Vimentin inhibits peste des petits ruminants virus replication by interaction with nucleocapsid protein

The Peste des petits ruminant virus (PPRV) is a member of the Paramyxoviridae family and is classified into the genus Measles virus. PPRV predominantly infects small ruminants, leading to mortality rates of nearly 100%, which have caused significant economic losses in developing countries. Host proteins are important in virus replication, but the PPRV nucleocapsid (N) protein-host interacting partners for regulating PPRV replication remain unclear. The present study confirmed the interaction between PPRV-N and the host protein vimentin by co-immunoprecipitation and co-localization experiments. Overexpression of vimentin suppressed PPRV replication, whereas vimentin knockdown had the opposite effect. Mechanistically, N was subjected to degradation via the ubiquitin/proteasome pathway, where vimentin recruits the E3 ubiquitin ligase NEDD4L to fulfill N-ubiquitination, resulting in the degradation of the N protein. These findings suggest that the host protein vimentin and E3 ubiquitin ligase NEDD4L have an anti-PPRV effect.

Potential role of peste des petits ruminants virus in small ruminant abortions

The aim of the present study was to investigate the frequency, genetic variability, and phylogeny of the peste des petits ruminants virus (PPRV) in ovine and caprine fetuses. During 2014 and 2017, a total of 1054 embryos/fetuses were collected in Turkey. A real-time RT-PCR assay was used for the detection of the PPRV RNA. Genetic characterization and phylogenetic analysis of the PPRV field isolates were conducted by sequencing fusion (F) protein and nucleoprotein (N) gene segments. Samples were also collected from ewes (n = 83) and nanny goats (n = 3) that had aborted and whose embryos/fetuses were found to be PPRV positive. PPRV positive embryos/fetuses were also tested for the presence of Listeria monocytogenes, Campylobacter spp., Coxiella burnetii, Chlamydophila abortus, Brucella spp., akabane virus, aino virus, bluetongue virus, border disease virus, bovine viral diarrhea virus, Cache Valley virus, and Schmallenberg virus. PPRV RNA was detected in 123 (11.7%) of the 1054 embryos/fetuses, 78 of the 83 (94%) ewes and 3 (100%) nanny goats. Border disease virus RNA and Chlamydophila abortus DNA were detected in 7 and 12 PPRV positive sheep fetuses, respectively, while other bacterial and viral agents were not detected. Phylogenetically, the field isolates in this study belong to lineage IV, and compared to other strains of lineage IV considered in this study, they showed 1 and 5 new amino acid substitutions in the F and N gene sequences, respectively. The results of the study suggest that PPRV plays an important role in abortion. Therefore, PPRV needs to be taken into consideration in sheep and goats abortions.

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.

Carboplatin restricts peste des petits ruminants virus replication by suppressing the STING-mediated autophagy

Peste des petits ruminants virus (PPRV) is a morbillivirus that causes the acute and highly pathogenic infectious disease peste des petits ruminants (PPR) in small ruminants and poses a major threat to the goat and sheep industries. Currently, there is no effective treatment for PPRV infection. Here, we propose Carboplatin, a platinum-based regimen designed to treat a range of malignancies, as a potential antiviral agent. We showed that Carboplatin exhibits significant antiviral activity against PPRV in a cell culture model. The mechanism of action of Carboplatin against PPRV is mainly attributed to its ability to block STING mediated autophagy. Together, our study supports the discovery of Carboplatin as an antiviral against PPRV and potentially other closely related viruses, sheds light on its mode of action, and establishes STING as a valid and attractive target to counteract viral infection.

Comparative evolutionary analyses of peste des petits ruminants virus genetic lineages

Peste des petits ruminants virus (PPRV) causes a highly infectious disease affecting mainly goats and sheep in large parts of Africa, Asia, and the Middle East and has an important impact on the global economy and food security. Full genome sequencing of PPRV strains has proved to be critical to increasing our understanding of PPR epidemiology and to inform the ongoing global efforts for its eradication. However, the number of full PPRV genomes published is still limited and with a heavy bias towards recent samples and genetic Lineage IV (LIV), which is only one of the four existing PPRV lineages. Here, we generated genome sequences for twenty-five recent (2010-6) and seven historical (1972-99) PPRV samples, focusing mainly on Lineage II (LII) in West Africa. This provided the first opportunity to compare the evolutionary pressures and history between the globally dominant PPRV genetic LIV and LII, which is endemic in West Africa. Phylogenomic analysis showed that the relationship between PPRV LII strains was complex and supported the extensive transboundary circulation of the virus within West Africa. In contrast, LIV sequences were clearly separated per region, with strains from West and Central Africa branched as a sister clade to all other LIV sequences, suggesting that this lineage also has an African origin. Estimates of the time to the most recent common ancestor place the divergence of modern LII and LIV strains in the 1960s-80s, suggesting that this period was particularly important for the diversification and spread of PPRV globally. Phylogenetic relationships among historical samples from LI, LII, and LIII and with more recent samples point towards a high genetic diversity for all these lineages in Africa until the 1970s-80s and possible bottleneck events shaping PPRV's evolution during this period. Molecular evolution analyses show that strains belonging to LII and LIV have evolved under different selection pressures. Differences in codon usage and adaptative selection pressures were observed in all viral genes between the two lineages. Our results confirm that comparative genomic analyses can provide new insights into PPRV's evolutionary history and molecular epidemiology. However, PPRV genome sequencing efforts must be ramped up to increase the resolution of such studies for their use in the development of efficient PPR control and surveillance strategies.

First Report of the Emergence of Peste des Petits Ruminants Lineage IV Virus in Senegal

Peste des petits ruminants (PPR) is a highly contagious viral disease and one of the deadliest affecting wild goats, sheep, and small ruminants; however, goats are generally more sensitive. The causative agent is the Peste des Petits Ruminants virus (PPRV), which is a single-stranded RNA virus of negative polarity belonging to the Paramyxoviridae family. In February 2020, an active outbreak of PPR was reported in a herd of a transhumant farmer in the village of Gainth Pathé (department of Kounguel, Kaffrine region, Senegal). Of the ten swabs collected from the goats, eight returned a positive result through a quantitative real-time PCR. The sample that yielded the strongest signal from the quantitative real-time PCR was further analyzed with a conventional PCR amplification and direct amplicon sequencing. A phylogenetic analysis showed that the sequence of the PPR virus obtained belonged to lineage IV. These results confirm those found in the countries bordering Senegal and reinforce the hypothesis of the importance of animal mobility between these neighboring countries in the control of PPRV. In perspective, following the discovery of this lineage IV in Senegal, a study on its dispersion is underway throughout the national territory. The results that will emerge from this study, associated with detailed data on animal movements and epidemiological data, will provide appropriate and effective information to improve PPR surveillance and control strategies with a view to its eradication.

Development and characterization of a novel nanobody with SRMV neutralizing activity

Peste des petits ruminants (PPR) is an acute, contact infectious disease caused by the small ruminant morbillivirus (SRMV), and its morbidity in goats and sheep can be up to 100% with significant mortality. Nanobody generated from camelid animals such as alpaca has attracted wide attention because of its unique advantages compared with conventional antibodies. The main objective of this study was to produce specific nanobodies against SRMV and identify its characteristics. To obtain the coding gene of SRMV-specific nanobodies, we first constructed an immune phage-displayed library from the VHH repertoire of alpaca that was immunized with SRMV-F and -H proteins. By using phage display technology, the target antigen-specific VHHs can be obtained after four consecutive rounds of biopanning. Results showed that the size of this VHH library was 2.26 × 1010 CFU/mL and the SRMV-F and -H specific phage particles were greatly enriched after four rounds of biopanning. The positive phage clones were selected and sequenced, and total of five independent different sequences of SRMV-specific nanobodies were identified. Subsequently, the DNA fragments of the five nanobodies were cloned into E. coli BL21(DE3), respectively, and three of them were successfully expressed and purified. Specificity and affinity towards inactivated SRMV of these purified nanobodies were then evaluated using the ELISA method. Results demonstrated that NbSRMV-1-1, NbSRMV-2-10, and NbSRMV-1-21 showed no cross-reactivity with other antigens, such as inactivated BTV, inactivated FMDV, His-tag labeled protein, and BSA. The ELISA titer of these three nanobodies against inactivated SRMV was up to 1:1000. However, only NbSRMV-1-21 displayed SRMV neutralizing activity at a maximum dilution of 1:4. The results indicate that the nanobodies against SRMV generated in this study could be useful in future applications. This study provided a novel antibody tool and laid a foundation for the treatment and detection of SRMV.

Molecular Epidemiology of Peste Des Petits Ruminants Virus in West Africa: Is Lineage IV Replacing Lineage II in Burkina Faso?

This study aimed at investigating the genetic lineages of peste des petits ruminants virus (PPRV) currently circulating in Burkina Faso. As part of PPR surveillance in 2021 and 2022, suspected outbreaks in different regions were investigated. A risk map was produced to determine high-risk areas for PPR transmission. Based on alerts, samples were obtained from three regions and all sampled localities were confirmed to fall within PPR high risk areas. We collected swab samples from the eyes, mouth, and nose of sick goats. Some tissue samples were also collected from dead animals suspected to be infected by PPRV. In total, samples from 28 goats were analysed. Virus confirmation was performed with RT-PCR amplification targeting the nucleocapsid (N) gene. Partial N gene sequencing (350 bp) was carried out using the RT-PCR products of positives samples to characterise the circulating lineages. Eleven sequences, including ten new sequences, have been obtained. Our study identified the presence of the PPRV lineage IV in the three studied regions in Burkina Faso with a genetic heterogeneity recorded for the sequences analysed. Previously published data and results of this study suggest that PPRV lineage IV seems to be replacing lineage II in Burkina Faso.

The Live Attenuated Vaccine Strain "ARRIAH" Completely Protects Goats from a Virulent Lineage IV Field Strain of Peste Des Petits Ruminants Virus

Peste des petits ruminants (PPR) is a transboundary viral disease that affects small ruminants, such as goats and sheep, in Africa, the Middle East, and Asia, causing substantial damage to livelihoods and disrupting livestock trade. Although Russia is PPR virus (PPRV)-free, controlling PPRV in neighboring countries is the top national priority. Recent PPR outbreaks in Mongolia and other countries in the Middle East caused by a lineage IV virus represent a risk of transboundary emergence in neighboring countries, including China, Kazakhstan, and Russia. In the present study, we assessed the potency and safety of the ARRIAH live attenuated PPRV vaccine (lineage II) in Zaannen and Nubian goat breeds by challenging them with a virulent lineage IV Mongolia/2021 isolate. For comparison, two commercial vaccines of Nigeria75/1 strain were used. The ARRIAH-vaccinated animals showed an increase in body temperature of 1-1.5 °C above the physiological norm, similar to the animals vaccinated with Nigeria75/1 vaccines. In all vaccinated groups, the average rectal temperature never exceeded 39.4-39.7 °C throughout the infection period, and no clinical signs of the disease were observed, demonstrating vaccine efficacy and safety in the current experimental setting. However, the control group (mock vaccinated) challenged with Mongolia/2021 PPRV exhibited moderate-to-severe clinical signs. Overall, the findings of the present study demonstrate that the ARRIAH vaccine strain has a promising protective phenotype compared with Nigeria75/1 vaccines, suggesting its potential as an effective alternative for curbing and controlling PPR in affected countries. Although the ARRIAH vaccine against PPR is not currently endorsed by the World Organization for Animal Health due to its incomplete safety and potency profile, this study is the first step to provide experimentally validated data on the ARRIAH vaccine.

Prokaryotic expression of the V protein of the peste des petits ruminants virus and development of an indirect ELISA

In this study, we recombinantly expressed the V protein of the peste des petits ruminants virus (PPRV) and evaluated its diagnostic value for PPRV infection using an indirect ELISA (i-ELISA). The optimal concentration of the coated antigen of V protein was 15 ng/well at a serum dilution of 1:400, and the optimal positive threshold value was 0.233. A cross-reactivity assay showed that the V protein-based i-ELISA was specific to PPRV with consistent reproducibility and showed a specificity of 82.6% and a sensitivity of 100% with a virus neutralization test. Using the recombinant V protein as an antigen in ELISA is useful for seroepidemiological studies of PPRV infections.

Seroprevalence and risk factors of Peste des petits ruminants in different production systems in Uganda

Peste des petits ruminants (PPR) is a highly contagious and fatal disease of mostly domestic goats and sheep. First reported in Uganda in 2007, the extent of peste des petits ruminants virus (PPRV) exposure, geographical distribution and risk factors of its transmission and spread are not clearly understood. In this study, we used cluster random sampling methodology to select study villages from three districts representing three different production systems along Uganda's "cattle corridor". Between October and December 2022, 2520 goat and sheep serum samples were collected from 252 households with no history of PPR vaccination in the past one year. The household heads were interviewed to assess possible risk factors of PPRV transmission using a structured questionnaire. The serum samples were screened with a commercial competitive enzyme-linked immunosorbent assay (cELISA) for PPRV antibodies. The determined overall true seroprevalence of PPRV was 27.3% [95% CI: 25.4-29.1]. The seroprevalence of PPRV antibodies in different production systems was 44.1% [95% CI: 40.6-47.7], 31.7% [95% CI: 28.4-35.0] and 6.1% [95% CI: 4.4-7.9] for pastoral, agropastoral and mixed crop-livestock production systems respectively. A mixed-effects multivariable logistic regression model revealed strong statistical evidence of association between female animals and PPRV antibody seropositivity compared to males [OR= 2.45, 95% CI: 1.7-3.5, p < 0.001]. The likelihood of being PPRV antibody seropositive significantly increased with increasing small ruminant age. Animals older than 3 years were more than three times as likely to be PPRV seropositive compared to animals aged under 1 year [OR= 3.41, 95% CI: 2.39-4.85, p < 0.001]. There was no statistical evidence of association between small ruminant species and PPRV antibody seropositivity (p = 0.423). Village flocks that interacted with neighboring flocks daily during grazing (IRR = 1.59, 95% CI: 1.19-2.13) and watering around swamps (IRR = 1.59, 95% CI: 1.19-2.13) were highly correlated with increased number of PPRV seropositive animals as compared to flocks that were more restricted in grazing and watered around other water sources other than swamps. Flocks from pastoral and agropastoral production systems were more than 10 times more likely to have seropositive animals than mixed crop-livestock flocks. Targeting PPR control interventions (vaccination and livestock movement control) to pastoral and agro-pastoral small ruminant production systems that are very prone to PPR incursions is recommended to prevent PPRV spread to low-risk smallholder mixed crop-livestock production systems.

Development of a sensitive immunochromatographic method using lanthanide fluorescent microsphere for rapid test for PPRV antibody

Peste des petits ruminants virus (PPRV) causes a very devastating disease in sheep and goats. Rapid diagnosis and immunisation have been identified as key strategies for successful prevention of the disease. Therefore, a sensitive fluorescent microsphere immunochromatography test strips (FM-ICTS) was developed for rapid detection of special antibodies of PPRV in goats and sheep serum. The FM-ICTS were successfully prepared by fluorescent microspheres (FM) as tracer, which were covalently coupled to PPRV nucleocapsid protein (NP). The NP and monoclonal antibody of NP were separately dispensed onto a nitrocellulose membrane as test and quality control lines, respectively. The critical threshold for determining negative or positive through the ratio of the fluorescent signal of the test line and the control line (T/C) is 0.050. The repeatability of the FM-ICTS was excellent, with an overall average CV of 3.17 %. The detection limit of this assay was 1:5120. Additionally, the FM-ICTS no cross reaction with the sera of other related diseases was observed, only reacting with anti-PPRV serum. 70 serum samples were tested by FM-ICTS and commercial ELISA kit, and the results showed good agreement. Overall, a promising pen-side diagnostic tool was developed for the rapid qualitatively/semi-quantitatively detection of PPRV antibodies within 15 min.

Comparative study of HA and HNB staining RT-LAMP assays for peste des petits ruminants virus detection in West African Dwarf goats

Peste des petits ruminants (PPR) cause severe economic losses to many countries of the world where the disease is endemic. It has been targeted for global eradication by 2030 following the successful eradication of rinderpest in 2011. The proposed eradication program would benefit from efficient and relatively reliable diagnostic tools for early PPR virus (PPRV) detection. A total of 33 eight to 12 months old West African Dwarf (WAD) goats were used. Nineteen goats infected by commingling with two PPR virus-positive animals formed the infected group (PPRV-infected goats) while 14 non-infected goats formed the control group (CTG). The suitability of hydroxyl naphthol blue (HNB) staining of reverse transcription loop-mediated isothermal amplification (RT-LAMP) and haemagglutination (HA) assays was compared for their sensitivity to detect the PPRV in PPRV-infected goats and non-infected CTG. PPR disease severity in WAD goats at different days post infection (dpi) was evaluated by clinical scoring and haemagglutination titre (HAT). HNB staining RT-LAMP reaction and HA showed sensitivities of 100% and 73.68%, respectively, for PPRV detection. Expression of PPR clinical signs began from 3 dpi, attained peak at 5 dpi, thereafter showed irregular patterns till 24 dpi. Evaluation of HAT in PPRV-infected goats at 12 dpi ranged from 2 to 64 haemagglutination units (HAU), while CTG goats had 0 HAU. In conclusion, HA could be a good tool for rapid diagnosis of PPRV in a developing country setting. However, HNB staining RT-LAMP assay demonstrated high sensitivity for accurate diagnoses of PPRV and as an important diagnostic tool when precise phenotyping is desired.

Complete genome of a 2014 isolate of peste des petits ruminants virus from Ethiopia

This report describes the complete genome sequence of a peste des petits ruminants virus (PPRV) isolate from Ethiopia in 2014. The strain (PPRV/Ethiopia/Habru/2014), which showed a normal virulence and relatively low morbidity in the field, belongs to the North African subclade of Lineage IV.

Assessment and verification of chemical inactivation of peste des petits ruminants virus by virus isolation following virus capture using Nanotrap magnetic virus particles

This study reports development and optimization of a new method for the assessment and verification of the inactivation of peste des petits ruminants virus (PPRV) by chemical agents, including Triton X-100 and commercially available viral lysis buffers. Virus inactivation was confirmed by virus isolation (VI) on Vero cells following capture of the potential residual viruses from treated samples using Nanotrap magnetic virus particles (NMVPs). Since chemical agents are cytotoxic, treated PPRV samples could not be used directly for VI on Vero cell monolayers; instead, they were diluted in Eagle's Minimum Essential Medium (EMEM) to neutralize cytotoxicity and then subjected to virus capture using NMVPs. The NMVPs and the captured viruses were then clarified on a magnetic stand, reconstituted in EMEM, and inoculated onto Vero cells that were examined for cytopathic effect (CPE). No CPE was observed on cells inoculated with treated viruses captured by NMVPs; but CPE was observed on cells inoculated with untreated viruses, including those captured by NMVPs. For further verification, the supernatants of the VI cultures (treated or untreated) were subjected to RNA extraction and PPRV-specific real-time RT-PCR (RT-qPCR). The cycle threshold values were undetectable for the supernatants of VI cultures inoculated with NMVPs reconstituted from treated PPRV but detectable for the supernatants of VI cultures inoculated with untreated PPRV or the NMVPs reconstituted from untreated PPRV, indicating complete inactivation of PPRV. This new method of verification of virus inactivation using NMVPs can be applied to other high impact viruses of agricultural or public health importance. IMPORTANCE Research including diagnosis on highly contagious viruses at the molecular level such as PCR and next-generation sequencing requires complete inactivation of the virus to ensure biosafety and biosecurity so that any accidental release of the virus does not compromise the safety of the susceptible population and the environment. In this work, peste des petits ruminants virus (PPRV) was inactivated with chemical agents, and the virus inactivation was confirmed by virus isolation (VI) using Vero cells. Since the chemical agents are cytotoxic, inactivated virus (PPRV) was diluted 1:100 to neutralize cytotoxicity, and the residual viruses (if any) were captured using Nanotrap magnetic virus particles (NMVPs). The NMVPs and the captured viruses were subjected to VI. No CPE was observed, indicating complete inactivation, and the results were further supported by real-time RT-PCR. This new protocol to verify virus inactivation can be applicable to other viruses.

Changes in m6A RNA methylation of goat lung following PPRV infection

Peste des petits ruminants (PPR) is an acute, highly contagious viral disease of goats and sheep, caused by the Peste des petits ruminants virus (PPRV). Earlier studies suggest the involvement of diverse regulatory mechanisms in PPRV infection. Methylation at N6 of Adenosine called m6A is a type RNA modification that influences various physiological and pathological phenomena. As the lung tissue represents the primary target organ of PPRV, the present study explored the m6A changes and their functional significance in PPRV disease pathogenesis. m6A-seq analysis revealed 1289 m6A peaks to be significantly altered in PPRV infected lung in comparison to normal lung, out of which 975 m6A peaks were hypomethylated and 314 peaks were hypermethylated. Importantly, hypomethylated genes were enriched in Interleukin-4 and Interleukin-13 signaling and various processes associated with extracellular matrix organization. Further, of the 843 differentially m6A-containing cellular transcripts, 282 transcripts were also found to be differentially expressed. Functional analysis revealed that these 282 transcripts are significantly enriched in signaling by Interleukins, extracellular matrix organization, cytokine signaling in the immune system, signaling by receptor tyrosine kinases, and Toll-like Receptor Cascades. We also found m6A reader HNRNPC and the core component of methyltransferase complex METTL14 to be highly upregulated than the m6A readers - HNRNPA2B1 and YTHDF1 at the transcriptome level. These findings suggest that alteration in the m6A landscape following PPRV is implicated in diverse processes including Interleukin signaling.

Peste Des Petits Ruminants in the Middle East: Epidemiological Situation and Status of Control and Eradication Activities after the First Phase of the PPR Global Eradication Program (2017–2021)

Peste des petits ruminants (PPR) is a burdensome viral disease primarily affecting small ruminants, which is currently targeted for eradication by 2030 through the implementation of a Global Control and Eradication Strategy (PPR GCES). The PPR GCES, launched in 2015, has strongly encouraged countries to participate in Regional PPR Roadmaps, designated according to the Food and Agricultural Organization of the United Nations (FAO) and World Organisation for Animal Health (WOAH) regions and epidemiological considerations, with each targeted by dedicated meetings and activities. Following the conclusion of the first phase of the PPR Global Eradication Program (PPR GEP) (2017–2021), the present work focuses on the disease situation and status of the eradication campaign in the fourteen countries of the PPR GCES Middle Eastern Roadmap as well as Egypt. PPR is endemic to or suspected to be present in most of the region, except for Bahrain, which, as of 2021, is preparing to apply for official recognition as being free of PPR. Some substantial shortcomings are observed in surveillance and disease reporting, as well as in the implemented control strategies, most notably vaccination. Since many of these limitations are shared by many of the investigated countries, the international cooperation and harmonization of control efforts appears crucial to making PPR eradication attainable in the Middle East.

Serological study and risk factor analysis on Peste des Petits Ruminants in sheep in Bangladesh

A cross-sectional study was conducted to determine the seroprevalence of the Peste des Petits Ruminant (PPR) virus (PPRV) in sheep populations and to determine the potential epidemiological risk factors associated with this infection. Between October 2014 and March 2017, 2420 sheep serum samples were collected from ten selected PPR outbreak-prone districts in Bangladesh. The collected sera were analysed by competitive enzyme-linked immunosorbent assay (cELISA) test to detect antibodies against PPR. A previously designed disease report form was used to gather data on important epidemiological risk factors, and a risk analysis was performed to ascertain their association with PPRV infection. By cELISA, 44.3 % (95 % confidence interval:42.4-46.4 %) of sheep sera were positive for PPRV antibodies against PPR. In univariate analysis, the Bagerhat district had significantly higher seropositivity (54.1 %, 156/288) than other districts. Moreover, significantly higher (p < 0.05) seropositivity was found in the Jamuna River Basin (49.1 %, 217/442) compared to other ecological zones, in crossbreeds (60 %; 600/1000) related to native sheep, in males (69.8 %, 289/414) associated with females, in imported sheep (74.3 %, 223/300) compared to other sources, and in winter (57.2 %, 527/920) than in other seasons. In the multivariate logistic regression model, six possible risk factors were identified: study location, ecological zone, breed, sex, source, and season. The high seroprevalence of PPRV is significantly associated with several risk factors, suggesting that PPR is epizootic throughout the country.

Peste Des Petits Ruminants Virus Nucleocapsid Protein Interacts with Protein Kinase R-Activating Protein and Induces Stress Granules To Promote Viral Replication

The pathogenic mechanisms of peste des petits ruminants virus (PPRV) infection remain poorly understood, leaving peste des petits ruminants (PPR) control and eradication especially difficult. Here, we determined that PPRV nucleocapsid (N) protein triggers formation of stress granules (SGs) to benefit viral replication. A mass spectrometry-based profiling of the interactome of PPRV N protein revealed that PPRV N protein interacted with protein kinase R (PKR)-activating protein (PACT), and this interaction was confirmed in the context of PPRV infection. PACT was essential for PPRV replication. Besides, the ectopic expression of N activated the PKR/eIF2α (α subunit of eukaryotic initiation factor 2) pathway through induction of PKR phosphorylation, but it did not induce PKR phosphorylation in PACT-deficient (PACT^-/-) cells. PPRV N interacted with PACT, impairing the interaction between PACT and a PKR inhibitor, transactivation response RNA-binding protein (TRBP), which subsequently enhanced the interaction between PACT and PKR and thus promoted the activation of PKR and eIF2α phosphorylation, resulting in formation of stress granules (SGs). Consistently, PPRV infection induced SG formation through activation of the PKR/eIF2α pathway, and knockdown of N impaired PPRV-induced SG formation. PPRV-induced SG formation significantly decreased in PACT^-/- cells as well. The role of SG formation in PPRV replication was subsequently investigated, which showed that SG formation plays a positive role in PPRV replication. By using an RNA fluorescence in situ hybridization assay, we found that PPRV-induced SGs hid cellular mRNA rather than viral mRNA. Altogether, our data provide the first evidence that PPRV N protein plays a role in modulating the PKR/eIF2α/SG axis and promotes virus replication through targeting PACT. IMPORTANCE Stress granule (SG) formation is a conserved cellular strategy to reduce stress-related damage regulating cell survival. A mass spectrometry-based profiling of the interactome of PPRV N protein revealed that PPRV N interacted with PACT to regulate the assembly of SGs. N protein inhibited the interaction between PACT and a PKR inhibitor, TRBP, through binding to the M1 domain of PACT, which enhanced the interaction between PACT and PKR and thus promoted PKR activation and subsequent eIF2α phosphorylation as well as SG formation. The regulatory function of N protein was strikingly abrogated in PACT^-/- cells. SGs induced by PPRV infection through the PKR/eIF2α pathway are PACT dependent. The loss-of-function assay indicated that PPRV-induced SGs were critical for PPRV replication. We concluded that the PPRV N protein manipulates the host PKR/eIF2α/SG axis to favor virus replication.

Prevalence of peste des petits ruminants virus antibodies in sheep and goats sera from Central-Western Sudan

Clinical signs suggestive of peste des petits ruminants (PPR) involved herds of small ruminants, which were described elsewhere in Sudan. Peste des petits ruminants was confirmed using an Immunocapture ELISA (IC-ELISA) assay in samples of infected and dead animals in areas of outbreaks. Therefore, to update information regarding the current situation and for assessment of the serological prevalence of PPR in small ruminants mingled at Central and Western Sudan during 2018-2019, 368 sera were collected from sheep (325 sera) and goats (43 sera) with different ages and breeds. These sera included 186 sera (173 sheep and 13 goats) from White Nile State and 182 sera (152 sheep and 30 goats) from Kordofan States. Competitive ELISA demonstrated higher prevalence of PPRV antibodies of 88.9%, 90.7% and 88.6% in both sheep and goats, goats, and sheep sera, respectively. Moreover, 100%, 94.7% and 78.5% seroprevalence values were demonstrated in South Kordofan, North Kordofan and White Nile States. The higher seroprevalence values detected in sera of unvaccinated sheep and goats indicated the wide exposure of these animals to PPRV and presence of protection following PPR viral infection. The findings of the study indicated that PPR is endemic in the surveyed areas of Sudan.Contribution: The study will contribute effectively to the global eradication programme of PPR organised by the World Organization for Animal Health (WOAH, formerly OIE) and Food and Agriculture Organization (FAO). To completely eliminate PPR from Sudan by 2030, local efforts should be directed towards effectively and wholly vaccinating small ruminants using PPRV vaccine especially in routes of seasonal animal's movement and shared grazing areas.

Molecular detection of mixed infection with peste des petits ruminants and retroviruses in Egyptian sheep and goats

Peste des petits ruminants (PPR) is a contagious viral disease causing massive economic loss to animal industries in endemic countries including Egypt. Although a vaccine is available, coinfections can overwhelm the animal immune system and interfere with vaccine protection. Small ruminant retrovirus (SRR), including enzootic nasal tumor virus (ENTV) and Jaagsiekte sheep retrovirus (JSRV), is responsible for coinfections with PPR. Investigation of clinical cases in this study confirmed the presence of PPR virus by RT-PCR among four flocks. Sequence of five PPR amplicons revealed that all strains had 100% aa similarity and belonged to lineage IV. In addition, these strains had 98-99% nt similarity with all previous Egyptian and African strains from Sudan (MK371449) and Ethiopia (MK371449). Illumina sequencing of a representative sample showed a genome of 5753 nt compatible with ENT-2 virus with 98.42% similarity with the Chinese strain (MN564750.1). Four ORFs representing gag, pro, pol, and env genes were identified and annotated. Pro gene was highly stable while gag, pol, and env showed eight, two, and three aa differences with the reference strains. Sanger sequencing revealed that two amplicons were ENT-2 virus, and one was JSRV. ENT-2 sequences had 100% similarity with KU258870 and KU258871 reference strains while JSRV was 100% similar to the EF68031 reference strain. The phylogenetic tree showed a close relationship between the ENT of goats and the JSRV of sheep. This study highlights the complexity of PPR molecular epidemiology, with SRR that was not molecularly characterized previously in Egypt.

A Clinical, Pathological, Epidemiological and Molecular Investigation of Recent Outbreaks of Peste des Petits Ruminants Virus in Domestic and Wild Small Ruminants in the Abu Dhabi Emirate, United Arab Emirates

(1) Background: Peste des petits ruminants (PPR) is a highly contagious animal disease affecting small ruminants, leading to significant economic losses. There has been little published data on PPR virus (PPRV) infection in the United Arab Emirates (UAE); (2) Methods: four outbreaks reported in goats and Dama gazelle in 2021 were investigated using pathological and molecular testing; (3) Results: The infected animals showed symptoms of dyspnea, oculo-nasal secretions, cough, and diarrhea. Necropsy findings were almost similar in all examined animals and compliant to the classical forms of the disease. Phylogenetic analysis based on N gene and F gene partial sequences revealed a circulation of PPRV Asian lineage IV in the UAE, and these sequences clustered close to the sequences of PPRV from United Arab Emirates, Pakistan, Tajikistan and Iran; (4) Conclusions: PPRV Asian lineage IV is currently circulating in the UAE. To the best of our knowledge, this is a first study describing PPRV in domestic small ruminant in the UAE.

Long noncoding RNA IRF1-AS is associated with peste des petits ruminants infection

Peste des petits ruminants (PPR) is an acute and highly contagious disease and has long been a significant threat to small ruminant productivity worldwide. However, the molecular mechanism underlying host-PPRV interactions remains unclear and the long noncoding RNAs (lncRNAs) regulation of PPR virus (PPRV) infection has rarely been reported so far. Here, we first demonstrated that PPRV infection can induce an obvious innate immune response in caprine endometrial epithelial cells (EECs) at 48 h post-infection (hpi) with an MOI of 3. Subsequently, we determined that PPRV infection is associated with 191 significantly differentially expressed (SDE) lncRNAs, namely, 137 upregulated and 54 downregulated lncRNAs, in caprine EECs compared with mock control cells at 48 hpi by using deep sequencing technology. Importantly, bioinformatics preliminarily analyses revealed that these DE lncRNAs were closely related to the immune response. Furthermore, we identified a system of lncRNAs related to the immune response and focused on the role of lncRNA 10636385 (IRF1-AS) in regulating the innate immune response. Interestingly, we found that IRF1-AS was a potent positive regulator of IFN-β and ISG production, which can significantly inhibit PPRV replication in host cells. In addition, our data revealed that IRF1-AS was positively correlated with its potential target gene, IRF1, which enhanced the activation of IRF3 and the expression of ISGs and interacted with IRF3. This study suggests that IRF1-AS could be a new host factor target for developing antiviral therapies against PPRV infection.

A Morbillivirus Infection Shifts DC Maturation Toward a Tolerogenic Phenotype to Suppress T Cell Activation

Viruses have evolved numerous strategies to impair immunity so that they can replicate more efficiently. Among those, the immunosuppressive effects of morbillivirus infection can be particularly problematic, as they allow secondary infections to take hold in the host, worsening disease prognosis. In the present work, we hypothesized that the highly contagious morbillivirus peste des petits ruminants virus (PPRV) could target monocytes and dendritic cells (DC) to contribute to the immunosuppressive effects produced by the infection. Monocytes isolated from healthy sheep, a natural host of the disease, were able be infected by PPRV and this impaired the differentiation and phagocytic ability of immature monocyte-derived DC (MoDC). We also assessed PPRV capacity to infect differentiated MoDC. Ovine MoDC could be productively infected by PPRV, and this drastically reduced MoDC capacity to activate allogeneic T cell responses. Transcriptomic analysis of infected MoDC indicated that several tolerogenic DC signature genes were upregulated upon PPRV infection. Furthermore, PPRV-infected MoDC could impair the proliferative response of autologous CD4⁺ and CD8⁺ T cell to the mitogen concanavalin A (ConA), which indicated that DC targeting by the virus could promote immunosuppression. These results shed new light on the mechanisms employed by morbillivirus to suppress the host immune responses. IMPORTANCE Morbilliviruses pose a threat to global health given their high infectivity. The morbillivirus peste des petits ruminants virus (PPRV) severely affects small-ruminant-productivity and leads to important economic losses in communities that rely on these animals for subsistence. PPRV produces in the infected host a period of severe immunosuppression that opportunistic pathogens exploit, which worsens the course of the infection. The mechanisms of PPRV immunosuppression are not fully understood. In the present work, we demonstrate that PPRV can infect professional antigen-presenting cells called dendritic cells (DC) and disrupt their capacity to elicit an immune response. PPRV infection promoted a DC activation profile that favored the induction of tolerance instead of the activation of an antiviral immune response. These results shed new light on the mechanisms employed by morbilliviruses to suppress the immune responses.

Extracellular vesicles derived from PPRV-infected cells enhance signaling lymphocyte activation molecular (SLAM) receptor expression and facilitate virus infection

Peste des petits ruminants virus (PPRV) is an important pathogen that seriously influences the productivity of small ruminants worldwide. PPRV is lymphotropic in nature and SLAM was identified as the primary receptor for PPRV and other Morbilliviruses. Many viruses have been demonstrated to engage extracellular vesicles (EVs) to facilitate their replication and pathogenesis. Here, we provide evidence that PPRV infection significantly induced the secretion levels of EVs from goat PBMC, and that PPRV-H protein carried in EVs can enhance SLAM receptor expression in the recipient cells via suppressing miR-218, a negative miRNA directly targeting SLAM gene. Importantly, EVs-mediated increased SLAM expression enhances PPRV infectivity as well as the expression of various cytokines related to SLAM signaling pathway in the recipient cells. Moreover, our data reveal that PPRV associate EVs rapidly entry into the recipient cells mainly through macropinocytosis pathway and cooperated with caveolin- and clathrin-mediated endocytosis. Taken together, our findings identify a new strategy by PPRV to enhance virus infection and escape innate immunity by engaging EVs pathway.

Peste des petitsruminants virus (PPRV) infection induces a transient but severe immunosuppression in the host, which threatens both small livestock and endangered susceptible wildlife populations in many countries. Despite extensive research, the mechanism underlying pathogenesis of PPRV infection remains elusive. Our data provide the first direct evidence that the EVs derived from PPRV-infected cells are involved in PPRV replication. In this study, the EVs derived from PPRV-infected goat PBMCs can enhance SLAM expression in the recipient cells, and more importantly, EVs-mediated increased SLAM expression enhances PPRV replication as well as the expression of various cytokines related to SLAM signaling pathway in the recipient cells. Taken together, our research has provided new insight into understanding the effect of EVs on PPRV replication and pathogenesis, and revealed a potential therapeutic target for antiviral intervention.

Expression and Evaluation of a Novel PPRV Nanoparticle Antigen Based on Ferritin Self-Assembling Technology

Peste des Petits Ruminants (PPR) is a highly pathogenic disease that is classified as a World Organization for Animal Health (OIE)-listed disease. PPRV mainly infects small ruminants such as goats and sheep. In view of the global and high pathogenicity of PPRV, in this study, we proposed a novel nanoparticle vaccine strategy based on ferritin (Fe) self-assembly technology. Using Helicobacter pylori (H. pylori) ferritin as an antigen delivery vector, a PPRV hemagglutinin (H) protein was fused with ferritin and then expressed and purified in both Escherichia coli (E. coli) and silkworm baculovirus expression systems. Subsequently, the nanoparticle antigens’ expression level, immunogenicity and protective immune response were evaluated. Our results showed that the PPRV hemagglutinin–ferritin (H-Fe) protein was self-assembled in silkworms, while it was difficult to observe the correctly folded nanoparticle in E. coli. Meanwhile, the expression level of the H-Fe protein was higher than that of the H protein alone. Furthermore, the immunogenicity and protective immune response of H-Fe nanoparticle antigens expressed by silkworms were improved compared with the H antigen alone. Particularly, the protective immune response of H-Fe antigens expressed in E. coli did not change, as opposed to the H antigen, which was probably due to the incomplete nanoparticle structure in E. coli. This study indicated that the use of ferritin nanoparticles as antigen delivery carriers could increase the expression of antigen proteins and improve the immunogenicity and immune effect of antigens.

Peste des Petits Ruminants (PPR) Vaccination Cost Estimates in Burkina Faso

Every year the government organizes country-wide vaccination campaigns targeting peste des petits ruminants (PPR) for small ruminants (sheep and goats). Despite the heavy investment in vaccination, no study has either rigorously estimated or described the cost of vaccine delivery. This study aimed to fill this gap by assessing and describing the cost of delivery of vaccines against PPR using the 2020 vaccination campaign data. The microcosting approach based on the World Health Organization (WHO) guidelines to construct comprehensive multiyear plans (cMYP) for human immunization programs was used. The cost data is presented for the public and private vaccine delivery channels separately and analyzed using three approaches considering activity lines, inputs, and nature of cost (fixed versus variable). Results show that the unit cost of vaccinating a sheep or goat is estimated at XOF 169 (USD 0.3) and XOF 103 (USD 0.18) through the public and private channels, respectively. Using the activity line framework, we found that the field activities including charges for vaccinator, cost of vaccination materials, and field transportation account for more than 50% of the vaccination cost. In terms of inputs, the personnel cost is the most significant contributor with 65%. Fixed costs are higher in the public sector with up to 46% compared to the private sector which is estimated to take 26% of the cost. This study informs veterinary services’ investment decision options for a better allocation of resources in implementing PPR and other small ruminant disease control efforts in Burkina Faso and the Sahel.

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.

Expansion in host dynamics of peste des petits ruminants: Potential attribute of outbreaks in disease-endemic settings

Since the first case report in 1942, the peste-des-petits-ruminants virus (PPRV) has been causing infection in a wide range of susceptible hosts, particularly in disease-endemic regions. In the last 40 years, various reports highlighted the evidence of disease and viral genome in around 46 animal species from nine diverse families, including Bovidae, Cervidae, Camelidae, Suidae, Canidae, Felidae, Muridae, and Elephantidae. This evidence of clinical and/ or subclinical infection and the presence of the virus in an extended range of susceptible hosts emphasizes the cross-species transmission that remains a significant obstacle to effective control, particularly in disease-endemic regions. Therefore, a better understanding of virus transmission, host susceptibility, and epidemiological investigation of the disease is crucial to achieving the goals of efficient disease control and eradication programs initiated by OIE and FAO in various diseases-endemic regions. Nevertheless, the propensity of PPRV to inter- and intra-transmission may be a possible constraint in disease control strategies in terms of the new outbreak with the involvement of unusual or novel hosts. Considering this aspect, we tried to summarize the scattered data on PPR in available information about the susceptibility of a wide range of wildlife species, large ruminants, camels, and unusual hosts.

Epidemiology of Peste des Petits Ruminants in Nigeria: A Review

Peste des petits ruminants (PPR) is a major constraint to the productivity of small ruminants in Nigeria. Understanding of the current epidemiological status of PPR is crucial to its effective control. A review of the epidemiology of PPR in Nigeria was performed and research gaps were identified. Thirty-seven eligible articles were reviewed: these presented information from 30 of the 36 states of Nigeria. Most studies focused on goats and/or sheep (n = 33) but camels (n = 4), cattle (n = 1) and wild ruminants (n = 2) were also considered. Fourteen (37.8%) of the articles reported seroprevalence in small ruminants, which varied from 0.0% to 77.5% where more than 10 animals were sampled. Molecular characterization and phylogenetic analysis were performed in 6 studies, with lineages II and IV, detected in sheep and goats. In one study in small ruminants, sequences clustering into lineage I showed a similarity to the vaccine strain, Nigeria 75/1, based on phylogenetic analysis of F gene sequences. However, if the preferred method of sequencing the N gene had been performed, this isolate would have been grouped into lineage II. According to N gene phylogenetic analysis in the other studies, sequences were identified that clustered with clade II-NigA, II-NigB (closely related to the Nigeria 75/1 vaccine strain), and others which were well separated, suggesting a high diversity of PPRV in Nigeria. Five articles reported the detection of lineage IV in 22/36 states, with IV-NigA and IV-NigB detected, highlighting its widespread distribution in Nigeria. Risk factors for PPRV seropositivity were reported in 10/37 (27.0%) articles, with a higher seroprevalence observed in female animals, although differing results were observed when considering species and age separately. There were inconsistencies in study design and data reporting between studies which precluded conduct of a meta-analysis. Nevertheless, several research gaps were identified including the need to investigate the low uptake of PPRV vaccine, and the economic benefits of PPR control measures to small ruminant farmers. Such data will inform PPR control strategies in Nigeria and subsequently contribute to the global 2030 PPR eradication strategy.

Peste des petits ruminants virus induces ERS-mediated autophagy to promote virus replication

Peste des petits ruminants virus (PPRV) has long been a significant threat to small ruminant productivity worldwide. Virus infection-induced endoplasmic reticulum (ER) stress (ERS) and the subsequently activated unfolded protein response (UPR) play significant roles in viral replication and pathogenesis. However, the relationship between ERS and PPRV infection is unknown. In this study, we demonstrated that ERS was induced during PPRV infection in caprine endometrial epithelial cells (EECs). Importantly, we demonstrated that the induction of autophagy by PPRV was mediated by ERS. Furthermore, we found that the PERK/eIF2α pathway but not the ATF6 or IRE1 pathway was activated and that the activated PERK/eIF2α pathway participated in regulating ERS-mediated autophagy. Moreover, virus replication was required for PPRV infection-induced ERS-mediated autophagy and PERK pathway activation. Additionally, we revealed that either the viral nucleocapsid (N) or nonstructural protein C was sufficient to elicit ERS and activate the PERK/eIF2α pathway, which further increased autophagy. Taken together, these results suggest that PPRV N and C protein-induced autophagy enhances viral replication through the induction of ERS and that the PERK pathway may be involved in the activation of ERS-mediated autophagy during PPRV infection.

Isolation and Molecular Characterization of Peste des Petits Ruminants Virus from Outbreaks in Southern Ethiopia, 2020

Peste des petits ruminants (PPR) is one of the most important transboundary diseases of small ruminants. In this study, nasal and oral swabs (n = 24) were collected from sheep (n = 7) and goats (n = 17) with clinical signs in southern Ethiopia in March 2020. PPR virus was isolated on Vero dog cells expressing the signaling lymphocyte activation molecule (VDS) and screened using RT-qPCR. Positive samples were confirmed by conventional RT-PCR followed by sequencing of a partial nucleoprotein (N) gene segment. Results revealed that 54% (n = 13/24) of the tested samples were PPRV-positive Phylogenetic analysis revealed that the viruses belonged to lineage IV and lineage II. The lineage IV viruses were similar, although not identical, to other lineage IV viruses previously reported in Ethiopia and other East African countries while the lineage II viruses have been reported for the first time in Ethiopia showed a high nucleotide identity (99.06%) with the vaccine (Nigeria 75/1) that is currently used in Ethiopia for the prevention of PPR. Further investigations are therefore recommended in order to fully understand the true nature of the lineage II PPRVs in Ethiopia.

Development and Evaluation of Molecular Pen-Side Assays without Prior RNA Extraction for Peste des Petits Ruminants (PPR) and Foot and Mouth Disease (FMD)

Animal diseases such as peste des petits ruminants (PPR) and foot and mouth disease (FMD) cause significant economic losses in endemic countries and fast, accurate in-field diagnostics would assist with surveillance and outbreak control. The detection of these pathogens is usually performed at reference laboratories, tested using assays that are recommended by The World Organisation for Animal Health (OIE), leading to delays in pathogen detection. This study seeks to demonstrate a proof-of-concept approach for a molecular diagnostic assay that is compatible with material direct from nasal swab sampling, without the need for a prior nucleic acid extraction step, that could potentially be applied at pen-side for both PPR and FMD. The use of such a rapid, low-cost assay without the need for a cold chain could permit testing capacity to be established in remote, resource limited areas and support the surveillance activities necessary to meet the goal of eradication of PPR by 2030. Two individual assays were developed that detect > 99% of PPR and FMD sequences available in GenBank, demonstrating pan-serotype FMD and pan-lineage PPR assays. The ability for the BioGene XF reagent that was used in this study to lyse FMD and PPR viruses and amplify their nucleic acids in the presence of unprocessed nasal swab eluate was evaluated. The reagent was shown to be capable of detecting the viral RNA present in nasal swabs collected from naïve and infected target animals. A study was performed comparing the relative specificity and sensitivity of the new assays to the reference assays. The study used nasal swabs collected from animals before and after infection (12 cattle infected with FMDV and 5 goats infected with PPRV) and both PPR and FMD viral RNA were successfully detected two to four days post-infection in all animals using either the XF or reference assay reagents. These data suggest that the assays are at least as sensitive as the reference assays and support the need for further studies in a field setting.

PPRV-Induced Autophagy Facilitates Infectious Virus Transmission by the Exosomal Pathway

Peste des petits ruminants virus (PPRV) is an important pathogen that seriously influences the productivity of small ruminants worldwide. We showed previously that PPRV induced sustained autophagy for their replication in host cells. Many studies have shown that exosomes released from virus-infected cells contain a variety of viral and host cellular factors that are able to modulate the recipient's cellular response and result in productive infection of the recipient host. Here, we show that PPRV infection results in packaging of the viral genomic RNA and partial viral proteins into exosomes of Vero cells and upregulates exosome secretion. We provide evidence showing that the exosomal viral cargo can be transferred to and establish productive infection in a new target cell. Importantly, our study reveals that PPRV-induced autophagy enhances exosome secretion and exosome-mediated virus transmission. Additionally, our data show that TSG101 may be involved in the sorting of the infectious PPRV RNA into exosomes to facilitate the release of PPRV through the exosomal pathway. Taken together, our results suggest a novel mechanism involving autophagy and exosome-mediated PPRV intercellular transmission. IMPORTANCE Autophagy plays an important role in PPRV pathogenesis. The role of exosomes in viral infections is beginning to be appreciated. The present study examined the role of autophagy in secretion of infectious PPRV from Vero cells. Our data provided the first direct evidence that ATG7-mediated autophagy enhances exosome secretion and exosome-mediated PPRV transmission. TSG101 may be involved in the sorting of the infectious PPRV RNA genomes into exosomes to facilitate the release of PPRV through the exosomal pathway. Inhibition of PPRV-induced autophagy or TSG101 expression could be used as a strategy to block exosome-mediated virus transmission.

Crossing the Line: Seroprevalence and Risk Factors for Transboundary Animal Diseases Along the Tanzania-Zambia Border

Transboundary pathogens pose a threat to livelihood security in countries such as Zambia and Tanzania. This study aimed to investigate the seroprevalence of peste des petits ruminants virus (PPRV), foot and mouth disease virus (FMDV), sheep and goat pox virus (SGPV), Rift Valley fever virus (RVFV) and Brucella spp. in sheep and goats along the Tanzania-Zambia border. Another aim was to assess the association between certain predictor variables and seroprevalence, focusing on trade and proximity to an international border, to a town and to the Tanzania-Zambia highway. During September-October 2018, 486 serum samples from small ruminants in Zambia and 491 in Tanzania were collected and analyzed using enzyme-linked immunosorbent assays (ELISA). A questionnaire focused on management strategies was administered to each household. The animal-level seroprevalence in Zambia was 0.21% [95% confidence interval (CI) (0.01–1.14) for PPRV, 1.03% (95% CI 0.33–2.39) for FMDV, 0% (95% CI 0–0.76) for SGPV, 2.26% (95% CI 1.14–4.01) for RVFV and 1.65% (95% CI 0.71–3.22) for Brucella spp.]. In Tanzania, animal-level seroprevalence was 2.85% (95% CI 1.57–4.74) for PPRV, 16.9% (95% CI 13.7–20.5) for FMDV, 0.20% (95% CI 0.01–1.13) for SGPV, 3.26% (95% CI 1.87–5.24) for RVFV and 20.0% (95% CI 14.5–26.5) for Brucella spp. For PPRV (OR 6.83, 95% CI 1.37–34.0, p = 0.019) and FMDV (OR 5.68, 95% CI 1.58–20.3, p = 0.008), herds situated more than 30 km from an international border were more likely to be seropositive, while being located 10–30 km (OR 4.43, 95% CI 1.22–16.1 p = 0.024) from a border was identified as a risk factor for Brucella spp. For FMDV (OR 79.2, 95% CI 4.52–1388.9, p = 0.003), being situated within 30 km from a town was associated with seropositivity. Furthermore, contact with wild ruminants (OR 18.2, 95% CI 1.36–244), and the presence of sheep in the household (OR 5.20, 95% CI 1.00–26.9, p = 0.049), was associated with seropositivity for PPRV, and FMDV. No significant associations between trade or distance to the Tan-Zam highway and seroprevalence were found. We recommend that the impact of trade and proximity to borders, towns and roads should be further evaluated in larger studies, ideally incorporating aspects such as temporal trade fluctuations.

A curated dataset of peste des petits ruminants virus sequences for molecular epidemiological analyses

Peste des petits ruminants (PPR) is a highly contagious and devastating viral disease infecting predominantly sheep and goats. Tracking outbreaks of disease and analysing the movement of the virus often involves sequencing part or all of the genome and comparing the sequence obtained with sequences from other outbreaks, obtained from the public databases. However, there are a very large number (>1800) of PPRV sequences in the databases, a large majority of them relatively short, and not always well-documented. There is also a strong bias in the composition of the dataset, with countries with good sequencing capabilities (e.g. China, India, Turkey) being overrepresented, and most sequences coming from isolates in the last 20 years. In order to facilitate future analyses, we have prepared sets of PPRV sequences, sets which have been filtered for sequencing errors and unnecessary duplicates, and for which date and location information has been obtained, either from the database entry or from other published sources. These sequence datasets are freely available for download, and include smaller datasets which maximise phylogenetic information from the minimum number of sequences, and which will be useful for simple lineage identification. Their utility is illustrated by uploading the data to the MicroReact platform to allow simultaneous viewing of lineage date and geographic information on all the viruses for which we have information. While preparing these datasets, we identified a significant number of public database entries which contain clear errors, and propose guidelines on checking new sequences and completing metadata before submission.

Differential expression of long non-coding RNAs under Peste des petits ruminants virus (PPRV) infection in goats

Peste des petits ruminants (PPR) characterized by fever, sore mouth, conjunctivitis, gastroenteritis, and pneumonia, is an acute, highly contagious viral disease of sheep and goats. The role of long non-coding RNAs (lncRNAs) in PPRV infection has not been explored to date. In this study, the transcriptome profiles of virulent Peste des petits ruminants virus (PPRV) infected goat tissues – lung and spleen were analyzed to identify the role of lncRNAs in PPRV infection. A total of 13,928 lncRNA transcripts were identified, out of which 170 were known lncRNAs. Intergenic lncRNAs (7625) formed the major chunk of the novel lncRNA transcripts. Differential expression analysis revealed that 15 lncRNAs (11 downregulated and 4 upregulated) in the PPRV infected spleen samples and 16 lncRNAs (13 downregulated and 3 upregulated) in PPRV infected lung samples were differentially expressed as compared to control. The differentially expressed lncRNAs (DElncRNAs) possibly regulate various immunological processes related to natural killer cell activation, antigen processing and presentation, and B cell activity, by regulating the expression of mRNAs through the cis- or trans-regulatory mechanism. Functional enrichment analysis of differentially expressed mRNAs (DEmRNAs) revealed enrichment of immune pathways and biological processes in concordance with the pathways in which correlated lncRNA-neighboring genes were enriched. The results suggest that a coordinated immune response is raised in both lung and spleen tissues of the goat through mRNA-lncRNA crosstalk.

Spatiotemporal characteristics analysis and potential distribution prediction of peste des petits ruminants (PPR) in China from 2007-2018

Peste des petits ruminants (PPR) is a highly infectious disease that mainly infects small ruminants. To date, PPR has been confirmed in more than 70 countries. In China, PPR has occurred in more than 20 provinces and cities. In this study, based on geographic information system (GIS), spatial analysis was used to examine the occurrence of PPR in China from 2007 to 2018. The results showed that PPR first occurred in Tibet and gradually spread to other provinces. The outbreaks of PPR were concentrated in 2014, 2015 and 2018. Combining climate factors with the maximum entropy (MaxEnt), the results also suggested that the potential risk areas of PPR outbreaks in China were mainly Jiangsu, Yunnan and Anhui in Southeast China. Finally, a phylogenetic tree was used to analyse the evolutionary relationship between the peste des petits ruminants virus (PPRV) in China and the global ones, and it was found that the one in China had a close genetic relationship with the one in Mongolia, India and Bangladesh. Understanding and forecasting the distribution of PPR in China will help policymakers develop targeted monitoring plans. Likewise, analysing the global PPRV epidemic trends will play an important role in the elimination and prevention of PPR.

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.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12866-021-02372-2.

1. Assessment and detection of source of re-emergence of Peste des Petits Ruminants virus in goats.

2. High rate of mortality than morbidity in domestic and captive wild goat herds.

3. Identification of novel sub-types (I&II) of lineage IV.

4. Regular monitoring and strategies for improving on-site control and trade regulations enables mitigating risk of outbreaks.

Nucleotide amplification and sequencing of the GC-rich region between matrix and fusion protein genes of peste des petits ruminants virus

Peste des petits ruminants virus (PPRV) causes a highly devastating disease of sheep and goats, that threatens the conservation of small wild ruminants. The development of PPRV vaccines, diagnostics and therapeutics, greatly depends on in-depth genomic data. Yet, high guanine-cytosine (GC) content between matrix (M) and fusion (F) genes of PPRV poses difficulty for both primer design and nucleotide amplification. In turn, this has led into absence or low nucleotide sequence coverage in this region. This poses a risk of missing important part of the genome that could help to infer viral evolution. Here, an overlapping long-read primer-based amplification strategy was developed to amplify the GC-rich fragments between M-F gene junction using nexus gradient polymerase chain reaction (PCR). The resulting amplicons were sequenced by dideoxynucleotide cycle sequencing and compared with other PPRV nucleotide sequences available at GenBank. Our findings indicate clear PCR amplification products with expected size of the GC-rich fragments on agarose gel electrophoresis. The sequencing results of these fragments indicate 99.5 % nucleotide identity with PPRV strain KY628761. An extremely difficult PCR target of 67.4 % GC contents was successfully amplified and sequenced using this long-read primer approach. The long-read primer set may be used in tiling multiplex PCR for complete genome sequencing of PPRV.

Molecular insights into peste des petits ruminants virus identified in Bangladesh between 2008 and 2020

An in-depth knowledge of the molecular evolution of the peste des petits ruminants virus (PPRV) is critical for the success of the current global eradication program. For this reason, a molecular evolutionary analysis of PPRVs circulating in Bangladesh over a decade (2008-2020) was performed. The complete genome sequencing of three PPRV isolates from 2008 (BD2), 2015 (BD12) and 2017 (BD17) as well as full length nucleocapsid (N), matrix (M) and fusion (F) gene sequencing of seven more samples from 2015 to 2020 was performed. Phylogenetic analysis classified all ten PPRVs from Bangladesh as members of lineage IV and showed that they were closely related to PPRV strains detected in China and Tibet during 2007-2008, and India during 2014-2018. Time scale Bayesian Maximum Clade Credibility (MCC) phylogenetic analysis of the three complete genomes revealed a mean Time to Most Recent Common Ancestor (TMRCA) of 2000. Comparative deduced amino acid residue analysis at various functional motifs of PPRVs related to virus structure and function, virulence and host adaptation, receptor binding sites and polymerase activity revealed conserved residues among the PPRVs from Bangladesh. In total sixteen epitopes were predicted from four immunogenic proteins i.e. N, M, F and haemagglutinin (H). Interestingly, the predicted epitopes from the N and M proteins shared conserved epitopes with two vaccine strains currently being used, indicating that the strains from Bangladesh could be potentially used as alternative local vaccines.

Analysis and Sequence Alignment of Peste des Petits Ruminants Virus ChinaSX2020

The peste des petits ruminants virus (PPRV) mainly infects goats and sheep and causes a highly contagious disease, PPR. Recently, a PPRV strain named ChinaSX2020 was isolated and confirmed following an indirect immunofluorescence assay and PCR using PPRV-specific antibody and primers, respectively. A sequencing of the ChinaSX2020 strain showed a genome length of 15,954 nucleotides. A phylogenetic tree analysis showed that the ChinaSX2020 genome was classified into lineage IV of the PRRV genotypes. The genome of the ChinaSX2020 strain was found to be closely related to PPRVs isolated in China between 2013 and 2014. These findings revealed that not a variety of PRRVs but similar PPRVs were continuously spreading and causing sporadic outbreaks in China.

Molecular epidemiology of peste des petits ruminants virus emergence in critically endangered Mongolian saiga antelope and other wild ungulates

Peste des petits ruminants virus (PPRV) causes disease in domestic and wild ungulates, is the target of a Global Eradication Programme, and threatens biodiversity. Understanding the epidemiology and evolution of PPRV in wildlife is important but hampered by the paucity of wildlife-origin PPRV genomes. In this study, full PPRV genomes were generated from three Mongolian saiga antelope, one Siberian ibex, and one goitered gazelle from the 2016-2017 PPRV outbreak. Phylogenetic analysis showed that for Mongolian and Chinese PPRV since 2013, the wildlife and livestock-origin genomes were closely related and interspersed. There was strong phylogenetic support for a monophyletic group of PPRV from Mongolian wildlife and livestock, belonging to a clade of lineage IV PPRV from livestock and wildlife from China since 2013. Discrete diffusion analysis found strong support for PPRV spread into Mongolia from China, and phylogeographic analysis indicated Xinjiang Province as the most likely origin, although genomic surveillance for PPRV is poor and lack of sampling from other regions could bias this result. Times of most recent common ancestor (TMRCA) were June 2015 (95 per cent highest posterior density (HPD): August 2014 to March 2016) for all Mongolian PPRV genomes and May 2016 (95 per cent HPD: October 2015 to October 2016) for Mongolian wildlife-origin PPRV. This suggests that PPRV was circulating undetected in Mongolia for at least 6 months before the first reported outbreak in August 2016 and that wildlife were likely infected before livestock vaccination began in October 2016. Finally, genetic variation and positively selected sites were identified that might be related to PPRV emergence in Mongolian wildlife. This study is the first to sequence multiple PPRV genomes from a wildlife outbreak, across several host species. Additional full PPRV genomes and associated metadata from the livestock-wildlife interface are needed to enhance the power of molecular epidemiology, support PPRV eradication, and safeguard the health of the whole ungulate community.

Development and Evaluation of a Nested PCR for Improved Diagnosis and Genetic Analysis of Peste des Petits Ruminants Virus (PPRV) for Future Use in Nascent PPR Eradication Programme

Peste des petits ruminants (PPR) is a highly contagious viral disease of small ruminants caused by PPR virus (PPRV). PPR is endemic in Asia, the Middle East and across large areas of Africa and is currently targeted for global eradication by 2030. The virus exists as four different lineages that are usually limited to specific geographical areas. However, recent reports of spread of PPRV, in particular of lineage IV viruses to infection-free countries and previously PPR endemic areas are noteworthy. A rapid and accurate laboratory diagnosis and reports on its epidemiological linkage for virus spread play a major role in the effective control and eradication of the disease. Currently, molecular assays, including conventional reverse transcription-polymerase chain reaction (RT-PCR) and real-time RT-PCR (RT-qPCR) are usually used for diagnosis of PPR while the sequencing of part of the nucleocapsid gene is usually carried out for the viral lineage identification. However, it is difficult to diagnose and sequence the genetic material if the animal excreted a low level of virus at the initial stage of infection or if the PPRV is degraded during the long-distance transportation of samples to the reference laboratories. This study describes the development of a novel nested RT-PCR assay for the detection of the PPRV nucleic acid by targeting the N-protein gene, compares the performance of the assay with the existing conventional RT-PCR and also provides good-quality DNA suitable for sequencing in order to identify circulating lineages. The 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. This assay provides a solution with an easy, accurate, rapid and cost-effective PPR diagnostic and partial genome sequencing for use in resource-limited settings.

Emergence and radiation of distemper viruses in terrestrial and marine mammals

Canine distemper virus (CDV) and phocine distemper virus (PDV) are major pathogens to terrestrial and marine mammals. Yet little is known about the timing and geographical origin of distemper viruses and to what extent it was influenced by environmental change and human activities. To address this, we (i) performed the first comprehensive time-calibrated phylogenetic analysis of the two distemper viruses, (ii) mapped distemper antibody and virus detection data from marine mammals collected between 1972 and 2018, and (iii) compiled historical reports on distemper dating back to the eighteenth century. We find that CDV and PDV diverged in the early seventeenth century. Modern CDV strains last shared a common ancestor in the nineteenth century with a marked radiation during the 1930s-1950s. Modern PDV strains are of more recent origin, diverging in the 1970s-1980s. Based on the compiled information on distemper distribution, the diverse host range of CDV and basal phylogenetic placement of terrestrial morbilliviruses, we hypothesize a terrestrial CDV-like ancestor giving rise to PDV in the North Atlantic. Moreover, given the estimated timing of distemper origin and radiation, we hypothesize a prominent role of environmental change such as the Little Ice Age, and human activities like globalization and war in distemper virus evolution.

Ongoing Assessment of the Molecular Evolution of Peste Des Petits Ruminants Virus Continues to Question Viral Origins

Understanding the evolution of viral pathogens is critical to being able to define how viruses emerge within different landscapes. Host susceptibility, which is spread between different species and is a contributing factor to the subsequent epidemiology of a disease, is defined by virus detection and subsequent characterization. Peste des petits ruminants virus is a plague of small ruminant species that is a considerable burden to the development of sustainable agriculture across Africa and much of Asia. The virus has also had a significant impact on populations of endangered species in recent years, highlighting its significance as a pathogen of high concern across different regions of the globe. Here, we have re-evaluated the molecular evolution of this virus using novel genetic data to try and further resolve the molecular epidemiology of this disease. Viral isolates are genetically characterized into four lineages (I-IV), and the historic origin of these lineages is of considerable interest to the molecular evolution of the virus. Our re-evaluation of viral emergence using novel genome sequences has demonstrated that lineages I, II and IV likely originated in West Africa, in Senegal (I) and Nigeria (II and IV). Lineage III sequences predicted emergence in either East Africa (Ethiopia) or in the Arabian Peninsula (Oman and/or the United Arab Emirates), with a paucity of data precluding a more refined interpretation. Continual refinements of evolutionary emergence, following the generation of new data, is key to both understanding viral evolution from a historic perspective and informing on the ongoing genetic emergence of this virus.

Identification of Differential Responses of Goat PBMCs to PPRV Virulence Using a Multi-Omics Approach

Peste des petits ruminants (PPR) is an acute transboundary infectious viral disease of small ruminants, mainly sheep and goats. Host susceptibility varies considerably depending on the PPR virus (PPRV) strain, the host species and breed. The effect of strains with different levels of virulence on the modulation of the immune system has not been thoroughly compared in an experimental setting so far. In this study, we used a multi-omics approach to investigate the host cellular factors involved in different infection phenotypes. Peripheral blood mononuclear cells (PBMCs) from Saanen goats were activated with a T-cell mitogen and infected with PPRV strains of different virulence: Morocco 2008 (high virulence), Ivory Coast 1989 (low virulence) and Nigeria 75/1 (live attenuated vaccine strain). Our results showed that the highly virulent strain replicated better than the other two in PBMCs and rapidly induced cell death and a stronger inhibition of lymphocyte proliferation. However, all the strains affected lymphocyte proliferation and induced upregulation of key antiviral genes and proteins, meaning a classical antiviral response is orchestrated regardless of the virulence of the PPRV strain. On the other hand, the highly virulent strain induced stronger inflammatory responses and activated more genes related to lymphocyte migration and recruitment, and inflammatory processes. Both transcriptomic and proteomic approaches were successful in detecting viral and antiviral effectors under all conditions. The present work identified key immunological factors related to PPRV virulence in vitro.

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.