The International Pig Veterinary Society (IPVS) is an association of pig health and production specialists founded in 1967. Since 1972, congresses have been held every other year. Recently, the 27th IPVS Congress was held in Leipzig, Germany. The 28th Congress is scheduled for Ho Chi Minh City, Vietnam in 2026, and the 29th Congress is scheduled for Minneapolis, United States in 2028. The objectives of the IPVS are 1) the holding of international congresses for the exchange of knowledge related to pig health and production; and 2) the promotion of the formation of Pig Veterinary Societies in all pig-producing countries and the promotion of cooperation between such societies. We have selected some examples of the work presented at the recent IPVS and share them with you on this and last week’s science page.
Implementing A Modified Air Washing System To Prevent Bioaerosol Emission From The Exhaust Air Of Pig Barns
N. Volkmann1, N. Lisa1, N. Kemper1, J. Schulz1, 1. University of Veterinary Medicine Hannover
Background and Objectives: The air of pig fattening farms contains high amounts of bioaerosols, ammonia and dust. Usually, the primary purpose of exhaust air treatment is the reduction of ammonia, dust and odor. Since dust is reduced by washing or by passing biofilters, exhaust air treatment additionally has the potential to reduce bioaerosol concentrations. This study aimed to investigate the reduction of potentially harmful bioaerosol contents by an exhaust air washer with multiple cleaning stages in a field study.
Material and Methods: Air samples were taken with impingers from a three-stage-system (stage 1 washer, stage 2 chemical washer, stage 3 biofilter) installed at a finisher barn. The third stage was a modified biofilter, half filled with wood chips (WC) and half with paper pads (PP). Air samples were taken by impingement. Concentrations of bacteria, Streptococci and endotoxins were measured in the untreated air, behind stage 2 and behind both biofilter materials, each. To compare the differences of filtration performance between the stages, a Wilcoxon rank sum test was conducted.
Results: The average concentration of mesophilic bacteria in the barn air was 5.47 log10cfu/m³. This concentration was reduced to -1.4 log10cfu/m³ behind PP and to -1.6 log10cfu/m³ behind WC. Similar reduction efficiencies were achieved for Streptococci (mean: 4.5 log10cfu/m³, behind PP: -1.5 log10cfu/m³, behind WC: -1.6 log10cfu/m³) and endotoxins (mean: 2.7 log10EU/m³, behind PP: -0.9 log10EU/m³, behind WC: -1.2 log10EU/m³). Reductions behind PP differed significantly from WC. Significant differences between bacterial and endotoxin contents were also found in comparison of the second and third filter stages.
Discussion and Conclusion: The results showed that the treatment with a three-stage-system can reduce the examined bioaerosol contents efficiently (>80%). Humans, animals and nature in the vicinity of barns are less exposed to harmful bioaerosols when such systems are installed. Thus, this treatment contributes to prevention in line with the One Health principle. The project was supported by funds of the Federal Ministry of Food and Agriculture (BMEL) based on a decision of the parliament of the Federal Republic of Germany via the Federal Office for Agriculture and Food (BLE) under the innovation support program.
Recommendations For Sampling And Shipment Of Materials For PCR-Tests For Surveillance Of PRRS-Virus In Danish Herds
E.O. Nielsen1, L.K. Kvisgaard2, C.K. Hjulsager3, A. Droce4, L.E. Larsen5, 1. SEGES Innovation P/S, Denmark; 2. University of Copenhagen, Denmark; 3. Statens Serum Institute, Denmark; 4. L&F Diagnostic laboratory, Denmark; 5. University of Copenhagen, Denmark
Background and Objectives: A program to reduce the prevalence of porcine reproduction and respiratory syndrome (PRRS) in Denmark was initiated in 2022. The efforts to eliminate PRRS-virus demands more RT-qPCR-tests for PRRSV using a variety of sample materials including non-invasive samples like Processing Fluid (PF), Tongue Tip Fluid (TTF), and oral fluid (OF). The aim of the project was to develop validated recommendations for optimal collection, storage and transport of the different sampling material for PRRSV detection to avoid false negative test results.
Material and Methods: The influence of storage temperature and time on the decay of PRRSV RNA in OF and PF was tested by spike of negative sampling material with a PRRSV-1 cell culture isolate. The spiked materials were stored at a combination of different temperatures and times and finally extracted viral RNA was tested by RT-qPCR to monitor the impact of the different processes.
Results: The results showed that storage of serum, OF and PF at 40C; -200C and -800C for up to 30 days had limited impact on the Cq value of the RT-qPCR. One round of freeze-thaw had limited impact of the Cq value whereas 2-3 rounds had a more pronounced negative effect especially on OF samples. In contrast, storage at room temperature (RT) for just one day resulted in a significant increase in Cq values for all sampling materials, showing a severe impairment of detection of PRRS-virus.
Discussion and Conclusion: Correct handling of samples for PCR analyses are essential to avoid false-negative test results. Based on the results of this study we recommend that PF and TTF samples should be frozen at – 20 0C immediately after sampling and then be thawed at a temperature not exceeding 4-8 0C before the fluid is collected. Previously, we also detected a relative pronounced negative impact of storage of serum at RT and therefore we recommend keeping all samples for RT-qPCR cooled as soon as possible after sampling. Samples should also be kept cooled during transportation to the laboratory and therefore styrofoam cool box and ice packs are advised for all types of material.