Human cowpox virus infection acquired from a circus elephant in Germany

Cross-species transmission and host range genes in poxviruses

The persistent epidemic of human mpox, caused by mpox virus (MPXV), raises concerns about the future spread of MPXV and other poxviruses. MPXV is a typical zoonotic virus which can infect human and cause smallpox-like symptoms. MPXV belongs to the Poxviridae family, which has a relatively broad host range from arthropods to vertebrates. Cross-species transmission of poxviruses among different hosts has been frequently reported and resulted in numerous epidemics. Poxviruses have a complex linear double-strand DNA genome that encodes hundreds of proteins. Genes related to the host range of poxvirus are called host range genes (HRGs). This review briefly introduces the taxonomy, phylogeny and hosts of poxviruses, and then comprehensively summarizes the current knowledge about the cross-species transmission of poxviruses. In particular, the HRGs of poxvirus are described and their impacts on viral host range are discussed in depth. We hope that this review will provide a comprehensive perspective about the current progress of researches on cross-species transmission and HRG variation of poxviruses, serving as a valuable reference for academic studies and disease control in the future.

Poxviruses from the Concept of One Health

In the last 4 years, the world has experienced two pandemics of bat-borne viruses. Firstly, in 2019 the SARS-CoV-2 pandemic started and has been causing millions of deaths around the world. In 2022, a Monkeypox pandemic rose in various countries of the world. Those pandemics have witnessed movements and initiatives from healthcare and research institutions to establish a worldwide understanding to battle any future pandemics and biological threats. One Health concept is a modern, comprehensive, unifying ways to improve humans, animals, and ecosystems' health. This concept shows how much they are intertwined and related to one another, whether it is an environmental, or a pathological relation. This review aims to describe Poxviridae and its impact on the One Health concept, by studying the underlying causes of how poxviruses can affect the health of animals, humans, and environments. Reviewing the effect of disease transmission between animal to human, human to human, and animal to animal with pox viruses as a third party to achieve a total understanding of infection and viral transmission. Thus, contributing to enhance detection, diagnosis, research, and treatments regarding the application of One Health.

From high-flying trapeze to highly infectiousdisease: The history of dermatology in the circus

There is fascination with the bright lights and high-risk stunts of circus performances that originated in 18th-century Paris. The idea began as a way to display the impressive horsemanship skills of trick-riders. In London, England, former cavalry Sergeant-Major Philip Astley (1742-1814) created a grand performance of horseback riders by adding several unique acts to distinguish his show. Astley's original riding school would later become his own circus, the Amphitheatre Anglais. By 1782, the Amphitheatre Anglais could boast of performances by acrobats, jugglers, gymnasts, and tight-rope walkers. Since then, the circus, as the concept became formally known, has grown worldwide. With its development, however, several unanticipated occurrences have followed, including various dermatologic pathologies. High physical demands on circus performers and close physical contact led to cellulitis, pyoderma, callosities, and various other soft tissue manifestations. However, some members of the circus family were, in fact, chosen due to their genetic and acquired aesthetic abnormalities: the more grotesque, the more sought after.

Fatal Cowpox Virus Infection in Human Fetus, France, 2017

Cowpox virus (CPXV) has an animal reservoir and is typically transmitted to humans by contact with infected animals. In 2017, CPXV infection of a pregnant woman in France led to the death of her fetus. Fetal death after maternal orthopoxvirus (smallpox) vaccination has been reported; however, this patient had not been vaccinated. Investigation of the patient’s domestic animals failed to demonstrate prevalence of CPXV infection among them. The patient’s diagnosis was confirmed by identifying CPXV DNA in all fetal and maternal biopsy samples and infectious CPXV in biopsy but not plasma samples. This case of fetal death highlights the risk for complications of orthopoxvirus infection during pregnancy. Among orthopoxviruses, fetal infection has been reported for variola virus and vaccinia virus; our findings suggest that CPXV poses the same threats for infection complications as vaccinia virus.

What a Difference a Gene Makes: Identification of Virulence Factors of Cowpox Virus

Cowpox virus (CPXV) is a zoonotic orthopoxvirus (OPV) that causes spillover infections from its animal hosts to humans. In 2009, several human CPXV cases occurred through transmission from pet rats. An isolate from a diseased rat, RatPox09, exhibited significantly increased virulence in Wistar rats and caused high mortality compared to that caused by the mildly virulent laboratory strain Brighton Red (BR). The RatPox09 genome encodes four genes which are absent in the BR genome. We hypothesized that their gene products could be major factors influencing the high virulence of RatPox09. To address this hypothesis, we employed several BR-RatPox09 chimeric viruses. Using Red-mediated mutagenesis, we generated BR-based knock-in mutants with single or multiple insertions of the respective RatPox09 genes. High-throughput sequencing was used to verify the genomic integrity of all recombinant viruses, and transcriptomic analyses confirmed that the expression profiles of the genes that were adjacent to the modified ones were unaltered. While the in vitro growth kinetics were comparable to those of BR and RatPox09, we discovered that a knock-in BR mutant containing the four RatPox09-specific genes was as virulent as the RatPox09 isolate, causing death in over 75% of infected Wistar rats. Unexpectedly, the insertion of gCPXV0030 (g7tGP) alone into the BR genome resulted in significantly higher clinical scores and lower survival rates matching the rate for rats infected with RatPox09. The insertion of gCPXV0284, encoding the BTB (broad-complex, tramtrack, and bric-à-brac) domain protein D7L, also increased the virulence of BR, while the other two open reading frames failed to rescue virulence independently. In summary, our results confirmed our hypothesis that a relatively small set of four genes can contribute significantly to CPXV virulence in the natural rat animal model.IMPORTANCE With the cessation of vaccination against smallpox and its assumed cross-protectivity against other OPV infections, waning immunity could open up new niches for related poxviruses. Therefore, the identification of virulence mechanisms in CPXV is of general interest. Here, we aimed to identify virulence markers in an experimental rodent CPXV infection model using bacterial artificial chromosome (BAC)-based virus recombineering. We focused our work on the recent zoonotic CPXV isolate RatPox09, which is highly pathogenic in Wistar rats, unlike the avirulent BR reference strain. In several animal studies, we were able to identify a novel set of CPXV virulence genes. Two of the identified virulence genes, encoding a putative BTB/POZ protein (CPXVD7L) and a B22R-family protein (CPXV7tGP), respectively, have not yet been described to be involved in CPXV virulence. Our results also show that single genes can significantly affect virulence, thus facilitating adaptation to other hosts.

Use of Next Generation Sequencing to study two cowpox virus outbreaks

Background

Between 2008 and 2011 about 40 cases of human cowpox were reported from Germany and France. Infections had been acquired via close contact to infected, young pet rats. An identical and unique sequence of the hemagglutinin gene was found in various cowpox virus (CPXV) isolates pointing to a common source of infection. In a second CPXV outbreak in cats in a small animal clinic in Germany in 2015, four out of five hospitalized cats showed identical hemagglutinin sequences and thus, a hospital-acquired transmission had been assumed. Next-Generation Sequencing was performed in order to re-investigate the outbreaks, as epidemiological data could not confirm all cases.

Methods

Homogenates of lesion material from rats, cats and humans were cultivated in cell culture. The genomes of four virus isolates, nine CPXVs from our strain collections and from DNA of three paraffin-embedded lesion materials were determined by Next Generation Sequencing (NGS). For phylogenetic analyses a MAFFT-alignment was generated. A distance matrix based on concatenated SNPs was calculated and plotted as dendrogram using Unweighted Pair Group Method with Arithmetic mean (UPGMA) for visualization.

Results

Aligning of about 200.000 nucleotides of 8 virus isolates associated with the pet rat outbreak revealed complete identity of six genomes, the remainder two genomes differed in as little as 3 SNPs. When comparing this dataset with four already published CPXV genomes also associated with the pet rat outbreak, again a maximum difference of 3 SNPs was found. The outbreak which lasted from 2008 till 2011 was indeed caused by a single strain which has maintained an extremely high level of clonality over 4 years. Aligning genomic sequences from four cases of feline cowpox revealed 3 identical sequences and one sequence which differed in 65 nucleotides. Although identical hemagglutinin sequences had been obtained from four hospitalized cats, genomic sequencing proved that a hospital-acquired transmission had occurred in only three cats.

Conclusion

Analyzing the rather short sequence of the hemagglutinin gene is not sufficient to conduct molecular trace back analyses. Instead, whole genome sequencing is the method of choice which can even be applied to paraffin-embedded specimens.

Atypical Cowpox Virus Infection in a Series of Cats

Within 4 weeks, five cats with skin lesions affecting the hindlimbs and mainly consisting of oedema, hyperaemia and plaque-like alterations were presented to the same veterinary clinic. The cats were suffering from lameness, trauma, renal insufficiency or complicated tail amputation. Although the lesions seemed unusual for a poxvirus infection, microscopical examination of biopsy samples or specimens taken during necropsy examination revealed ballooning degeneration of keratinocytes with eosinophilic, cytoplasmic inclusion bodies indicative of an orthopoxvirus infection. Cowpox virus infection was verified using immunohistochemistry and virus isolation. Molecular analysis revealed identical haemagglutinin gene sequences in four cases and spatiotemporal circumstances in some cases pointed to hospital-acquired transmission. Unusual manifestations of feline cowpox may have an unexpected risk for human infection.

Revisiting Jenner's mysteries, the role of the Beaugency lymph in the evolutionary path of ancient smallpox vaccines

In 1796, Edward Jenner developed the smallpox vaccine consisting of pustular material obtained from lesions on cows affected by so-called cow-pox. The disease, caused by cowpox virus, confers crossprotection against smallpox. However, historical evidence suggests that Jenner might have used vaccinia virus or even horsepox virus instead of cowpox virus. Mysteries surrounding the origin and nature of the smallpox vaccine persisted during the 19th century, a period of intense exchange of vaccine strains, including the Beaugency lymph. This lymph was obtained from spontaneous cases of cow-pox in France in 1866 and then distributed worldwide. A detailed Historical Review of the distribution of the Beaugency lymph supports recent genetic analyses of extant vaccine strains, suggesting the lymph was probably a vaccinia strain or a horsepox-like virus. This Review is a historical investigation that revisits the mysteries of the smallpox vaccine and reveals an intricate evolutionary relationship of extant vaccinia strains.

Classification of Cowpox Viruses into Several Distinct Clades and Identification of a Novel Lineage

Cowpox virus (CPXV) was considered as uniform species within the genus Orthopoxvirus (OPV). Previous phylogenetic analysis indicated that CPXV is polyphyletic and isolates may cluster into different clades with two of these clades showing genetic similarities to either variola (VARV) or vaccinia viruses (VACV). Further analyses were initiated to assess both the genetic diversity and the evolutionary background of circulating CPXVs. Here we report the full-length sequences of 20 CPXV strains isolated from different animal species and humans in Germany. A phylogenetic analysis of altogether 83 full-length OPV genomes confirmed the polyphyletic character of the species CPXV and suggested at least four different clades. The German isolates from this study mainly clustered into two CPXV-like clades, and VARV- and VACV-like strains were not observed. A single strain, isolated from a cotton-top tamarin, clustered distantly from all other CPXVs and might represent a novel and unique evolutionary lineage. The classification of CPXV strains into clades roughly followed their geographic origin, with the highest clade diversity so far observed for Germany. Furthermore, we found evidence for recombination between OPV clades without significant disruption of the observed clustering. In conclusion, this analysis markedly expands the number of available CPXV full-length sequences and confirms the co-circulation of several CPXV clades in Germany, and provides the first data about a new evolutionary CPXV lineage.

Evidence of zoonotic Poxviridae coinfections in clinically diagnosed papillomas using a newly developed mini-array test

Our study describes a newly developed mini-array test for the rapid detection of poxviruses in animals and humans. The method is based on detection that combines target nucleic acid amplification by polymerase chain reaction and specific hybridization, using enzyme-linked antibodies, allowing identification of zoonotic orthopoxviruses and parapoxviruses in animal and human biological samples. With 100% specificity, the test rules out the possibility of cross-reactions with viral agents causing look-alike diseases. The assay was employed in the field to investigate the causes of several outbreaks of a malignant proliferative skin disease that affected domestic ruminants in Sicily during 2011-2014. Due to specific aspects of the lesions, the animals were clinically diagnosed with papillomatosis. The mini-array test allowed the identification of coinfections caused by more than 1 viral species belonging to the Parapoxvirus and Orthopoxvirus genera, either in goats or in cattle. Our study suggests that the so-called "papillomatosis" can be the result of multiple infections with epitheliotropic viruses, including zoonotic poxviruses that cannot be properly identified with classical diagnostic techniques.

Investigation of the first laboratory-acquired human cowpox virus infection in the United States

BACKGROUND

Cowpox virus is an Orthopoxvirus that can cause infections in humans and a variety of animals. Infections occur in Eurasia; infections in humans and animals have not been reported in the United States. This report describes the occurrence of the first known human case of laboratory-acquired cowpox virus infection in the United States and the ensuing investigation.

METHODS

The patient and laboratory personnel were interviewed, and laboratory activities were reviewed. Real-time polymerase chain reaction (PCR) and serologic assays were used to test the patient's specimens. PCR assays were used to test specimens obtained during the investigation.

RESULTS

A specimen from the patient's lesion tested positive for cowpox virus DNA. Genome sequencing revealed a recombinant region consistent with a strain of cowpox virus stored in the research laboratory's freezer. Cowpox virus contamination was detected in 6 additional laboratory stocks of viruses. Orthopoxvirus DNA was present in 3 of 20 environmental swabs taken from laboratory surfaces.

CONCLUSIONS

The handling of contaminated reagents or contact with contaminated surfaces was likely the mode of transmission. Delays in recognition and diagnosis of this infection in a laboratory researcher underscore the importance of a thorough patient history-including occupational information-and laboratory testing in facilitating a prompt investigation and application of control and remediation measures.

Mutations conferring resistance to viral DNA polymerase inhibitors in camelpox virus give different drug-susceptibility profiles in vaccinia virus

Cidofovir or (S)-HPMPC is one of the three antiviral drugs that might be used for the treatment of orthopoxvirus infections. (S)-HPMPC and its 2,6-diaminopurine counterpart, (S)-HPMPDAP, have been described to select, in vitro, for drug resistance mutations in the viral DNA polymerase (E9L) gene of vaccinia virus (VACV). Here, to extend our knowledge of drug resistance development among orthopoxviruses, we selected, in vitro, camelpox viruses (CMLV) resistant to (S)-HPMPDAP and identified a single amino acid change, T831I, and a double mutation, A314V+A684V, within E9L. The production of recombinant CMLV and VACV carrying these amino acid substitutions (T831I, A314V, or A314V+A684V) demonstrated clearly their involvement in conferring reduced sensitivity to viral DNA polymerase inhibitors, including (S)-HPMPDAP. Both CMLV and VACV harboring the A314V change showed comparable drug-susceptibility profiles to various antivirals and similar impairments in viral growth. In contrast, the single change T831I and the double change A314V+A684V in VACV were responsible for increased levels of drug resistance and for cross-resistance to viral DNA polymerase antivirals that were not observed with their CMLV counterparts. Each amino acid change accounted for an attenuated phenotype of VACV in vivo. Modeling of E9L suggested that the T→I change at position 831 might abolish hydrogen bonds between E9L and the DNA backbone and have a direct impact on the incorporation of the acyclic nucleoside phosphonates. Our findings demonstrate that drug-resistance development in two related orthopoxvirus species may impact drug-susceptibility profiles and viral fitness differently.

Zoonotic Poxviruses Associated with Companion Animals

Simple Summary

Contemporary enthusiasm for the ownership of exotic animals and hobby livestock has created an opportunity for the movement of poxviruses—such as monkeypox, cowpox, and orf—outside their traditional geographic range bringing them into contact with atypical animal hosts and groups of people not normally considered at risk. It is important that pet owners and practitioners of human and animal medicine develop a heightened awareness for poxvirus infections and understand the risks that can be associated with companion animals and livestock. This article reviews the epidemiology and clinical features of zoonotic poxviruses that are most likely to affect companion animals.

Abstract

Understanding the zoonotic risk posed by poxviruses in companion animals is important for protecting both human and animal health. The outbreak of monkeypox in the United States, as well as current reports of cowpox in Europe, point to the fact that companion animals are increasingly serving as sources of poxvirus transmission to people. In addition, the trend among hobbyists to keep livestock (such as goats) in urban and semi-urban areas has contributed to increased parapoxvirus exposures among people not traditionally considered at high risk. Despite the historic notoriety of poxviruses and the diseases they cause, poxvirus infections are often missed. Delays in diagnosing poxvirus-associated infections in companion animals can lead to inadvertent human exposures. Delays in confirming human infections can result in inappropriate treatment or prolonged recovery. Early recognition of poxvirus-associated infections and application of appropriate preventive measures can reduce the spread of virus between companion animals and their owners. This review will discuss the epidemiology and clinical features associated with the zoonotic poxvirus infections most commonly associated with companion animals.

Necrotic ulcerated lesion in a young boy caused by cowpox virus infection

The case presented here points towards the fact that skin lesion observed with a cowpox virus is a rare event but should be considered more as the number of cases has increased in the last years. Cowpox virus (CPXV) belongs to the Poxviridae family. The transmission of CPXV to humans is caused by wild rodents or mostly by domestic animals and pet rats. In humans, CPXV is responsible for localized skin lesions regularly accompanied by lymphadenopathy. The lesions remain localized but self-inoculation from the primary lesions could occur. Then physicians have to be vigilant concerning bandages. In this case report, a necrotic and ulcerated lesion of a CPXV infection in a young boy is reported. The CPXV was possibly transmitted by wild rodents. The importance of performing the diagnosis is also pointed out. Virus information was obtained from phylogenetic analyses showing that the CPXV isolate was distinct from outbreaks of human cowpox which occurred in 2009 in France and Germany but was close to the CPXV Brighton Red strain. For several years, cases of viral zoonosis caused by CPXV have increased and physicians should be made aware that people could be infected without history of direct contact with animals.

Experimental cowpox virus infection in rats

A pet rat derived cowpox virus strain, which was also the source of human infections, was used to infect young Wistar and fancy rats. After an incubation period of 6 days the animals developed a severe, often fatal disease with high amounts of virus detected in oropharyngeal secretions.