Dr. Scott Dee - New Information on the Aerobiology and Biosecurity of PRRSV and Mycoplasma...
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Transcript of Dr. Scott Dee - New Information on the Aerobiology and Biosecurity of PRRSV and Mycoplasma...
New Information on the Aerobiologyand Biosecurity of PRRSV andMycoplasma hyopneumoniae.
S Dee, A Pitkin, S Otake, S Oliveira, J Deen, P Davies, S Pohl G Spronk, D Reicks, P Ruen
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.
SDEC partners
Corporate members PIC Genetiporc Boehringer-Ingelheim Pfizer Novartis Vet Provisions Noveko Camfil Farr Bayer Japanese Association of
Swine Veterinarians
Practice members Pipestone Vet Clinic Fairmont Vet Clinic Swine Vet Center Clinique Demeter
Disclosure I do not
Receive royalties or commissions on the sales offilters or filtration equipment.
Hold any patents on filtration inventions.
Have research contracts or consultingagreements/retainers with filtration/equipmentcompanies.
Use monetary contributions from filtrationcompanies to conduct filtration-based research
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 denseregions
4. New developments in air filtration equipment and technology
Project 1: Transmission and biosecurity of PRRSVand 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
Year 3: Production Region Model
Source PopulationPRRSV MN-184
M hyo 232
120 m
Treatment 1
Treatment 2
Control
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
Meteorological data (means) recorded duringdetection of PRRSV and M hyo in the air
Parameter PRRSV (37 days) M hyo (20 days)Pressure (hPa) 982 982Temp (C) -3.0 -5.0RH (%) 86 82Wind speed/gusts (m/s) 2.0/3.0 1.0/1.0Wind direction 2680 2940
Solar (watts) 64 107Solar (photons) 178 294
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
952 days down, 259 days to go!
Project 2: Long distance airborne transportof PRRSV and M hyo
Objective Provide evidence of PRRSV and M hyo in air
samples collected at long distances from aninfected source population.
Hypothesis: Long-distance airborne transport of both
organisms can occur given the proper conditions.
Sampling area landscape
T ½ of PRRSV in aerosols (Hermann, Vet Res, 2009)
Use equation to predict whether an aerosolcould 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
Conclusions 1. Airborne transport of PRRSV
and M hyo was documented outto 4.7 km.
2. The organisms recoveredwere homologous to thosepresent in the source population.
3. Infectious PRRSV waspresent at 4.7 km.
Project 3: Efficacy of air filtration in large sowherds 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
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 testingto assess external virus introduction
PCR and ORF 5 sequencing
Characteristics of filtered and non-filtered farms
Treatments (n=10) BH Inventory
Mean = 2721 sows Range = 2402-3827
External virus introduction Mean = 1 every 13.1 mths Range = 1 every 8-15 mths
# sites within 4.7 km Mean = 8 Range = 4-17
Controls (n=21) BH Inventory
Mean = 3329 sows Range = 2506-5578
External virus introduction Mean = 1 every 12.8 mths Range = 1 every 11-13
mths
# sites within 4.7 km Mean = 8 Range = 4-13
Ceiling inlets after filtration boxes installedCeiling inlets after filtration boxes installed
Observations: 9/08-8/09
1. No external virus introductions in any ofthe 4 filtered farms.
2. External virus introductions in 13 of 21control farms.
3. Improved performance.
Kaplan-Meier plot of survival of herds between PRRSbreaks
Filtered
Control
Prefiltered
Months
4. New developments
1. A new filter candidate on the market
2. A tool to reduce the risk of back drafting ofair through idle fans
3. The effect of filter damage on viruspenetration
Dual chamber model (Dee et al, Vet Microbiol, 2009)
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)
2. Back drafting: AP Dual shutter
3. Effect of filter damage on viruspenetration Occurs during installation
4 degrees of damage Mild
Shallow finger depressions Moderate
Laceration Severe
Deep finger depressions Rodent
Holes
Take Home Messages
1. PRRSV can be transported over longdistances via the airborne route.
2. Air filtration is an effective tool for thecontrol of airborne diseases in swine-denseregions. Technological advancements have been made.
3. For the first time in 20+ years we actuallycan prevent PRRSV transmission betweenfarms.