First record of experimentally induced salmon gill poxvirus disease (SGPVD) in Atlantic salmon (Salmo salar L.).

Salmon gill poxvirus (SGPV) infection is a common denominator in many cases of complex gill disease in the Norwegian salmon farming industry and may, as a single agent infection, result in salmon poxvirus disease (SGPVD). Experiences from the field suggest that stress may be a decisive factor for the induction of SGPVD. Here we investigated the effect of stress hormone treatment on SGPV kinetics and disease development. In our experiment, Atlantic salmon were divided into four groups. Two groups of fish received an intraperitoneal injection of hydrocortisone dissolved in a fatty vehicle, whereas fish in the other two groups received a sham injection of the vehicle. After 24 h, one group with hydrocortisone injection and one with sham injection were exposed to dead SGPV-infected fish. Plasma cortisol level, virus kinetics, virus localization, and pathological gill were monitored for 4 weeks post-exposure. Hydrocortisone injected fish displayed higher plasma cortisol and SGPV loads than non-hydrocortisone treated fish. Signs of SGPVD and ensuing mortality appeared only in fish exposed to the virus and injected with hydrocortisone around 2 weeks post-exposure. No clinical signs of disease or mortality were recorded in the other groups. Further, gill histopathology in diseased fish correlated well with SGPV load, with the infection apparently confined to gill epithelial cells. The current findings suggest elevated plasma cortisol being a prerequisite for the development of SGPVD and recommend minimization of stressful farming activities, particularly if SGPV infection has been previously identified.

Two cases of monkeypox imported to the United Kingdom, September 2018.

In early September 2018, two cases of monkeypox were reported in the United Kingdom (UK), diagnosed on 7 September in Cornwall (South West England) and 11 September in Blackpool (North West England). The cases were epidemiologically unconnected and had recently travelled to the UK from Nigeria, where monkeypox is currently circulating. We describe the epidemiology and the public health response for the first diagnosed cases outside the African continent since 2003.

Flavobacteria as secondary pathogens in carp suffering from koi sleepy disease.

Koi sleepy disease (KSD) is a disease with increasing importance in global common carp aquaculture. Despite the fact that carp edema virus (CEV) is most likely the causative agent of KSD, the disease often presents itself as multifactorial with several parasites and bacteria species present on gills, skin or in internal organs. Therefore, in this study, we analysed and presented initial results on an interaction of flavobacteria and CEV in the development of clinical KSD in carp suffering from proliferative gill disease. We examined selected field samples from Germany and Hungary and confirmed the presence of CEV and flavobacteria co-infections in subset of the samples. In several infection experiments, we studied the transfer and dynamics of both infections. Furthermore, we analysed which Flavobacterium species could be isolated from KSD-affected fish and concluded that Flavobacterium branchiophilum is a possible copathogen. Antibiotic treatment experiments showed that CEV seems to be the primary pathogen causing an insult to the gills of carp and by these enabling other pathogens, including F. branchiophilum, to establish co-infections. Despite the fact that F. branchiophilum co-infection is not required for the development of clinical KSD, it could contribute to the pathological changes recorded during the outbreaks.

Infection with diverse immune-modulating poxviruses elicits different compositional shifts in the mouse gut microbiome.

It is often not possible to demonstrate causality within the context of gut microbiota dysbiosis-linked diseases. Thus, we need a better understanding of the mechanisms whereby an altered host immunophysiology shapes its resident microbiota. In this regard, immune-modulating poxvirus strains and mutants could differentially alter gut mucosal immunity in the context of a natural immune response, providing a controlled natural in vivo setting to deepen our understanding of the immune determinants of microbiome composition. This study represents a proof-of-concept that the use of an existing collection of different immune-modulating poxviruses may represent an innovative tool in gut microbiome research. To this end, 16S rRNA amplicon sequencing and RNAseq transcriptome profiling were employed as proxies for microbiota composition and gut immunophysiological status in the analysis of caecal samples from control mice and mice infected with various poxvirus types. Our results show that different poxvirus species and mutants elicit different shifts in the mice mucosa-associated microbiota and, in some instances, significant concomitant shifts in gut transcriptome profiles, thus providing an initial validation to the proposed model.

[Recent developments in the diagnosis of parapoxviruses]. / Neuentwicklungen in der Diagnostik von Parapockenviren.

Neutralizing and non-neutralizing monoclonal antibodies against parapoxviruses (PPV) were generated by immunizing BALB/c-mice with gradient-purified PPV Orf D-1701 or purified envelopes. Epitope specificity studies identified three distinct epitopes localized in the virus envelope. These antigenic sites allowed a differentiation between orf and stomatitis papulosa viruses. For a rapid diagnosis of parapoxviruses transmission-electron microscopy, immunofluorescence- or immunoperoxidase-staining, antigen capture ELISA, and polymerase-chain-reaction were used.

[Congenital "ectromelia" in fur-bearing animals caused by Orthopoxvirus muris]. / Kongenitale "Ektromelie" bei Pelztieren durch Orthopoxvirus muris.

Orthopox virus infection is endemic in farms with fur-bearing animals in the Czech Republic (Bohemia and Moravia). This disease is called ectromelia of silver foxes and minks. The infection is congenitally transmitted and manifests itself in reproductive disorders, stillbirth or birth of sick neonates. Adult animals are usually free of clinical symptoms. The infective agent was isolated from recent outbreaks and was identified as a mouse pox virus (Orthopoxvirus muris) by its cultural and immunological characteristics. The significance of this pox virus infection, hitherto not described in Western Europe, is discussed.

Isolation and antibody prevalence of a parapoxvirus in wild Japanese serows (Capricornis crispus).

An epizootic suspected to be caused by parapoxviruses occurred in winter, 1984-85, among wild Japanese serows (Capricornis crispus) with nodular or papular lesions in Gifu Prefecture, Japan. Virus isolations were attempted on 30 animals using bovine fetal testicle cell cultures. Viral agents growing with cytopathic effects were isolated from six animals. The agents were identified as parapoxvirus from electron microscopic findings and physico-chemical characteristics. Antibody prevalence to the isolated agent, named S-1, was examined by enzyme-linked immunosorbent assay. No antibodies were detected among 153 sera obtained during two winters 1981-82 and 1982-83, but one of 189 sera collected in the winter of 1983-84 was positive. In contrast, 75 (32%) of 237 sera had antibodies to S-1 in 1984-85, when the disease was first detected. Antibody prevalences of 1984-85 were highest (39%) in December 1984, the first month of animal capture, and declined gradually to 20% in March 1985.

Differentiation of species of the genus Orthopoxvirus in a dot blot assay using digoxigenin-labeled DNA-probes.

A dot blot assay using five different digoxigenin-labeled probes was established for specific detection and differentiation of four species belonging to the genus Orthopoxvirus. As little as 20 pg orthopoxvirus DNA can be detected, corresponding to approximately 8 x 10(4) DNA molecules. A total of 37 orthopoxvirus strains and isolates of different origin were investigated and could be assigned to the species vaccinia, cowpox, camelpox, and mousepox virus. These findings agree with their identification by biological means. Additionally, a simple procedure to isolate orthopoxvirus DNA directly from scab material was developed. This allows a fast classification without isolating the virus.

Virological investigations of specimens from buffaloes affected by buffalopox in Maharashtra State, India between 1985 and 1987.

Isolates of poxviruses were made from thirteen of eighteen specimens of scabs taken from pox lesions on buffaloes in five different districts of Maharashtra State, India, between December, 1985 and February, 1987. The biological characters of twelve of the isolates resembled those of the Hissar strain of buffalopox virus; the thirteenth isolate appeared to be vaccinia. The Hin dIII restriction profiles of DNA from all 13 isolates and from the Hissar strain were typical of those given by vaccinia strains. DNA from all twelve Maharashtra buffalopox (BPV) isolates gave identical profiles with each of three additional endonucleases; these viruses appear to be repeated isolations of a single strain of BPV. The DNA profile of this strain was not the same as that of the Hissar strain of BPV and both could readily be distinguished from each of the three strains of vaccinia virus which had been used in India. The thirteenth Maharashtra isolate was indistinguishable from vaccinia in its biological properties, but the restriction profile of its DNA differed from those of three vaccinia strains and the BPV isolates. These observations, made 6-8 years after cessation of smallpox vaccination indicate that BPV is an emerging enzootic virus and is a subspecies of vaccinia virus.

Further characterization of the biological and pathogenic properties of erythromelalgia-related poxviruses.

Six isolates of erythromelalgia-related poxvirus (ERPV) were characterized with respect to host range, c.p.e. and inclusions, pock formation on chorioallantoic membrane (CAM), morphogenesis, serological reactivity, pathogenesis in animals and DNA restriction fragment profile. The results suggest that ERPV is either a new member of the Orthopoxvirus genus or a subspecies of ectromelia virus. Evidence is provided that (i) ERPV has a wide host range in vitro in which characteristic viral c.p.e. and inclusion bodies are induced; (ii) ERPV, unlike ectromelia virus, causes the formation of tiny greyish-white pocks on CAM both at 34 degrees C and 39 degrees C; (iii) eosinophilic A-type inclusions of ERPV do not contain viral particles; (iv) ERPV isolates are neutralized by both rabbit anti-vaccinia virus and mouse anti-ectromelia virus sera, but not vice versa; (v) young rabbits are not susceptible to ERPV by skin and/or corneal scratch infection even though ERPV is lethal for mice by intraperitoneal inoculation; (vi) the HindIII and SalI fragment profiles of ERPV P-4 DNA are similar to, but obviously different from, those of Chinese ectromelia virus. These biological and pathogenic characteristics of ERPV are distinguishable from those of other members of the genus Orthopoxvirus currently described in the literature.

[Parapox in a pigmy chimpanzee]. / Parapocken beim Zwergschimpansen.

Parapoxvirus was found using electron microscopy in skin scrapings from a pygmy chimpanzee with a pustular skin disease. Clinical findings are described and possible ways of transmission are discussed. It seems remarkable that this is the first time parapoxvirus has been diagnosed in a nonhuman primate.

Immunohistological detection of orthopox virus antigen.

This paper describes the immunohistochemical staining of orthopox virus (OPV) antigen in liver tissue of experimentally infected mice and in cell cultures. Using two different monoclonal antibodies, virus detection was achieved in cryostat-, but not in paraffin-sections.

[Variola or a severe case of varicella? A case of human variola due to monkeypox virus in a child from the Cameroon]. / Variole ou varicelle grave? Un cas de variole humaine à monkeypox virus chez un enfant Camerounais.

Human monkeypox was suspected on clinical grounds in a seven years old child in Cameroon. The diagnosis was confirmed at the Center for Disease Control (CDC) in Atlanta, USA. This condition is rare. The present case is the third in Cameroon. An epidemiological and clinical survey carried out in the family and in the area where the patient lives, did not allow to identify other cases. The clinical evolution of the case was good as in those described elsewhere.

[Milker's nodes: transmission by fomites and virological identification]. / Nódulos de los ordeñadores: transmisión por fomites e identificación virológica.

We report a case of milker's nodules in a male who was not a professional cattle raiser with indirect and accidental transmission by fomites. A parapoxvirus was demonstrated from cutaneous lesions by electron microscopy with negative stain.

Poxvirus pathogenesis.

Poxviruses are a highly successful family of pathogens, with variola virus, the causative agent of smallpox, being the most notable member. Poxviruses are unique among animal viruses in several respects. First, owing to the cytoplasmic site of virus replication, the virus encodes many enzymes required either for macromolecular precursor pool regulation or for biosynthetic processes. Second, these viruses have a very complex morphogenesis, which involves the de novo synthesis of virus-specific membranes and inclusion bodies. Third, and perhaps most surprising of all, the genomes of these viruses encode many proteins which interact with host processes at both the cellular and systemic levels. For example, a viral homolog of epidermal growth factor is active in vaccinia virus infections of cultured cells, rabbits, and mice. At least five virus proteins with homology to the serine protease inhibitor family have been identified and one, a 38-kDa protein encoded by cowpox virus, is thought to block a host pathway for generating a chemotactic substance. Finally, a protein which has homology with complement components interferes with the activation of the classical complement pathway. Poxviruses infect their hosts by all possible routes: through the skin by mechanical means (e.g., molluscum contagiosum infections of humans), via the respiratory tract (e.g., variola virus infections of humans), or by the oral route (e.g., ectromelia virus infection of the mouse). Poxvirus infections, in general, are acute, with no strong evidence for latent, persistent, or chronic infections. They can be localized or systemic. Ectromelia virus infection of the laboratory mouse can be systemic but inapparent with no mortality and little morbidity, or highly lethal with death in 10 days. On the other hand, molluscum contagiosum virus replicates only in the stratum spinosum of the human epidermis, with little or no involvement of the dermis, and does not spread systemically from the site of infection. The host response to infection is progressive and multifactorial. Early in the infection process, interferons, the alternative pathway of complement activation, inflammatory cells, and natural killer cells may contribute to slowing the spread of the infection. The cell-mediated response involving learned cytotoxic T lymphocytes and delayed-type hypersensitivity components appears to be the most important in recovery from infection. A significant role for specific antiviral antibody and antibody-dependent cell-mediated cytotoxicity has yet to be demonstrated in recovery from a primary infection, but these responses are thought to be important in preventing reinfection.

Observations on a field outbreak of pox virus infection in young Nile crocodiles (Crocodylus niloticus).

A field outbreak of pox virus infection in juvenile Nile crocodiles (Crocodylus niloticus), in which high morbidity and negligible mortality occurred, is described. Histopathological examination of the skin lesions revealed numerous large intracytoplasmic inclusions in the dermis and a very mild dermal inflammatory reaction. Scanning electron microscopical examination of the skin revealed the presence of large numbers of virus particles in the inclusions. Skin lesions persisted for 5 to 6 months.