New Information on the Aerobiology and Biosecurity of PRRSV and Mycoplasma hyopneumoniae - Dr. Scott Dee, D.V.M , University of Minnesota, at the Boehringer Ingelheim Vetmedica, Inc. Swine Health Seminar, August 15, 2009, Carolina Beach, North Carolina, USA.

1. New Information on the Aerobiology
and Biosecurity of PRRSV and
Mycoplasma hyopneumoniae.
S Dee, A Pitkin, S Otake, S Oliveira, J Deen, P Davies, S Pohl
G Spronk, D Reicks, P Ruen

2. Disclosure and Acknowledgements
 USDA NRI PRRS CAP 1 and 2
 National Pork Board
 MN Pork Board
 MN Rapid Agricultural Response Fund
 Boehringer-Ingelheim
 Genetiporc
 Preserve International
 MN Veterinary Diagnostic Laboratory
 Midwest Microtek
 Filtration Systems, Inc.

3. SDEC partners
 Corporate members  Practice members
 PIC  Pipestone Vet Clinic
 Genetiporc  Fairmont Vet Clinic
 Boehringer-Ingelheim  Swine Vet Center
 Pfizer  Clinique Demeter
 Novartis
 Vet Provisions
 Noveko
 Camfil Farr
 Bayer
 Japanese Association of
Swine Veterinarians

4. Disclosure
 I do not
 Receive royalties or commissions on the sales of
filters or filtration equipment.
 Hold any patents on filtration inventions.
 Have research contracts or consulting
agreements/retainers with filtration/equipment
companies.
 Use monetary contributions from filtration
companies to conduct filtration-based research

5. Agenda for today
 1. Transmission and biosecurity of PRRSV and M hyo (Yr 3)
 2. Long distance airborne transport of PRRSV and M hyo
 3. Evaluation of air filtration in large sow herds in swine dense
regions
 4. New developments in air filtration equipment and technology

6. Project 1: Transmission and biosecurity of PRRSV
and Mycoplasma hyopneumoniae (Year 3)
 Modifications from year 2
 Mechanical filter facility
 Substitute MERV 14 (EU8) for MERV 16 (EU9)
 75% efficient vs. 95% efficient
 33% cost reduction
 Better airflow
 Antimicrobial filter facility
 Chemicals impregnated into filter fabric
 Operates on “contact kill” principle

7. Year 3: Production Region Model
Source Population
PRRSV MN-184
M hyo 232
120 m
Treatmen Treatmen Control
t t
1 2

8. Year 3: 9 month summary
 MERV 14
 No airborne transport or transmission detected
 183 air samples collected: all PCR negative for both agents
 Antimicrobial
 PRRSV and M hyo airborne transport detected in 17/183 air samples
 12 PRRSV PCR (+) samples
 5 M hyo PCR (+) samples
 No transmission observed
 Non-filtered
 Airborne transport and transmission detected in 7/9 replicates
 Replicate 14: negative
 Replicate 15: PRRSV
 Replicate 16: M hyo
 Replicate 17: PRRSV & M hyo
 Replicate 18: PRRSV
 Replicate 19: PRRSV & M hyo
 Replicate 20: PRRSV
 Replicate 21: negative
 Replicate 22: PRRSV

9. Meteorological data (means) recorded during
detection of PRRSV and M hyo in the air
Parameter PRRSV (37 days) M hyo (20 days)
Pressure (hPa) 982 982
Temp (C) -3.0 -5.0
RH (%) 86 82
Wind speed/gusts (m/s) 2.0/3.0 1.0/1.0
Wind direction 2680 2940
Solar (watts) 64 107
Solar (photons) 178 294

10. Preliminary observations
 The “region” is under heavy challenge.
 Both types of filters are preventing infection.
 The study will conclude in 11/09.
 New Assessment (1/09-6/10):
 MERV 11
 2-year old antimicrobial

11. 952 days down, 259 days to go!

12. Project 2: Long distance airborne transport
of PRRSV and M hyo
 Objective
 Provide evidence of PRRSV and M hyo in air
samples collected at long distances from an
infected source population.
 Hypothesis:
 Long-distance airborne transport of both
organisms can occur given the proper conditions.

14. Sampling area landscape

16. T ½ of PRRSV in aerosols (Hermann, Vet Res, 2009)
 Use equation to predict whether an aerosol
could transport infectious virus 4.7 km:
 At 7.10 C and 89% RH:
 The T1/2 of PRRSV in an aerosol would be 74
minutes
 At 3 m/s wind velocity:
 The virus-laden aerosol would travel the 4.7 km
distance in 26 minutes

18. Conclusions
 1. Airborne transport of PRRSV
and M hyo was documented out
to 4.7 km.
 2. The organisms recovered
were homologous to those
present in the source population.
 3. Infectious PRRSV was
present at 4.7 km.

19. Project 3: Efficacy of air filtration in large sow
herds in swine-dense regions
 Project Participants:
 UMN, SDSU, PVC, FVC, SVC
 Selection criteria:
 > 2400 sows
 > 3 external virus introductions over the past 4 years
 > 4 pig sites within 4.7 km radius of candidate herd
 Industry standard biosecurity
 Duration of study:
 4 years
 Outcomes measured:
 External virus introduction
 Cost-benefit

20. Year 1: 9/08-8/09
 1. Team building
 Universities, practices, financing program established
 2. Selection of farms
 10 treatment farms & 21 control farms at this time
 3. Installation of filtration systems
 4 farms under 100% filtration since 9/2008
 6 farms to filter this summer
 4. Monthly biosecurity audits and diagnostic testing
to assess external virus introduction
 PCR and ORF 5 sequencing

21. Characteristics of filtered and non-filtered farms
 Treatments (n=10)  Controls (n=21)
 BH Inventory  BH Inventory
 Mean = 2721 sows  Mean = 3329 sows
 Range = 2402-3827  Range = 2506-5578
 External virus introduction  External virus introduction
 Mean = 1 every 13.1 mths  Mean = 1 every 12.8 mths
 Range = 1 every 8-15 mths  Range = 1 every 11-13
mths
 # sites within 4.7 km
 Mean = 8  # sites within 4.7 km
 Range = 4-17  Mean = 8
 Range = 4-13

22. Ceiling inlets after filtration boxes installed

24. Observations: 9/08-8/09
 1. No external virus introductions in any of
the 4 filtered farms.
 2. External virus introductions in 13 of 21
control farms.
 3. Improved performance.

25. Kaplan-Meier plot of survival of herds between PRRS
breaks
Filtered
Control
Prefiltered
Months

26. 4. New developments
 1. A new filter candidate on the market
 2. A tool to reduce the risk of back drafting of
air through idle fans
 3. The effect of filter damage on virus
penetration

27. Dual chamber model (Dee et al, Vet Microbiol, 2009)

28. 1. New filter candidate
 Clarcor
 Electrostatic charged polypropylene media
 MERV 16 rating
 Virus challenge
 Tests as MERV 16 when charged
 Tests as MERV 14 when discharged
 Air flow
 Tests as MERV 14 when discharged
 (S. Pohl, SDSU)

29. 2. Back drafting: AP Dual shutter

30. 3. Effect of filter damage on virus
penetration
 Occurs during installation
 4 degrees of damage
 Mild
 Shallow finger depressions
 Moderate
 Laceration
 Severe
 Deep finger depressions
 Rodent
 Holes

32. Take Home Messages
 1. PRRSV can be transported over long
distances via the airborne route.
 2. Air filtration is an effective tool for the
control of airborne diseases in swine-dense
regions.
 Technological advancements have been made.
 3. For the first time in 20+ years we actually
can prevent PRRSV transmission between
farms.