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.