Suchergebnisse

Background The genus Capripoxvirus (CaPV) within the family Poxviridae com-prises three closely related viruses, sheep poxvirus (SPPV), goat poxvirus (GTPV) and lumpy skin disease virus (LSDV) causing sheep pox (SPP), goat pox (GTP) and lumpy skin disease (LSD) in small ru-minants and cattle respectively. LSD has emerged in Europe in 2015 and first incursions of SPP in the European Union were reported in Bulgaria and Greece in 2013. Live attenuated SPPV vaccines are widely used in many countries to control SPP and GTP. With the in-creasing number of reports on SPP in previously vaccinated sheep herds, it is imperative to develop new diagnostic tools for differen-tiation of SPPV field strains from attenuated vaccine strains. Objective This work aimed at identifying appropriate diagnostic targets to de-velop assays for the rapid and accurate differentiation SPPV vaccine strains from SPPV field isolates and other CaPVs. Methodology To identify a suitable molecular target for the development of these assays, the full genomes of several SPPV vaccines strains and SPPV field isolates were compared. A unique 84-base pair nucleotide dele-tion located between the DNA ligase and the B22R gene was exploit-ed to develop a gel-based PCR, and a region containing a 48bp de-letion within the B22R gene of SPPV vaccines strains only, as well as species-specific nucleotide difference between SPPV field isolates, GTPV and LSDV, was targeted to develop a HRM assay. Results The gel-based assay was readily able to differentiate SPPV vaccines from field isolates. However, this method alone could not differen-tiate SPPV field isolates from GTPV and LSDV. In contrast, the HRM based method allowed the differentiation of SPPV vaccines from field isolates and further enabled the genotyping of capripoxviruses isolates. Out of 61 samples tested, we identified 4 SPPV vaccines, 14 SPPV field isolates, 11 GTPVs and 32 LSDVs. The two assays were both sensitive and specific and in agreement with the sequencing data of the tested samples. Conclusion The assays described herein are reliable and rapid methods for the differentiation of SPPV Vaccines from SPPV field isolates. While the gel based assay needs to be combined with capripoxvirus spe-cies-specific assays, the HRM assay stands alone as a tool to differen-tiate SPPV vaccines from field isolates and simultaneously genotype SPPVs, GTPVs and LSDVs. The methods are suited for routine use during outbreak investigations in both capripoxvirus enzootic and disease-free countries.

International audience ; Peste des petits ruminants (PPR) is an acute, contagious viral disease of small ruminants, goats and sheep. The Democratic Republic of the Congo (DRC) was a PPR-free country until 2007, although in 2006, scare alerts were received from the east and the southwest of the country, reporting repeated mortalities, specifically in goats. In 2008, PPR outbreaks were seen in several villages in the west, leading to structured veterinary field operations. Blood, swabs and pathological specimens consisting of tissues from lungs, spleens, lymph nodes, kidneys, livers and hearts were ethically collected from clinically infected and/or dead animals, as appropriate, in 35 districts. Epidemiological information relating to major risk factors and socio-economic impact was progressively collected, revealing the deaths of 744,527 goats, which converted to a trade value of USD 35,674,600. Samples from infected and dead animals were routinely analyzed by the Central Veterinary Laboratory at Kinshasa for diagnosis, and after official declaration of PPR outbreaks by the FAO in July 2012, selected tissue samples were sent to The Pirbright Institute, United Kingdom, for genotyping. As a result of surveys undertaken between 2008 and 2012, PPR virus (PPRV)-specific antibodies were detected in 25 locations out of 33 tested (75.7%); PPRV nucleic acid was detected in 25 locations out of 35 (71.4%); and a typical clinical picture of PPR was observed in 23 locations out of 35 (65.7%). Analysis of the partial and full genome sequences of PPR viruses (PPRVs) obtained from lymphoid tissues of dead goats collected in Tshela in the DRC in 2012 confirmed the circulation of lineage IV PPRV, showing the highest homology (99.6−100%) with the viruses circulating in the neighboring countries of Gabon, in the Aboumi outbreak in 2011, and Nigeria (99.3% homology) in 2013, although recent outbreaks in 2016 and 2018 in the western part of the DRC that borders with East Africa demonstrated circulation of lineage II and lineage III ...

International audience ; Peste des petits ruminants (PPR) is an acute, contagious viral disease of small ruminants, goats and sheep. The Democratic Republic of the Congo (DRC) was a PPR-free country until 2007, although in 2006, scare alerts were received from the east and the southwest of the country, reporting repeated mortalities, specifically in goats. In 2008, PPR outbreaks were seen in several villages in the west, leading to structured veterinary field operations. Blood, swabs and pathological specimens consisting of tissues from lungs, spleens, lymph nodes, kidneys, livers and hearts were ethically collected from clinically infected and/or dead animals, as appropriate, in 35 districts. Epidemiological information relating to major risk factors and socio-economic impact was progressively collected, revealing the deaths of 744,527 goats, which converted to a trade value of USD 35,674,600. Samples from infected and dead animals were routinely analyzed by the Central Veterinary Laboratory at Kinshasa for diagnosis, and after official declaration of PPR outbreaks by the FAO in July 2012, selected tissue samples were sent to The Pirbright Institute, United Kingdom, for genotyping. As a result of surveys undertaken between 2008 and 2012, PPR virus (PPRV)-specific antibodies were detected in 25 locations out of 33 tested (75.7%); PPRV nucleic acid was detected in 25 locations out of 35 (71.4%); and a typical clinical picture of PPR was observed in 23 locations out of 35 (65.7%). Analysis of the partial and full genome sequences of PPR viruses (PPRVs) obtained from lymphoid tissues of dead goats collected in Tshela in the DRC in 2012 confirmed the circulation of lineage IV PPRV, showing the highest homology (99.6−100%) with the viruses circulating in the neighboring countries of Gabon, in the Aboumi outbreak in 2011, and Nigeria (99.3% homology) in 2013, although recent outbreaks in 2016 and 2018 in the western part of the DRC that borders with East Africa demonstrated circulation of lineage II and lineage III PPRV.

Background Lumpy Skin Disease (LSD), Sheeppox (SPP) and Goatpox (GTP) are contagious diseases of ruminants with a devastating impact on the livestock industry and trade, also affecting the living conditions of poor rural and small farmers. LSD, SPP, GTP were mainly confined to Africa, the Middle East and Asia, with some sporadic incursions of SPP in Greece and Bulgaria. However, in 2015 the first incursions of LSD occurred in the European Union. Due to their potential for rapid spreading, a highly sensitive and specific serological method for active and passive surveillance of SPP, GTP and LSD is needed. In addition, such a tool could serve for post-vaccination monitoring. Objective The aim of this work was to evaluate recombinants proteins of the capripoxvirus virion for use in an indirect ELISA (iELISA) to detect anti-capripox antibodies in vaccinated and naturally infected small ruminants and cattle sera. Method We have identified, characterized, expressed and purified capripox-virus virion surface protein (CVSP) that react to positive SPP, GTP and LSD sera samples by Western Blot and iELISA. The iELISA was further optimised and evaluated using sera samples from vaccinat-ed, experimentally and naturally infected sheep, goat and cattle. Results Twenty experimentally infected positive and 130 negative LSD, SPP and GTP sera samples were tested and correctly identified using the CVSP iELISA. We tested sera collected at multiple time points from several LSD experimentally infected animals. We observed a time dependant increased in anti-LSD antibody production after day 14 post infection. For specificity, five ORF positive sera were tested. None of the ORF positive sera was positive in the CVSP iELISA. A number of field sera collected during capripoxvirus outbreaks and vaccination campaigns from animals with known infection/vaccina-tion status were tested by the CVSP iELISA and compared to the virus neutralization assay. The complete dataset and results of the field test evaluation will be presented. Conclusion As capripox diseases spread, and to strengthen disease surveillance and control programmes, there is an ever-increasing need for rapid and effective antibody detection assays. The CVSP tested in the pres-ent study demonstrated to be good antigen candidates for the de-velopment of sensitive and specific serological assays. The prototype iELISA developed has the potential to be used as an effective and rapid method for capripoxvirus antibody detection in vaccinated, experimentally and naturally infected sheep, goat and cattle sera.

African swine fever (ASF) is a devastating disease of domestic pigs. It is a socioeconomically important disease, initially described from Kenya, but subsequently reported in most Sub-Saharan countries. ASF spread to Europe, South America and the Caribbean through multiple introductions which were initially eradicated—except for Sardinia—followed by re‑introduction into Europe in 2007. In this study of ASF within the Democratic Republic of the Congo, 62 domestic pig samples, collected between 2005–2012, were examined for viral DNA and sequencing at multiple loci: C-terminus of the B646L gene (p72 protein), central hypervariable region (CVR) of the B602L gene, and the E183L gene (p54 protein). Phylogenetic analyses identified three circulating genotypes: I (64.5% of samples), IX (32.3%), and XIV (3.2%). This is the first evidence of genotypes IX and XIV within this country. Examination of the CVR revealed high levels of intra-genotypic variation, with 19 identified variants.