Peste-des-petits ruminants virus (PPRV) is a viral pathogen that causes a devastating plague of small ruminants. PPRV is an economically significant disease that continues to be a major obstacle to the development of sustainable agriculture across the developing world. The current understanding of PPRV pathogenesis has been heavily assumed from the closely related rinderpest virus (RPV) and other morbillivirus infections alongside data derived from field outbreaks. There have been few studies reported that have focused on the pathogenesis of PPRV and very little is known about the processes underlying the early stages of infection. In the present study, 15 goats were challenged by the intranasal route with a virulent PPRV isolate, Côte d’Ivoire ’89 (CI/89) and sacrificed at strategically defined time-points post infection to enable pre- and post-mortem sampling. This approach enabled precise monitoring of the progress and distribution of virus throughout the infection from the time of challenge, through peak viraemia and into a period of convalescence. Observations were then related to findings of previous field studies and experimental models of PPRV to develop a clinical scoring system for PPRV. Importantly, histopathological investigations demonstrated that the initial site for virus replication is not within the epithelial cells of the respiratory mucosa, as has been previously reported, but is within the tonsillar tissue and lymph nodes draining the site of inoculation. We propose that virus is taken up by immune cells within the respiratory mucosa which then transport virus to lymphoid tissues where primary virus replication occurs, and from where virus enters circulation. Based on these findings we propose a novel clinical scoring methodology for PPRV pathogenesis and suggest a fundamental shift away from the conventional model of PPRV pathogenesis.

The eradication of rinderpest virus (RPV) from the globe was possible through the availability of a safe and effective live attenuated vaccine and a suitable companion diagnostic test. However, the inability to serologically 'Differentiate between naturally Infected and Vaccinated Animals' (DIVA) meant that both the time taken to complete the eradication programme and the economic burden on countries involved was significantly greater than if a vaccine and companion diagnostic test that fulfilled the DIVA concept had been available. During the RPV eradication campaign serosurveillance for RPV was primarily based on a competitive ELISA using a RPV specific (C1) monoclonal antibody (mAb) directed against the viral haemagglutinin (H) protein but this test was not able to meet DIVA requirements. To provide proof of concept for the generation of novel morbillivirus DIVA vaccines we have identified, by phage display, and mutated residues critical for C1 mAb binding and assessed the functionality of mutants in an in vitro fusion assay. Finally we have incorporated mutated epitopes into a full length clone and rescued recombinant RPV using reverse genetics techniques. Here we describe a novel mechanism of marking morbillivirus vaccines, using RPV as a proof of concept, and discuss the applicability of this method to the development of marked vaccines for peste des petits ruminants virus (PPRV).

The Global Rinderpest Eradication Program (GREP) aimed to eradicate rinderpest by 2010 and it is widely believed to have been successful. An integral part of the program was the submission of samples from suspect rinderpest positive animals to a local Reference Laboratory for final confirmation. Confirmation of rinderpest in field samples is often hampered because of poor quality of the sample upon receipt. As part of GREP a rapid diagnostic strip test for the detection of rinderpest virus (RPV) in the field was developed allowing a rapid response to suspect outbreaks. The feasibility of extracting viral RNA from the used rapid diagnostic rinderpest devices for final confirmation in the laboratory is described. Viral material contained within used rinderpest devices was stable enough after storage for one week at 21°C to extract RNA from five different RPV strains and amplify it by reverse transcriptase polymerase chain reaction (RT-PCR). Temperature did not affect adversely the extraction and amplification of the viral RNA but humidity impaired RNA extraction and amplification. Used rinderpest devices from field diagnosed rinderpest-positive animals could represent an ideal additional sample for submission to the Reference Laboratories for confirmation of preliminary diagnosis in the field.

Morbillivirus infection of marine mammals has been documented across all of the world's oceans. Whilst infection is generally demonstrated using a variety of histopathological and serological techniques, where possible, the use of molecular techniques is being used to enable accurate genetic typing of virus strains through sequence analysis. Here, we present genetic data from dolphins and pilot whales affected by morbillivirus infection in the recent outbreak in the Mediterranean Sea during a six-month period from the end of October 2006 to April 2007. To date, very few studies have looked at characterizing outbreaks of morbillivirus infections in whale species at the molecular level. Here, we provide a full sequence for the haemagglutinin (H) gene from material derived from both a dolphin and a pilot whale from the 2007 outbreak in the Mediterranean Sea and show this virus to be 100% identical across the region analysed. Furthermore, we compare partial sequence data from the nucleocapsid (N) gene of the pilot whale material with previously published data and show evidence for strong protein conservation between these different isolates. Finally, we discuss the current classification of cetacean morbilliviruses as a single species.

A full-length DNA clone of a virulent strain of rinderpest virus was constructed with the gene for the enhanced green fluorescent protein (eGFP) inserted as a separate transcription unit between the P and M genes Rescue of the virus from the modified clone using reverse genetics generated a virus that grew to the same levels as the virus rescued from the unmodified DNA clone in cell culture The recombinant virus expressed eGFP to a high level and was used to follow virus replication in real-time using live-cell imaging Cattle infected with both the recombinant wild-type virus and the recombinant eGFP expressing virus developed clinical disease similar to that of the wild-type natural virus isolate Detection of virus in circulating peripheral blood leukocytes was equivalent to that of the animals infected with the wild-type virus The high level of expression of soluble eGFP by this virus allowed us to detect viral replication in infected animals by confocal microscopy Imaging vibrating microtome sections by confocal microscopy provided good preservation of tissue and cellular architecture as well as revealing the sites of replication of the virus in different tissues of infected animals

To investigate the possible origin and spread of the dramatic re-emergent 2002 distemper epizootic observed among seals in Danish Waters, we have sequenced wild-type genes of the attachment (H) glycoproteins of viruses from both the 2002 and 1988 epizootics. Phylogenetic analysis of the H genes of phocine distemper virus (PDV) together with other morbilliviruses, suggests that the re-emergent 2002 PDV is more closely related to a putative recent ancestral PDV than the 1988 PDV isolates. Moreover, upsurges of distemper disease in land-living carnivores linked in time and locality to the 2002 seal epizootic in Danish Waters was investigated and determined to be caused by canine distemper virus, the closest relative of PDV, revealing no direct epidemiological link to the seal epizootics.

In July 2007, >100 striped dolphins, Stenella coeruleoalba, were found dead along the coast of the Spanish Mediterranean. Of 10 dolphins tested, 7 were positive for a virus strain closely related to the dolphin morbillivirus that was isolated during a previous epizootic in 1990.

Peste-des-petits ruminants virus (PPRV) causes acute febrile illness in both farmed and wild small ruminants, with associated mortality rates of 50–80%. PPRV is a member of the Morbillivirus genus within the Paramyxovirus family and although there are many full length genome sequences available for members of this family, their availability for PPRV in particular is limited. We have determined the full length sequences representing two virulent strains of PPRV, the Côte d’Ivoire 1989 (CI/89) and Nigeria 1976 (Ng76/1) strains. We present an alignment of the promoter regions of these viruses with other available PPRV promoter sequences and have identified domains in PPRV proteins believed to be critical for paramyxovirus promoter attenuation. We have also analysed the proteins of these viruses, comparing them to other available PPRV protein sequences and identified motifs that were previously recognised as being required for the function of other paramyxovirus proteins.

Veterinary RecordVolume 162, Issue 17 p. 555-556 Short Communication Mass mortality in harbour seals and harbour porpoises caused by an unknown pathogen T. Harkonen PhD, T. Harkonen PhD Swedish Museum of Natural History, Box 50007, 104 05 Stockholm, SwedenSearch for more papers by this authorB. M. Bäcklin PhD, B. M. Bäcklin PhD Swedish Museum of Natural History, Box 50007, 104 05 Stockholm, SwedenSearch for more papers by this authorT. Barrett DVM, PhD, T. Barrett DVM, PhD Institute for Animal Health, Ash Road, Pirbright, Surrey, GU24 0NFSearch for more papers by this authorA. Bergman PhD, A. Bergman PhD Swedish Museum of Natural History, Box 50007, 104 05 Stockholm, SwedenSearch for more papers by this authorM. Corteyn MSc, M. Corteyn MSc Institute for Animal Health, Ash Road, Pirbright, Surrey, GU24 0NFSearch for more papers by this authorR. Dietz PhD, R. Dietz PhD National Environmental Research Institute, University of Aarhus, Box 358, DK-4000 Roskidle, DenmarkSearch for more papers by this authorK. C. Harding PhD, K. C. Harding PhD Department of Marine Ecology, Gothenburg University, Box 461, 405 30 Gothenburg, SwedenSearch for more papers by this authorJ. Malmsten, J. Malmsten National Veterinary Institute, 751 89 Uppsala, SwedenSearch for more papers by this authorA. Roos MSc, A. Roos MSc Swedish Museum of Natural History, Box 50007, 104 05 Stockholm, SwedenSearch for more papers by this authorJ. Teilmann PhD, J. Teilmann PhD National Environmental Research Institute, University of Aarhus, Box 358, DK-4000 Roskidle, DenmarkSearch for more papers by this author T. Harkonen PhD, T. Harkonen PhD Swedish Museum of Natural History, Box 50007, 104 05 Stockholm, SwedenSearch for more papers by this authorB. M. Bäcklin PhD, B. M. Bäcklin PhD Swedish Museum of Natural History, Box 50007, 104 05 Stockholm, SwedenSearch for more papers by this authorT. Barrett DVM, PhD, T. Barrett DVM, PhD Institute for Animal Health, Ash Road, Pirbright, Surrey, GU24 0NFSearch for more papers by this authorA. Bergman PhD, A. Bergman PhD Swedish Museum of Natural History, Box 50007, 104 05 Stockholm, SwedenSearch for more papers by this authorM. Corteyn MSc, M. Corteyn MSc Institute for Animal Health, Ash Road, Pirbright, Surrey, GU24 0NFSearch for more papers by this authorR. Dietz PhD, R. Dietz PhD National Environmental Research Institute, University of Aarhus, Box 358, DK-4000 Roskidle, DenmarkSearch for more papers by this authorK. C. Harding PhD, K. C. Harding PhD Department of Marine Ecology, Gothenburg University, Box 461, 405 30 Gothenburg, SwedenSearch for more papers by this authorJ. Malmsten, J. Malmsten National Veterinary Institute, 751 89 Uppsala, SwedenSearch for more papers by this authorA. Roos MSc, A. Roos MSc Swedish Museum of Natural History, Box 50007, 104 05 Stockholm, SwedenSearch for more papers by this authorJ. Teilmann PhD, J. Teilmann PhD National Environmental Research Institute, University of Aarhus, Box 358, DK-4000 Roskidle, DenmarkSearch for more papers by this author First published: 26 April 2008 https://doi.org/10.1136/vr.162.17.555Citations: 1Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article.Citing Literature Volume162, Issue17April 2008Pages 555-556 RelatedInformation

The nucleocapsid (N) protein of all morbilliviruses has a highly conserved central region that is thought to interact with and encapsidate the viral RNA. The C-terminal third of the N protein is highly variable among morbilliviruses and is thought to be located on the outer surface and to be available to interact with other viral proteins such as the phosphoprotein, the polymerase protein and the matrix protein. Using reverse genetics, a chimeric rinderpest virus (RPV)/peste-des-petits-ruminants virus (PPRV) was rescued in which the RPV N gene open reading frame had been replaced with that of PPRV (RPV-PPRN). The chimeric virus maintained efficient replication in cell culture. Cattle vaccinated with this chimeric vaccine showed no adverse reaction and were protected from subsequent challenge with wild-type RPV, indicating it to be a safe and efficacious vaccine. The carboxyl-terminal variable region of the rinderpest N protein was cloned and expressed in Escherichia coli. The expressed protein was used to develop an indirect ELISA that could clearly differentiate between RPV- and PPRV-infected animals. The possibility of using this virus as a marker vaccine in association with a new diagnostic ELISA in the rinderpest eradication programme is discussed.

More than 10,000 Caspian seals (Phoca caspica) were reported dead in the Caspian Sea during spring and summer 2000. We performed necropsies and extensive laboratory analyses on 18 seals, as well as examination of the pattern of strandings and variation in weather in recent years, to identify the cause of mortality and potential contributory factors. The monthly stranding rate in 2000 was up to 2.8 times the historic mean. It was preceded by an unusually mild winter, as observed before in mass mortality events of pinnipeds. The primary diagnosis in 11 of 13 seals was canine distemper, characterized by broncho-interstitial pneumonia, lymphocytic necrosis and depletion in lymphoid organs, and the presence of typical intracytoplasmic inclusion bodies in multiple epithelia. Canine distemper virus infection was confirmed by phylogenetic analysis of reverse transcriptase-polymerase chain reaction products. Organochlorine and zinc concentrations in tissues of seals with canine distemper were comparable to those of Caspian seals in previous years. Concurrent bacterial infections that may have contributed to the mortality of the seals included Bordetella bronchiseptica (4/8 seals), Streptococcus phocae (3/8), Salmonella dublin (1/8), and S. choleraesuis (1/8). A newly identified bacterium, Corynebacterium caspium, was associated with balanoposthitis in one seal. Several infectious and parasitic organisms, including poxvirus, Atopobacter phocae, Eimeria- and Sarcocystis-like organisms, and Halarachne sp. were identified in Caspian seals for the first time.

This chapter summarizes the molecular biology of the morbilliviruses and other negative strand RNA viruses. Rinderpest virus (RPV), a member of the Morbillivirus genus within the family Paramyxoviridae, shares structural, biological, antigenic, and molecular features in common with the other members of the group. Members of the Paramyxoviridae are indistinguishable in the electron microscope where the virions are seen as pleomorphic particles with a lipid envelope enclosing a ribonucleoprotein (RNP) core. This RNP core contains the genome, a single strand of negative polarity RNA, encapsidated by the nucleocapsid protein giving it a characteristic herring-bone appearance. The RPV virions have a maximum diameter of 300nm while those of the other ruminant morbillivirus, peste des petits ruminants virus (PPRV), are larger and have a mean diameter of 400–500nm. The most extensively studied morbillivirus at the molecular level is the human pathogen measles virus (MV), although similar studies are also being carried out on RPV, PPRV, and canine distemper virus.

The matrix (M) protein of paramyxoviruses forms an inner coat to the viral envelope and serves as a bridge between the surface glycoproteins (F and H) and the ribonucleoprotein core. Previously, a marker vaccine (RPV-PPRFH) was produced for the control of peste des petits ruminants (PPR) disease, where the F and H genes of Rinderpest virus (RPV) were replaced with the equivalent genes from Peste-des-petits-ruminants virus (PPRV); however, this virus grew poorly in tissue culture. The poor growth of the RPV-PPRFH chimeric virus was thought to be due to non-homologous interaction of the surface glycoproteins with the internal components of the virus, in particular with the M protein. In contrast, replacement of the M gene of RPV with that from PPRV did not have an effect on the viability or replication efficiency of the recombinant virus. Therefore, in an effort to improve the growth of the RPV-PPRFH virus, a triple chimera (RPV-PPRMFH) was made, where the M, F and H genes of RPV were replaced with those from PPRV. As expected, the growth of the triple chimera was improved; it grew to a titre as high as that of the unmodified PPRV, although comparatively lower than that of the parental RPV virus. Goats infected with the triple chimera showed no adverse reaction and were protected from subsequent challenge with wild-type PPRV. The neutralizing-antibody titre on the day of challenge was approximately 17 times higher than that in the RPV-PPRFH group, indicating RPV-PPRMFH as a promising marker-vaccine candidate.

This chapter provides an overview of the concepts prevailing about rinderpest until the discovery of the virus by Nicolle and Adil-Bey in 1902. Rinderpest was clearly identified for the first time by the Latin writer Severus Sanctus Endeleichus, who described a contagious disease occurring as a major epizootic in cattle. The first written report of rinderpest inoculation was published as a letter signed ‘T.S.’ in the November 1754 issue of the Gentleman's Magazine, a journal then widely read by educated people in Britain and also on the Continent. After the discovery of the vaccination against smallpox by Edward Jenner in 1796, and due to the suspected analogy between the two diseases, there were trials to vaccinate cattle against rinderpest using the smallpox vaccine. From ancient times, numerous outbreaks of rinderpest must have occurred in Asia. Based on the fragmented information available, the historical aspects of rinderpest in three Asian countries—India, Korea and Japan—are described in this discussion.

Recombinant DNA technology has been widely used to produce new vaccines for many diseases, including rinderpest and thermolability, which was the main reason used to justify the development of the recombinant rinderpest vaccines. The first recombinant vaccine to be produced were vaccinia recombinants, so called vectored vaccines, which used the DNA genome of an established vaccine strain of vaccinia (the vector) as the backbone for the insertion of foreign genes coding for immunogenic proteins from the desired pathogen. Vaccination with the recombinant then induces a protective immune response to the disease concerned. Poxvirus vector, capripox virus (the agent of sheep and goat pox) has also been used to produce a recombinant rinderpest vaccine. Using the established capripox vaccine as a vector, it is possible to protect the cattle against two diseases: rinderpest and lumpy skin disease. The vaccinia and capripox recombinant vaccines can also act as effective marker vaccines for rinderpest and peste des petits ruminants as their serological signature lacks responses to the nucleocapsid (N) proteins of the viruses.

Negative-strand RNA viruses encode a single RNA-dependent RNA polymerase (RdRp) which transcribes and replicates the genome. The open reading frame encoding the RdRp from a virulent wild-type strain of rinderpest virus (RPV) was inserted into an expression plasmid. Sequences encoding enhanced green fluorescent protein (EGFP) were inserted into a variable hinge of the RdRp. The resulting polymerase was autofluorescent, and its activity in the replication/transcription of a synthetic minigenome was reduced. We investigated the potential of using this approach to rationally attenuate a virus by inserting the DNA sequences encoding the modified RdRp into a full-length anti-genome plasmid from which a virulent virus (rRPV(KO)) can be rescued. A recombinant virus, rRPV(KO)L-RRegfpR, which grew at an indistinguishable rate and to an identical titer as rRPV(KO) in vitro, was rescued. Fluorescently tagged polymerase was visible in large cytoplasmic inclusions and beneath the cell membrane. Subcutaneous injection of 10(4) TCID(50) of the rRPV(KO) parental recombinant virus into cattle leads to severe disease symptoms (leukopenia/diarrhea and pyrexia) and death by 9 days postinfection. Animals infected with rRPV(KO)L-RRegfpR exhibited transient leukopenia and mild pyrexia, and the only noticeable clinical signs were moderate reddening of one eye and a slight ocular-nasal discharge. Viruses that expressed the modified polymerase were isolated from peripheral blood lymphocytes and eye swabs. This demonstrates that a virulent morbillivirus can be attenuated in a single step solely by modulating RdRp activity and that there is not necessarily a correlation between virus growth in vitro and in vivo.

Rinderpest, or cattle plague, is caused by Rinderpest virus (RPV), which is related most closely to human Measles virus (MV), both being members of the genus Morbillivirus , a group of viruses known to have strong immunosuppressive effects in vitro and in vivo . Here, it was shown that peripheral blood mononuclear cells (PBMCs) isolated from cattle experimentally infected with either wild-type or vaccine strains of RPV impaired the proliferation of PBMCs derived from uninfected animals; however, in contrast to either mild or virulent strains of wild-type virus, the inhibition induced by the vaccine was both weak and transient. Flow-cytometric analysis of PBMCs obtained from cattle infected with different strains of RPV showed that the proportion of infected cells was virus dose-dependent and correlated with lymphoproliferative suppression.

Rinderpest is an economically devastating disease of cattle (cattle plague), but a live-attenuated vaccine has been very successfully used in a global rinderpest eradication campaign. As a consequence, the endemic focus of the virus has been reduced to an area in eastern Africa known as the Kenya-Somali ecosystem. Although the vaccine is highly effective, it has a drawback in that vaccinated animals are serologically indistinguishable from those that have recovered from natural infection. In the final stages of the eradication campaign, when vaccination to control the spread of disease will only be used in emergencies to contain an outbreak, a marker vaccine would be a very useful tool to monitor possible wild virus spread outside the vaccination area. Marker vaccines for rinderpest, and other viruses with negative-sense RNA genomes, can now be produced using reverse genetics, and the development of such marker vaccines for rinderpest virus is described.