contact. Illness is usually self-limiting, but severe disease can occur in specific groups - particularly children, and people who are immunocompromised or pregnant. Clinical presentation may include fever, lymphadenopathy and skin rash, but the rash may occur without other symptoms. Complications can include secondary bacterial infection of skin lesions, vision loss from corneal involvement, pneumonia, sepsis and encephalitis. Diagnosis of monkeypox requires consideration of epidemiological, clinical and laboratory findings, with sensitive history-taking, to elicit close contacts, critical. Supportive management is usually sufficient, but treatment options (where required) include antivirals and vaccinia immune globulin. A paucity of safety data for relevant antivirals may limit their use. There are two types of monkeypox vaccines: a replication-competent vaccinia vaccine, the use of which is logistically and clinically complex, and a replication-deficient modified vaccinia Ankara virus vaccine. Preparedness of health systems for addressing the current outbreak is constrained by historic underfunding for research, and compounded by stigma and discrimination against cases and affected communities. Key challenges in halting transmission include improving vaccine equity and countering discrimination against men who have sex with men to aid diagnosis and treatment.

Drivers of African Filovirus (Ebola and Marburg) Outbreaks

Outbreaks of African filoviruses often have high mortality, including more than 11,000 deaths among 28,562 cases during the West Africa Ebola outbreak of 2014-2016. Numerous studies have investigated the factors that contributed to individual filovirus outbreaks, but there has been little quantitative synthesis of this work. In addition, the ways in which the typical causes of filovirus outbreaks differ from other zoonoses remain poorly described. In this study, we quantify factors associated with 45 outbreaks of African filoviruses (ebolaviruses and Marburg virus) using a rubric of 48 candidate causal drivers. For filovirus outbreaks, we reviewed >700 peer-reviewed and gray literature sources and developed a list of the factors reported to contribute to each outbreak (i.e., a "driver profile" for each outbreak). We compare and contrast the profiles of filovirus outbreaks to 200 background outbreaks, randomly selected from a global database of 4463 outbreaks of bacterial and viral zoonotic diseases. We also test whether the quantitative patterns that we observed were robust to the influences of six covariates, country-level factors such as gross domestic product, population density, and latitude that have been shown to bias global outbreak data. We find that, regardless of whether covariates are included or excluded from models, the driver profile of filovirus outbreaks differs from that of background outbreaks. Socioeconomic factors such as trade and travel, wild game consumption, failures of medical procedures, and deficiencies in human health infrastructure were more frequently reported in filovirus outbreaks than in the comparison group. Based on our results, we also present a review of drivers reported in at least 10% of filovirus outbreaks, with examples of each provided.

Monkeypox: A focused narrative review for emergency medicine clinicians

Introduction

Monkeypox is an emerging viral disease that has been declared a global health emergency. While this disease has been present for over 50 years, the recent surge in cases and expanding knowledge of this has prompted a need for a focused review for practicing clinicians.

Objective

This narrative review provides a focused overview of the epidemiology, presentation, evaluation, and management of monkeypox for emergency clinicians.

Discussion

Monkeypox is an orthopoxvirus endemic to central and western Africa. An outbreak in May and June 2022 across Asia, Europe, North America, and South America was declared a global health emergency in July 2022. The disease can be transmitted via contact with an infected animal or human, as well as contact with a contaminated material. The disease presents with a prodromal flu-like illness and lymphadenopathy. A rash spreading in a centrifugal manner involving the oral mucosa, face, palms, and soles is typical. Lesions progress along various stages. Complications such as bacterial skin infection, pneumonitis, ocular conditions, and encephalitis are uncommon. Confirmation typically includes polymerase chain reaction testing. The majority of patients improve with symptomatic therapy, and as of July 2022, there are no United States Food and Drug Administration-approved treatments specifically for monkeypox. However, antiviral treatment should be considered for several patient populations at risk for severe outcomes.

Conclusion

An understanding of the presentation, evaluation, and management of monkeypox is essential for emergency clinicians to ensure appropriate diagnosis and treatment of this emerging disease.

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.

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.

Molecular Genetic Insights Into Varicella Zoster Virus (VZV), the vOka Vaccine Strain, and the Pathogenesis of Latency and Reactivation

Genetic tools for molecular typing of varicella zoster virus (VZV) have been used to understand the spread of virus, to differentiate wild-type and vaccine strains, and to understand the natural history of VZV infection in its cognate host. Molecular genetics has identified 7 clades of VZV (1-6 and 9), with 2 more mooted. Differences between the vOka vaccine strain and wild-type VZVs have been used to distinguish the cause of postimmunization events and to provide insight into the natural history of VZV infections. Importantly molecular genetics has shown that reinfection with establishment of latency by the reinfecting strain is common, that dual infections with different viruses can occur, and that reactivation of the superinfecting genotype can both occur. Whole-genome sequencing of the vOka vaccine has been used to show that vesicles form from a single virion, that latency is established within a few days of inoculation, and that all vaccine strains are capable of establishing latency and reactivating. Novel molecular tools have characterized the transcripts expressed during latent infection in vitro.

Varicella in Tshuapa Province, Democratic Republic of Congo, 2009-2014

OBJECTIVE

To describe varicella cases in Tshuapa Province of the Democratic Republic of the Congo identified during monkeypox surveillance.

METHODS

Demographic, clinical and epidemiological data were collected from each suspected monkeypox case 2009-2014. Samples were tested by PCR for both Orthopoxviruses and varicella-zoster virus (VZV); a subset of VZV-positive samples was genotyped. We defined a varicella case as a rash illness with laboratory-confirmed VZV.

RESULTS

There were 366 varicella cases were identified; 66% were ≤19 years old. Most patients had non-typical varicella rash with lesions reported as the same size and stage of evolution (86%), deep and profound (91%), on palms of hands and/or soles of feet (86%) and not itchy (49%). Many had non-typical signs and symptoms, such as lymphadenopathy (70%) and sensitivity to light (23%). A higher proportion of persons aged ≥20 years than persons aged ≤19 years had ≥50 lesions (79% vs. 65%, P = 0.007) and were bedridden (15% vs. 9%, P = 0.056). All VZV isolates genotyped from 79 varicella cases were clade 5. During the surveillance period, one possible VZV-related death occurred in a 7-year-old child.

CONCLUSIONS

A large proportion of patients presented with non-typical varicella rash and clinical signs and symptoms, highlighting challenges identifying varicella in an area with endemic monkeypox. Continued surveillance and laboratory diagnosis will help in rapid identification and control of both monkeypox and varicella and improve our understanding of varicella epidemiology in Africa.

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.

Low Varicella Zoster Virus Seroprevalence Among Young Children in the Democratic Republic of the Congo

BACKGROUND

Varicella zoster virus (VZV) causes both varicella (chickenpox) and herpes zoster (shingles) and is associated with significant global morbidity. Most epidemiological data on VZV come from high-income countries, and to date there are limited data on the burden of VZV in Africa.

METHODS

We assessed the seroprevalence of VZV antibodies among children in the Democratic Republic of Congo in collaboration with the 2013-2014 Demographic and Health Survey. Dried blood spot samples collected from children 6-59 months of age were run on Dynex™ Technologies Multiplier FLEX® chemiluminescent immunoassay platform to assess serologic response. Multivariate logistic regression was then used to determine risk factors for VZV seropositivity.

RESULTS

Serologic and survey data were matched for 7,195 children 6-59 months of age, among whom 8% were positive and 2% indeterminate for VZV antibodies in weighted analyses. In multivariate analyses, the odds of seropositivity increased with increasing age, increasing socioeconomic status, mother's education level, rural residence, and province (South Kivu, North Kivu, Bandundu, Bas Congo had the highest odds of a positive test result compared with Kinshasa).

CONCLUSION

Our data suggest that VZV is circulating in DRC, and seropositivity is low among children 6-59 months. Seropositivity increased with age and varied by other sociodemographic factors, such as geographic location. This study provides the first nationally representative estimates of VZV infection among children in the DRC.

Enhancing case definitions for surveillance of human monkeypox in the Democratic Republic of Congo

BACKGROUND

Human monkeypox (MPX) occurs at appreciable rates in the Democratic Republic of Congo (DRC). Infection with varicella zoster virus (VZV) has a similar presentation to that of MPX, and in areas where MPX is endemic these two illnesses are commonly mistaken. This study evaluated the diagnostic utility of two surveillance case definitions for MPX and specific clinical characteristics associated with laboratory-confirmed MPX cases.

METHODOLOGY/PRINCIPAL FINDINGS

Data from a cohort of suspect MPX cases (identified by surveillance over the course of a 42 month period during 2009-2014) from DRC were used; real-time PCR diagnostic test results were used to establish MPX and VZV diagnoses. A total of 333 laboratory-confirmed MPX cases, 383 laboratory-confirmed VZV cases, and 36 cases that were determined to not be either MPX or VZV were included in the analyses. Significant (p<0.05) differences between laboratory-confirmed MPX and VZV cases were noted for several signs/symptoms including key rash characteristics. Both surveillance case definitions had high sensitivity and low specificities for individuals that had suspected MPX virus infections. Using 12 signs/symptoms with high sensitivity and/or specificity values, a receiver operator characteristic analysis showed that models for MPX cases that had the presence of 'fever before rash' plus at least 7 or 8 of the 12 signs/symptoms demonstrated a more balanced performance between sensitivity and specificity.

CONCLUSIONS

Laboratory-confirmed MPX and VZV cases presented with many of the same signs and symptoms, and the analysis here emphasized the utility of including 12 specific signs/symptoms when investigating MPX cases. In order to document and detect endemic human MPX cases, a surveillance case definition with more specificity is needed for accurate case detection. In the absence of a more specific case definition, continued emphasis on confirmatory laboratory-based diagnostics is warranted.

Varicella Coinfection in Patients with Active Monkeypox in the Democratic Republic of the Congo

From 2006 to 2007, an active surveillance program for human monkeypox (MPX) in the Democratic Republic of the Congo identified 151 cases of coinfection with monkeypox virus and varicella zoster virus from 1158 suspected cases of human MPX (13%). Using clinical and socio-demographic data collected with standardized instruments by trained, local nurse supervisors, we examined a variety of hypotheses to explain the unexpectedly high proportion of coinfections among the sample, including the hypothesis that the two viruses occur independently. The probabilities of disease incidence and selection necessary to yield the observed sample proportion of coinfections under an assumption of independence are plausible given what is known and assumed about human MPX incidence. Cases of human MPX are expected to be underreported, and more coinfections are expected with improved surveillance.

Rapid and sensitive point-of-care detection of Orthopoxviruses by ABICAP immunofiltration

Background

The rapid and reliable detection of infectious agents is one of the most challenging tasks in scenarios lacking well-equipped laboratory infrastructure, like diagnostics in rural areas of developing countries. Commercially available point-of-care diagnostic tests for emerging and rare diseases are particularly scarce.

Results

In this work we present a point-of-care test for the detection of Orthopoxviruses (OPV). The OPV ABICAP assay detects down to 1 × 10⁴ plaque forming units/mL of OPV particles within 45 min. It can be applied to clinical material like skin crusts and detects all zoonotic OPV infecting humans, including Vaccinia, Cowpox, Monkeypox, and most importantly Variola virus.

Conclusions

Given the high sensitivity and the ease of handling, the novel assay could be highly useful for on-site diagnostics of suspected Monkeypox virus infections in areas lacking proper laboratory infrastructure as well as rapid on-site testing of suspected bioterrorism samples.

Electronic supplementary material

The online version of this article (doi:10.1186/s12985-016-0665-5) contains supplementary material, which is available to authorized users.

Species-specific differentiation of variola, monkeypox, and varicella-zoster viruses by multiplex real-time PCR assay

A method of one-stage rapid detection and differentiation of epidemiologically important variola virus (VARV), monkeypox virus (MPXV), and varicella-zoster virus (VZV) utilizing multiplex real-time TaqMan PCR assay was developed. Four hybridization probes with various fluorescent dyes and the corresponding fluorescence quenchers were simultaneously used for the assay. The hybridization probes specific for the VARV sequence contained FAM/BHQ1 as a dye/quencher pair; MPXV-specific, JOE/BHQ1; VZV-specific, TAMRA/BHQ2; and internal control-specific, Cy5/BHQ3. The specificity and sensitivity of the developed method were assessed by analyzing DNA of 32 strains belonging to orthopoxvirus and herpesvirus species.

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.

Simple technique for in field samples collection in the cases of skin rash illness and subsequent PCR detection of orthopoxviruses and varicella zoster virus

Background

In case of outbreak of rash illness in remote areas, clinically discriminating monkeypox (MPX) from severe form of chickenpox and from smallpox remains a concern for first responders.

Objective

The goal of the study was therefore to use MPX and chickenpox outbreaks in Democratic Republic of Congo (DRC) as a test case for establishing a rapid and specific diagnosis in affected remote areas.

Methods

In 2008 and 2009, successive outbreaks of presumed MPX skin rash were reported in Bena Tshiadi, Yangala and Ndesha healthcare districts of the West Kasai province (DRC). Specimens consisting of liquid vesicle dried on filter papers or crusted scabs from healing patients were sampled by first responders. A field analytical facility was deployed nearby in order to carry out a real-time PCR (qPCR) assay using genus consensus primers, consensus orthopoxvirus (OPV) and smallpox-specific probes spanning over the 14 kD fusion protein encoding gene. A PCR-restriction fragment length polymorphism was used on-site as backup method to confirm the presence of monkeypox virus (MPXV) in samples. To complete the differential diagnosis of skin rash, chickenpox was tested in parallel using a commercial qPCR assay. In a post-deployment step, a MPXV-specific pyrosequencing was carried out on all biotinylated amplicons generated on-site in order to confirm the on-site results.

Results

Whereas MPXV proved to be the agent causing the rash illness outbreak in the Bena Tshiadi, VZV was the causative agent of the disease in Yangala and Ndesha districts. In addition, each on-site result was later confirmed by MPXV-specific pyrosequencing analysis without any discrepancy.

Conclusion

This experience of rapid on-site dual use DNA-based differential diagnosis of rash illnesses demonstrates the potential of combining tests specifically identifying bioterrorism agents and agents causing natural outbreaks. This opens the way to rapid on-site DNA-based identification of a broad spectrum of causative agents in remote areas.

Evaluation of disease and viral biomarkers as triggers for therapeutic intervention in respiratory mousepox - an animal model of smallpox

The human population is currently faced with the potential use of natural or recombinant variola and monkeypox viruses as biological weapons. Furthermore, the emergence of human monkeypox in Africa and its expanding environs poses a significant natural threat. Such occurrences would require therapeutic and prophylactic intervention with antivirals to minimize morbidity and mortality of exposed populations. Two orally-bioavailable antivirals are currently in clinical trials; namely CMX001, an ether-lipid analog of cidofovir with activity at the DNA replication stage and ST-246, a novel viral egress inhibitor. Both of these drugs have previously been evaluated in the ectromelia/mousepox system; however, the trigger for intervention was not linked to a disease biomarker or a specific marker of virus replication. In this study we used lethal, intranasal, ectromelia virus infections of C57BL/6 and hairless SKH1 mice to model human disease and evaluate exanthematous rash (rash) as an indicator to initiate antiviral treatment. We show that significant protection can be provided to C57BL/6 mice by CMX001 or ST-246 when therapy is initiated on day 6 post infection or earlier. We also show that significant protection can be provided to SKH1 mice treated with CMX001 at day 3 post infection or earlier, but this is four or more days before detection of rash (ST-246 not tested). Although in this model rash could not be used as a treatment trigger, viral DNA was detected in blood by day 4 post infection and in the oropharyngeal secretions (saliva) by day 2–3 post infection – thus providing robust and specific markers of virus replication for therapy initiation. These findings are discussed in the context of current respiratory challenge animal models in use for the evaluation of poxvirus antivirals.

Serologic evidence of human orthopoxvirus infections in Sierra Leone

Background

Orthopoxviruses, including variola virus, vaccinia virus, and monkeypox virus, have previously been documented in humans in West Africa, however, no cases of human orthopoxvirus infection have been reported in the region since 1986. We conducted a serosurvey to determine whether human exposure to orthopoxviruses continues to occur in eastern Sierra Leone.

Findings

To examine evidence of exposure to orthopoxviruses in the Kenema District of Sierra Leone, we collected and tested sera from 1596 persons by IgG ELISA and a subset of 313 by IgM capture ELISA. Eleven persons born after the cessation of smallpox vaccination had high orthopoxvirus-specific IgG values, and an additional 6 persons had positive IgM responses. No geographic clustering was noted.

Conclusions

These data suggest that orthopoxviruses continue to circulate in Sierra Leone. Studies aimed at obtaining orthopoxvirus isolates and/or genetic sequences from rodents and symptomatic humans in the area are indicated.

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.