Identification of Peste des Petits Ruminants Virus, Georgia, 2016

A phylogenetic analysis of samples taken from reported outbreaks of peste des petits ruminants virus (PPRV) in Georgia revealed a closer relationship to viruses from northern and eastern Africa than to viruses from countries closer to Georgia. This finding has crucial implications for the control of PPRV in the region

The Economic Impact of Eradicating Peste des Petits Ruminants:A Benefit-Cost Analysis

Peste des petits ruminants (PPR) is an important cause of mortality and production loss among sheep and goats in the developing world. Despite control efforts in a number of countries, it has continued to spread across Africa and Asia, placing an increasing burden on the livelihoods of livestock keepers and on veterinary resources in affected countries. Given the similarities between PPR and rinderpest, and the lessons learned from the successful global eradication of rinderpest, the eradication of PPR seems appealing, both eliminating an important disease and improving the livelihoods of the poor in developing countries. We conducted a benefit-cost analysis to examine the conomic returns from a proposed programme for the global eradication of PPR. Based on our knowledge and experience, we developed the eradication strategy and estimated its costs. The benefits of the programme were determined from (i) the averted mortality costs, based on an analysis of the literature, (ii) the downstream impact of reduced mortality using a social accounting matrix, and (iii) the avoided control costs based on current levels of vaccination. The results of the benefit-cost analysis suggest strong economic returns from PPR eradication. Based on a 15-year programme with total discounted costs of US$2.26 billion, we estimate discounted benefits of US$76.5 billion, yielding a net benefit of US$74.2 billion. This suggests a benefit cost ratio of 33.8, and an internal rate of return (IRR) of 199%. As PPR mortality rates are highly variable in different populations, we conducted a sensitivity analysis based on lower and higher mortality scenarios. All the scenarios examined indicate that investment in PPR eradication would be highly beneficial economically. Furthermore, removing one of the major constraints to small ruminant production would be of considerable benefit to many of the most vulnerable communities in Africa and Asia

Peste des Petits Ruminants (PPR) in Ethiopia: Analysis of a national serological survey

<p>Abstract</p> <p>Background</p> <p>Peste des petits ruminants (PPR) is a contagious viral disease of small ruminants in Africa and Asia. In 1999, probably the largest survey on PPR ever conducted in Africa was initiated in Ethiopia where 13 651 serum samples from 7 out of the 11 regions were collected and analyzed by competitive enzyme-linked immunosorbent assay (cELISA). The objective of this paper is to present the results of this survey and discuss their practical implications for PPR-endemic regions.</p> <p>Methods</p> <p>We explored the spatial distribution of PPR in Ethiopia and we investigated risk factors for positive serological status. Intracluster correlation coefficients (ρ), were calculated for 43 <it>wereda </it>(administrative units).</p> <p>Results</p> <p>Seroprevalence was very heterogeneous across regions and even more across <it>wereda</it>, with prevalence estimates ranging from 0% to 52.5%. Two groups of <it>weredas </it>could be distinguished on the basis of the estimated ρ: a group with very low ρ (ρ < 0.12) and a group with very high ρ (ρ > 0.37).</p> <p>Conclusion</p> <p>The results indicate that PPRV circulation has been very heterogeneous, the values for the ρ may reflect the endemic or epidemic presence of the virus or the various degrees of mixing of animals in the different areas and production systems. Age appears as a risk factor for seropositive status, the linear effect seeming to confirm in the field that PPRV is highly immunogenic. Our estimates of intracluster correlation may prove useful in the design of serosurveys in other countries where PPR is of importance.</p

Serological profile of foot-and-mouth disease in wildlife populations of West and Central Africa with special reference to Syncerus caffer subspecies

The role which West and Central African wildlife populations might play in the transmission dynamics of FMD is not known nor have studies been performed in order to assess the distribution and prevalence of FMD in wild animal species inhabiting those specific regions of Africa. This study reports the FMD serological profile extracted from samples (n = 696) collected from wildlife of West and Central Africa between 1999 and 2003. An overall prevalence of FMDV NSP reactive sera of 31.0% (216/696) was estimated, where a significant difference in seropositivity (p = 0.000) was reported for buffalo (64.8%) as opposed to other wild animal species tested (17.8%). Different levels of exposure to the FMDV resulted for each of the buffalo subspecies sampled (p = 0.031): 68.4%, 50.0% and 0% for Nile Buffalo, West African Buffalo and African Forest Buffalo, respectively. The characterisation of the FMDV serotypes tested for buffalo found presence of antibodies against all the six FMDV serotypes tested, although high estimates for type O and SAT 3 were reported for Central Africa. Different patterns of reaction to the six FMDV serotypes tested were recorded, from sera only positive for a single serotype to multiple reactivities. The results confirmed that FMDV circulates in wild ruminants populating both West and Central Africa rangelands and in particular in buffalo, also suggesting that multiple FMDV serotypes might be involved with type O, SAT 2 and SAT 1 being dominant. Differences in serotype and spill-over risk between wildlife and livestock likely reflect regional geography, historical circulation and differing trade and livestock systems

Optimization and evaluation of a non-invasive tool for peste des petits ruminants surveillance and control

Peste des petits ruminants (PPR) is a highly contagious and devastating viral disease affecting mainly sheep and goats, but also a large number of wild species within the order Artiodactyla. A better understanding of PPR transmission dynamics in multi-host systems is necessary to efficiently control the disease, in particular where wildlife and livestock co-occur. Notably, the role of wildlife in PPR epidemiology is still not clearly understood. Non-invasive strategies to detect PPR infection without the need for animal handling could greatly facilitate research on PPR epidemiology and management of the disease in atypical hosts and in complex field situations. Here, we describe optimized methods for the direct detection of PPR virus genetic material and antigen in fecal samples. We use these methods to determine the detection window of PPR in fecal samples, and compare the sensitivity of these methods to standard invasive sampling and PPR diagnostic methods using field samples collected at a wildlife-livestock interface in Africa. Our results show that quantitative reverse transcription PCR (RT-QPCR) amplification of PPRV from fecal swabs has good sensitivity in comparison to ocular swabs. Animals infected by PPRV could be identified relatively early on and during the whole course of infection based on fecal samples using RT-QPCR. Partial gene sequences could also be retrieved in some cases, from both fecal and ocular samples, providing important information about virus origin and relatedness to other PPRV strains. Non-invasive strategies for PPRV surveillance could provide important data to fill major gaps in our knowledge of the multi-host PPR epidemiology

Peste des Petits Ruminants (PPR) in Ethiopia: Analysis of a national serological survey

Background: Peste des petits ruminants (PPR) is a contagious viral disease of small ruminants in Africa and Asia. In 1999, probably the largest survey on PPR ever conducted in Africa was initiated in Ethiopia where 13 651 serum samples from 7 out of the 11 regions were collected and analyzed by competitive enzyme-linked immunosorbent assay (cELISA). The objective of this paper is to present the results of this survey and discuss their practical implications for PPR-endemic regions. Methods: We explored the spatial distribution of PPR in Ethiopia and we investigated risk factors for positive serological status. Intracluster correlation coefficients (rho), were calculated for 43 wereda (administrative units). Results: Seroprevalence was very heterogeneous across regions and even more across wereda, with prevalence estimates ranging from 0% to 52.5%. Two groups of weredas could be distinguished on the basis of the estimated rho: a group with very low rho( rho 0.37). Conclusion: The results indicate that PPRV circulation has been very heterogeneous, the values for the. may reflect the endemic or epidemic presence of the virus or the various degrees of mixing of animals in the different areas and production systems. Age appears as a risk factor for seropositive status, the linear effect seeming to confirm in the field that PPRV is highly immunogenic. Our estimates of intracluster correlation may prove useful in the design of serosurveys in other countries where PPR is of importance

Peste des Petits Ruminants at the Wildlife–Livestock Interface in the Northern Albertine Rift and Nile Basin, East Africa

In the recent past, peste des petits ruminants (PPR) emerged in East Africa causing outbreaks in small livestock across different countries, with evidences of spillover to wildlife. In order to understand better PPR at the wildlife–livestock interface, we investigated patterns of peste des petits ruminants virus (PPRV) exposure, disease outbreaks, and viral sequences in the northern Albertine Rift. PPRV antibodies indicated a widespread exposure in apparently healthy wildlife from South Sudan (2013) and Uganda (2015, 2017). African buffaloes and Uganda kobs <1-year-old from Queen Elizabeth National Park (2015) had antibodies against PPRV N-antigen and local serosurvey captured a subsequent spread of PPRV in livestock. Outbreaks with PPR-like syndrome in sheep and goats were recorded around the Greater Virunga Landscape in Kasese (2016), Kisoro and Kabale (2017) from western Uganda, and in North Kivu (2017) from eastern Democratic Republic of the Congo (DRC). This landscape would not be considered typical for PPR persistence as it is a mixed forest–savannah ecosystem with mostly sedentary livestock. PPRV sequences from DRC (2017) were identical to strains from Burundi (2018) and confirmed a transboundary spread of PPRV. Our results indicate an epidemiological linkage between epizootic cycles in livestock and exposure in wildlife, denoting the importance of PPR surveillance on wild artiodactyls for both conservation and eradication programs

Identification of Peste-des-petits ruminants, Georgia

Background The Peste-des-petits ruminants virus (PPRV) is the cause of a highly infectious transboundary animal disease that primarily affects sheep, goats and small wild ruminants. It is presently being targeted by international organizations for global eradication by 2030. Between January and March 2016, outbreaks of PPR were reported in three farms located near Tbilisi, the capital of Georgia. Of 3,740 susceptible sheep 415 (11%) showed symptoms of PPR. Methods Organ and swab (nasal and ocular) samples were collected and tested in the Laboratory of the Ministry of Agriculture, Tbilisi using a PPR Antigen Capture ELISA (ID.Vet, France). Six positive samples were individually adsorbed onto the matrix of a ViveSTTM transport tube (ViveBio, USA) and were shipped to the Institute for Veterinary Disease Control, Austria, for further characterization. Upon arrival in Austria, the samples were eluted from the ViveSTTM with 1 ml of Dulbecco's Modified Eagle's Medium High Glucose medium and stored at –80°C. Total RNA was extracted from 200 µl aliquots using an RNeasy kit (Qiagen, Germany). The extracted RNA samples were analysed by RT-PCR to amplify a fragment of both the PPRV Nucleo-protein (N) and Fusion protein (F) genes. Three of the six samples tested were positive by RT-PCR. Amplicons were purified and sent for sequencing using standard Sanger methods at LGC genomics (Berlin, Germany). A phylogenetic tree of N and F gene segments from a representative selection of PPRV sequences available in GenBank was estimated using the maximum likelihood method available in MEGA6 employing the Kimura-2 parameter model of nucleotide substitution and 1000 bootstrap replications. Results The phylogenetic analysis revealed that the PPRVs present in the three Georgian samples were identical and belonged to lineage IV. Notably, the N gene fragment sequences were more related to those of viruses from, Egypt, Eritrea, Ethiopia, and Sudan while the F gene fragment sequences clustered with viruses from Egypt, Ethiopia and Sudan. Unexpectedly, the N and F gene fragment sequences for viruses isolated from countries close to Georgia (e.g. Turkey, Iran and Iraq) were less similar to the Georgian viruses. Conclusion This is the first report of PPR in Georgia. Since there is no obvious connection between Georgia and Egypt, Eritrea, Ethiopia or Sudan through the trade or import of small ruminants, further work is required to fully understand PPRV circulation at a regional level

Molecular Foundations of Reproductive Lethality in Arabidopsis thaliana

The SeedGenes database (www.seedgenes.org) contains information on more than 400 genes required for embryo development in Arabidopsis. Many of these EMBRYO-DEFECTIVE (EMB) genes encode proteins with an essential function required throughout the life cycle. This raises a fundamental question. Why does elimination of an essential gene in Arabidopsis often result in embryo lethality rather than gametophyte lethality? In other words, how do mutant (emb) gametophytes survive and participate in fertilization when an essential cellular function is disrupted? Furthermore, why do some mutant embryos proceed further in development than others? To address these questions, we first established a curated dataset of genes required for gametophyte development in Arabidopsis based on information extracted from the literature. This provided a basis for comparison with EMB genes obtained from the SeedGenes dataset. We also identified genes that exhibited both embryo and gametophyte defects when disrupted by a loss-of-function mutation. We then evaluated the relationship between mutant phenotype, gene redundancy, mutant allele strength, gene expression pattern, protein function, and intracellular protein localization to determine what factors influence the phenotypes of lethal mutants in Arabidopsis. After removing cases where continued development potentially resulted from gene redundancy or residual function of a weak mutant allele, we identified numerous examples of viable mutant (emb) gametophytes that required further explanation. We propose that the presence of gene products derived from transcription in diploid (heterozygous) sporocytes often enables mutant gametophytes to survive the loss of an essential gene in Arabidopsis. Whether gene disruption results in embryo or gametophyte lethality therefore depends in part on the ability of residual, parental gene products to support gametophyte development. We also highlight here 70 preglobular embryo mutants with a zygotic pattern of inheritance, which provide valuable insights into the maternal-to-zygotic transition in Arabidopsis and the timing of paternal gene activation during embryo development