Elimination of Influenza A from Sow Herds

Leman ConferenceSeptember 19, 2016

R Thompson, L Coleman, M Culhane

Introduction

• Successful IAV elimination is possible with sow herd closure

• A biosecure location or filtered sow farm• Double vaccination of all animals on site with a

matched vaccine• Diversion of weaned pig flow is required with an on-site

GDU• Estimate 10 weeks from the initial vaccination to

comfortably wean negative pigs on-site • With an on-site full GDU estimate 22 weeks to have all

inventory back in the herd

Introduction• Single IAV subtypes eliminated in multiple 5,600s filtered

& non-filtered F/W sow farms• Farms remained IAV negative for 24 months• Tested weekly with oral fluid PCRs• Negative gilt replacements vaccinations optional pre-breeding• No sow herd vaccination for IAV-S

• One 5,600 F/W sow farm project incorporated elimination in an additional 15,000 commercial sow farms

• Employees take temperature daily prior to entry• Two subtype IAV elimination in a 11,200 F/W sow farm• Single subtype elimination in a filtered 5,600 F/W sow

farm leaking virus in weaned pigs with no clinical signs on-site

Elimination Protocol

• Monitoring the herd of interest or weaned pig flow with oral fluids or nasal swabs

• Isolation of the subtypes - nasal swabs the best• Monitor the population with PCRs & identify subtypes if

positive• Sequence the PCR positives and compare to

commercial vaccines or create an autogenous vaccine• Develop an action plan with the production team to

establish timelines for the different steps.• Initial step starts with the first whole herd vaccination

Dates: 7/13/2015 7/20/2015 7/27/2015 8/3/2015 8/10/2015 8/17/2015 8/24/2015 8/31/2015

Week 29 30 31 32 33 34 35 36

Sow Herd

Whole herd vaccination with Harris IAV vaccine

Booster entire sow herd

Farrowing & Nursery

McRebel implemented in farrowing

Wean replacement gilts to W/F; No additional gilts weaned on-site

Sow Farm testing

Collected nasal swabs from 15 gilts per room in on-site nursery

Collect 30 nasal swabs each from the oldest two rooms in lactation

Collect 30 nasal swabs each from the oldest two rooms in lactation

Collect 30 nasal swabs each from the oldest two rooms in lactation

Dates: 7/20/2015 7/27/2015 8/3/2015 8/10/2015 8/17/2015 8/24/2015 8/31/2015Week 30 31 32 33 34 35 36

Gilt Movements

All gilt replacements to W/F

As replacement gilts staying on-site move from the nursery to the GDU they will be given two vaccinations three weeks apart when a GDU room is full.

As replacement gilts staying in GJW move from the nursery to the GDU they will be given two vaccinations three weeks apart when a GDU room is full.

As replacement gilts staying in GJW move from the nursery to the GDU they will be given two vaccinations three weeks apart when a GDU room is full.

Nursery empty

Jones W/F Receive N Lot 27 Receive N Lot 28

Receive N Lot 30

Receive N Lot 31

Receive N Lot 32

Receive N Lot 33

Receive N Lot 34

IAV PCR testing 2 ropes per room

IAV PCR testing 2 ropes per room

IAV PCR testing 2 ropes per room

IAV PCR testing 2 ropes per room

IAV PCR testing 2 ropes per room

IAV PCR testing 2 ropes per room

IAV PCR testing 2 ropes per room

Protocol continued

• No vaccine used in on-site nursery• Implement strict McRebel in farrowing Week 1• Start weaning replacement gilts off-site Week 2• Second whole herd vaccination 3 weeks later• Nasal swabs, 30 each in oldest two farrowing rooms

Week 6 & 8• As replacement gilts in the on-site nursery moved to

the GDU, when the room was full, received 2 vaccinations

• On-site nursery depopulated, washed, disinfected and dried

• Minimum of 2 weeks downtime in the nursery rooms

Protocol continued

• With negative PCR results from previous weeks in oldest farrowing rooms, Week 10 start weaning on-site.

• Stop weaning to the off-site W/F • In W/F site allow the virus to circulate naturally• Monitor circulation with oral fluids, 2 ropes per room• Seven weeks after W/F closure vaccinate the entire site

(15 weeks after initial sow herd vaccination)• Replacement gilts receive two doses of the autogenous

vaccine 5 and 2 weeks prior to returning to the sow farm.

• The entire population at the sow farm was boostered for a third time two weeks prior to the off-site gilts returning to the sow herd.

Diagnostic Background

• Isolates H1, H3 & H1H3/N1N2, H1p

• Sequenced the isolates• H3 and H1 antigens used to create a bivalent vaccine• Verified sequence homology prior to whole herd

vaccinations• Verified sequence homology a second time, all amino

acids are still the same• In the bivalent herd, only the H3N2 subtype was being

isolated at the time of whole herd vaccination in W/F sites.

Recent Case

• Isowean customer complaint – gilts coughing off truck at delivery – April ‘16

• Cough had spread through the nursery• No clinical signs at source farm in sows or suckling pigs• 3/17/16 - Nasal swabs 4 wk. gilts PCR (-)• 4/13/16 - Nasal swabs 1/5 pools PCR (+) @ 32.2CT• 5/12/16 - Nasal swabs 3/5 PCR (+), 1 Suspect• Sequenced virus H1N1p

• 97.5% homology to Zoetis Pandemic• Fabio – Compared with antigen match – 1 amino acid

difference• Cross HI comparison 1:320 dilution

Case Study

• Week 24 - 1st whole herd vaccination• Week 25 McRebel in farrowing• Week 27 – 2nd whole herd vaccination• Week 28 - weaned down to 16 days of age & emptied

on-site nurseries• Off-site GDU – vaccinate whole rooms for 8 weeks• Sow herd ELISA serology April ‘16 100% positive• Mid- July weaned pigs PCR (-) nasal swabs

Questions?