Peste des Petits Ruminants Virus

Long-term trial of protection provided by adenovirus-vectored vaccine expressing the PPRV H protein

A recombinant, replication-defective, adenovirus-vectored vaccine expressing the H surface glycoprotein of peste des petits ruminants virus (PPRV) has previously been shown to protect goats from challenge with wild-type PPRV at up to 4 months post vaccination. Here, we present the results of a longer-term trial of the protection provided by such a vaccine, challenging animals at 6, 9, 12 and 15 months post vaccination. Vaccinated animals developed high levels of anti-PPRV H protein antibodies, which were virus-neutralising, and the level of these antibodies was maintained for the duration of the trial. The vaccinated animals were largely protected against overt clinical disease from the challenge virus. Although viral genome was intermittently detected in blood samples, nasal and/or ocular swabs of vaccinated goats post challenge, viral RNA levels were significantly lower compared to unvaccinated control animals and vaccinated goats did not appear to excrete live virus. This protection, like the antibody response, was maintained at the same level for at least 15 months after vaccination. In addition, we showed that animals that have been vaccinated with the adenovirus-based vaccine can be revaccinated with the same vaccine after 12 months and showed an increased anti-PPRV antibody response after this boost vaccination. Such vaccines, which provide a DIVA capability, would therefore be suitable for use when the current live attenuated PPRV vaccines are withdrawn at the end of the ongoing global PPR eradication campaign.

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.

Seroprevalence of peste des petits ruminants disease in Indonesian buffaloes may be an emerging threat to small ruminants

Background and Aim

The peste des petit ruminants (PPR) is a disaster-class virus that causes catastrophic drawbacks to small ruminant industries in affected countries. As PPR disease has been reported in neighboring countries, Indonesia, which has a large population of sheep and goats, has become prone to the emerging threat of infection. Because the virus can also infect other animals with subclinical manifestations, large ruminants, such as buffaloes, may play an important role in spreading the virus in the environment. Therefore, the main objective of this study was to identify PPR seroprevalence in the buffalo population of Indonesia.

Materials and Methods

A competitive enzyme-linked immunosorbent assay was performed to identify the specific antibody for PPR viruses in the buffalo population using serum bank collection from the National Research and Innovation Agency, Indonesia.

Results

PPR virus seroprevalence was detected in buffalo from Central Java, East Java, and East Nusa Tenggara Province in Indonesia. Although seroprevalence was low in the population, the antibody titer was relatively high in the positive samples. Sex and age were identified as determinant factors in the seroprevalence distribution of the buffalo population.

Conclusion

The presence of antibodies against the PPR virus in buffaloes may indicate that PPR virus is circulating in the buffalo population of Indonesia.

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.

Modeling for Smart Vaccination against Peste des Petits Ruminants (PPR) in the Emirate of Abu Dhabi, United Arab Emirates

Peste des petits ruminants (PPR) is a contagious and economically important transboundary viral disease of small ruminants. The United Arab Emirates (UAE) national animal health plan aimed to control and eradicate PPR from the country by following the global PPR control and eradication strategy which adopts small ruminants' mass vaccination to eradicate the disease from the globe by 2030. A smart vaccination approach, which is less expensive and has longer-term sustainable benefits, is needed to accelerate the eradication of PPR. In this study, a mathematical algorithm was developed based on animals' identification and registration data, belonging to the Abu Dhabi Agriculture and Food Safety Authority (ADAFSA), and other different parameters related to PPR risk occurrence. The latter included animal holding vaccination history, the number of animals per holding, forecasting of the number of animals and newborns per holding, the proximity of an animal holding to a PPR outbreak and the historical animal holding owner vaccination rejection attitude. The developed algorithm successfully prioritized animal holdings at risk of PPR infection within Abu Dhabi Emirate to be targeted by vaccination. This in turn facilitated the mobilization of field vaccination teams to target specific sheep and goat holdings to ensure the generation of immunity against the disease on a risk-based approach. The vaccination coverage of the targeted livestock population was increased to 86% and the vaccination rejection attitude was reduced by 35%. The duration of the vaccination campaign was reduced to 30 compared to 70 working days and hence can alleviate the depletion of human and logistic resources commonly used in classical mass vaccination campaigns. The results obtained from implementing the algorithm-based PPR vaccination campaign will reduce the negative impact of PPR on the UAE livestock sector and accelerate the achievement of the national PPR eradication plan requirements.

Quantitative analysis of acetylation in peste des petits ruminants virus-infected Vero cells

BACKGROUND

Peste des petits ruminants virus (PPRV) is a highly contagious pathogen that strongly influences the productivity of small ruminants worldwide. Acetylation is an important post-translational modification involved in regulation of multiple biological functions. However, the extent and function of acetylation in host cells during PPRV infection remains unknown.

METHODS

Dimethylation-labeling-based quantitative proteomic analysis of the acetylome of PPRV-infected Vero cells was performed.

RESULTS

In total, 1068 proteins with 2641 modification sites were detected in response to PPRV infection, of which 304 differentially acetylated proteins (DAcPs) with 410 acetylated sites were identified (fold change < 0.83 or > 1.2 and P < 0.05), including 109 up-regulated and 195 down-regulated proteins. Gene Ontology (GO) classification indicated that DAcPs were mostly located in the cytoplasm (43%) and participated in cellular and metabolic processes related to binding and catalytic activity. Functional enrichment indicated that the DAcPs were involved in the minichromosome maintenance complex, unfolded protein binding, helicase activity. Only protein processing in endoplasmic reticulum pathway was enriched. A protein-protein interaction (PPI) network of the identified proteins further indicated that a various chaperone and ribosome processes were modulated by acetylation.

CONCLUSIONS

To the best of our knowledge, this is the first study on acetylome in PPRV-infected host cell. Our findings establish an important baseline for future study on the roles of acetylation in the host response to PPRV replication and provide novel insights for understanding the molecular pathological mechanism of PPRV infection.

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.

Inhibition of caspase-1-dependent apoptosis suppresses peste des petits ruminants virus replication

BACKGROUND

Peste des petits ruminants (PPR), caused by the PPR virus (PPRV), is an acute and fatal contagious disease that mainly infects goats, sheep, and other artiodactyls. Peripheral blood mononuclear cells (PBMCs) are considered the primary innate immune cells.

OBJECTIVES

PBMCs derived from goats were infected with PPRV and analyzed to detect the relationship between PPRV replication and apoptosis or the inflammatory response.

METHODS

Quantitative real-time polymerase chain reaction was used to identify PPRV replication and cytokines expression. Flow cytometry was conducted to detect apoptosis and the differentiation of CD4+ and CD8+ T cells after PPRV infection.

RESULTS

PPRV stimulated the differentiation of CD4+ and CD8+ T cells. In addition, PPRV induced apoptosis in goat PBMCs. Furthermore, apoptosis and the inflammatory response induced by PPRV could be suppressed by Z-VAD-FMK and Z-YVAD-FMK, respectively. Moreover, the virus titer of PPRV was attenuated by inhibiting caspase-1-dependent apoptosis and inflammation.

CONCLUSIONS

This study showed that apoptosis and the inflammatory response play an essential role in PPR viral replication in vitro, providing a new mechanism related to the cell host response.

Seroepidemiology of peste des petits ruminants virus in small ruminants in selected districts in Northwest Ethiopia

BACKGROUND

Peste des petits ruminants (PPR) is one of the most severe diseases of small ruminants, causing the loss of millions of dollars annually. A cross-sectional study was conducted to determine the seroepidemiology of peste des petits ruminants virus (PPRV) in unvaccinated sheep and goats in selected districts in Northwest Ethiopia.

OBJECTIVES

The study was designed to investigate the epidemiology of PPRV in unvaccinated sheep and goats and risk factors in the study areas.

METHODS

A multi-stage sampling was used to select study districts, villages and households with a random sampling approach. Study animals (403 sheep and goats) older than 5 months were selected with a systematic random sampling approach. From the animals, blood samples were aseptically collected and PPRV antibodies from the serum were analysed with enzyme-linked immunosorbent assay (ELISA).

RESULTS

The overall seroprevalence of antibodies to PPRV was 32.5% in both species. It was higher in goats with a prevalence of 34.7% than in sheep (28.3%). District, herd size, sex, animal origin and grazing management were significantly associated with seropositivity of animals to PPRV antibodies. If an animal was from the Dangur district, it had 2.6 times higher chance of being positive than in the Dibati district (OR = 2.6, p = 0.01 and 95% CI = 1.2- 5.6). Herd size was also significantly correlated with the seropositivity with (OR = 4, p = 0.001, and 95% CI = 1.8-9). Also, male animals had 1.7 times higher chance of being positive than females. Further, if an animal comes from the market, it has 2.7 times higher chance of being positive compared to animals born and raised on the farm.

CONCLUSIONS

The seropositivity indicates that the disease is circulating in the study areas. Hence, preventive approaches, like vaccination campaigns and strict biosecurity measures, are highly advised to avoid the catastrophic impact of the diseases if an outbreak occurs.

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.

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.

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.

Comparative pathogenesis of peste des petits ruminants virus strains of difference virulence

Peste des petits ruminants (PPR) is an acute disease of small ruminants caused by a morbillivirus. Clinical observation of the disease in the field revealed that several species of small ruminants are affected to varying degrees. This difference in disease-related effects could depend either on the host or on the virulence of the virus strain. A previous study highlighted the difference in virulence between two strains of PPRV used to infect Saanen goats. For this breed, PPRV Morocco 2008 strain (MA08) was highly virulent while PPRV Côte d’Ivoire 1989 (IC89) strain induced mild disease. Experimental studies generally based on healthy and young animals do not permit exploration of the natural variability of the host susceptibility to PPRV. Therefore, building on the previous study on Saanen goats, the current study focussed on this breed of goat and used commercially available animals with an unknown history of infection with other pathogens. Results confirmed the previous disease pattern for PPRV IC89 and MA08 strains. Viral RNA detection, macroscopic and histological lesions were stronger for the highly virulent MA08 strain. We show here for the first time that viral RNA can be detected in the tissues of vaccinated animals. Viral RNA was also detected for the first time in serum samples, which is in agreement with the role of circulating immune cells in transporting the virus into host target organs. Thus, this study provides insight into the pathogenesis of strains of different virulence of PPRV and will help to better understand the onset of the disease.

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.

Determination of Intestinal Viral Loads and Distribution of Bovine Viral Diarrhea Virus, Classical Swine Fever Virus, and Peste Des Petits Ruminants Virus: A Pilot Study

The aim of this pilot study was to determine viral loads and distribution over the total length, at short distances, and in the separate layers of the intestine of virus-infected animals for future inactivation studies. Two calves, two pigs, and two goats were infected with bovine viral diarrhoea virus (BVDV), classical swine fever virus (CSFV), and peste des petits ruminants virus (PPRV), respectively. Homogenously distributed maximum BVDV viral loads were detected in the ileum of both calves, with a mean titer of 6.0 log10 TCID50-eq/g. The viral loads in colon and caecum were not distributed homogenously. In one pig, evenly distributed CSFV mean viral loads of 4.5 and 4.2 log10 TCID50-eq/g were found in the small and large intestines, respectively. Mucosa, submucosa, and muscular layer/serosa showed mean viral loads of 5.3, 3.4, and 4.0 log10 TCID50-eq/g, respectively. Homogenous distribution of PPRV was shown in the ileum of both goats, with a mean viral load of 4.6 log10 TCID50-eq/g. Mean mucosa, submucosa, and muscular layer/serosa viral loads were 3.5, 2.8, and 1.7 log10 TCID50-eq/g, respectively. This pilot study provides essential data for setting up inactivation experiments with intestines derived from experimentally infected animals, in which the level and the homogeneous distribution of intestinal viral loads are required.

Environmental sampling for the detection of foot-and-mouth disease virus and peste des petits ruminants virus in a live goat market, Nepal

Livestock markets are considered vital parts of the agricultural economy, particularly in developing countries where livestock keeping contributes to both food security and economic stability. Animals from diverse sources are moved to markets, they mix while they are there and are subsequently redistributed over wide geographic areas. Consequently, markets provide an opportunity for targeted surveillance for circulating pathogens. This study investigated the use of environmental sampling at a live goat market in Nepal for the detection of foot-and-mouth disease virus (FMDV) and peste des petits ruminants virus (PPRV), both of which are endemic. Five visits to the market were carried out between November 2016 and April 2018, with FMDV RNA detected on four visits and PPRV RNA detected on all five visits. Overall, 4.1% of samples (nine out of 217) were positive for FMDV RNA and 60.8% (132 out of 217) were positive for PPRV RNA, though the proportion of positive samples varied amongst visits. These results demonstrate that non-invasive, environmental sampling methods have the potential to be used to detect circulation of high priority livestock diseases at a live animal market and, hence, to contribute to their surveillance and control.

Inhibiting pyrimidine biosynthesis impairs Peste des Petits Ruminants Virus replication through depletion of nucleoside pools and activation of cellular immunity

Replication of peste des petits ruminants virus (PPRV) strongly depends on the cellular environment and resources of host cells including nucleoside pool. Thus, enzymes involved in nucleoside biosynthesis (such as pyrimidine biosynthesis pathway) are regarded as attractive targets for antiviral drug development. Here, we demonstrate that brequinar (BQR) and leflunomide (LFM) which are two specific inhibitors of DHODH enzyme and 6-azauracil (6-AU) which is an ODase enzyme inhibitor robustly inhibit PPRV replication in HEK293T cell line as well as in peripheral blood mononuclear cells isolated from goat. We further demonstrate that these agents exert anti-PPRV activity via the depletion of purimidine nucleotide. Interestingly, these inhibitors can trigger the transcription of antiviral interferon-stimulated genes (ISGs). However, the induction of ISGs is largely independent of the classical JAK-STAT pathway. Combination of BQR with interferons (IFNs) exerts enhanced ISG induction and anti-PPRV activity. Taken together, this study reveals an unconventional novel mechanism of crosstalk between nucleotide biosynthesis pathways and cellular antiviral immunity in inhibiting PPRV replication. In conclusion, targeting pyrimidine biosynthesis represents a potential strategy for developing antiviral strategies against PPRV.

Quantitative Proteomics Reveals a Novel Role of the E3 Ubiquitin-Protein Ligase FANCL in the Activation of the Innate Immune Response through Regulation of TBK1 Phosphorylation during Peste des Petits Ruminants Virus Infection

Peste des petits ruminants virus (PPRV) infection causes considerable innate immunosuppression in its host, which promotes viral replication. However, how the host rescues the innate immune response to counteract this immunosuppression during viral replication remains largely unknown. To explore the mechanisms of how a host counteracts PPRV-mediated innate immunosuppression, a high-throughput quantitation proteomic approach (isobaric tags for relative and absolute quantitation in conjunction with LC-MS/MS) was used to investigate the proteome landscape of goat fetal fibroblasts (GFFs) in response to PPRV infection. Eventually, 497 upregulated proteins and 358 downregulated proteins were identified. Many of the differentially expressed proteins were enriched in immune-related pathways. Blocking the activation of the innate immune response with a specific inhibitor BX795 in GFFs remarkably promoted PPRV replication, suggesting the significant antiviral role of the enriched immune-related pathways. The GO enrichment analysis showed that the host protein FANCL revealed a similar expression pattern to these innate immune-related proteins. In addition, the analysis of protein-protein interaction networks reveals a potential relationship between FANCL and the innate immune pathway. We determined that FANCL inhibited PPRV infection by enhancing type I interferon (IFN) and IFN-stimulated gene expression. Further investigation determined that FANCL induced type I IFN production by promoting TBK1 phosphorylation, thus impairing PPRV-mediated immunosuppression.

Transboundary Animal Diseases, an Overview of 17 Diseases with Potential for Global Spread and Serious Consequences

Animals provide food and other critical resources to most of the global population. As such, diseases of animals can cause dire consequences, especially disease with high rates of morbidity or mortality. Transboundary animal diseases (TADs) are highly contagious or transmissible, epidemic diseases, with the potential to spread rapidly across the globe and the potential to cause substantial socioeconomic and public health consequences. Transboundary animal diseases can threaten the global food supply, reduce the availability of non-food animal products, or cause the loss of human productivity or life. Further, TADs result in socioeconomic consequences from costs of control or preventative measures, and from trade restrictions. A greater understanding of the transmission, spread, and pathogenesis of these diseases is required. Further work is also needed to improve the efficacy and cost of both diagnostics and vaccines. This review aims to give a broad overview of 17 TADs, providing researchers and veterinarians with a current, succinct resource of salient details regarding these significant diseases. For each disease, we provide a synopsis of the disease and its status, species and geographic areas affected, a summary of in vitro or in vivo research models, and when available, information regarding prevention or treatment.

Assessment of the control measures of the category A diseases of Animal Health Law: peste des petits ruminants

EFSA received a mandate from the European Commission to assess the effectiveness of some of the control measures against diseases included in the Category A list according to Regulation (EU) 2016/429 on transmissible animal diseases ('Animal Health Law'). This opinion belongs to a series of opinions where these control measures will be assessed, with this opinion covering the assessment of control measures for peste des petits ruminants (PPR). In this opinion, EFSA and the AHAW Panel of experts review the effectiveness of: (i) clinical and laboratory sampling procedures, (ii) monitoring period and (iii) the minimum radii of the protection and surveillance zones, and the minimum length of time the measures should be applied in these zones. The general methodology used for this series of opinions has been published elsewhere; nonetheless, the transmission kernels used for the assessment of the minimum radii of the protection and surveillance zones are shown. Several scenarios for which these control measures had to be assessed were designed and agreed prior to the start of the assessment. The monitoring period of 21 days was assessed as effective, except for the first affected establishments detected, where 33 days is recommended. It was concluded that beyond the protection (3 km) and the surveillance zones (10 km) only 9.6% (95% CI: 3.1-25.8%) and 2.3% (95% CI: 1-5.5%) of the infections from an affected establishment may occur, respectively. This may be considered sufficient to contain the disease spread (95% probability of containing transmission corresponds to 5.3 km). Recommendations provided for each of the scenarios assessed aim to support the European Commission in the drafting of further pieces of legislation, as well as for plausible ad-hoc requests in relation to PPR.

Zinc finger antiviral protein (ZAP) inhibits small ruminant morbillivirus replication in vitro

Small ruminant morbillivirus (SRMV) is a highly contagious and economically important viral disease of small domestic and wild ruminants. Difficulty with its stable proliferation in ovis aries-derived cells has led to a relative lag in the study of its natural immunity and pathogenesis. Here we report the antiviral properties of ZAP against SRMV, a single-stranded negative-stranded RNA virus of the genus Morbillivirus. ZAP expression was significantly induced in sheep endometrial epithelial cells following SRMV infection. ZAP inhibited SRMV replication in cells after infection, while its overexpression in Vero-SLAM cells significantly increased their resistance to SRMV replication. The ZAP protein co-localized with SRMV RNA in the cytoplasm and ZAP-responsive elements were mapped to the 5' untranslated region of SRMV nucleocapsid, phosphoprotein, matrix, and fusion. In summary, ZAP confers resistance to SRMV infection by directly targeting viral RNA and inhibiting viral replication. Our findings further extend the ranges of viral targets of ZAP and help elucidate the mechanism of SRMV replication.

In vitro and in vivo analyses of co-infections with peste des petits ruminants and capripox vaccine strains

BACKGROUND

Peste des petits ruminants (PPR) and goat pox (GTP) are two devastating animal epidemic diseases that affect small ruminants. Vaccination is one of the most important measures to prevent and control these two severe infectious diseases.

METHODS

In this study, we vaccinated sheep with PPR and POX vaccines to compare the changes in the antibody levels between animals vaccinated with PPRV and POX vaccines alone and those co-infected with both vaccines simultaneously. The cell infection model was used to explore the interference mechanism between the vaccines in vitro. The antibody levels were detected with the commercial ELISA kit. The Real-time Quantitative PCR fluorescent quantitative PCR method was employed to detect the viral load changes and cytokines expression after the infection.

RESULTS

The concurrent immunization of GTP and PPR vaccine enhanced the PPR vaccine's immune effect but inhibited the immune effect of the GTP vaccine. After the infection, GTP and PPR vaccine strains caused cytopathic effect; co-infection with GTP and PPR vaccine strains inhibited the replication of PPR vaccine strains; co-infection with GTP and PPR vaccine strains enhanced the replication of GTP vaccine strains. Moreover, virus mixed infection enhanced the mRNA expressions of TNF-α, IL-1β, IL-6, IL-10, IFN-α, and IFN-β by 2-170 times. GTP vaccine strains infection alone can enhanced the mRNA expression of IL-1β, TNF-α, IL-6, IL-10, while the expression of IFN-α mRNA is inhibited. PPR vaccine strains alone can enhanced the mRNA expression of IFN-α, IFN-β, TNF-α, and has little effect the mRNA expression of IL-1β, IL-6 and IL-10. The results showed that GTP and PPR vaccine used simultaneously in sheep enhanced the PPR vaccine's immune effect but inhibited the immune effect of the GTP vaccine in vivo. Furthermore, an infection of GTP and PPR vaccine strains caused significant cell lesions in vitro; co-infection with GTP + PPR vaccine strains inhibited the replication of PPR vaccine strains, while the co-infection of GTP followed by PPR infection enhanced the replication of GTP vaccine strains. Moreover, virus infection enhanced the expressions of TNF-α, IL-1β, IL-6, IL-10, IFN-α, and IFN-β.

CONCLUSIONS

Peste des petits ruminants and capripox vaccine strains interfere with each other in vivo and vitro.

PPRV-induced novel miR-3 contributes to inhibit type I IFN production by targeting IRAK1

Peste des petits ruminants virus (PPRV) is an important pathogen that seriously influences the productivity of small ruminants worldwide. PPRV has evolved several mechanisms to evade IFN-I responses. We report that a novel microRNA in goat PBMCs, novel miR-3, was upregulated by PPRV to facilitate virus infection. Furthermore, PPRV V protein alone was sufficient to induce novel miR-3 expression, and NF-κB and p38 pathway may involved in the induction of novel miR-3 during PPRV infection. Importantly, we demonstrated that novel miR-3 was a potent negative regulator of IFN-α production by targeting IRAK1, which resulted in the enhancement of PPRV infection. In addition, we found that PPRV infection can activated ISGs through IFN independent and IRF3 dependent pathway. Moreover, our data revealed that novel miR-3 mediated regulation of IFN-α production may involve in the differential susceptibility between goat and sheep to PPRV. Taken together, our findings identified a new strategy taken by PPRV to escape IFN-I-mediated antiviral immune responses by engaging cellular microRNA and, thus, improve our understanding of its pathogenesis.IMPORTANCE: Peste des petits ruminants virus (PPRV) induce in the hosts a transient but severe immunosuppression, which threatens both small livestock and endangered susceptible wildlife populations in many countries. Despite extensive research has been explored, the mechanism underlying PPRV immune system evasion remains elusive. Our data provided the first direct evidence that novel microRNA-3 (novel miR-3) feedback inhibits type I IFN signaling when goat PBMCs are infected with PPRV vaccine strain N75/1, thus promoting the infection. In this study, the target of novel miR-3, IRAK1, which are important for PPRV-induced type I IFN production, have also been found. Moreover, we identified NF-κB and p38 pathways may involve in novel miR-3 induction in response to PPRV infection. Taken together, our research has provided new insight into understanding the effects of miRNA on host-virus interactions, and revealed a potential therapeutic target for antiviral intervention.

Temporal and Spatial Epidemiological Analysis of Peste Des Petits Ruminants Outbreaks from the Past 25 Years in Sheep and Goats and Its Control in India

This study was aimed to understand the temporal and spatial epidemiology of peste des petits ruminants (PPR) in India using national surveillance data available in the National Animal Diseases Referral Expert System (NADRES) along with its control plan undertaken. On analysis of the outbreaks/cases reports in sheep and goats in NADRES database from 1995 to 2019, it was observed that PPR features among the top ten diseases and stands first among viral diseases, and among reported deaths, PPR accounts for 36% of mortality in sheep and goats. PPR outbreaks occur round the year in all the seasons but are encountered most frequently during the lean period especially, in the winter season (January to February) in different regions/zones. The reported outbreaks have been progressively declined in most of the states in India due to the implementation of a mass vaccination strategic program since 2011. On state-wise analysis, the PPR risk-areas showed wide variations with different levels of endemicity. Andhra Pradesh, West Bengal, and Karnataka were the top three outbreaks reported states during 1995-2010, whereas Jharkhand and West Bengal states reported more outbreaks during 2011-2015 and 2016-2019 periods. The temporal and spatial distribution of PPR in India provides valuable information on the hotspot areas/zones to take appropriate policy decisions towards its prevention and control in different regions/zones of India. The study also identifies when and where intensive surveillance and vaccination along with biosecurity measures need to be implemented for the control and eradication of the disease from India in consonance with the PPR Global Control and Eradication Strategy.

Caprine MAVS Is a RIG-I Interacting Type I Interferon Inducer Downregulated by Peste des Petits Ruminants Virus Infection

The mitochondrial antiviral-signaling protein (MAVS, also known as VISA, IPS-1, or CARDIF) plays an essential role in the type I interferon (IFN) response and in retinoic acid-inducible gene I (RIG-I) mediated antiviral innate immunity in mammals. In this study, the caprine MAVS gene (caMAVS, 1566 bp) was identified and cloned. The caMAVS shares the highest amino acid similarity (98.1%) with the predicted sheep MAVS. Confocal microscopy analysis of partial deletion mutants of caMAVS revealed that the transmembrane and the so-called Non-Characterized domains are indispensable for intracellular localization to mitochondria. Overexpression of caMAVS in caprine endometrial epithelial cells up-regulated the mRNA levels of caprine interferon-stimulated genes. We concluded that caprine MAVS mediates the activation of the type I IFN pathway. We further demonstrated that both the CARD-like domain and the transmembrane domain of caMAVS were essential for the activation of the IFN-β promotor. The interaction between caMAVS and caprine RIG-I and the vital role of the CARD and NC domain in this interaction was demonstrated by co-immunoprecipitation. Upon infection with the Peste des Petits Ruminants Virus (PPRV, genus Morbillivirus), the level of MAVS was greatly reduced. This reduction was prevented by the addition of the proteasome inhibitor MG132. Moreover, we found that viral protein V could interact and colocalize with MAVS. Together, we identified caMAVS as a RIG-I interactive protein involved in the activation of type I IFN pathways in caprine cells and as a target for PPRV immune evasion.

Combining viral genetic and animal mobility network data to unravel peste des petits ruminants transmission dynamics in West Africa

Peste des petits ruminants (PPR) is a deadly viral disease that mainly affects small domestic ruminants. This disease threaten global food security and rural economy but its control is complicated notably because of extensive, poorly monitored animal movements in infected regions. Here we combined the largest PPR virus genetic and animal mobility network data ever collected in a single region to improve our understanding of PPR endemic transmission dynamics in West African countries. Phylogenetic analyses identified the presence of multiple PPRV genetic clades that may be considered as part of different transmission networks evolving in parallel in West Africa. A strong correlation was found between virus genetic distance and network-related distances. Viruses sampled within the same mobility communities are significantly more likely to belong to the same genetic clade. These results provide evidence for the importance of animal mobility in PPR transmission in the region. Some nodes of the network were associated with PPRV sequences belonging to different clades, representing potential "hotspots" for PPR circulation. Our results suggest that combining genetic and mobility network data could help identifying sites that are key for virus entrance and spread in specific areas. Such information could enhance our capacity to develop locally adapted control and surveillance strategies, using among other risk factors, information on animal mobility.

Hemagglutinin protein of Peste des Petits Ruminants virus (PPRV) activates the innate immune response via Toll-like receptor 2 signaling

The toll-like receptor (TLR) family comprises both cell-surface and intracellular receptors that recognize different types of pathogen-associated molecular patterns (PAMPs) leading to the production of pro-inflammatory cytokines and subsequent development of adaptive immunity. TLR2 is a cell-surface receptor initially thought to act as a bacterial sentinel but also shown to recognize a number of viral glycoproteins. In this study, we sought to characterize the role of TLR2 in the activation of the immune response by peste des petits ruminants virus (PPRV), a morbillivirus of the Paramixoviridae family that causes an acute, highly contagious disease in goats and sheep. Using human embryonic kidney (HEK) 293 cells stably expressing human (h)TLR2 but lacking any other TLR, we found that PPRV induces IL-8 production in a dose-dependent manner. That activation is only observed in cells expressing hTLR2 and is greatly reduced when the receptor is blocked by pretreatment with specific antibody. We identified hemagglutinin (H) as the viral protein responsible of TLR2 activation by performing the same assays with purified recombinant mammalian-expressed H protein. Exogenous addition of recombinant H protein to cell culture induces high levels of interleukin (IL)-8 only in TLR2-expressing cells. Moreover, H engagement on TLR2 in the monocytic cell line THP-1 activates extracellular-signal-regulated kinase (ERK) signaling. Stimulation of primary ovine dendritic cells with either inactivated PPRV or purified recombinant H protein results in transcription of pro-inflammatory cytokines and the secretion of the Th1-polarizing cytokine IL-12. The role of these host immune mechanisms in the control of PPR is discussed.

Depletion of CD8+ T cells from vaccinated goats does not affect protection from challenge with wild-type peste des petits ruminants virus

Peste des petits ruminants (PPR) is a severe disease of goats and sheep that is widespread in Africa, the Middle East and Asia. The disease is caused by peste des petits ruminants virus (PPRV); cell culture-attenuated strains of PPRV have been shown, both experimentally and by extensive use in the field, to be effective vaccines and are widely used. We have previously demonstrated that these vaccines elicit both serological (PPRV-specific antibody) and cell-based (PPRV-specific CD4⁺ and CD8⁺ T cells) immune responses. However, it is not known which of these responses are required for protection from PPRV, information that would be useful in the evaluation of new vaccines that are being developed to provide the capability to differentiate infected and vaccinated animals (DIVA capability). To begin to address this issue, we have used a complement-fixing monoclonal antibody recognizing caprine CD8 to deplete >99.9% of circulating CD8⁺ T cells from vaccinated goats. Animals were then infected with wild-type PPRV. Despite the absence of the CD8⁺ T-cell component of the vaccine-induced immune response, the vaccinated animals were almost fully protected, showing no pyrexia or viraemia, and almost no clinical signs. These data suggest that a virus-specific CD8⁺ T-cell response is not critical for protection against PPRV and that virus-specific antibody and/or CD4⁺ T cells are the main mediators of protection. We have also shown that the leucopenia caused by infection with wild-type PPRV affects all major classes of circulating leucocytes.

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.

Antiviral responses of ATG13 to the infection of peste des petits ruminants virus through activation of interferon response

Not only are autophagy-related (ATG) proteins the essential orchestrators of the autophagy machinery, but also they regulate many other cellular pathways. Here, we demonstrated that ATG13 exerted an obviously antiviral activity against the infection of peste des petits ruminants virus (PPRV) in cell culture model. We found that PPRV infection or the treatment with interferon (IFN) against PPRV infection significantly induced ATG13 expression. Mechanistically, ATG13 stimulated interferon expression and the subsequent activation of the JAK-STAT cascade. These activations triggered the transcription of interferon-stimulated genes (ISGs) to exert antiviral activity. Conversely, the loss of ATG13 significantly attenuated the potency of RIG-IN in activating IFN responses. In summary, we have demonstrated that basal ATG13 was involved in host antiviral activities against PPRV infection and the over-expression of ATG13 activated IFN production to inhibit PPRV replication in an unconventional fashion.

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

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

RNAseq Reveals the Contribution of Interferon Stimulated Genes to the Increased Host Defense and Decreased PPR Viral Replication in Cattle

Peste des petits ruminants virus (PPRV) is known to replicate in a wide variety of ruminants causing very species-specific clinical symptoms. Small ruminants (goats and sheep) are susceptible to disease while domesticated cattle and buffalo are dead-end hosts and do not display clinical symptoms. Understanding the host factors that influence differential pathogenesis and disease susceptibility could help the development of better diagnostics and control measures. To study this, we generated transcriptome data from goat and cattle peripheral blood mononuclear cells (PBMC) experimentally infected with PPRV in-vitro. After identifying differentially expressed genes, we further analyzed these immune related pathway genes using the Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) and selected candidate genes were validated using in-vitro experiments. Upon PPRV infection, we identified 12 and 22 immune related genes that were differentially expressed in goat and cattle respectively. In both species, this included the interferon stimulated genes (ISGs) IFI44, IFI6, IFIT1, IFIT2, IFIT3, ISG15, Mx1, Mx2, OAS1X, RSAD2, IRF7, DDX58 and DHX58 that were transcribed significantly higher in cattle. PPRV replication in goat PBMCs significantly increased the expression of phosphodiesterase 12 (PDE12), a 2′,5′-oligoadenylate degrading enzyme that contributes to the reduced modulation of interferon-regulated gene targets. Finally, a model is proposed for the differential susceptibility between large and small ruminants based on the expression levels of type-I interferons, ISGs and effector molecules.

Complete Genome Sequence of a Lineage IV Peste des Petits Ruminants Virus from Turkey, 2018

We report the whole-genome sequence of a peste des petits ruminants virus (PPRV) from a lamb exhibiting clinical signs in Turkey in September 2018. The genome of PPRV/Turkey/Central_Anatolia/2018 shows the highest nucleotide sequence identity (97.63%) to PPRV isolated in Turkey in 2000.

Identification of amino acid residues involved in the interaction between peste-des-petits-ruminants virus haemagglutinin protein and cellular receptors

Peste-des-petits-ruminants virus (PPRV) haemagglutinin (H) protein mediates binding to cellular receptors and then initiates virus entry. To identify the key residues of PPRV H (Hv) protein of the Nigeria 75/1 strain involved in binding to receptors, interaction of the Hv and mutated Hv (mHv) proteins with receptors (SLAM and Nectin 4) and their mutants (mSLAM1, mSLAM2, mSLAM3 and mNectin 4) was investigated using surface plasmon resonance imaging (SPRi) and coimmunoprecipitation (co-IP) assays. The results showed that the Hv protein failed to interact with mSLAM3, but interacted at a strong or medium intensity with SLAM, mSLAM2, Nectin 4 and mNectin 4, and at a low level with mSLAM1. The mHv protein was unable to interact with SLAM and its mutants, but bound to Nectin 4 and mNectin 4 with medium and weak intensity, respectively. Further analysis showed that the Hv protein could precipitate mSLAM1, mSLAM2 and mNectin 4, but not mSLAM3. The mHv protein failed to coprecipitate with SLAM and its mutants. The binding activities of mNectin 4 and Nectin 4 to mHv were less than 30.36 and 51.94 % of the wild-type levels, respectively. Based on the results obtained, amino acids at positions R389, L464, I498, R503, R533, Y541, Y543, F552 and Y553 of H protein and I61, H62, L64, K76, K78, E123, H130, I210, A211, S226 and R227 in SLAM were identified to be essential for the specificity of H-SLAM interaction, while the critical residues of H-Nectin 4 interaction require further study. These findings would improve our understanding of the invasive mechanisms of PPRV.

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

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

Epitope-Containing Short Peptides Capture Distinct IgG Serodynamics That Enable Differentiating Infected from Vaccinated Animals for Live-Attenuated Vaccines

Differentiating infected from vaccinated animals (DIVA) strategies have been central enabling techniques in several successful viral disease elimination programs. However, owing to their long and uncertain development process, no DIVA-compatible vaccines are available for many important diseases. We report herein a new DIVA strategy based on hybrid protein-peptide microarrays which can theoretically work with any vaccine. Leading from our findings from peste des petits ruminants (PPR) virus, we found 4 epitope-containing short peptides (ECSPs) which have distinct IgG serodynamics: anti-ECSP IgGs only exist for 10 to 60 days postvaccination (dpv), while anti-protein IgGs remained at high levels for >1,000 dpv. These data enabled the design of a DIVA diagnostic microarray containing 4 ECSPs and 3 proteins, which, unlike competitive enzyme-linked immunosorbent assay (cELISA) and virus neutralization tests (VNTs), enables ongoing monitoring of serological differences between vaccinated individuals and individuals exposed to the pathogen. For 25 goats after 60 dpv, 13 were detected with positive anti-ECSP IgGs, indicating recent infections in vaccinated goat herds. These DIVA diagnostic microarrays will almost certainly facilitate eradication programs for (re)emerging pathogens and zoonoses.IMPORTANCE Outbreaks of infectious diseases caused by viruses, such as pseudorabies (PR), foot-and-mouth disease (FMD), and PPR viruses, led to economic losses reaching billions of dollars. Both PR and FMD were eliminated in several countries via large-scale vaccination programs using DIVA-compatible vaccines, which lack the gE protein and nonstructural proteins, respectively. However, there are still extensive challenges facing the development and deployment of DIVA-compatible vaccines because they are time-consuming and full of uncertainty. Further, the negative marker strategy used for DIVA-compatible vaccines is no longer functional for live-attenuated vaccines. To avoid these disadvantageous scenarios, a new strategy is desired. Here, we made the exciting discovery that different IgG serodynamics can be monitored when using protein-based assays versus arrays comprising ECSPs. This DIVA microarray strategy should, in theory, work for any vaccine.

MicroRNA-1 Negatively Regulates Peripheral NK Cell Function via Tumor Necrosis Factor-Like Weak Inducer of Apoptosis (TWEAK) Signaling Pathways During PPRV Infection

Peste des petits ruminants virus (PPRV) has emerged as a significant threat to the productivity of small ruminants worldwide. PPRV is lymphotropic in nature and induces in the hosts a transient but severe immunosuppression, especially innate immunity. However, it remains largely unknown how NK cells respond and are regulated at the earliest time points after an acute viral PPRV infection in goats. In this study, we revealed that multiple immune responses of goat peripheral NK cells were compromised during PPRV infection, including the cytolytic effector molecule expression and cytokine production. Importantly, we demonstrated that PPRV infection stimulated the expression of TWEAK, a negative regulator of cytotoxic function of NK cells, which may be involved in the suppression of cytotoxicity as well as cytokine production in infected goat NK cells. Furthermore, we found that PPRV infection induced TWEAK expression in goat NK cells involving post-transcription by suppressing miR-1, a novel negative miRNA directly targeting the TWEAK gene. Moreover, replication of virus is required for inhibition of miR-1 expression during PPRV infection, and the non-structural V protein of PPRV plays an important role in miR-1 mediated TWEAK upregulation. Additionally, we revealed that the regulation of NK cell immune responses by TWEAK is mediated by MyD88, SOCS1, and STAT3. Taken together, our results demonstrated that TWEAK may play a key role in regulating goat peripheral NK cell cytotoxicity and cytokine expression levels during PPRV infection.

Molecular epidemiology of peste des petits ruminants in Niger: An update

Like many West African countries, outbreaks of peste des petits ruminants (PPR), an economically important disease of goats and sheep, are regularly reported in Niger. The causative virus, peste des petits ruminants virus (PPRV), can be differentiated into four genetically distinct lineages. A publication in 2018 identified three PPRV lineages circulating in the country in 2001 (lineages I and II) and 2013 (lineage IV), respectively. In this present study, more recent samples were collected from goats and sheep in locations throughout Niger between 2011 and 2017. Twelve PPRV-positive samples were characterized by sequencing of a segment of the nucleocapsid protein (N) gene. Phylogenetic analysis of the sequences identified viruses from lineages II and IV only. The analysis also indicated a shared origin of the viruses from Niger with PPRVs from neighbouring countries suggesting transboundary movement.

Peste des petits ruminants virus hemagglutinin (H) induces lysosomal degradation of host cyclophilin A to facilitate viral replication

Peste des petits ruminants virus (PPRV) is a highly contagious disease that affects sheep and goats. To better understand PPRV replication and virulence, cyclophilin A (CypA), a multifunctional goat host protein, was selected for further studies. CypA has been reported to inhibit or facilitate viral replication. However, the precise roles of CypA during PPRV infection remain unclear. Our data show for the first time that CypA suppressed PPRV replication by its PPIase activity, and PPRV infection decreased CypA protein levels. Detailed analysis revealed that PPRV H protein was responsible for the reduction of CypA, which was dependent on the lysosome pathway. No interaction was identified between H and CypA. Furthermore, the 35-58 region of H was essential for the reduction of CypA. In conclusion, our findings identify the antiviral role of CypA against PPRV and provide key insights into how PPRV H protein antagonizes host antiviral response.

Transcriptional Profiles of Murine Bone Marrow-Derived Dendritic Cells in Response to Peste des Petits Ruminants Virus

Background: Peste des petits ruminants virus (PPRV) is the causative agent of PPR, which can cause an acute, highly contagious and fatal disease of sheep and goats, resulting in significant economic losses for commercial animal husbandry due to its high mortality and morbidity. As professional antigen-presenting cells, dendritic cells (DCs) play a unique role in innate immunity. This study aimed to gain a deeper understanding of the transcriptional response of bone marrow-derived dendritic cells (BMDCs) stimulated with PPRV. Results: Transcriptional profiling was performed using RNA sequencing. Herein, we reported that compared to untreatedBMDCs, 4492 differentially expressed genes (DEGs) were identified following PPRV stimulation, out of these DEGs 2311 were upregulated and 2181 were downregulated, respectively. A total of three gene ontology (GO) term clusters of biological process, cell component and molecular function were significantly enriched in 963 GO terms in the PPRV-stimulated BMDCs. These GO clusters were related to inflammatory response, cell division and vacuole, anchoring junction, positive regulation of cellular component and nucleoside binding. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways of DEGs were enriched in a chemokine signaling pathway, protein processing in endoplasmic reticulum, cell cycle and mTOR signaling pathway. Additionally, identified DEGs of BMDCs were further validated by qRT-PCR and the results were in accordance with the change of the genes. This study suggested the effects of PPRV stimulation on the maturation and function of BMDCs. Conclusion: We found that the dramatic BMDCs transcriptome changes triggered were predominantly related to an inflammatory response and chemokine signaling pathway.

Peste des Petits Ruminants Virus Surveillance in Domestic Small Ruminants, Mozambique (2015 and 2017)

Peste des Petits Ruminants (PPR), a transboundary animal disease affecting mainly goats and sheep is caused by a morbillivirus and threatens food security and livelihoods as morbidity and mortality rates can reach 90%. There are no records of PPR in Mozambique, but the disease situation in Tanzania and the ability of PPR virus to rapidly spread across countries constitute a high risk for about 4.7 million goats and sheep in Mozambique. A total of 4,995 goats and sheep were sampled in several provinces during 2015 and 2017 to assess the status of PPR virus (PPRV) in Mozambique and to contribute to surveillance along the border with Tanzania. The sera were screened for anti-PPRV antibodies using a commercial PPR competition ELISA (c-ELISA) and the haemagglutinin based PPR blocking ELISA (HPPR-bELISA). The swabs were tested using one-step RT-PCR for detection of PPRV RNA. The overall percentage of animals with anti-PPRV antibodies by c-ELISA, was 0.46% [0.30–0.70]. However, all the sera positive on c-ELISA were confirmed to be negative by the HPPR-bELISA. Considering that all the swabs were negative for detection of PPRV, no clinical cases were observed during passive surveillance and active sampling, and no symptoms were reported, these results suggest that PPRV is not present in Mozambique.

Peste des petits ruminants viruses of lineages II and III identified in the Democratic Republic of the Congo

Understanding the molecular epidemiology and evolution of peste des petits ruminants virus (PPRV), the causative agent of Peste des petits ruminants, can assist in the control of the transboundary spread of this economically important disease. To date, despite having been reported in the majority of northern and central African countries, no molecular epidemiological data on PPRVs are available for the Democratic Republic of the Congo (DRC). This study reports the collection and analysis of 11 samples collected from three provinces of the DRC in 2016 and 2018. Sequence analysis identified two (i.e. II and III) of the four known lineages of PPRV in the country providing important information that will assist in the global eradication of PPR.

Progress to Control and Eradication of Peste des Petits Ruminants in the Southern African Development Community Region

In southern Africa, small ruminants are an important source of nutrition and income to resource-poor small holder farmers. After spreading from West to Central and Eastern Africa, peste des petits ruminants (PPR) emerged in the United Republic of Tanzania in 2008 and has since been reported in Angola, the Democratic Republic of the Congo, and the Comoros. The disease can cause considerable morbidity and mortality in naïve sheep and goat populations and severely impact rural livelihoods, particularly those of women. Gaps in the knowledge of PPR epidemiology still exist, particularly around the role of small-ruminant movement and the role of the abundant wildlife in southern Africa. The capacity of veterinary services to undertake surveillance and control PPR is heterogeneous within the region, with vaccination being limited. The Pan African strategy for the control and eradication of PPR mirrors the Global Strategy and provides the framework for the Southern African Development Community (SADC) region to meet the 2030 goal of eradication. Five countries and one zone within Namibia are officially PPR free according to OIE Standards. Most countries have developed national strategies for the control and eradication of PPR. To strengthen national and regional PPR eradication programme goals, there is a need for a regional risk-based surveillance adapted to infected, high-risk and lower-risk countries that will enable targeted and efficient control, rapid response to incursions and prevention of spread as well as improved preparedness. Continued international and national support will be necessary including laboratory diagnostics and enhancing surveillance capacity to prevent further spread southwards on the continent.

MicroRNA-218 Regulates Signaling Lymphocyte Activation Molecular (SLAM) Mediated Peste des Petits Ruminants Virus Infectivity in Goat Peripheral Blood Mononuclear Cells

Peste des petits ruminants virus (PPRV) has emerged as a significant threat to the productivity of small ruminants worldwide. SLAM was identified as the primary receptor for PPRV and other Morbilliviruses, although the regulation of SLAM expression is not yet fully understood. In this study, we revealed a novel mechanism by which PPRV upregulates its receptor SLAM expression and thereby benefits its replication via suppressing miR-218, a novel negative miRNA directly targeting SLAM gene. We demonstrated that PPRV infection downregulates miR-218, which in turn enhances SLAM expression on the surface of goat peripheral blood mononuclear cells (PBMCs), thus promoting PPRV replication. Since SLAM signaling may modulate the immune responses induced by PPRV infection, we further examined the effect of SLAM expression on the production of various cytokines by PBMCs in the absence or presence of PPRV. We demonstrated that miR-218-mediated SLAM expression modulates the expression of IFN-γ, TNF-α, and IL-10, importantly, these modulatory effects were enhanced in the presence of PPRV infection. Furthermore, our data clearly showed that PPRV H protein is sufficient to regulate miR-218-mediated SLAM expression. Taken together, our results suggest a novel mechanism involving post-transcriptional regulation of SLAM receptor expression on goat PBMCs during PPRV infection.

Basal interferon signaling and therapeutic use of interferons in controlling peste des petits ruminants virus infection

Peste des petits ruminants virus (PPRV) is a morbillivirus which causes severe disease in ruminants. Since interferons (IFNs) serve as the important defense line against viral infection, we have investigated the roles of types I and III IFNs in PPRV infection in vitro. Upon PPRV infection, IFN-λ3 was strongly induced, while IFN-β and IFN-λ2 were moderately induced at transcriptional level in human embryonic kidney 293 T (HEK293T) cells. Although the transcription of type I and III IFNs were triggered, the production of functional IFN products was not detected. Importantly, the replication of PPRV was strongly inhibited in HEK293T cells treated by the exogenous IFNs (IFN-α-2b, IFN-β and IFN-λ3). Consistently, these IFNs significantly activate a panel of IFN-stimulated genes (ISGs). The inhibition of JAK-STAT pathway by JAK I inhibitor can abrogate the anti-PPRV activity of IFNs. Thus, our study shall contribute to better understanding of the complex PPRV-host interactions and provide rationale for therapeutic development of IFN-based treatment against PPRV infection.

Expression and characterization of the non-structural protein V of small ruminant morbillivirus

Peste-des-petits ruminants is a transboundary viral disease of small ruminants caused by small ruminant morbillivirus (SRMV). In the present study, the full-length V gene of SRMV was constructed through site-directed mutagenesis from the P gene transcripts of the vaccine virus (Sungri/96 India) and expressed in a prokaryotic expression system. In animals, the seroconversion against this protein occurs from 14-days and is getting produced from 48 h in cell culture. An indirect ELISA developed using this protein has a relative sensitivity and relative specificity of 77.73% and 73.775%, respectively as compared to c-ELISA. In this ELISA, it was observed that most of the convalescent animals elicited higher level of antibodies than vaccinated animals.

A comparative phylogenomic analysis of peste des petits ruminants virus isolated from wild and unusual hosts

Peste des petits ruminants virus (PPRV) infects a wide range of domestic and wild ruminants, and occasionally unusual hosts such as camel, cattle and pig. Given their broad host-spectrum and disease endemicity in several developing countries, it is imperative to elucidate the viral evolutionary insights for their dynamic pathobiology and differential host-selection. For this purpose, a dataset of all available (n = 37) PPRV sequences originating from wild and unusual hosts was composed and in silico analysed. Compared to domestic small ruminant strains of same geographical region, phylogenomic and residue analysis of PPRV sequences originating from wild and unusual hosts revealed a close relationship between strains. A lack of obvious difference among the studied sequences and deduced residues suggests that these are the host factors that may play a role in their susceptibility to PPRV infection, immune response, pathogenesis, excretion patterns and potential clinical signs or resistance to clinical disease. Summarizing together, the comparative analysis enhances our understanding towards molecular epidemiology of the PPRV in wild and unusual hosts for appropriate intervention strategies particularly at livestock-wildlife interface.

The Nucleoprotein and Phosphoprotein of Peste des Petits Ruminants Virus Inhibit Interferons Signaling by Blocking the JAK-STAT Pathway

Peste des petits ruminants virus (PPRV) is associated with global peste des petits ruminants resulting in severe economic loss. Peste des petits ruminants virus dampens host interferon-based signaling pathways through multiple mechanisms. Previous studies deciphered the role of V and C in abrogating IFN-β production. Moreover, V protein directly interacted with signal transducers and activators of transcription 1 (STAT1) and STAT2 resulting in the impairment of host IFN responses. In our present study, PPRV infection inhibited both IFN-β- and IFN-γ-induced activation of IFN-stimulated response element (ISRE) and IFN-γ-activated site (GAS) element, respectively. Both N and P proteins, functioning as novel IFN response antagonists, markedly suppressed IFN-β-induced ISRE and IFN-γ-induced GAS promoter activation to impair downstream upregulation of various interferon-stimulated genes (ISGs) and prevent STAT1 nuclear translocation. Specifically, P protein interacted with STAT1 and subsequently inhibited STAT1 phosphorylation, whereas N protein neither interacted with STAT1 nor inhibited STAT1 phosphorylation as well as dimerization, suggesting that the N and P protein antagonistic effects were different. Though they differed in their relationship to STAT1, both proteins blocked JAK-STAT signaling, severely negating the host antiviral immune response. Our study revealed a new mechanism employed by PPRV to evade host innate immune response, providing a platform to study the interaction of paramyxoviruses and host response.

Proteomic analysis of murine bone marrow derived dendritic cells in response to peste des petits ruminants virus

Peste des petits ruminants virus (PPRV) poses a great threat to livestock husbandry, especially goat farming due to its high mortality and morbidity. Dendritic cells (DCs), as the principal stimulators of naive Th cells were widely used in antigen processing and presenting. In the previous study, we tested the effects of PPRV on murine bone marrow derived dendritic cells (BMDCs) including surface markers and cytokines. While the aim of this study is to detect the proteomic profile of BMDCs stimulated with PPRV towards key proteins involved in. Following PPRV stimulation, 110 differentially expressed proteins (DEPs) were identified through iTRAQ labelling with LC-MS/MS approach, of which 94 DEPs were up-regulated and 16 DEPs were down-regulated, respectively. Among them 15 out of 110 DGPs were related to innate immune system, three were involved in cell apoptosis, RPS15a and Smox were related to translation of viral mRNA. Additionally, western blot analysis showed identical results to iTRAQ analysis. There will be profound significance for understanding antigen-presenting of BMDCs after stimulation with PPRV.