Evaluation of the efficacy of one dose of autogenous MJPRRS vaccine in

nursery pigs

Dr. Mark Wagner, DVMFairmont Veterinary Clinic

Fairmont, MN

Purpose of study

• Gain a better understanding of the role and efficacy of using the autogenous MJPRRS vaccine in controlling or managing PRRS virus

Trial data to be presented

• Trial #1– Vaccination of PRRS naïve pigs at 21 days of age

and challenge with field virus at 32 days post vaccination

• Trial #2– Similar repeat of trial #1, pigs challenged at 28

days post vaccination

• Trial #3– Vaccination of PRRS viremic pigs at peak viremia

Trial design

• Challenge material– Virulent field virus with a 1-18-2 RFLP

• Group D-4 under MJPRRS virus grouping system

• Preparation of virus material– A 21 day old PRRS naïve pig inoculated with the 1-18-2 field virus– Serum collected 5 days post inoculation and frozen– An aliquot of serum inoculated on cell culture and

harvested 7 days later, then frozen

Trial design

• Analysis of challenge material– Sequencing completed to confirm 1-18-2 virus– Quantitative PRRS PCR’s completed along with

TCID50’s

Inoculum material

ORF6-copies per ml

Calculated IVP’s per ml TCID50

Serum 109 2,341 102

Cell Culture 1010 24,416 103

Trial design

• Challenge dose– Trial #1• 0.5ml IM plus 0.5ml IN (serum material = 100 viruses) (culture material = 1,000 viruses)

– Trial #2• 0.5ml IM plus 0.5ml IN (culture material = 1,000 viruses)

– Trial #3• 0.05ml IM plus 0.5ml IN (serum material = 55 viruses)

Trial design

• Vaccination protocol– Treatment group• MJPRRS

– 2ml dose that included 10% extra adjuvant (final 20%)• Mycoplasma

– 2ml dose

– Control groups• Mycoplasma

– 2ml dose

Trial design

• Data collection included– Body temperature– Virus replication based on PRRS Q-PCR’s– Mortality– Average daily gain weight

PRRS virus replication data:

Data compiled for Trial #1, Trial #2, and Trial #3

Summary PRRS virus replication in MJPRRS vaccinated compared to non-vaccinated 21 day old PRRS naïve pigs when challenged to

a field virus at 53 and 49 days old (Trial #1 & #2 data)

Serum Challenged Culture Challenged

Days Post Challenge

Vaccinated Non–Vaccinated Vaccinated Non–Vaccinated

ORF6 copies* IVP# ORF6 copies IVP ORF6 copies IVP ORF6 copies IVP

51.8 x 109 704 2.8 x 109 1,118 1.3 x 109

--------------9.3 x 108

674-----------

367

2.2 x 109

---------------8.4 x 108

867----------

328

116.4 x 107 25 2.7 x 108 106 1.1 x 108

--------------4.2 x 107

44-----------

16

2.1 x 108

---------------7.2 x 107

83----------

28

235.4 x 105 0.21 2.0 x 106 0.79 2.2 x 106

--------------5.1 x 106

0.88-----------

1.9

1.4 x 106

---------------2.1 x 106

0.50----------

0.80

* ORF6 Copies per ml by Quantitative PCR# Infective Virus Particles calculated per ml based on Q-PCR

Summary of PRRS virus replication in 26 day old PRRS viremic pigs vaccinated with MJPRRS vaccine at the peak of

viremia compared to non-vaccinated controls (Trial #3 data)

Serum Challenged then Vaccinated Non-Vaccinated

ORF6 Copies* IVP# ORF6 Copies IVP

5 Days post challenge(Day of vaccination) 3.5 x 109 1,355 3.3 x 109 1,144

7 Days post challenge(2 Days post vaccination) 5.2 x 109 2,079 5.6 x 109 2,215

14 Days post challenge(7 Days post vaccination) 3.5 x 108 103 1.2 x 109 488

24 Days post challenge(10 Days post vaccination) 1.8 x 108 55 5.5 x 108 123

* ORF6 Copies per ml by Quantitative PCR# Infective Virus Particles calculated per ml based on Q-PCR

Average daily gain data:

Data compiled for Trial #1 and Trial #2

Summary of Average Daily Gain (ADG) performance in MJPRRS vaccinated compared to non-vaccinated 21 day old PRRS naïve pigs when challenged to a field strain of

PRRS at 53 days of age (Trial #1 data)

Day 1 Day 32 post arrival Day 55 post arrival Overall

Day of Vaccination Challenged* Day 1-23 post challenge Day 1-55 arrival

Weight (Ibs) Average Average ADG Average ADG# ADG

Vaccinated 14.5 36.5 0.71 54.0 0.76 0.74

Non-Vaccinated 16.0 32.5 0.53 53.0 0.89 0.68

* All pigs challenged with PRRSv at 32 days post arrival (53 days of age)# ADG affected by mortality;

Vaccinated group, 1 of 22 dead Non-vaccinated group, 4 of 22 dead

Summary of Average Daily Gain (ADG) performance in MJPRRS vaccinated compared to non-vaccinated 21 day old PRRS naïve pigs when challenged to a field strain of PRRS at 49 days of age

(Trial #2 data)

Day 1 Day 28 post arrival

Day 40 post arrival Day 54 post arrival Overall

Day of Vaccination Challenged* Day 1 – 11 post challenge

Day 11 – 24 post challenge

Day 1-54 arrival

Weight (Ibs) Average# Average ADG Average ADG Average ADG ADG

Vaccinated 13.7 31.2 0.62 34.2 0.27 49.0 1.14 0.74

Non-vaccinated 14.2 35.5 0.76 37.6 0.19 48.0 0.80 0.52

* All pigs challenged with PRRSv at 28 days post arrival (49 days of age)

Mortality data:

Data compiled for Trial #1, Trial #2, and Trial #3

Summary of Mortality in MJPRRS vaccinated compared to non-vaccinated 21 day old pigs when challenged to a field strain of

PRRS at 53 or 49 days of age (Trial #1 and #2 data)

Trial #1Challenge material Treatment group Mortality at 23 days post challenge

SerumNon-Vaccinated 3 of 11 (27%)

Vaccinated 1 of 11 (9%)

CultureNon-Vaccinated 1 of 11 (9%)

Vaccinated 0 of 11 (0%)

Trial # 2Challenge material Treatment group Mortality at 23 days post challenge

CultureNon-Vaccinated 0 of 16 (0%)

Vaccinated 0 of 16 (0%)

Overall mortality for non-vaccinated groups, 18.2%Overall mortality for vaccinated groups, 4.5%

Summary of Mortality in 26 day old PRRS viremic pigs vaccinated with MJPRRS vaccine at peak viremia compared to non-vaccinated

controls (Trial #3 data)

Trial # 3Challenge material Treatment group Mortality at 10 days post vaccination*

SerumNon-Vaccinated 3 of 12 (25%)

Vaccinated 2 of 12 (16%)

* 15 days post challenge

Summary (I)

• Virus Replication– For trial #1, a statistical reduction in virus replication

shown between the MJPRRS vaccinates compared to the non-vaccinates at days 5 and 11 post challenge (p value = 0.04 and 0.0098, respectively)

– For trial #2, no statistical difference noted– For trial #3, a statistical reduction in virus replication

during vaccination at peak viremia at day 7 and 10 post vaccination (p value = 0.048 and 0.002, respectively)

Summary (II)

• Average Daily Gain (ADG)– For trial #1, no statistical difference noted

Numerically: Vaccinates, Day 1-23 post challenge, 0.76 Non-Vaccinates, Day 1-23 post challenge, 0.89

High mortality in non-vaccinates likely affected ADG differences in calculation

– For trial #2, A statistical difference (p value = 0.026)between MJPRRS vaccinated group vs. controls during Day 1-24

Numerically: Vaccinates, Day 1-24 post challenge, 0.74 Non-Vaccinates, Day 1-24 post challenge, 0.52

Summary (III)• Mortality– For trial #1• Vaccinates = 1 of 22 (4.5%)• Non Vaccinates = 4 of 22 (18%)

– For trial #2• No mortality in either group

– For trial #3• Vaccinates = 2 of 12 (16%)• Non Vaccinates = 3 of 12 (25%)

Conclusions• Data demonstrated that PRRS naïve or viremic pigs

were able to respond to one dose of autogenous MJPRRS vaccine with extra adjuvant.

• A reduction on virus replication was statistically demonstrated (2 of 3 trials).

• A numerical improvement in ADG was demonstrated (2 of 2 trials). A statistical difference noted also (1 of 2 trials).

• A numerical improvement in Mortality was demonstrated (2 of 3 trials).

Thank you