Seroprevalence and Risk Factors Possibly Associated with Emerging Zoonotic Vaccinia Virus in a Farming Community, Colombia

Poxvirus Epidemiology

Illnesses caused by poxviruses have plagued humanity for millennia. The most notable are caused by viruses comprising the orthopoxvirus genus. Smallpox (caused by Variola virus) became the first eradicated disease in 1980. Devotion to smallpox eradication required significant orthopoxvirus research and discovery including vaccine and medical countermeasure development. Here we describe historical and current poxvirus epidemiology, with particular emphasis on orthopoxviruses including Monkeypox virus and Vaccinia virus.

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

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

Structural and functional insights into the helicase protein E5 of Mpox virus

Mpox virus (MPXV) can cause mpox in humans. Due to its quick and wide spread in the past two years, mpox has turned into a significant public health concern. Helicase E5 is a multi-domain protein; its primer synthesis and DNA unwinding activity are required for genome uncoating and DNA replication of MPXV. However, the in vitro DNA unwinding activity has never been demonstrated. Here, we report the structural and biochemical studies of MPXV E5, showing that the full-length protein adopts an auto-inhibited conformation. Truncation of the N-terminus can recover the in vitro unwinding activity of E5 towards the forked DNA. Further structural analysis reveals that MPXV E5 shares a conserved mechanism in DNA unwinding and primer synthesis with the homologous proteins. These findings not only advance our understanding on the function of MPXV E5, but also provide a solid basis for the development of anti-poxvirus drugs.

Bioinformatics-based screening tool identifies a wide variety of human and zoonotic viruses in Trujillo-Peru wastewater

Peru was one of the most affected countries during the COVID-19 pandemic. Moreover, multiple other viral diseases (enteric, respiratory, bloodborne, and vector-borne) are endemic and rising. According to Peru's Ministry of Health, various health facilities in the country were reallocated for the COVID-19 pandemic, thereby leading to reduced action to curb other diseases. Many viral diseases in the area are under-reported and not recognized. The One Health approach, in addition to clinical testing, incorporates environmental surveillance for detection of infectious disease outbreaks. The purpose of this work is to use a screening tool that is based on molecular methods, high throughput sequencing and bioinformatics analysis of wastewater samples to identify virus-related diseases circulating in Trujillo-Peru. To demonstrate the effectiveness of the tool, we collected nine untreated wastewater samples from the Covicorti wastewater utility in Trujillo-Peru on October 22, 2022. High throughput metagenomic sequencing followed by bioinformatic analysis was used to assess the viral diversity of the samples. Our results revealed the presence of sequences associated with multiple human and zoonotic viruses including Orthopoxvirus, Hepatovirus, Rhadinovirus, Parechovirus, Mamastrovirus, Enterovirus, Varicellovirus, Norovirus, Kobuvirus, Bocaparvovirus, Simplexvirus, Spumavirus, Orthohepevirus, Cardiovirus, Molliscipoxvirus, Salivirus, Parapoxvirus, Gammaretrovirus, Alphavirus, Lymphocryptovirus, Erythroparvovirus, Sapovirus, Cosavirus, Deltaretrovirus, Roseolovirus, Flavivirus, Betacoronavirus, Rubivirus, Lentivirus, Betapolyomavirus, Rotavirus, Hepacivirus, Alphacoronavirus, Mastadenovirus, Cytomegalovirus and Alphapapillomavirus. For confirmation purposes, we tested the samples for the presence of selective viruses belonging to the genera detected above. PCR based molecular methods confirmed the presence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), monkeypox virus (MPXV), noroviruses GI and GII (NoVGI and NoVGII), and rotavirus A (RoA) in our samples. Furthermore, publicly available clinical data for selected viruses confirm our findings. Wastewater or other environmental media surveillance, combined with bioinformatics methods, has the potential to serve as a systematic screening tool for the identification of human or zoonotic viruses that may cause disease. The results of this method can guide further clinical surveillance efforts and allocation of resources. Incorporation of this bioinformatic-based screening tool by public health officials in Peru and other Latin American countries will help manage endemic and emerging diseases that could save human lives and resources.

The global landscape of smallpox vaccination history and implications for current and future orthopoxvirus susceptibility: a modelling study

BACKGROUND

More than four decades after the eradication of smallpox, the ongoing 2022 monkeypox outbreak and increasing transmission events of other orthopoxviruses necessitate a greater understanding of the global distribution of susceptibility to orthopoxviruses. We aimed to characterise the current global landscape of smallpox vaccination history and orthopoxvirus susceptibility.

METHODS

We characterised the global landscape of smallpox vaccination at a subnational scale by integrating data on current demography with historical smallpox vaccination programme features (coverage and cessation dates) from eradication documents and published literature. We analysed this landscape to identify the factors that were most associated with geographical heterogeneity in current vaccination coverage. We considered how smallpox vaccination history might translate into age-specific susceptibility profiles for orthopoxviruses under different vaccination effectiveness scenarios.

FINDINGS

We found substantial global spatial heterogeneity in the landscape of smallpox vaccination, with vaccination coverage estimated to range from 7% to 60% within admin-1 regions (ie, regions one administrative level below country) globally, with negligible uncertainty (99·6% of regions have an SD less than 5%). We identified that geographical variation in vaccination coverage was driven mostly by differences in subnational demography. Additionally, we found that susceptibility for orthopoxviruses was highly age specific based on age at cessation and age-specific coverage; however, the age profile was consistent across vaccine effectiveness values.

INTERPRETATION

The legacy of smallpox eradication can be observed in the current landscape of smallpox vaccine protection. The strength and longevity of smallpox vaccination campaigns globally, combined with current demographic heterogeneity, have shaped the epidemiological landscape today, revealing substantial geographical variation in orthopoxvirus susceptibility. This study alerts public health decision makers to non-endemic regions that might be at greatest risk in the case of widespread and sustained transmission in the 2022 monkeypox outbreak and highlights the importance of demography and fine-scale spatial dynamics in predicting future public health risks from orthopoxviruses.

FUNDING

US National Institutes of Health and US National Science Foundation.

Smallpox, Monkeypox and Other Human Orthopoxvirus Infections

Considering that vaccination against smallpox with live vaccinia virus led to serious adverse effects in some cases, the WHO, after declaration of the global eradication of smallpox in 1980, strongly recommended to discontinue the vaccination in all countries. This led to the loss of immunity against not only smallpox but also other zoonotic orthopoxvirus infections in humans over the past years. An increasing number of human infections with zoonotic orthopoxviruses and, first of all, monkeypox, force us to reconsider a possible re-emergence of smallpox or a similar disease as a result of natural evolution of these viruses. The review contains a brief analysis of the results of studies on genomic organization and evolution of human pathogenic orthopoxviruses, development of modern methods for diagnosis, vaccination, and chemotherapy of smallpox, monkeypox, and other zoonotic human orthopoxvirus infections.

Enhancing the Immunogenicity of Vaccinia Virus

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

[Mutations in the A34R gene increase the immunogenicity of vaccinia virus]

Самым простым и надежным способом защиты от вирусных инфекций является вакцинопрофилактика. При этом наибольшей протективной эффективностью обладают живые вакцины, в основе которых используют слабовирулентные для человека вирусы, близкородственные патогенным, или аттенуированные (ослабленные за счет мутаций/делеций в вирусном геноме) варианты патогенного для человека вируса. Вакцинация против оспы с использованием живого вируса осповакцины (vaccinia virus, VACV), близкородственного вирусу натуральной оспы, сыграла важнейшую роль в успехе программы глобальной ликвидации оспы, которая осуществлялась под эгидой Всемирной организации здравоохранения. Прекращение после 1980 г. противооспенной вакцинации привело к тому, что огромная часть населения Земли в настоящее время не имеет иммунитета не только к оспе, но и любым другим зоонозным ортопоксвирусным инфекциям. Это создает возможность циркуляции зоонозных ортопоксвирусов в человеческой популяции и, как следствие, приводит к изменению экологии и круга чувствительных хозяев для разных видов ортопоксвирусов. При этом использование классической живой вакцины на основе VACV для защиты от этих инфекций в настоящее время не приемлемо, так как она может обусловливать тяжелые побочные реакции. В связи с этим все более актуальной становится разработка новых безопасных вакцин против ортопоксвирусных инфекций человека и животных. Аттенуация (ослабление вирулентности) VACV достигается в результате направленной инактивации определенных генов вируса и обычно приводит к уменьшению эффективности размножения VACV in vivo. Следствием этого может быть снижение иммунного ответа при введении аттенуированного вируса пациентам в стандартных дозах. Часто используемым для встройки/инактивации в геноме VACV является ген тимидинкиназы, нарушение которого приводит к аттенуации вируса. В данной работе изучено, как введение двух точечных мутаций в ген A34R аттенуированного штамма LIVP-GFP (ТК-), увеличивающих выход внеклеточных оболочечных вирионов (EEV), влияет на свойства пато- и иммуногенности варианта VACV LIVP-GFP-A34R при интраназальном заражении лабораторных мышей. Показано, что увеличение продукции EEV рекомбинантным штаммом VACV LIVP-GFP-A34R не меняет аттенуированный фенотип, характерный для родительского штамма LIVP-GFP, но приводит к существенно большей продукции VACV-специфичных антител. Ключевые слова: вирус осповакцины; направленные мутации; аттенуация; иммуногенность.

The Disease Ecology, Epidemiology, Clinical Manifestations, Management, Prevention, and Control of Increasing Human Infections with Animal Orthopoxviruses

Zoonotic orthopoxvirus outbreaks have occurred repeatedly worldwide, including monkeypox in Africa and the United States, cowpox in Europe, camelpox in the Middle East and India, buffalopox in India, vaccinia in South America, and novel emerging orthopoxvirus infections in the United States, Europe, Asia, and South America. Waning smallpox immunity may increase the potential for animal-to-human transmission followed by further community transmission person-to-person (as demonstrated by monkeypox and buffalopox outbreaks) and by contact with fomites (as demonstrated by camelpox, cowpox, and, possibly, Alaskapox). The objectives of this review are to describe the disease ecology, epidemiology, clinical manifestations, prevention, and control of human infections with animal orthopoxviruses and to discuss the association with diminished population herd immunity formerly induced by vaccinia vaccination against smallpox. Internet search engines were queried with key words, and case reports, case series, seroprevalence studies, and epidemiologic investigations were found for review.

Twenty Years after Bovine Vaccinia in Brazil: Where We Are and Where Are We Going?

Orthopoxvirus (OPV) infections have been present in human life for hundreds of years. It is known that Variola virus (VARV) killed over 300 million people in the past; however, it had an end thanks to the physician Edward Jenner (who developed the first vaccine in history) and also thanks to a massive vaccination program in the 20th century all over the world. Although the first vaccine was created using the Cowpox virus (CPXV), it turned out later that the Vaccinia virus was the one used during the vaccination program. VACV is the etiological agent of bovine vaccinia (BV), a zoonotic disease that has emerged in Brazil and South America in the last 20 years. BV has a great impact on local dairy economies and is also a burden to public health. In this review, we described the main events related to VACV and BV emergence in Brazil and South America, the increase of related scientific studies, and the issues that science, human and animal medicine are going to face if we do not be on guard to this virus and its disease.

Enhancing the Protective Immune Response to Administration of a LIVP-GFP Live Attenuated Vaccinia Virus to Mice

Following the WHO announcement of smallpox eradication, discontinuation of smallpox vaccination with vaccinia virus (VACV) was recommended. However, interest in VACV was soon renewed due to the opportunity of genetic engineering of the viral genome by directed insertion of foreign genes or introduction of mutations or deletions into selected viral genes. This genomic technology enabled production of stable attenuated VACV strains producing antigens of various infectious agents. Due to an increasing threat of human orthopoxvirus re-emergence, the development of safe highly immunogenic live orthopoxvirus vaccines using genetic engineering methods has been the challenge in recent years. In this study, we investigated an attenuated VACV LIVP-GFP (TK^-) strain having an insertion of the green fluorescent protein gene into the viral thymidine kinase gene, which was generated on the basis of the LIVP (Lister-Institute for Viral Preparations) strain used in Russia as the first generation smallpox vaccine. We studied the effect of A34R gene modification and A35R gene deletion on the immunogenic and protective properties of the LIVP-GFP strain. The obtained data demonstrate that intradermal inoculation of the studied viruses induces higher production of VACV-specific antibodies compared to their levels after intranasal administration. Introduction of two point mutations into the A34R gene, which increase the yield of extracellular enveloped virions, and deletion of the A35R gene, the protein product of which inhibits presentation of antigens by MHC II, enhances protective potency of the created LIVP-TK^--A34R*-dA35R virus against secondary lethal orthopoxvirus infection of BALB/c mice even at an intradermal dose as low as 10³ plaque forming units (PFU)/mouse. This virus may be considered not only as a candidate attenuated live vaccine against smallpox and other human orthopoxvirus infections but also as a vector platform for development of safe multivalent live vaccines against other infectious diseases using genetic engineering methods.

Genomic diversity of vaccinia virus strain Cantagalo isolated in southeastern Brazil during the early years of the outbreak, 1999-2006

Outbreaks of a vesiculopustular disease in dairy cattle and milkers have been frequently reported in Brazil since 1999 when the vaccinia virus strain Cantagalo was first isolated in the State of Rio de Janeiro. However, the genomic diversity of the viral isolates associated with these outbreaks is not well known, particularly in the southeastern states that represent the focal point of virus spread to other regions. Here, we report the genomic sequences and an analysis of the polymorphic site profiles and genotypic diversity of four clinical isolates of vaccinia virus strain Cantagalo collected from 1999 to 2006 in southeastern Brazil.

The Influence of an Elevated Production of Extracellular Enveloped Virions of the Vaccinia Virus on Its Properties in Infected Mice

The modern approach to developing attenuated smallpox vaccines usually consists in targeted inactivation of vaccinia virus (VACV) virulence genes. In this work, we studied how an elevated production of extracellular enveloped virions (EEVs) and the route of mouse infection can influence the virulence and immunogenicity of VACV. The research subject was the LIVP strain, which is used in Russia for smallpox vaccination. Two point mutations causing an elevated production of EEVs compared with the parental LIVP strain were inserted into the sequence of the VACV A34R gene. The created mutant LIVP-A34R strain showed lower neurovirulence in an intracerebral injection test and elevated antibody production in the intradermal injection method. This VACV variant can be a promising platform for developing an attenuated, highly immunogenic vaccine against smallpox and other orthopoxvirus infections. It can also be used as a vector for designing live-attenuated recombinant polyvalent vaccines against various infectious diseases.

Antiviral effect of Hornstedtia bella Škorničk essential oil from the whole plant against vaccinia virus (VV)

In the prevention of epidemic and pandemic emerging and neglected viral infections, natural products are an important source of lead compounds. Hornstedtia bella Škorničkis is a rhizomatous herb growing in the forest of central Vietnam. Hornstedtia bella essential oil (Hb EO) was recently characterised by our group as endowed of antimicrobial activity against Staphylococcus aureus Methicillin-Resistant strains. Here, we describe for the first time the evaluation of Hb EO against a spectrum of viruses responsible for important human diseases. Hb EO resulted active against Vaccinia virus (VV) (EC₅₀ values 80 μg/mL), closely related to variola virus, causative agent of smallpox. Hb EO was able to strongly reduce the viral VV titer in cell-based assay at not cytotoxic concentration and its potential mode of action was characterised by virucidal activity evaluation followed by time-of-addition assay. Furthermore, Hb EO antiviral activity was implemented in a combination study with the mycophenolic acid.