Peste des petits ruminants virus in Tibet, China

Epidemiology of peste des petits ruminants in selected districts of Borena zone, Ethiopia

BACKGROUND

Peste des petits ruminant (PPR) is a contagious disease caused by the peste des petits ruminants virus (PPRV). The disease poses a significant economic threat to small ruminant production in Ethiopia, particularly to the striving pastoral production system. A cross-sectional study was conducted to estimate the seroprevalence and associated risk factors of PPR in the small ruminants of the Borena Zone. A total of 384 serum samples were collected randomly from sheep and goats and examined for the presence of PPRV antibodies using competition enzyme-linked immune sorbent assay (c-ELISA). Additionally, a retrospective analysis of five years of outbreak data was performed to provide insight into the spatial and temporal distribution of the disease.

RESULTS

The seroprevalence of PPRV antibodies in nonvaccinated, vaccinated, and unknown vaccination status of small ruminants in this study was found to be 32.1%, 68.8%, and 45.5%, respectively. Multivariable logistic analysis revealed a statistically significant association between PPRV seropositivity and several factors, including age, animal origin, flock size, and veterinary services status. A retrospective analysis revealed 53 PPR outbreaks in the Borena Zone from 2018 to 2022, exacerbated by low vaccination coverage relative to the at-risk animal population.

CONCLUSION

The study revealed significant gaps in current vaccination efforts, with herd immunity levels falling below the FAO-WOAH recommended threshold of 80%. Despite Ethiopia's ambitious goal to eradicate PPR by 2027, the frequent outbreaks and insufficient herd immunity highlight the inadequacy of the existing strategies. To effectively move toward eradication, Ethiopia must align its approach with the global PPR eradication framework, which emphasizes a comprehensive strategy that includes diagnostics, surveillance, prevention, and the establishment of a robust veterinary regulatory system, rather than relying solely on vaccination. Overcoming logistical challenges, improving vaccination coverage, and optimizing the timing of vaccination campaigns, especially in hard-to-reach areas, will be crucial for reducing outbreaks and making progress toward eradication.

Establishment of a RAA-CRISPR Cas12a based diagnostic method for peste des petits ruminants virus N gene and M gene

Peste des petis ruminants (PPR) is an acute, highly contagious fatal disease affecting both domestic and wild small ruminants, caused by Morbillivirus caprinae (also known as peste des petis ruminants virus (PPRV)). Herein, a rapid method based on recombinase aided amplification-clustered regularly interspaced short palindromic repeats-Cas12a (RAA-CRISPR Cas12a) to detect PPRV was developed. CRISPR RNAs and RAA primers for PPRV-N (nucleocapsid) and PPRV-M (matrix) fragments were designed. The reaction system was constructed following screening and optimization. Detection could be completed within in 50 minutes at 37°C. Detection of gradient dilutions of plasmids carrying of PPRV N and M gene fragments indicated a minimum limit of detection of 10 copies/μL. There were no cross-reactions with related viruses and all tested lineages of PPRV were detected successfully. The method also showed good repeatability. The detection of clinical samples (previously detected using reverse transcription polymerase chain reaction (RT-PCR)) indicated good consistency between the RAA-CRISPR Cas12a method and RT-PCR. Thus, the RAA-CRISPR Cas12a method for rapid PPRV diagnosis has strong specificity, high sensitivity, and stable repeatability. Moreover, the results can be observed visually under blue or UV light or using lateral flow strips without complex instruments.

A novel quantitative real-time PCR with the GAPDH reference gene for peste des petits ruminants

Peste des petits ruminants (PPR) is a serious acute, highly contagious disease caused by the peste des petits ruminants virus (PPRV). This study aims to establish a qRT-PCR assay with an internal amplification control for the rapid and accurate detection of PPRV. The primers and probes for PPRV N were based on the national standard of the diagnostic techniques for PPR of China, and a pair of primers and TaqMan probes for the internal reference gene of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was designed. Optimisation of the reaction conditions, specificity, sensitivity and reproducibility tests, and clinical sample detection were conducted. The results showed that the optimal primers and probe concentrations of PPRV were 0.4 μmol/l and 0.4 μmol/l, respectively, and were 0.4 μmol/l and 0.2 μmol/l for the reference gene GAPDH, respectively. The established method has no cross-reaction with other viruses. The minimum detection limit was 6.8 copies/μl for PPRV and 190 copies/μl for GAPDH. The coefficients of variation (CV%) of PPRV and GAPDH were both lower than 2%. The results suggest that the PPRV qRT-PCR method containing internal reference genes has strong specificity, high sensitivity, and good reproducibility. The addition of internal reference genes for the sample quality control improves the accuracy of the detection.

Simultaneous detection and identification of Peste des petits ruminants Virus Lineages II and IV by MCA-Based real-time quantitative RT-PCR assay within single reaction

BACKGROUND

Peste des petits ruminants (PPR) disease is a cross-species infectious disease that severely affects small ruminants and causes great losses to livestock industries in various countries. Distinguishing vaccine-immunized animals from naturally infected animals is an important prerequisite for the eradication of PPR. At present PPRV are classified into lineages I through IV, and only one vaccination strain, Nigeria/75/1, belongs to lineage II, but all of the epidemic strains in China at present are from lineage IV.

RESULTS

To achieve this goal, we developed an SYBR Green I real-time qRT-PCR method for rapid detection and identification of PPRV lineages II and IV by analyzing different melting curve analyses. The negative amplification of other commonly circulating viruses such as orf virus, goat poxvirus, and foot-and-mouth disease virus demonstrated that primers targeting the L gene of PPRV were extremely specific. The sensitivity of the assay was assessed based on plasmid DNA and the detection limit achieved was 100 copies of PPRV lineages II and IV.

CONCLUSION

Since the method has high sensitivity, specificity, and reproducibility, it will be effectively differentiated PPRV lineages II from PPRV lineages IV in PPRV infected animals.

Construction of Recombinant Rabies Virus Vectors Expressing H or F Protein of Peste des Petits Ruminants Virus

Simple Summary

Peste des petits ruminants (PPR) is one of the most contagious and fatal diseases of small ruminants. In this study, two recombinant viruses rSRV9-H and rSRV9-F, which express the envelope glycoprotein H (hemagglutinin protein) or F (fusion protein) protein, respectively, were successfully generated with a rabies virus as vector. The constructed viruses had good proliferative activity and stability and provided potential bivalent inactivated vaccine candidate strains for the prevention of PPR and livestock rabies.

Abstract

Peste des petits ruminants (PPR) is one of the most contagious and fatal diseases of small ruminants in the world and is classified as a category A epidemic disease. It is the target of a global eradication campaign led by the Office International des Epizooties (OIE) and Food and Agriculture Organization of the United Nations (FAO). The PPR live attenuated vaccine is currently the most widely used and approved vaccine, but the use of this vaccine interferes with the serological testing of the PPR elimination program, and there is a potential safety risk. Viral vector vaccines are one of the most promising methods to solve this dilemma. In this study, the full-length infectious clone plasmid of rabies virus (RABV), pD-SRV9-PM-LASV, was used as the backbone, and the envelope glycoprotein H (hemagglutinin protein) or F (fusion protein) gene of PPRV was inserted into the backbone plasmid to construct the infectious clones pD-SRV9-PM-PPRV-H and pD-SRV9-PM-PPRV-F, which express the PPRV H and PPRV F genes, respectively. The correct construction of these infectious clones was verified after sequencing and double digestion. The infectious clones were transfected with a helper plasmid into BSR/T7 cells, and recombinant viruses were successfully rescued by direct immunofluorescence, indirect immunofluorescence, Western blotting, and transmission electron microscopy and named rSRV9-H and rSRV9-F. The results of growth kinetics studies indicated that the inserted gene did not affect virus proliferation. Stability studies revealed that the inserted target gene was stably expressed in recombinant RABV for at least 15 generations. In this study, the recombinant viruses rSRV9-H and rSRV9-F were successfully rescued. The constructed viruses had good proliferative activity and stability and provided potential bivalent inactivated vaccine candidate strains for the prevention of PPR and livestock rabies.

Evolutionary dynamics of codon usages for peste des petits ruminants virus

Peste des petits ruminants virus (PPRV) is an important agent of contagious, acute and febrile viral diseases in small ruminants, while its evolutionary dynamics related to codon usage are still lacking. Herein, we adopted information entropy, the relative synonymous codon usage values and similarity indexes and codon adaptation index to analyze the viral genetic features for 45 available whole genomes of PPRV. Some universal, lineage-specific, and gene-specific genetic features presented by synonymous codon usages of the six genes of PPRV that encode N, P, M, F, H and L proteins reflected evolutionary plasticity and independence. The high adaptation of PPRV to hosts at codon usages reflected high viral gene expression, but some synonymous codons that are rare in the hosts were selected in high frequencies in the viral genes. Another obvious genetic feature was that the synonymous codons containing CpG dinucleotides had weak tendencies to be selected in viral genes. The synonymous codon usage patterns of PPRV isolated during 2007–2008 and 2013–2014 in China displayed independent evolutionary pathway, although the overall codon usage patterns of these PPRV strains matched the universal codon usage patterns of lineage IV. According to the interplay between nucleotide and synonymous codon usages of the six genes of PPRV, the evolutionary dynamics including mutation pressure and natural selection determined the viral survival and fitness to its host.

Peste des Petits Ruminants in Central and Eastern Asia/West Eurasia: Epidemiological Situation and Status of Control and Eradication Activities after the First Phase of the PPR Global Eradication Programme (2017–2021)

Simple Summary

Peste des petits ruminants (PPR) is a highly contagious viral disease of domestic and wild small ruminants. The disease is endemic to large parts of Africa, the Middle East and Asia and causes severe socioeconomic losses, especially in developing countries reliant on small ruminant value chains. Currently, PPR is the only animal disease targeted by the Global Eradication Programme (PPR GEP), which aims to eradicate the disease by 2030. Following the end of the first five-year phase of the PPR GEP, the goal of this review is to provide an update on the status of the eradication progress in one of the nine regions targeted for coordinated action in the PPR Global Control and Eradication Strategy, denominated Central Asia/West Eurasia. In addition to the original nine countries, regional meetings and activities have involved four additional countries based on shared epidemiological features, which are also reviewed here. The considered area spans from Eastern Europe to East Asia and features remarkable variability in terms of both PPR presence and enacted control efforts. The achievements and constraints encountered at regional and national levels are discussed, thus providing useful data for tailoring the next steps of the eradication programme to the peculiarities of the region.

Abstract

Peste des petits ruminants (PPR) is a highly contagious infectious disease of small ruminants caused by peste des petits ruminants virus (PPRV). PPR poses a significant threat to sheep and goat systems in over 65 endemic countries across Africa, the Middle East and Asia. It is also responsible for devastating outbreaks in susceptible wildlife, threatening biodiversity. For these reasons, PPR is the target of the Global Eradication Programme (PPR GEP), launched in 2016, which is aimed at eradicating the disease by 2030. The end of the first five-year phase of the PPR GEP (2017–2021) provides an ideal opportunity to assess the status of the stepwise control and eradication process. This review analyses 13 countries belonging to Eastern Europe, Transcaucasia, and Central and East Asia. Substantial heterogeneity is apparent in terms of PPR presence and control strategies implemented by different countries. Within this region, one country is officially recognised as PPR-free, seven countries have never reported PPR, and two have had no outbreaks in the last five years. Therefore, there is real potential for countries in this region to move forward in a coordinated manner to secure official PPR freedom status and thus reap the trade and socioeconomic benefits of PPR eradication.

Research Progress on Emerging Viral Pathogens of Small Ruminants in China during the Last Decade

China is the country with the largest number of domestic small ruminants in the world. Recently, the intensive and large-scale sheep/goat raising industry has developed rapidly, especially in nonpastoral regions. Frequent trading, allocation, and transportation result in the introduction and prevalence of new pathogens. Several new viral pathogens (peste des petits ruminants virus, caprine parainfluenza virus type 3, border disease virus, enzootic nasal tumor virus, caprine herpesvirus 1, enterovirus) have been circulating and identified in China, which has attracted extensive attention from both farmers and researchers. During the last decade, studies examining the etiology, epidemiology, pathogenesis, diagnostic methods, and vaccines for these emerging viruses have been conducted. In this review, we focus on the latest findings and research progress related to these newly identified viral pathogens in China, discuss the current situation and problems, and propose research directions and prevention strategies for different diseases in the future. Our aim is to provide comprehensive and valuable information for the prevention and control of these emerging viruses and highlight the importance of surveillance of emerging or re-emerging viruses.

Pheno- and genotypic characterization and identification of novel subtypes of Peste des Petits Ruminants virus in domestic and captive wild goats in Northern Iraq

BACKGROUND

Peste des Petits Ruminants (PPR) is an acute or peracute contagious transboundary viral disease that mainly affects caprine and ovine and causes significant economic impact in developing countries. After two PPR virus outbreaks in 2011 and 2014, an investigation, from August 2015 to September 2016, was carried out in Northern Iraq when an increased morbidity and mortality rates were reported in the domestic and captive wild goats. In the present study, ten domestic goat farms and seven captive wild goat herds located in seven geographical areas of Northern Iraq were clinically, pathologically, serologically and genotypically characterized to determine the prevalence and potential cause of PPR virus outbreak.

RESULTS

The outbreak occurred with rate of morbidity (26.1%) and mortality (11.1%) in domestic goat farms as compared to captive wild goat herds where relatively high mortality (42.9%) and low morbidity (10.9%) rates were recorded. Based on the clinical symptoms (mucopurulent nasal discharges, ulceration and erosion of oral mucosa, profuse watery diarrhea) and necropsy (hemorrhage and congestion on mucous membranes of the colon and rectum with zebra stripes lesions) results, overall, the serological test findings revealed a high frequency (47.9%) of positive samples for anti-PPRV nucleoprotein antibodies. Furthermore, the nucleoprotein (N) gene was detected in 63.2 and 89.1% of samples using conventional and reverse transcription real-time quantitative PCR assays. A phylogenetic analysis of N gene amino acid sequences clustered with the reference strain revealed lineage IV similar to the strains isolated in 2011 and 2014, respectively. However, two sub-types of lineage IV (I and II), significantly distinct from the previous strains, were also observed.

CONCLUSION

The phylogenetic analysis suggests that movements of goats are possible cause and one of the important factors responsible for the spread of virus across the region. The study results would help in improving farm management practices by establishing a PPR virus eradication program using regular monitoring and vaccination program to control and mitigate the risk of re-emergence of PPR virus infection in domestic and captive wild goats in Iraq.

Transboundary spread of peste des petits ruminants virus in western China: A prediction model

In pan Pamir Plateau countries, Peste des petits ruminants (PPR) has brought huge losses to the livestock industry and threaten the endangered wildlife. In unknown regions, revealing PPRV transmission among countries is the premise of effective prevention and control, therefore calls for quantified monitoring on disease communication among countries. In this paper, a MaxEnt model was built for the first time to predict the PPR risk within the research area. The least cost path (LCP) for PPR transboundary communication were calculated and referred to as the maximum available paths (MAP). The results show that there are many places with high-risk in the research area, and the domestic risk in China is lower than that in foreign countries and is mainly determined by human activities. Five LCPs representing corridors among Kazakhstan, Tajikistan, Pakistan, India and China were obtained. This study proves for the first time that there is the possibility of cross-border transmission of diseases by wild and domestic animals. In the future, it will play an important role in monitoring the PPR epidemic and blocking-up its cross-border transmission.

A predictive analysis on the risk of peste des petits ruminants in livestock in the Trans-Himalayan region and validation of its transboundary transmission paths

Although the Trans-Himalayan region (THR) is an important endemic and rendezvous area of peste des petits ruminants (PPR), monitoring and prevention measurements are difficult to execute because of the rough geographical conditions. Besides, a heterogeneous breeding system and the poor veterinary service of susceptible animals compound the existing problems. Here, we propose a forecasting system to define the key points of PPR prevention and aid the countries in saving time, labor, and products to achieve the goal of the global eradication project of PPR. The spatial distribution of PPR was predicted in the THR for the first time using a niche model that was constructed with a combination of eco-geographical, anthropoid, meteorological, and host variables. The transboundary least-cost paths (LCPs) of small ruminants in the THR were also calculated. Our results reveal that the low-elevation area of the THR had a higher PPR risk and was mainly dominated by human variables. The high-elevation area had lower risk and was mainly dominated by natural variables. Eight LCPs representing corridors among India, Nepal, Bhutan, Bangladesh, and China were obtained. This confirmed the potential risk of transboundary communication by relying on PPR contamination on the grasslands for the first time. The predicted potential risk communication between the two livestock systems and landscapes (high and low elevation) might play a role in driving PPR transboundary transmission.

Dysregulation of the RIG-I-like Receptor Pathway Signaling by Peste des Petits Ruminants Virus Phosphoprotein

Peste des petits ruminants virus (PPRV) is a Morbillivirus that causes highly contagious and severe disease in various ruminants. PPRV infection leads to a severe inhibition of host antiviral immune response. Our previous study demonstrated that PPRV V protein blocks IFN response by targeting STAT proteins. In the current study, we identified the phosphoprotein (P) as a novel antagonistic factor of PPRV to counteract host antiviral innate immune response. PPRV P protein significantly suppressed RIG-I-like receptor pathway signaling and impaired IFN-β and ISGs expression by targeting IFN regulatory factor (IRF)3 in both human embryonic kidney 293T cells and primary goat fibroblasts. The 1-102 region of P protein was critical for the antagonistic function of P protein. P protein interacted with IRF association domain (IAD) of IRF3 to block the interaction between TBK1 and IRF3. The interaction between TBK1 and the IAD of IRF3 is responsible for triggering the phosphorylation of IRF3. P protein competed with TBK1 to bind to the IAD of IRF3 that contributed to the decreased phosphorylation of IRF3, which, in turn, interfered with the dimerization of IRF3 and blocked IRF3 nuclear transportation. Besides, we also found that P protein interacted with IRF5 and IRF8. However, the involved mechanism remains unknown. Taken together, our results reveal a novel mechanism by which PPRV P protein antagonizes host antiviral innate immune response by interacting with the transcription factor IRF3, thereby inhibiting the type I IFN production and promoting viral replication.

Peste des petits ruminants (PPR) in Africa and Asia: A systematic review and meta-analysis of the prevalence in sheep and goats between 1969 and 2018

BACKGROUND

Peste des petits ruminants (PPR) is a prevalent viral disease of sheep and goats that impacts productivity and international animal trade. Despite the substantial economic consequences related to PPR, little is known about the prevalence of this disease at the broad geographical levels.

OBJECTIVE

The present study aimed to use a systematic approach to assess the regional prevalence of PPR in sheep and goats, and the associated factors that contribute to prevalence estimates.

METHODS

Published articles on PPR in sheep and goats were searched in PubMed, Web of Science, Scopus, Google Scholar and the reference lists of articles reporting the prevalence from 1 January 1969 to 31 December 2018. Articles were selected using inclusion and exclusion criteria. Since the heterogeneity among the studies was significant, pooled prevalences were estimated by a random effect meta-analysis model.

RESULTS

Data on the prevalence of PPR were obtained from Africa and Asia, where the pooled prevalence estimates were 40.99% (95% CI: 37.20%-44.79%) and 38.43% (95% CI: 35.64%-41.22%) respectively. Overall, the estimated pooled prevalence at Africa-Asia level in sheep was 39.31% (95% CI: 35.75%-42.88%) and in goats was 39.57% (95% CI: 36.66%-42.48%). Significant heterogeneity (I²  > 80%) was noted in most pooled estimates.

CONCLUSION

The results on the regional prevalence estimates of PPR presented here will be useful in raising awareness and advocating for Governments to engage in initiatives to eradicate PPR and prevent it from spreading to other continents.

Virus-Like Particles Derived From a Virulent Strain of Pest des Petits Ruminants Virus Elicit a More Vigorous Immune Response in Mice and Small Ruminants Than Those From a Vaccine Strain

Peste des petits ruminants (PPRs) is highly contagious, acute or subacute disease of small ruminants caused by peste des petits ruminants virus (PPRV). To date, several studies have designed and evaluated PPRV-like particles (VLPs) as a vaccine candidate for the prevention and control of PPR, with the majority of these VLPs constructed using sequences derived from a PPRV vaccine strain due to its high immunogenicity. However, because of the lack of available genetic material and certain structural proteins and/or the alteration of posttranslational glycosylation modifications, the immunogenicity of VLPs derived from a vaccine strain is not always optimal. In this study, two PPRV VLP candidates, derived from either the lineage IV Tibet/30 virulent strain or the lineage II Nigeria 75/1 vaccine strain, were generated using a baculovirus system through the coexpression of the PPRV matrix (M), hemagglutinin (H), and fusion (F) proteins in the high expression level cell line High Five. These VLPs were then used to immunize mice, goats, and sheep followed by two boosts after primary immunization. Both VLPs were found to induce a potent humoral immune response as demonstrated by the high ratio of immunoglobulin G1 (IgG1) to IgG2a. In all animals, both VLPs induced high titers of virus-neutralizing antibodies (VNAs), as well as H- and F-specific antibodies, with the Tibet/30 VLPs yielding higher antibody titers by comparison to the Nigeria 75/1 VLPs. Studies in mice also demonstrated that the Tibet/30 VLPs induced a more robust interleukin 4 and interferon γ response than the Nigeria 75/1 VLPs. Goats and sheep immunized with both VLPs exhibited a robust humoral and cell-mediated immune response. Furthermore, our results demonstrated that the VLPs derived from the virulent lineage IV Tibet/30 strain were more immunogenic, inducing a more potent and robust humoral and cell-mediated immune response in vaccinated animals by comparison to the lineage II Nigeria 75/1 vaccine strain VLPs. In addition, VNA titers were significantly higher among animals vaccinated with the Tibet/30 VLPs by comparison to the Nigeria 75/1 VLPs. Taken together, these findings suggest that VLPs derived from the virulent lineage IV Tibet/30 strain are more immunogenic by comparison to those derived from the lineage II Nigeria 75/1 vaccine strain and thus represent a promising vaccine candidate for the control and eradication of PPR.

Expanding Diversity of Susceptible Hosts in Peste Des Petits Ruminants Virus Infection and Its Potential Mechanism Beyond

Peste des petits ruminants (PPR) is a severe respiratory and digestive tract disease of domestic small ruminants caused by PPR virus (PPRV) of the genus Morbillivirus. Although the primary hosts of PPRV are goats and sheep, the host range of PPRV has been continuously expanding and reported to infect various animal hosts over the last decades, which could bring a potential challenge to effectively control and eradicate PPR globally. In this review, we focused on current knowledge about host expansion and interspecies infection of PPRV and discussed the potential mechanisms involved.

Development of vaccines for prevention of peste-des-petits-ruminants virus infection

Peste des petits ruminants (PPR) is a highly contagious and fatal disease of small ruminants, particularly sheep and goats. This disease leads to high morbidity and mortality of small ruminants, thus resulting in devastating economic loss to the livestock industry globally. The severe disease impact has prompted the Food and Agriculture Organization of the United Nations (FAO) and the World Organization for Animal Health (OIE) to develop a global strategy for the control and eradication of PPR by 2030. Over the past decades, the control of PPR is mainly achieved through vaccinating the animals with live-attenuated vaccines, e.g., rinderpest vaccines. As a closely related disease to PPR of large ruminants, rinderpest was eradicated in 2011 and its vaccines subsequently got banned in order to keep rinderpest-free zones. Consequently, it is desirable to develop homologous PPR vaccines to control the disease. The present review summarizes the objectives of PPR control and eradication by focusing on the homologous PPR vaccines.

Neuropathology mediated through caspase dependent extrinsic pathway in goat kids naturally infected with PPRV

Peste des petits ruminant (PPR), a highly contagious viral disease of small ruminants, is characterized by erosive stomatitis and pneumo-enteritis. However, its neurovirulence potential as observed with other morbilliviruses has not been fully investigated. The present study describes the neuropathological alterations induced by PPR virus through apoptotic pathway. A total number of 12 carcasses of local breed goat kids of either sex were received for postmortem examination. The clinical history was described as symptoms of mucopurulent nasal discharge, high to low grade fever, erosive stomatitis, dyspnoea and profuse watery diarrhoea followed by mortality of 35 goat kids within a week. The pathoanatomical lesions and immunohistochemical demonstration of PPRV antigen in lungs, intestine, spleen and lymph nodes confirmed PPR disease in goats. Grossly, five brain specimens showed moderate to severe leptomeningeal congestion during necropsy. Microscopically, brain sections showed leptomeningitis and nonsuppurative encephalitis characterized by vascular congestion, haemorrhages in the parenchyma, perivascular cuffing with mild to moderate mononuclear cells (mainly lymphocytes and few macrophages), focal to diffuse microgliosis, neuronal degeneration, satellitosis and neuronophagia. Immunolabelling of viral antigen was observed in the cytoplasm of neurons and glial cells. The RT-PCR amplification of N gene fragment also confirmed the presence of PPRV in the brain. The strong immunoreactivity of Caspase-3, Caspase-8 and comparatively lower expression of caspase-9 along with the absence of any reactivity for Apaf-1 antigen in the brain sections indicated the role of caspase dependent extrinsic pathway in inducing neuropathological changes. The presence of apoptotic neurons in the brain by TUNEL assay further confirmed the apoptosis and strong immunoreactivity of iNOS in neurons which suggested the generation of oxidative stress, that might have induced the apoptosis. The overall findings confirm the neurovirulence potential of PPR virus, via the extrinsic pathway of apoptosis, in natural cases of PPR disease in goat kids.

Immunoinformatics Approach for Multiepitope Vaccine Prediction from H, M, F, and N Proteins of Peste des Petits Ruminants Virus

Background

Small ruminant morbillivirus or peste des petits ruminants virus (PPRV) is an acute and highly contagious viral disease of goats, sheep, and other livestock. This study aimed at predicting an effective multiepitope vaccine against PPRV from the immunogenic proteins haemagglutinin (H), matrix (M), fusion (F), and nucleoprotein (N) using immunoinformatics tools.

Materials and Methods

The sequences of the immunogenic proteins were retrieved from GenBank of the National Center for Biotechnology Information (NCBI). BioEdit software was used to align each protein from the retrieved sequences for conservancy. Immune Epitope Database (IEDB) analysis resources were used to predict B and T cell epitopes. For B cells, the criteria for electing epitopes depend on the epitope linearity, surface accessibility, and antigenicity.

Results

Nine epitopes from the H protein, eight epitopes from the M protein, and ten epitopes from each of the F and N proteins were predicted as linear epitopes. The surface accessibility method proposed seven surface epitopes from each of the H and F proteins in addition to six and four epitopes from the M and N proteins, respectively. For antigenicity, only two epitopes ₁₄₂PPERV₁₄₆ and ₆₃DPLSP₆₇ were predicted as antigenic from H and M, respectively. For T cells, MHC-I binding prediction tools showed multiple epitopes that interacted strongly with BoLA alleles. For instance, the epitope ₄₅MFLSLIGLL₅₃ from the H protein interacted with four BoLA alleles, while ₂₇₆FKKILCYPL₂₈₄ predicted from the M protein interacted with two alleles. Although F and N proteins demonstrated no favorable interaction with B cells, they strongly interacted with T cells. For instance, ₃₅₈STKSCARTL₃₆₆ from the F protein interacted with five alleles, followed by ₃₄₀SQNALYPMS₃₄₈ and ₄₄₂IDLGPAISL₄₅₀ that interacted with three alleles each. The epitopes from the N protein displayed strong interaction with BoLA alleles such as ₄₉₀RSAEALFRL₄₉₈ that interacted with five alleles, followed by two epitopes ₂ATLLKSLAL₁₀ and ₃₀₄QQLGEVAPY₃₁₂ that interacted with four alleles each. In addition to that, four epitopes ₃TLLKSLALF₁₁, ₃₅₆YFDPAYFRL₃₆₄, ₃₆₀AYFRLGQEM₃₆₈, and ₄₁₂PRQAQVSFL₄₂₀ interacted with three alleles each.

Conclusion

Fourteen epitopes were predicted as promising vaccine candidates against PPRV from four immunogenic proteins. These epitopes should be validated experimentally through in vitro and in vivo studies.

Spatio-temporal analysis of peste des petits ruminants outbreaks in PR China (2013-2018): Updates based on the newest data

Peste des petits ruminants (PPR) is a highly contagious disease of small ruminants. The purpose of this study was to investigate the epidemic characteristics of PPR outbreaks in the People's Republic of China (PR China) from 2013 to 2018. A total of 41,876 PPR outbreaks were recorded in small ruminant populations in PR China during that period. Data from February to June 2018 were used to study new developments in the PPR epidemic in PR China. Spatio-temporal clusters and temporal distribution patterns were studied based on PPR notifications. We also used multiple logistic regression to examine the contribution of anthropogenic, climatic and topographic factors to PPR outbreaks. Distance to the nearest road (OR = 1.007 [95% CI: 1.001-1.014]), price of mutton (OR = 1.904 [95% CI: 1.358-2.668]) and mean monthly temperature in July (OR 1.156 = [95% CI: 1.110-1.204]) showed positive effects on PPR outbreaks. Negative effects were observed for number of large-scale farms (OR = 0.962 [95% CI: 0.940-0.985]). We also found that observed patterns of seasonality were characterized by peaks in April of 2014. Spatio-temporal clusters occurred in Yunnan, Jiangsu, Anhui, Heilongjiang province and Chongqing municipality. Hunan province reported PPR occurrences every year from 2014 to June 2018. Yunnan, Jiangsu and Anhui province have 56, 33 and 30 epidemic locations, respectively. PPR infections were first reported as the cause of death for 19 wild bharals in Qinghai province in 2018. All of this suggests that domestic trading of sheep and goats may be closely related to the spread of PPR. Prophylactic immunization in suspected animal populations or areas is recommended for the control of PPR and wild small ruminants should be monitored. Results presented here provide improved knowledge about PPR dynamics in PR China, which could be helpful in designing more effective prevention strategies.

Molecular characterization of Peste des Petits ruminants virus isolated from four outbreaks occurred in southern Iran

Background

Peste des petits ruminants (PPR) is a severe infectious disease in both domestic and wild small ruminants. Due to its heavy economic burden and hence social and health impacts on human populations, Food and Agriculture Organization of the United Nations (FAO) and The World Organization for Animal Health (OIE) have targeted PPR for eradication by 2030. In order to plan and implement a successful eradication program, factual status assessments prior to devising disease control strategies is a vital criterion. The aim of this study was to isolate and characterize PPR virus from a rising wave of outbreaks in southern Iran.

Results

Twenty-one clinical samples, including blood as well as oral, nasal and ocular swabs were collected from ten sick animals in 4 various herds and were examined with ELISA and RT-PCR for the presence of PPR virus antigen and genome, respectively. The virus was successfully isolated in primary lamb kidney cell culture and identified by RT-PCR. Phylogenetic analysis of the sequenced N genes revealed that, while the earliest reports of Iran’s outbreaks were grouped into clusters with Saudi Arabia, Turkey and Africa, in this study reported sequences were grouped with samples from Pakistan, Tajikistan and China in particular. This observation suggests a shift in PPRV flow from the western borders of the country to the eastern neighboring countries.

Conclusions

Lineage IV of PPR virus is presently circulating in Iran, with certain levels of genetic diversity. Present study along with previous reports demonstrates the dispersal patterns and movements of PPR virus, which highlights the reversal pattern of virus flow in recent years. Such information is necessary to understand PPRV molecular epidemiology and to develop more proper control strategies to eradicate the disease in the planned time.

Electronic supplementary material

The online version of this article (10.1186/s12917-019-1920-y) contains supplementary material, which is available to authorized users.

Pathological and molecular characterisation of peste des petits ruminants in Nubian ibex (Capra nubiana) in Israel

Peste des petits ruminants (PPR) is a devastating disease that generally affects sheep and goats, mostly in Asia, the Middle East and Africa. The disease has been declared a target for global eradication. Despite its high prevalence in domestic flocks and its high seroprevalence among wildlife, it is rarely reported as a fulminant disease in wild ruminant species (with the exception of Central Asia). In this report, we describe a severe PPR outbreak in a zoo herd of Nubian ibex (Capra nubiana), causing the deaths of 2/3 of the herd. The clinical onset was acute with morbid animals exhibiting lethargy and watery-to-bloody diarrhea and death usually within 48 h. The most consistent gross pathologic findings were hemorrhagic abomasitis and enteritis. Oral lesions and pulmonary lesions were rare. Histology revealed necrohemorrhagic enteritis and abomasitis with myriad nuclear and cytoplasmic viral inclusion bodies. Molecular examinations confirmed the diagnosis of PPR and determined that the causative agent belongs to lineage IV. Further molecular examination showed that the virus belongs to the Asian clade of lineage IV and is closely related to a virus described in Turkey.

Peste des petits ruminants in Africa: Meta-analysis of the virus isolation in molecular epidemiology studies

Peste des petits ruminant (PPR) is a highly contagious, infectious viral disease of small ruminant species which is caused by the peste des petits ruminants virus (PPRV), the prototype member of the Morbillivirus genus in the Paramyxoviridae family. Peste des petits ruminant was first described in West Africa, where it has probably been endemic in sheep and goats since the emergence of the rinderpest pandemic and was always misdiagnosed with rinderpest in sheep and goats. Since its discovery PPR has had a major impact on sheep and goat breeders in Africa and has therefore been a key focus of research at the veterinary research institutes and university faculties of veterinary medicine in Africa. Several key discoveries were made at these institutions, including the isolation and propagation of African PPR virus isolates, notable amongst which was the Nigerian PPRV 75/1 that was used in the scientific study to understand the taxonomy, molecular dynamics, lineage differentiation of PPRV and the development of vaccine seeds for immunisation against PPR. African sheep and goat breeds including camels and wild ruminants are frequently infected, manifesting clinical signs of the disease, whereas cattle and pigs are asymptomatic but can seroconvert for PPR. The immunisation of susceptible sheep and goats remains the most effective and practical control measure against PPR. To carry out PPR vaccination in tropical African countries with a very high temperature, a thermostable vaccine using the rinderpest lyophilisation method to the attenuated Nigeria 75/1 PPR vaccine strain has been developed, which will greatly facilitate the delivery of vaccination in the control, prevention and global eradication of PPR. Apart from vaccination, other important questions that will contribute towards the control and prevention of PPR need to be answered, for example, to identify the period when a susceptible naïve animal becomes infectious when in contact with an infected animal and when an infectious animal becomes contagious.

Experimental infection of cattle with wild type peste-des-petits-ruminants virus - Their role in its maintenance and spread

Peste des petits ruminants (PPR) is a major Transboundary animal disease (TADs) of sheep and goats in tropical regions caused by PPRV which can also infect cattle without any clinical signs but inducing seroconversion. However the epidemiological role of cattle in the maintenance and spread of the disease is not known. For the purposes of the present study, cattle were infected with a wild type candidate from each of the four lineages of PPRV and placed in separate boxes. Naive goats were then introduced into each specific box for the 30 days duration of the experiment. The results showed that no clinical signs of PPR were recorded in these infected cattle nor in the in-contact goats. The nasal and oral swabs remained negative. Serum from animals infected with three (3) of the wild type isolates of PPRV showed high percentage inhibition (PI % > 65%) in a cELISA. Only two animals out of three infected with the Nigeria 75/3 strain of lineage 2 (mild strain) had specific anti-PPR antibodies but with PI% values around the threshold of the test. Our findings suggest that cattle are dead-end hosts for PPRV and do not play an epidemiological role in the maintenance and spread of PPRV. In a PPR surveillance programme, cattle can serve as indicators of PPRV infection.

Molecular detection, isolation and characterization of Peste-des-petits ruminants virus from goat milk from outbreaks in Bangladesh and its implication for eradication strategy

Peste-des-petits ruminants (PPR) is a highly contagious transboundary viral disease of small ruminants, which is endemic in much of Africa, the Middle East and Asia. In South Asia, PPR is of significant concern to the Indian subcontinent including Bangladesh as more than 30% of the world's sheep and goats are farmed in this region, predominantly by small, poor and marginal farmers. PPR virus was detected and isolated from goat milk from field samples from PPR outbreaks (2012-2015) in Bangladesh and its full-length sequences obtained. Sequence analysis of the partial N gene of Bangladesh isolates showed 99.3%-100% identity whereas 98.2%-99.6% identity was observed when compared with neighbouring Indian viruses. Further analysis of the full-length genomes indicated that the Bangladesh isolates were 99.3%-99.99% identical among themselves and 98.3%-98.4% identical to neighbouring Indian viruses. These findings further support the transboundary transmission of PPR virus across the Indian and Bangladesh border. In additional, the establishment of a cross-border strategy between India and Bangladesh will be of paramount importance for the eradication of PPR in this region. Molecular detection and isolation of PPR virus from milk is of significant potential concern for spread of the disease to free areas as the major producers of goat milk globally are PPR endemic countries in particular India and Bangladesh, as well as Sudan. Milk is a noninvasive sample type and bulk goat milk sampling for the detection of PPRV would be of practical significance for regional surveillance of PPRV as progress is made towards the targeted 2030 eradication.

The IMPDH inhibitors, ribavirin and mycophenolic acid, inhibit peste des petits ruminants virus infection

Peste des petits ruminants virus (PPRV) causes highly contagious diseases in domestic and particular wild small ruminants, leading to substantial economic loss. The development of effective and cheap antiviral medications shall help to circumvent this emerging burden. In this study, we found that ribavirin, a competitive inosine-5'-monophosphate dehydrogenase (IMPDH) inhibitor, significantly inhibits the replication of PPRV. As IMPDH is a key enzyme in purine nucleotide synthesis, supplementation of exogenous guanosine attenuate the anti-PPRV effect of ribavirin. Interestingly, an uncompetitive IMPDH inhibitor, mycophenolic acid (MPA), exerted more potent antiviral effect again PPRV. Similarly, this effect was largely restored upon supplementation of guanosine. Thus, we have demonstrated that the IMPDH inhibitors ribavirin and MPA combat PPRV infection through purine nucleotide depletion. Because both regimens have been widely used in the clinic for treating viral infection or organ rejection in transplantation patients for decades, respectively, repurposing these existing safe and cheap medications may provide a new avenue for combating PPRV infection.

Cross-sectional sero-prevalence study of Peste des Petits Ruminants (PPR) in goats of Syangja and Kaski districts of Nepal

A cross-sectional study was conducted to determine sero-prevalence of Peste des Petits Ruminants (PPR) among goat population of outbreak suspected areas; Kaski and Syangja districts of Nepal. A total of 460 goat serum samples were tested by using c-ELISA for the presence of antibodies against PPR. Out of the 460 samples tested, 380 samples were found positive, giving overall sero-positivity of 82.60%. Significantly higher sero-prevalence was found (*P < 0.05) in females (87.50%) compared to males (70.45%) and crossbreed goats were found highly susceptible than the pure breed goats (*P < 0.05). Likewise, higher sero-prevalence of PPR was observed in adults and cross breed goats compared to their counterparts and significantly higher sero-prevalence was observed in Syangja district compared to Kaski. Thus, adults, females and cross-breeds populations of goats are at higher risk of PPR whereas geographically, goat population of Syangja district were found significantly prone to PPR. Appropriate control measures, such as ring vaccination can be followed to prevent the potential outbreak situation.

Quantitative investigation of the direct interaction between Hemagglutinin and fusion proteins of Peste des petits ruminant virus using surface Plasmon resonance

Background

The specific and dynamic interaction between the hemagglutinin (H) and fusion (F) proteins of morbilliviruses is a prerequisite for the conformational rearrangements and membrane fusion during infection process. The two heptad repeat regions (HRA and HRB) of F protein are both important for the triggering of F protein.

Methods

In this study, the direct interactions of Peste des petits ruminants virus (PPRV) H with F, HRA and HRB were quantitatively evaluated using biosensor surface plasmon resonance (SPR).

Results

The binding affinities of immobilized pCMV-HA-H (HA-H) interacted with proteins pCMV-HA-F (HA-F) and pCMV-HA-HRB (HA-HRB) (K_D = 1.91 × 10^− 8 M and 2.60 × 10^− 7 M, respectively) reacted an order of magnitude more strongly than that of pCMV-HA-HRA (HA-HRA) and pCMV-HA-Tp IGFR-LD (HA) (K_D = 1.08 × 10^− 4 M and 1.43 × 10^− 4 M, respectively).

Conclusions

The differences of the binding affinities suggested that HRB is involved in functionally important intermolecular interaction in the fusion process.

Peste des petits ruminants in China since its first outbreak in 2007: A 10-year review

Peste des petits ruminants (PPR) is a highly infectious disease of small ruminants and caused by small ruminant morbillivirus (SRMV), formerly called peste-des-petits-ruminants virus (PPRV). This disease is circulating in Africa (except most countries in southern Africa), the Arabian Peninsula, the Middle East, and Central, East and South-East Asia. Peste des petits ruminants is still regarded as an exotic disease in China, where its first outbreak was reported in the Ngari region of Tibet in 2007, but effectively controlled by slaughter, vaccination and animal movement restriction in PPR-infected areas. However, PPR re-emerged in Xinjiang of China in December 2013, rapidly spread into much of China in the first half of 2014, but since then was substantially inhibited countrywide. Phylogenetic analysis shows that SRMVs from China share the highest homology with others from its neighbouring countries, possibly indicating the transboundary transmission of SRMVs. In 2015, a national eradication program for PPR was issued and has been being implemented in China, expecting to achieve a PPR-eradicating aim countrywide by 2020. Here, we reviewed a 10-year history (2007-2017) of PPR in China, including two major outbreaks, its infection in wild species, development of diagnostics and vaccines, and implementation of the national eradication program.

Morbillivirus Pathogenesis and Virus-Host Interactions

Despite the availability of safe and effective vaccines against measles and several animal morbilliviruses, they continue to cause regular outbreaks and epidemics in susceptible populations. Morbilliviruses are highly contagious and share a similar pathogenesis in their respective hosts. This review provides an overview of morbillivirus history and the general replication cycle and recapitulates Morbillivirus pathogenesis focusing on common and unique aspects seen in different hosts. It also summarizes the state of knowledge regarding virus-host interactions on the cellular level with an emphasis on viral interference with innate immune response activation, and highlights remaining knowledge gaps.

Confirmation and Sequence analysis of N gene of PPRV in South Xinjiang, China

ABSTRACT In China, Peste des petits ruminants (PPR) was officially first reported in 2007. From 2010 until the outbreak of 2013, PPRV infection was not reported. In November 2013, PPRV re-emerged in Xinjiang and rapidly spread to 22 P/A/M (provinces, autonomous regions and municipalities) of China. In the study, suspected PPRV-infected sheep in a breeding farm of South Xinjiang in 2014 were diagnosed and the characteristics of complete sequence of N protein gene of PPRV was analyzed. The sheep showed PPRV-infected signs, such as fever, orinasal secretions increase, dyspnea and diarrhea, with 60% of morbidity and 21.1% of fatality rate. The macroscopic lesions after autopsy and histopathological changes were observed under light microscope including stomatitis, broncho-interstitial pneumonia, catarrhal hemorrhagic enteritis and intracytoplasmic eosinophilic inclusions in multinucleated giantcell in lung. The formalin-fixed mixed tissues samples were positive by nucleic acid extraction and RT-PCR detection. The nucleotide of N protein gene of China/XJNJ/2014 strain was extremely high homology with the China/XJYL/2013 strain, and the highest with PRADESH_95 strain from India in exotic strains. Phylogenetic analysis based on complete sequence of N protein gene of PPRV showed that the China/XJNJ/2014 strain, other strain of 2013-2014 in this study and Tibetan strains all belonged to lineage Ⅳ, but the PPRV strains of 2013-2014 in this study and Tibetan strains were in different sub-branches.

Evolutionary dynamics of recent peste des petits ruminants virus epidemic in China during 2013-2014

Peste des petits ruminants virus (PPRV) causes a highly contagious disease, peste des petits ruminants (PPR), in sheep and goats which has been considered as a serious threat to the local economy in Africa and Asia. However, the in-depth evolutionary dynamics of PPRV during an epidemic is not well understood. We conducted phylogenetic analysis on genomic sequences of 25 PPRV strains from China 2013-2014 outbreaks. All these strains clustered into a novel clade in lineage 4. An evolutionary rate of 2.61 × 10-6 nucleotide substitutions per site per day was estimated, dating the most recent common ancestor of PPRV China 2013-2014 strains to early August 2013. Transmission network analysis revealed that all the virus sequences could be grouped into five clusters of infection, suggesting long-distance animal transmission play an important role in the spread of PPRV in China. These results expanded our knowledge for PPRV evolution to achieve effective control measures.

Spatiotemporal pattern of peste des petits ruminants and its relationship with meteorological factors in China

Peste des petits ruminants (PPR) is a severe infectious viral disease of domestic and wild small ruminants, and it threatens food security and livelihood of farmers across the world. In China, 292 PPR cases have been reported since it was first reported in 2007. Aiming to display the spatiotemporal patterns of PPR outbreaks and to understand its relationship with meteorological factors, we conducted a direction test, directional distribution analysis, and logistic regression analysis. The results showed that the spread of disease had a significant directional spread (P<0.05). Daily average temperature (DAT) [OR 0.063 (95% CI 0.047-0.076)], daily average relative humidity (DARH) [OR 0.871 (95% CI 0.804-0.944)], and daily hours of sunshine (DHS) [OR 0.411 (95% CI 0.389-0.582)] were inversely associated with the risk of PPR outbreak, while a positive association was observed for daily average air pressure (DAAP) [OR 1.211 (95% CI 1.036-1.417). Our findings indicate that meteorological factors may be important variables for affecting PPR transmission, and should be taken into account in the future monitoring programs for PPR.

Peste des petits ruminants infection in domestic ruminants in Sudan

The existence of peste des petits ruminants (PPR) in domestic ruminants and camels in Sudan during 2008-2012 was investigated. Lung tissues and serum samples were randomly collected from sheep, goats, cattle, and camels at different areas of Sudan. A total of 12,384 serum samples were collected from clinically healthy 7413 sheep, 1988 camels, 1501 cattle, 1459 goats, and 23 gazelles at different areas in the Sudan. They were examined for PPR antibodies using competitive ELISA (cELISA). The overall detected seroprevalence of PPR in tested sera was 49.4%; seroprevalence values within species were 67.1, 48.2, 25.8, 2.1, and 21.7% in sheep, goat, cattle, camels, and gazelles, respectively. The highest seroprevalence (68.1%) was observed in sera collected from Darfur states, then the central states (54.3%). A total of 1276 lung tissue samples (623 sheep, 324 cattle, 220 camels, and 109 goats) were collected. The majority of lung samples were collected from clinically healthy animals that showed lesions on PM in slaughterhouses (95%) and during PPR outbreaks; samples were tested for PPR antigen using immunocapture ELISA (IcELISA). PPR antigen was detected in 233 out of the 1276 tested samples (18.3%). Positive results were observed in samples collected from clinically healthy and diseased animals. The observed prevalence values in each species were 33.6, 21.1, 15.4, and 12.3% in camel, goat, sheep, and cattle, respectively. PPR antigen was detected in samples from different areas; however, the highest prevalence (63.9%) was found in samples collected from the eastern states, then Khartoum state (28%). Trials for virus isolation were done in different cell cultures. Out of 30 IcELISA-positive samples inoculated in primary bovine and ovine kidney cells, Vero cells, the PPR virus was successfully isolated from 15 (eight sheep, five camels, and two goats) samples in the three cell culture types. Using RT-PCR, PPRV nucleic acid was detected in all 25 IcELISA-positive tested samples.

M protein is sufficient for assembly and release of Peste des petits ruminants virus-like particles

Peste des petits ruminants virus (PPRV), belonging to paramyxoviruses, has six structure proteins (such as matrix protein (M), nucleocapsid proteins (N), fusion protein (F) and hemagglutinin protein (H)) and could cause high morbidity and mortality in sheep and goats. Although a vaccine strain of PPRV has been rescued and co-expression of M and N could yield PPRV-like particles, the roles of structure proteins in virion assembly and release have not been investigated in detail. In this study, plasmids carrying PPRV cDNA sequences encoding the N, M, H, and F proteins were expressed in Vero cells. The co-expression of all four proteins resulted in the release of virus-like particles (VLPs) with similar release efficiency to that of authentic virions. Moreover, the co-expression of M together with F also resulted in efficient VLPs release. In the absence of M protein, the expression of no combination of the other proteins resulted in particle release. In summary, a VLPs production system for PPRV has been established and M protein is necessary for promoting the assembly and release of VLPs, of which the predominant protein is M protein. Further study will be focused on the immunogenicity of the VLPs.

Diagnosis of Peste des Petits Ruminants in Wild and Domestic Animals in Xinjiang, China, 2013-2016

Peste des petits ruminants viruses (PPRVs) re-emerged in China at the end of 2013 and then spread rapidly into 22 provinces through movement of live goats and sheep. In this study, 96 samples of domestic animals and 13 samples of wildlife were analysed for the presence of PPRV infection by ELISA or RT-PCR. Of 96 samples from sheep and goats, 91 were PPRV positive, whereas all of the 13 samples from three wild species, Capra ibex (Capra ibex sibirica), argali (Ovis ammon) and Goitered gazelle (Gazella subgutturosa), were found to be positive. Five wildlife-origin isolates from the above samples were identified as the lineage IV by a multiple alignment of the partial sequences in N gene.

Persistence of Lineage IV Peste-des-petits ruminants virus within Israel since 1993: An evolutionary perspective

Peste-des-petits ruminants (PPR) is one of the most important infectious diseases of domesticated small ruminants. From the initial identification in 1942 in West Africa, PPR virus (PPRV) has spread throughout much of the developing world. PPRV is now considered endemic throughout Africa, with the notable exception of South Africa, the Middle-East and Israel, as well as South-, East-, and Central Asia. Despite this widespread dispersal, the evolution and transmission of PPRV in endemic populations is not well understood. This understanding will be critical in the planning of rational measures to eradicate PPRV by the planned time as defined by the FAO and OIE. To further advance the understanding of the evolution of PPRV the full genome sequence of 18 viruses isolated from Israel from consecutive years between 1997-2014 were generated. This data set is unique and crucial for the understanding of the evolution of PPRV, as it represents the first set of full-length sequence data available from consecutive years from a single geographic location. Analysis of these full genome sequences shows 96.2-99.9% nucleotide conservation across the Israel isolates and further demonstrates the strong purifying selection pressures on PPRV within Israel and globally. Four amino acid substitutions indicative of putative positive selection were additionally identified within the Israel isolates. The mean substitution rate per site per year was estimated to be 9.22 x 10-4 (95% HPD 6.206 x 10-4-1.26 x 10-3). Using Bayesian and phylogenetic analyses we further demonstrate that the PPRV isolates from Israel belongs to linage IV and form a single strong regional cluster within all other lineage IV viruses circulating worldwide implying a single incursion into Israel.

Comparison of nucleotide sequences of recent and previous lineages of peste-des-petits-ruminants viruses of sheep and goats in Nigeria

Peste-des-petits-ruminants virus (PPRV) is a highly contagious, fatal and economically important viral disease of small ruminants that is still endemic and militates against the production of sheep and goats in endemic areas of the world. The aim of this study was to describe the viral strains within the country. This was carried out by collecting tissue and swab samples from sheep and goats in various agro-ecological zones of Nigeria. The phylogeny of archived PPRV strains or isolates and those circulating and causing recent outbreaks was determined by sequencing of the nucleoprotein (N)-gene. Twenty tissue and swab samples from apparently healthy and sick sheep and goats were collected randomly from 18 states, namely 3 states in each of the 6 agro-ecological zones visited. A total of 360 samples were collected. A total of 35 samples of 360 (9.7%) tested positive by reverse transcriptase–polymerase chain reaction, of which 25 were from oculo-nasal swabs and 10 were from tissue samples. Neighbour-joining phylogenetic analysis using Phylogenetic Analysis Using Parsimony (PAUP) identified four different lineages, that is, lineages I, II, III and IV. Interestingly, the Nigerian strains described in this study grouped in two separate major lineages, that is, lineages II and IV. Strains from Sokoto, Oyo, Plateau and Ondo states grouped according to the historical distribution of PPRV together with the Nigerian 75/1 strain of lineage II, while other strains from Sokoto, Oyo, Plateau, Akwa-Ibom, Adamawa, Kaduna, Lagos, Bauchi, Niger and Kano states grouped together with the East African and Asian strains of lineage IV. This finding confirms that both lineage II and IV strains of PPRV are circulating in Nigeria. Previously, only strains of lineage II were found to be present in the country.

Rapid detection of lineage IV peste des petits ruminants virus by real-time RT-PCR

Peste des petits ruminants virus (PPRV) is the cause agent of peste des petitis ruminants (PPR). A novel lineage IV PPRV has reemerged in China in 2013 and 2014. Mass vaccination was implemented in most provinces in China. In order to detect lineage IV PPRV in clinical samples and to distinguish rapidly it from the other lineages PPRVs, a real-time RT-PCR assay was developed. This assay showed high sensitivity, specificity and efficiency in differentiating the lineage IV PPRV from others. The performance of this assay was evaluated by positive clinical samples of lineage IV viruses. This new real-time RT-PCR assay will facilitate epidemiological investigations and rapid differentiatial diagnosis in areas where lineage IV viruses are circulating.

Molecular evolution of peste des petits ruminants virus

Sequence data will increase understanding of virus evolution, adaptability, and pathogenicity.

Despite safe and efficacious vaccines against peste des petits ruminants virus (PPRV), this virus has emerged as the cause of a highly contagious disease with serious economic consequences for small ruminant agriculture across Asia, the Middle East, and Africa. We used complete and partial genome sequences of all 4 lineages of the virus to investigate evolutionary and epidemiologic dynamics of PPRV. A Bayesian phylogenetic analysis of all PPRV lineages mapped the time to most recent common ancestor and initial divergence of PPRV to a lineage III isolate at the beginning of 20th century. A phylogeographic approach estimated the probability for root location of an ancestral PPRV and individual lineages as being Nigeria for PPRV, Senegal for lineage I, Nigeria/Ghana for lineage II, Sudan for lineage III, and India for lineage IV. Substitution rates are critical parameters for understanding virus evolution because restrictions in genetic variation can lead to lower adaptability and pathogenicity.

Prevalence of peste des petits ruminants in the arid zone in the Republic of Niger

The study aimed to determine the prevalence of peste des petits ruminants in the arid zone (Niamey, Tillabéry and Tahoua) of the Republic of Niger. A serological survey was conducted and 519 serum samples were collected from 253 unvaccinated sheep and 266 unvaccinated goats. The sample included 340 female animals (168 sheep and 172 goats) and 160 kids and lambs (78 lambs and 82 kids). A competitive enzyme-linked immunosorbent assay yielded an overall seroprevalence of 45.0%. The prevalence in sheep was 42.0% compared with 47.9% in goats. The seroprevalence observed amongst small ruminants in Tahoua (49.8%) and Tillabéry (46.6%) was significantly higher (p = 0.001) than that observed in animals from Niamey (25.1%). It was also higher (p = 0.04) in sheep younger than two years (51.8%) than in adults (37.6%). Conversely, the seroprevalence showed no significant difference between male animals (35.8% in sheep; 50.1% in goats) and female animals (45.1% in sheep; 46.4% in goats). The prevalence of the disease observed amongst the sheep and goat populations confirms the continued danger of this disease in the areas studied. It is therefore necessary to develop strategies such as improving livestock services, providing effective vaccines and implementing a vaccination programme for an effective control of the disease in sub-Saharan Africa.

The global eradication of peste des petits ruminants (PPR) within 15 years--is this a pipe dream?

Gordon Scott did much to inspire the eradication of rinderpest, probably the most outstanding veterinary achievement of the twentieth century, and one currently inspiring is the proposed eradication of peste des petits ruminants (PPR), a disease of sheep and goats caused by a closely related Morbillivirus. The evolution and geographic spread of PPR along with its epidemiological characteristics are discussed and related to ways in which its spread can be reduced through the provision of diagnostic aids to sanitary livestock movement at local level. Taking a historical look at rinderpest eradication, it was shown that much could be achieved using a legislation-backed zoosanitary approach or, once developed, the build up of herd immunities in isolated populations. As the final cap to this (circa), two hundred-year-long process, major national and internationally funded vaccination programmes falling within the informal coordinatorship of the OIE and FAO showed that final eradication could be achieved with remarkable rapidity if the seat of infection was known and if appropriate national and international interventions were aimed at ending virus transmission. Were such international cooperation to be forthcoming once more, the understanding, tools and experiences now on offer suggest that PPR could be controlled and eradicated far more rapidly than rinderpest.

Diseases of Free-Ranging Snow Leopards and Primary Prey Species

Although a wide range of diseases have been reported in captive snow leopards, little is known about those affecting the species in the wild. However, the potential threat from diseases to wild snow leopards must not be underestimated as a consequence of lack of health surveillance throughout the inaccessible terrains they occupy. As a felid, the snow leopard is likely to be susceptible to most infectious agents affecting the domestic cat, and here we provide an overview of those with a risk of lethality for free-ranging snow leopards. In contrast to the health of snow leopards themselves, a great deal is known about the diseases affecting their primary prey species. We present these cases and highlight the importance of livestock as the main source of disease spillover to natural prey species. Further studies are required to understand the impact of infectious agents on intra- and interspecific population dynamics of snow leopards and associated prey.

Peste des Petits Ruminants Virus

Peste des petits ruminants virus (PPRV) causes a severe contagious disease of sheep and goats and has spread extensively through the developing world. Because of its disproportionately large impact on the livelihoods of low-income livestock keepers, and the availability of effective vaccines and good diagnostics, the virus is being targeted for global control and eventual eradication. In this review we examine the origin of the virus and its current distribution, and the factors that have led international organizations to conclude that it is eradicable. We also review recent progress in the molecular and cellular biology of the virus and consider areas where further research is required to support the efforts being made by national, regional, and international bodies to tackle this growing threat.

Peste des petits ruminants

Peste des petits ruminants virus causes a highly infectious disease of small ruminants that is endemic across Africa, the Middle East and large regions of Asia. The virus is considered to be a major obstacle to the development of sustainable agriculture across the developing world and has recently been targeted by the World Organisation for Animal Health (OIE) and the Food and Agriculture Organisation (FAO) for eradication with the aim of global elimination of the disease by 2030. Fundamentally, the vaccines required to successfully achieve this goal are currently available, but the availability of novel vaccine preparations to also fulfill the requisite for differentiation between infected and vaccinated animals (DIVA) may reduce the time taken and the financial costs of serological surveillance in the later stages of any eradication campaign. Here, we overview what is currently known about the virus, with reference to its origin, updated global circulation, molecular evolution, diagnostic tools and vaccines currently available to combat the disease. Further, we comment on recent developments in our knowledge of various recombinant vaccines and on the potential for the development of novel multivalent vaccines for small ruminants.

Peste des petits ruminants virus in Heilongjiang province, China, 2014

During March 25–May 5, 2014, we investigated 11 outbreaks of peste des petits ruminants in Heilongjiang Province, China. We found that the most likely source of the outbreaks was animals from livestock markets in Shandong. Peste des petits ruminants viruses belonging to lineages II and IV were detected in sick animals.

Genome characterization and phylogenetic analysis of a lineage IV peste des petits ruminants virus in southern China

Since 2013, the second outbreak of peste des petits ruminants (PPR) caused by Peste des petits ruminants virus (PPRV) has spread over more than 20 provinces, municipalities, and autonomous regions in China, resulting in major economic losses for livestock industry. In 2014, we encountered a clinical PPR case on a goat farm in Guangdong province, southern China. The complete genome of this PPRV strain, named CH/GDDG/2014, was sequenced to determine its similarities and differences with other strains. The CH/GDDG/2014 genome comprised 15,954 nucleotides (six nucleotides more than classical PPRVs identified before 2013, but complying with the rule of six) with six open reading frames encoding nucleocapsid protein, phosphoprotein, matrix protein, fusion protein, hemagglutinin, and large polymerase protein, respectively. The whole-genome-based alignment analysis indicated that CH/GDDG/2014 had the most proximate consensus (99.8 %) to China/XJYL/2013 and the least consensus (87.2 %) to KN5/2011. The phylogenetic analysis showed that CH/GDDG/2014 was clustered in one branch (lineage IV) with other emerging strains during the second outbreak. This study is the first report describing the whole-genome sequence of PPRV in Guangdong province, southern China and also suggests the PPR outbreak may be closely related to illegal cross-regional importation of goats.