Peste des petits ruminants diagnosis and diagnostic tools at a glance: perspectives on global control and 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 50minutes 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.

Canine morbillivirus (CDV): a review on current status, emergence and the diagnostics

The increasing host range of canine morbillivirus (CDV) affecting important wildlife species such as Lions, Leopard, and Red Pandas has raised the concern. Canine distemper is a pathogen of dogs affecting the respiratory, gastrointestinal, and nervous systems. Seventeen lineages of CDV are reported, and the eighteenth lineage was proposed in 2019 from India. Marked genomic differences in the genome of wild-type virus and vaccine strain are also reported.The variations at the epitope level can be differentiated using specific monoclonal antibodies in neutralization tests. Keeping in mind the current status of the emergence of CDV, genetic and molecular study of circulating strains of the specific geographical region are the essential components of the disease control strategy. New target-based diagnostics and vaccines are in need to counter the effects of the emerging virus population. Control of CDV is necessary to save the endangered, vulnerable, and many other wildlife species to maintain balance in the ecological system. This review provides an overview on emergence reported in CDV, diagnostics developed till today, and a perspective on the disease control strategy, keeping wildlife in consideration.

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.

Development of Nanobodies Targeting Peste des Petits Ruminants Virus: The Prospect in Disease Diagnosis and Therapy

Simple Summary

Peste des petits ruminants virus (PPRV) causes a highly devastating disease, peste des petits ruminants (PPR) of sheep and goats, that threatens food security, small ruminant production, and the conservation of wild small ruminants. Current efforts are directed towards the global control and eradication of PPRV, an initiative of the World Organisation for Animal Health and Food and the Agriculture Organisation of the United Nations. A plethora of diagnostic tools for PPR were primarily developed for livestock. New innovative diagnostic tools are needed to detect PPRV in atypical hosts (e.g., Camelidae, Suidae, and Bovinae), in wildlife ecosystems, and in complex field situations. Recent studies confirmed that single-domain antigen binding fragments (nanobodies) derived from heavy-chain-only camelid antibodies have proven to be a powerful tool in diagnostics and therapeutics due to their unique properties, such as small size and strong antigen-binding affinity. Therefore, the main objective of this study was to generate PPRV-reactive nanobodies in order to set a pace for the development of diagnostic and possibly therapeutic nanobodies in the future. Initially, a strategy was developed whereby an alpaca was immunized with PPRV in order to raise an affinity-matured immune response, from which an immune nanobody library was constructed. Following phage display, nine nanobodies that specifically recognise PPRV were identified on enzyme-linked immunosorbent assay. This study has generated PPRV-reactive nanobodies and have significant implications in the development of cost-effective diagnostic tools in context with the planned eradication of PPR in the world.

Abstract

Peste des petits ruminants virus (PPRV) causes a highly devastating disease, peste des petits ruminants (PPR) of sheep and goats, that threatens food security, small ruminant production, and the conservation of wild small ruminants in many developing countries, especially in Africa. Robust serological and molecular diagnostic tools are available to detect PPRV infection, but they were mainly developed for domestic sheep and goats. The presence of a wide host range for PPRV does present serological diagnostic challenges. New innovative diagnostic tools are needed to detect PPRV in atypical hosts (e.g., Camelidae, Suidae, and Bovinae), in wildlife ecosystems and in complex field situations. Interestingly, single-domain antigen binding fragments (nanobodies) derived from heavy-chain-only camelid antibodies have emerged as a new hope in the development of accurate, rapid, and cost-effective diagnostic tools in veterinary and biomedical fields that are suitable for low-income countries. The main objective of this study was to construct an immune nanobody library to retrieve PPRV-reactive nanobodies that enable the development of diagnostic and therapeutic nanobodies in the future. Here, a strategy was developed whereby an alpaca (Vicugna pacos) was immunized with a live attenuated vaccine strain (PPRV/N/75/1) to raise an affinity-matured immune response in the heavy-chain-only antibody classes. The nanobody gene repertoire was engineered in pMECS-GG phagemid, whereby a ccdB gene (encoding a lethal protein) was substituted by the nanobody gene. An immune nanobody library with approximately sixty-four million independent transformants was constructed, of which 100% contained an insert with the proper size of nanobody gene. Following phage display and biopanning, nine nanobodies that specifically recognise completely inactivated PPRV were identified on enzyme-linked immunosorbent assay. They showed superb potency in rapidly identifying PPRV, which is likely to open a new perspective in the diagnosis and possible treatment of PPR infection.

Comparative evaluation of different antigen detection methods for the detection of peste des petits ruminants virus

Peste des petits ruminants (PPR) is a fatal disease of small ruminants which has spread rapidly to previously PPR-free countries in recent decades, causing enormous economic losses in the affected regions. Here, two newly emerged PPR virus (PPRV) isolates from India and from the Middle East were tested in an animal trial to analyse their pathogenesis, and to evaluate serological and molecular detection methods. Animals infected with the two different PPRV isolates showed marked differences in clinical manifestation and scoring. The PPRV isolate from India was less virulent than the virus from the Middle East. Commercially available rapid detection methods for PPRV antigen (two Lateral Flow Devices (LFDs) and one antigen ELISA) were evaluated in comparison with a nucleic acid detection method. For this purpose, ocular and nasal swabs were used. Due to the easy non-invasive sampling, faecal samples were also analysed. For all rapid antigen detection methods, a high specificity of 100% was observed independent of the sample matrix and dilution buffers used. Both antigen ELISA and LFD tests showed highest sensitivities for nasal swabs. Here, the detection rate of the antigen ELISA, the LFD-PESTE-TEST and the LFD-ID Rapid-Test was 78%, 75% and 78%, respectively. Ocular swabs were less suitable for antigen detection of PPRV. These results reflect the increased viral load in nasal swabs of PPRV infected goats compared to ocular swabs. The faecal samples were the least suitable for antigen detection. In conclusion, nasal swab samples are the first choice for the antigen and genome detection of PPRV. Nevertheless, based on the excellent diagnostic specificity of the rapid tests, positive results generated with other sample matrices are solid. In contrast, negative test results can be caused on the reduced analytical sensitivity of the rapid antigen tests and must be treated with caution.

Eradicating the Scourge of Peste Des Petits Ruminants from the World

Peste des Petits Ruminants (PPR) is a highly contagious viral disease of both domestic (goats and sheep) and wild ruminants. Caused by a morbillivirus, that belongs to the family Paramyxoviridae. The disease is clinically and pathologically similar to rinderpest of cattle and human measles. PPR is one of the most economically devastating viral diseases of small ruminants. In April 2015, the Food and Agriculture Organization of the United Nations (FAO) and the World Organisation for Animal Health (OIE) launched the PPR Global Control and Eradication Strategy (PPR GCES) with the vision for global eradication by 2030. There is a strong and lasting international consensus to eradicate the disease in order to protect the livelihoods of the world's poorest populations. As with any disease, eradication is feasible when, policy, scientific and technical challenges are addressed. Ten majors challenges are described in this paper namely: understanding small ruminant production, facilitating research to support eradication, refining laboratory testing, improving epidemiological understanding of the virus, defining infection of wildlife and other species, optimizing vaccine delivery and novel vaccines, developing better control of animal movement, heightening serological monitoring, understanding socio-economic impact, and garnering funding and political will.

Peste des petits ruminants in large ruminants, camels and unusual hosts

Since its first report in 1942, peste-des-petits-ruminants virus (PPRV) has caused several epidemics in a wide range of susceptible hosts around the world. In the last 30 years, the evidence of natural and experimental infections and virus isolation were reported from novel but unusual hosts such as camel, cattle, buffalo, dogs, Asiatic lion and pigs. In addition, PPRV in a potential vector, biting midges (Culicoides imicola), has been reported. Either presented as clinical and/or subclinical infections, the presence of the virus in an extended range of susceptible hosts highlights the cross-species transmission and supports the hypothesis of an endemic circulation of PPRV among susceptible hosts. However, the potential role of large ruminants, camels and unusual hosts for PPRV epidemiology is still obscure. Therefore, there is a need for molecular and epidemiological investigations of the disease among usual and unusual hosts to achieve the goals of disease control and eradication programmes initiated by national and international organisations, such as the FAO and OIE. This review is the first to summarise the scattered data on PPR in large ruminants, camels and unusual hosts to obtain the global scientific communities' attention for further research on epidemiological aspects, not only in its native hosts, but also in large ruminants, camels and other unusual hosts.

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.

Paradigm shift in the diagnosis of peste des petits ruminants: scoping review

Peste des petits ruminants virus causes a highly contagious disease, which poses enormous economic losses in domestic animals and threatens the conservation of wild herbivores. Diagnosis remains a cornerstone to the Peste des petits ruminants Global Control and Eradication Strategy, an initiative of the World Organisation for Animal Health and the Food and Agriculture Organisation. The present review presents the peste des petits ruminants diagnostic landscape, including the practicality of commercially available diagnostic tools, prototype tests and opportunities for new technologies. The most common peste des petits ruminants diagnostic tools include; agar gel immunodiffusion, counter-immunoelectrophoresis, enzyme-linked immunosorbent assays, reverse transcription polymerase chain reaction either gel-based or real-time, reverse transcription loop-mediated isothermal amplification, reverse transcription recombinase polymerase amplification assays, immunochromatographic lateral flow devices, luciferase immunoprecipitation system and pseudotype-based assays. These tests vary in their technical demands, but all require a laboratory with exception of immunochromatographic lateral flow and possibly reverse transcription loop-mediated isothermal amplification and reverse transcription recombinase polymerase amplification assays. Thus, we are proposing an efficient integration of diagnostic tests for rapid and correct identification of peste des petits ruminants in endemic zones and to rapidly confirm outbreaks. Deployment of pen-side tests will improve diagnostic capacity in extremely remote settings and susceptible wildlife ecosystems, where transportation of clinical samples in the optimum cold chain is unreliable.

Rapid Detection of Peste des Petits Ruminants Virus (PPRV) Nucleic Acid Using a Novel Low-Cost Reverse Transcription Loop-Mediated Isothermal Amplification (RT-LAMP) Assay for Future Use in Nascent PPR Eradication Programme

Peste des petits ruminants (PPR) is a disease of small ruminants caused by peste des petits ruminants virus (PPRV), and is endemic in Asia, the Middle East and Africa. Effective control combines the application of early warning systems, accurate laboratory diagnosis and reporting, animal movement restrictions, suitable vaccination and surveillance programs, and the coordination of all these measures by efficient veterinary services. Molecular assays, including conventional reverse transcription-polymerase chain reaction (RT-PCR) and real-time RT-PCR (RT-qPCR) have improved the sensitivity and rapidity of diagnosing PPR. However, currently these assays are only performed within laboratory settings; therefore, the development of field diagnostics for PPR would improve the fast implementation of control policies, particularly when PPR has been targeted to be eradicated by 2030. Loop-mediated isothermal amplification (LAMP) assays are simple to use, rapid, and have sensitivity and specificity within the range of RT-qPCR; and can be performed in the field using disposable consumables and portable equipment. This study describes the development of a novel RT-LAMP assay for the detection of PPRV nucleic acid by targeting the N-protein gene. The RT-LAMP assay was evaluated using cell culture propagated PPRVs, field samples from clinically infected animals and samples from experimentally infected animals encompassing all four lineages (I-IV) of PPRV. The test displayed 100% concordance with RT-qPCR when considering an RT-qPCR cut-off value of C_T >40. Further, the RT-LAMP assay was evaluated using experimental and outbreak samples without prior RNA extraction making it more time and cost-effective. This assay provides a solution for a pen-side, rapid and inexpensive PPR diagnostic for use in the field in nascent PPR eradication programme.

PPR Control in a Sahelian Setting: What Vaccination Strategy for Mauritania?

Peste des Petits Ruminants (PPR) is a viral disease affecting domestic and small wild ruminants. Endemic in large parts of the world, PPR causes severe damages to animal production and household economies. In 2015, FAO and OIE launched a global eradication program (GCSE) based on vaccination campaigns. The success of GCSE shall depend on the implementation of vaccination campaigns, accounting for husbandry practices, mobility and the periodicity of small ruminants' population renewal. In Mauritania, PPR outbreaks occur annually despite ongoing annual vaccination campaigns since 2008. Here, we developed a mathematical model to assess the impact of four vaccination strategies (including the GSCE one), the importance of their timing of implementation and the usefulness of individual animal identification on the reduction of PPR burden. The model was calibrated on data collected through ad-hoc surveys about demographic dynamics, disease impact, and national seroprevalence using Monte Carlo Markov Chain procedure. Numerical simulations were used to estimate the number of averted deaths over the next 12 years. The model results showed that the GSCE strategy prevented the largest number of deaths (9.2 million vs. 6.2 for random strategy) and provided one of the highest economic returns among all strategies (Benefit-Cost Ratio around 16 vs. 7 for random strategy). According to its current cost, identification would be a viable investment that could reduce the number of vaccine doses to distribute by 20–60%. Whilst the implementation of the identification system is crucial for PPR control, its success depends also on a coordinated approach at the regional level.

Peste des Petits Ruminants (PPR) virus serological surveillance in goats in Lao PDR: Issues for disease eradication in a low-resource disease-free setting

Peste des Petits ruminants (PPR) is an economically important transboundary viral disease of goats. This study aimed to determine a baseline of serological evidence for Peste des petits ruminants virus (PPRV) in Lao goats. A total of 1,072 serum samples were collected by convenience sampling across five provinces in Laos and tested for antibody response to PPRV using a commercially available competitive ELISA. Positive antibody responses were found in 2.2% (95% CI 1.4, 3.2) of the samples. True prevalence calculations indicated a total overall sample prevalence of 1.7% (95% CI 0.9, 2.8). The highest provincial seroprevalences were Xiangkhouang (3.5%, 95% CI 1.6, 6.9) and Xayaboury (2.9% (95% CI 1.3, 5.7). There was no association between antibody response and each of the following factors: location, breed, gender or age. Considering the apparent absence of disease manifestation of PPR in Laos, likely explanations for the antibody positivity could include cross reaction to other Morbilliviruses such as Measles or Canine Distemper, importation of pre-vaccinated goats, need for test cut-off re-evaluation to be region specific, or a subclinical and a less virulent circulating virus. This study highlights that the sampled Lao goat population is highly likely to be naïve to PPRV and therefore at risk of an outbreak, possibly by transboundary incursion of livestock from PPR endemic China. Further work is required in the testing of small ruminants in Laos that may eventually provide evidence for a status of freedom from disease, particularly in support of programs aimed at global PPR eradication.

Monoclonal antibody resistant mutant of Peste des petits ruminants vaccine virus

The available vaccines for control of Peste des petits ruminants do not favour differentiation of infected and vaccinated animals (DIVA). Hence, the present study was aimed to isolate and characterize monoclonal antibody resistant mutant of an Indian strain of vaccine virus "PPRV-Sungri/96" under selection pressure of virus neutralizing monoclonal antibody '4B11' specific to haemagglutinin (H) protein. We successfully isolated five monoclonal antibody resistant (mAr) mutants (PPRV-RM5, PPRV-RM6, PPRV-RM7, PPRV- E6 and PPRV- E7). The mAr mutants did not react with the anti-H mAb 4B11 whereas reacted with control anti-nucleoprotein mAb 4G6, similar to the parent vaccine virus "PPRV-Sungri/96" in indirect ELISA, cell ELISA and indirect immunofluorescence test. Cytometry analysis of mAr mutants revealed loss of binding to mAb 4B11 while maintaining binding to mAb 4G6, more or less similar to "PPRV-Sungri/96". The sequence analysis of the H-protein gene of the mAr mutants resulted in identification of two nucleotide changes leading to amino acid substitutions at position 263 and 502 (L263P and R502P) of the H protein indicating that the epitope of mAb 4B11 could be conformational in nature. Though, mAr mutant grew to a similar titre as parent vaccine virus (PPRV-Sungri/96), the in vivo work in goats to study the mAr mutant as possible negative marker vaccine candidate could not be successfully proved with mAb 4B11 based competitive ELISA. However, one of the nucleotide change (T-C) at position 788, unique to mAr mutant virus resulted in abolition of a restriction enzyme recognition site (BglII). This could be used to differentiate mAr mutant vaccine virus from other available vaccine and field strains using restriction fragment length polymorphism. However, the mAr mutant PPRV-E6 cannot be used as a candidate strain for DIVA vaccine as immune response against it cannot be differentiated based on serology.

An overview of process intensification and thermo stabilization for upscaling of Peste des petits ruminants vaccines in view of global control and eradication

Peste des petits ruminants (PPR) has been recognized as a globally distributed disease affecting the small ruminant population. The disease results in severe economic losses mainly to small land holders and low input farming systems. The control of PPR is mainly achieved through vaccination with available live attenuated vaccines. The thermo labile nature of PPR virus poses a major constraint in production of quality vaccines which often results in vaccine failures. The lack of quality vaccine production jeopardize the wide vaccination coverage especially in countries with poor infrastructure due to which PPR persists endemically. The vaccine production system may require augmentation to attain consistent and quality vaccines through efforts of process intensification integrated with suitable stabilizer formulations with appropriate freeze drying cycles for improved thermo tolerance. Manufacturing of live attenuated PPR vaccines during batch cultures might introduce defective interfering particles (DIPs) as a result of high multiplicity of infection (MOI) of inoculums, which has a huge impact on virus dynamics and yield. Accumulation of DIPs adversely affects the quality of the manufactured vaccines which can be avoided through use of appropriate MOI of virus inoculums and quality control of working seed viruses. Therefore, adherence to critical manufacturing standard operating procedures in vaccine production and ongoing efforts on development of thermo tolerant vaccine will help a long way in PPR control and eradication programme globally. The present review focuses on the way forward to achieve the objectives of quality vaccine production and easy upscaling to help the global PPR control and eradication by mass vaccination as an important tool.

The effects of PPR on the reproductive health of Black Bengal goats and the possible role played by oxidative stress

Outbreaks of Peste des petits ruminants (PPR) viral disease in Black Bengal goats were investigated from the middle Indo-Gangetic Plains of India. Clinical profile of PPR-affected flocks was recorded from four different outbreak sites of the region. The PPR outbreak was diagnosed serologically using commercially available sandwich ELISA kit. Relatively, low mortality rate (mean 26.75%) for PPR outbreak was recorded due to the endemic status of the disease. To understand the role of oxidative stress in PPR virus pathogenesis, various oxidant and antioxidant parameters in goats infected with PPR were estimated and compared with the uninfected/healthy goats of the same flock. The measured high level of pro-oxidant malondialdehyde (MDA) obtained from lipid peroxidation along with lower levels of anti-oxidants viz. superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT) in PPR-affected Black Bengal goats suggests oxidative stress as one of the mechanism of pathogenesis of PPR virus. In addition, the correlation of oxidative stress due to PPR and the resulting reproductive disorders in the female goats were evaluated. The abortion in pregnant does observed during PPR outbreak was proportional to debility and oxidative stress manifested during PPR infection. The reproductive performance of recovered female goats in the period of 18 months of monitoring was significantly compromised in terms of kidding and twinning frequency. The mortality rate in kids born from PPR-recovered goats was significantly higher compared to those from health goats in the first 9 months post-recovery. From the present study, it may be concluded that together with the PPR virus, infection in goats and the resulting oxidative stress play a vital role for abortion and reduced post-reproductive performance in Black Bengal female goat.

Peste des Petits Ruminants Virus Enters Caprine Endometrial Epithelial Cells via the Caveolae-Mediated Endocytosis Pathway

Peste des petits ruminants virus (PPRV) causes an acute and highly contagious disease of sheep and goats and has spread with alarming speed around the world. The pathology of Peste des petits ruminants is linked to retrogressive changes and necrotic lesions in lymphoid tissues and epithelial cells. However, the process of PPRV entry into host epithelial cells remains largely unknown. Here, we performed a comprehensive study of the entry mechanism of PPRV into caprine endometrial epithelial cells (EECs). We clearly demonstrated that PPRV internalization was inhibited by chloroquine and ammonium chloride, which elevate the pH of various organelles. However, PPRV entry was not affected by chlorpromazine and knockdown of the clathrin heavy chain in EECs. In addition, we found that the internalization of PPRV was dependent on dynamin and membrane cholesterol and was suppressed by silencing of caveolin-1. Macropinocytosis did not play a role, but phosphatidylinositol 3-kinase (PI3K) was required for PPRV internalization. Cell type and receptor-dependent differences indicated that PPRV entry into caprine fetal fibroblast cells (FFCs) occurred via a different route. Taken together, our findings demonstrate that PPRV enters EECs through a cholesterol-dependent caveolae-mediated uptake mechanism that is pH-dependent and requires dynamin and PI3K but is independent of clathrin. This potentially provides insight into the entry mechanisms of other morbilliviruses.

Investigating peste des petits ruminants (PPR) in naturally infected goats and sheep in Anseba Region, Eritrea, by reverse transcription polymerase chain reaction (RT-PCR)

The impact of peste des petits ruminants (PPR) virus was investigated by reverse transcription polymerase chain reaction (RT-PCR) on different samples obtained from non-vaccinated diseased and necropsied sheep and goats showing PPR-like symptoms. The disease picture was typical and sheep were observed to be less susceptible. Nasal and rectal swabs, whole blood and pathological tissue samples from the lungs, intestine, and mesenteric lymph nodes were used for this study. The results of RT-PCR indicated that from a total of 32 samples collected, 12 (41%) were positive by this method. Out of those collected samples, 29 were from goats and 3 were from sheep. Nasal and rectal swabs and blood samples were superior in detection of the PPR virus compared to other tissue samples.

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.

Future research to underpin successful peste des petits ruminants virus (PPRV) eradication

Peste des petits ruminants virus (PPRV) is a significant pathogen of small ruminants and is prevalent in much of Africa, the Near and Middle East and Asia. Despite the availability of an efficacious and cheap live-attenuated vaccine, the virus has continued to spread, with its range stretching from Morocco in the west to China and Mongolia in the east. Some of the world's poorest communities rely on small ruminant farming for subsistence and the continued endemicity of PPRV is a constant threat to their livelihoods. Moreover, PPRV's effects on the world's population are felt broadly across many economic, agricultural and social situations. This far-reaching impact has prompted the Food and Agriculture Organization of the United Nations (FAO) and the World Organisation for Animal Health (OIE) to develop a global strategy for the eradication of this virus and its disease. PPRV is a morbillivirus and, given the experience of these organizations in eradicating the related rinderpest virus, the eradication of PPRV should be feasible. However, there are many critical areas where basic and applied virological research concerning PPRV is lacking. The purpose of this review is to highlight areas where new research could be performed in order to guide and facilitate the eradication programme. These areas include studies on disease transmission and epidemiology, the existence of wildlife reservoirs and the development of next-generation vaccines and diagnostics. With the support of the international virology community, the successful eradication of PPRV can be achieved.

Fine mapping and conservation analysis of linear B-cell epitopes of peste des petits ruminants virus hemagglutinin protein

Hemagglutinin protein (H), one of the two glycoproteins of peste des petits ruminants virus (PPRV), binds to its receptor on the host cell and acts as a major antigen that induces and confers highly protective immunity in the host. In order to delineate the epitopes on H protein, fine epitope mapping and conservation analysis of linear B-cell epitopes (BCEs) on PPRV H has been undertaken using biosynthetic peptides and rabbit anti-PPRV H sera. Thirteen linear BCEs were identified and their corresponding minimal motifs were located on the H protein of PPRV China/Tibet/Geg/07-30. Conservation analysis indicated that two of the 13 minimal motifs were conserved among 52 PPRV strains. Nine of the 13 peptides containing the minimal motifs were recognized using anti-PPRV serum from a goat immunized with PPRV vaccine strain Nigeria 75/1. Identified epitopes and their motifs improve our understanding of the antigenic characteristics of PPRV H and provide a basis for the development of epitope-based diagnostic assays and multiple epitopes vaccine.