Efficiency of different air filter types for pig facilities at laboratory scale

PLoS One. 2017 Oct 13;12(10):e0186558. doi: 10.1371/journal.pone.0186558. eCollection 2017.

Abstract

Air filtration has been shown to be efficient in reducing pathogen burden in circulating air. We determined at laboratory scale the retention efficiency of different air filter types either composed of a prefilter (EU class G4) and a secondary fiberglass filter (EU class F9) or consisting of a filter mat (EU class M6 and F8-9). Four filter prototypes were tested for their capability to remove aerosol containing equine arteritis virus (EAV), porcine reproductive and respiratory syndrome virus (PRRSV), bovine enterovirus 1 (BEV), Actinobacillus pleuropneumoniae (APP), and Staphylococcus (S.) aureus from air. Depending on the filter prototype and utilisation, the airflow was set at 1,800 m3/h (combination of upstream prefilter and fiberglass filter) or 80 m3/h (filter mat). The pathogens were aerosolized and their concentration was determined in front of and behind the filter by culture or quantitative real-time RT-PCR. Furthermore, survival of the pathogens over time in the filter material was determined. Bacteria were most efficiently filtered with a reduction rate of up to 99.9% depending on the filter used. An approximately 98% reduction was achieved for the viruses tested. Viability or infectivity of APP or PRRSV in the filter material decreased below the detection limit after 4 h and 24 h, respectively, whereas S. aureus was still culturable after 4 weeks. Our results demonstrate that pathogens can efficiently be reduced by air filtration. Consequently, air filtration combined with other strict biosecurity measures markedly reduces the risk of introducing airborne transmitted pathogens to animal facilities. In addition, air filtration might be useful in reducing bioaerosols within a pig barn, hence improving respiratory health of pigs.

MeSH terms

  • Air Filters / microbiology*
  • Air Microbiology*
  • Animals
  • Bacteria / isolation & purification
  • Kinetics
  • Laboratories*
  • Swine*
  • Viruses / isolation & purification

Grants and funding

This project was funded in part from a special purpose fund of the German federal government/Federal Ministry of Food and Agriculture by the Landwirtschaftliche Rentenbank (University of Leipzig grant number 741 120/1 and REVENTA® GmbH grant number 742 393/1). The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.