Additional file 1: of Outbreak tracking of Aleutian mink disease virus (AMDV) using partial NS1 gene sequencing

Supplementary material_phylogenetic tree. (PDF 1433 kb

Transmission of different variants of PCV2 and viral dynamics in a research facility with pigs mingled from PMWS-affected herds and non-affected herds

International audiencePostweaning Multisystemic Wasting Syndrome (PMWS) has been identified in most swine-producing countries worldwide. The disease has resulted in significant health challenges and economic damage to the swine industry. The aim of this study was to determine horizontal transmission of porcine circovirus type 2 (PCV2) and to examine viral dynamics in pigs in a controlled PMWS transmission study. In the study pigs from PMWS-affected herds and non-affected herds were permitted to have close contact (same pen), nose-to-nose contact (to pigs in neighbouring pens) or no physical contact (pen across the aisle and pens in other compartments). By DNA sequence analysis, eight variants of genotype PCV-2b were identified in the research facility. From the spread of these PCV2-variants it was concluded that PCV2 primarily infects through direct contact and nose-to-nose contact. PCV2 genome sequences were obtained from selected pigs at arrival to the research facility and again when the same pigs developed PMWS. This analysis showed that pigs from PMWS-affected herds developed PMWS caused by the same variant of PCV2 as they carried when entering the research facility. In contrast, pigs from non-affected herds developed PMWS with PCV2-variants identified in pigs from PMWS-affected herds. This was probably connected to at least 10 higher mean serum-titer of PCV2 in pigs from PMWS-affected herds as compared to pigs from non-affected herds at the beginning of the transmission study. The study further showed that pigs able to control the PCV2-infection, as measured by the PCV2-titer in serum, recovered clinically (pigs from PMWS-affected herds) or stayed healthy (pigs from non-affected herds). Like this, pigs with a PCV2 titer below 5×10 copies/ml serum during the study period had a chance of recover from the PCV2 infection whereas pigs with PCV2 titers above 5×10 copies/ml serum at any time point generally died from PMWS

Pig major acute-phase protein and haptoglobin serum concentrations correlate with PCV2 viremia and the clinical course of postweaning multisystemic wasting syndrome

International audienceThe aim of the present longitudinal study was to assess the evolution of two acute phase proteins (APPs), pig-major acute phase protein (pig-MAP) and haptoglobin (HPT), in serum from pigs that developed postweaning multisystemic wasting syndrome (PMWS) in comparison to healthy and wasted non-PMWS affected pigs. In addition, evidence of infection with other pathogens and its relation with variations in APPs concentrations was also assessed. Fourteen independent batches of 100 to 154 pigs were monitored from birth to PMWS outbreak occurrence in 11 PMWS affected farms. Pigs displaying PMWS-like signs and age-matched healthy controls were euthanized during the clinical outbreak. PMWS was diagnosed according to internationally accepted criteria and pigs were classified as: (i) PMWS cases, (ii) wasted non-PMWS cases and iii) healthy pigs. At the moment of PMWS occurrence, pig-MAP and HPT concentration in PMWS affected pigs were higher than in healthy ones (<0.0001). No differences in APPs serum concentrations between subclinically PCV2 infected pigs and healthy non-PCV2 infected pigs (based on quantitative PCR on serum results) were detected. Results showed a significant correlation between PCV2 loads and both pig-MAP (=0.487 to 0.602, <0.0001) and HPT (=0.326 to 0.550, <0.05 to 0.0001) concentrations in serum of PMWS affected pigs, indicating that the acute phase response in PMWS affected pigs occurred concomitantly to PCV2 viremia. No other pathogen, apart from PCV2, was consistently related with variations in APPs concentrations. A ROC analysis, made to determine the capacity of discrimination of both APPs between PMWS affected and non-affected pigs, showed higher sensitivity and specificity values using pig-MAP compared to HPT. These results suggest that pig-MAP might be a better indicator of PMWS status than HPT. Moreover, the fact that APR occurred some days before the start of clinical signs suggests that APPs could provide valuable prognostic information for PMWS development

The use of quantitative PCR for identification and quantification of Brachyspira pilosicoli, Lawsonia intracellularis and Escherichia coli fimbrial types F4 and F18 in pig feces

International audienceFour quantitative PCR (qPCR) assays were evaluated for quantitative detection of and fimbrial types F4 and F18 in pig feces. Standard curves were based on feces spiked with the respective reference strains. The detection limits from the spiking experiments were 10 bacteria/g feces for Bpilo-qPCR and Laws-qPCR, 10 CFU/g feces for F4-qPCR and F18-qPCR. The PCR efficiency for all four qPCR assays was between 0.91 and 1.01 with R above 0.993. Standard curves, slopes and elevation, varied between assays and between measurements from pure DNA from reference strains and feces spiked with the respective strains. The linear ranges found for spiked faecal samples differed both from the linear ranges from pure culture of the reference strains and between the qPCR tests. The linear ranges were five log units for F4-qPCR, and Laws-qPCR, six log units for F18-qPCR and three log units for Bpilo-qPCR in spiked feces. When measured on pure DNA from the reference strains used in spiking experiments, the respective log ranges were; seven units for Bpilo-qPCR, Laws-qPCR and F18-qPCR and six log units for F4-qPCR. This shows the importance of using specific standard curves, were each pathogen is analyzed in the same matrix as sample DNA. The qPCRs were compared to traditional bacteriological diagnostic methods and found to be more sensitive than cultivation for and . The qPCR assay for was also more sensitive than the earlier used method due to improvements in DNA extraction. In addition, as samples were not analyzed for all four pathogen agents by traditional diagnostic methods, many samples were found positive for agents that were not expected on the basis of age and case history. The use of quantitative PCR tests for diagnosis of enteric diseases provides new possibilities for veterinary diagnostics. The parallel simultaneous analysis for several bacteria in multi-qPCR and the determination of the quantities of the infectious agents increases the information obtained from the samples and the chance for obtaining a relevant diagnosis