Modification of PCV-2 virulence by substitution of the genogroup motif of the capsid protein

Porcine circovirus type 2 (PCV-2) is the causal agent of the post-weaning multisystemic wasting syndrome (PMWS). PCV-2 are small single-stranded circular DNA viruses clustered into two main genogroups: PCV-2a and PCV-2b. Each genogroup present a specific highly-conserved motif of six amino acids (between amino acids 86 and 91) in the PCV-2 capsid protein. The aim of this study was to verify whether the motif located in the capsid protein and specific to each PCV-2 genogroup contributes to virulence. Two parental DNA clones, PCV-2a and PCV-2b, were constructed as well as two mutants DNA clones, PCV-2a/motif 2b and PCV-2b/motif 2a by exchanging the capsid motif of each genogroup. The four DNA clones were characterized in vitro as well as in vivo. Cells transfected by the four DNA clones produced infectious viruses. In specific-pathogen-free piglets transfected by the four infectious DNA clones, PCV-2b/motif 2a virulence was not attenuated while the PCV-2a/motif 2b virulence was drastically reduced compared to their parent virulence. These results suggest that the amino acids between positions 86 and 91 of the capsid protein are determinant for the virulence of isolates. However, the environment of this motif seems also involved

Reproduction of PMWS in immunostimulated SPF piglets transfected with infectious cloned genomic DNA of type 2 porcine circovirus

Postweaning multisystemic wasting syndrome (PMWS) is a recently emerged disease affecting pigs. Type 2 porcine circovirus (PCV2) has been associated with this syndrome although other factors are required in association with this virus for PMWS expression. The aim of this study was to investigate whether general immunostimulation (injections of keyhole limpet hemocyanin emulsified in incomplete Freund adjuvant and of thioglycollate medium) could strengthen the severity of PMWS in six-week-old specific-pathogen-free (SPF) piglets transfected with pure tandem-cloned PCV2 DNA by the intramuscular route. Non-immunostimulated piglets transfected with the viral clone did not present clinical signs but only mild pathological microlesions characteristic of PMWS. These piglets seroconverted and high viral genome loads and infectious titers were detected in the lymphoid organs at the end of the trial. Mild-to-moderate forms of PMWS were generally observed in the immunostimulated transfected piglets, as well as one severe form for a piglet (8003) which died. These piglets with mild-to-moderate forms had higher DNA loads than the transfected-only animals. Thus, viral replication was enhanced by immunostimulation. This is the first time that clinical PMWS has been reported in an SPF immunostimulated piglet infected with a pure inoculum consisting of tandem-cloned PCV2 DNA. This result confirms that PCV2 is the agent of PMWS and that immunostimulation could enhance PMWS in SPF piglets transfected with a PCV2 DNA clone

Fungal protein produced on cassava for growing rats and pigs

This research is a nutritional assessment of a fungal (Aspergillus fumigatus 1-21A) single-cell protein (SCP) that was fed to rats and pigs. The sun-dried biomass resulted from fermentation of either fresh roots or cassava meal substrates and had the following percentage composition: crude protein (N x 6.25), 34.3; ether extract, 3.1; crude fiber, 20.0 ash, 4.3; N-free extract, 27.9; Ca, .20 and P, .79. The gross energy was 4,260 cal/g. An initial biological evaluation based on protein efficiency ratio (PER) and net protein ratio (NPR) methods was conducted using 70 growing rats. Growth responses in rats fed the dried product were similar to those produced by the casein control, provided the biomass was supplemented with DL-methionine. During the growing-finishing period (15.8 to 95.0 kg), pigs were given one of the following experimental diets: 1) control, sorghum + soybean meal (SBM), 2) cassava meal (CM) + SBM + .3% DL-methionine, 3) CM + SCP and 4) CM + SCP + .3% DL-methionine. Diets were calculated to supply 16 and 13% crude protein for the growing (15.8 to 50 kg) and finishing (50 to 95 kg) periods, respectively. The pigs fed the diet based on SCP without any methionine took longer (P<.05) to reach market weight and had poorer (P<.05) feed conversion than pigs fed the other diets. Supplementation with DL-methionine improved (P<.05) the nutritive quality of the fungal protein and the results were comparable to those obtained with diets based on SBM. The use of SCP as a total substitute for SBM did not affect the normal physical condition of the animals

MYOSITIS IN PATIENTS WITH PRIMARY SJÖGREN’S SYNDROME: DATA FROM A FRENCH NATIONWIDE SURVEY

International audienc

Diagnosis and treatment of Tropheryma whipplei infection in patients with inflammatory rheumatic disease: Data from the French Tw-IRD registry

International audienceTropheryma whipplei infection can manifest as inflammatory joint symptoms, which can lead to misdiagnosis of inflammatory rheumatic disease and the use of disease -modifying antirheumatic drugs. We investigated the impact of diagnosis and treatment of Tropheryma whipplei infection in patients with inflammatory rheumatic disease. Methods: We initiated a registry including patients with disease -modifying antirheumatic drugs -treated inflammatory rheumatic disease who were subsequently diagnosed with Tropheryma whipplei infection. We collected clinical, biological, treatment data of the inflammatory rheumatic disease, of Tropheryma whipplei infection, and impact of antibiotics on the evolution of inflammatory rheumatic disease. Results: Among 73 inflammatory rheumatic disease patients, disease-modifying antirheumatic drugs initiation triggered extra-articular manifestations in 27% and resulted in stabilisation (51%), worsening (34%), or improvement (15%) of inflammatory rheumatic disease. At the diagnosis of Tropheryma whipplei infection, all patients had rheumatological symptoms (mean age 58 years, median inflammatory rheumatic disease duration 79 months), 84% had extra-rheumatological manifestations, 93% had elevated C-reactive protein, and 86% had hypoalbuminemia. Treatment of Tropheryma whipplei infection consisted mainly of doxycycline plus hydroxychloroquine, leading to remission of Tropheryma whipplei infection in 79% of cases. Antibiotic treatment of Tropheryma whipplei infection was associated with remission of inflammatory rheumatic disease in 93% of cases and enabled disease-modifying antirheumatic drugs and glucocorticoid discontinuation in most cases. Conclusions: Tropheryma whipplei infection should be considered in inflammatory rheumatic disease patients with extra-articular manifestations, elevated C-reactive protein, and/or hypoalbuminemia before disease-modifying antirheumatic drugs initiation or in inflammatory rheumatic disease patients with an inadequate response to one or more disease-modifying antirheumatic drugs. Positive results of screening and diagnostic tests for Tropheryma whipplei infection involve antibiotic treatment, which is associated with complete recovery of Tropheryma whipplei infection and rapid remission of inflammatory rheumatic disease, allowing disease-modifying antirheumatic drugs and glucocorticoid discontinuation. (c) 2023 The Authors. Published by Elsevier Ltd on behalf of The British Infection Association