1. Efficacy of foot-and-mouth disease vaccines A22 Iraq 64 and A Malaysia 97 against challenge with a recent South East Asian serotype A field strain in cattle and sheep
Jacquelyn Horsington1, Nagendrakumar Singanallur1, Aldo Dekker2, Soren Alexandersen3, Wilna Vosloo1
1Australian Animal Health Laboratory, CSIRO, 5 Portarlington Rd, Geelong, Victoria, Australia
2Central Veterinary Institute (CVI), Wageningen UR, Lelystad, The Netherlands.
3National Centres for Animal Disease, Canadian Food Inspection Agency, 1015 Arlington St, Winnipeg, Manitoba, Canada
HEALTH AND BIOSECURITY

2. In memory..
Claudia Perez, SENASA, Buenos Aires, Argentina

3. FMDV Serotype A Widespread Antigenically and genetically heterogenous
26 regional genotypes within three continental topotypes

4. Serotype A in South East Asia: are there reasons for concern?

5. Vaccine Matching Studies with Serotype A
Major project objectives
increase our real-time understanding of the epidemiology of FMD in South East Asia (SEA)
perform vaccine matching studies and build capacity in both Australia and SEA
OIE Regional Reference Laboratory, based in Pakchong, Thailand
major collaborator
access to current viruses circulating in the region
Vaccines must protect against viruses circulating in the field
Australia has a limited number of vaccine strains in our FMD vaccine bank
Limited number of strains can be tested in in vivo challenge studies
Laboratory (in vitro) assays are used to predict which viruses should be prioritised for live animal studies

6. Vaccine matching or ‘r’-value of FMDV type A in SEA region
A22 IRAQ 64 BVS
A MAY 97 BVS
TAI/161/12
VIT/3/13
TAI/20/13
TAI/26-3/13
TAI /21-2/14
TAI/94-3/11
LAO/5/14
TAI/5/14
TAI/89-2/11
TAI/99-2/11
TAI/17-1/12
VIT/1/13
TAI/58/13
TAI/44/14
VIT/2/13
TAI/39/13
The in vitro assays determine the match between the vaccine strains and field viruses by establishing the relative homology or r1 values
Two serotype A vaccine strains in the vaccine bank were used as references (A MAY 97 and A22 IRQ) for the vaccine matching assays
LAO/2/14
TAI/1-2/14
TAI/2/14
TAI/65-1/14
TAI/47-2/13
TAI/53/13
TAI/60/13
TAI/10/14
TAI/13-2/14

7. Vaccine efficacy trials with A MAY 97 and A22 Iraq monovalent vaccine against challenge with A/VIT/15/2012 in cattle and sheep
A virus from the 2010–2013 cluster selected to test against the vaccine strains A22 IRQ and A MAY 97
Vietnamese serotype A isolate - A/VIT/15/2012
In vitro vaccine matching
A value of >0.3 is considered a match
Field isolate
r1-value
A22 IRQ
A MAY 97
A/VIT/15/2012
0.17
0.16

8. Unvaccinated controls
Testing efficacy A MAY 97 and A22 IRQ monovalent vaccines against challenge with A/VIT/15/2012 in cattle
5 cattle/test group
Vaccine - A22 Iraq or A MAY 97
Vaccination 7 or 21 days prior to challenge
High potency >6 PD50
Virus - A/VIT/15/2012
Donors inoculated by intradermal lingual (IDL) injection
Vaccine
Group
Day of challenge
A22 IRQ
1 (5 cattle)
21 dpv
3 (5 cattle)
7 dpv
A MAY 97
2 (5 cattle)
4 (5 cattle)
Unvaccinated controls
5 (3 cattle)
Vaccination
Day: -7 10 14 35
Sampling Weekly
Sampling Daily
Termination
Challenge
-21

9. Clinical Signs Complete Protection! Complete Protection!
A22 IRQ 64; challenged 21 dpv
A MAY 97; challenged 21 dpv
Complete Protection!
Complete Protection!
UV Controls
A22 IRQ 64; challenged 7 dpv
A MAY 97; challenged 7 dpv
Partial Protection!
Partial Protection!
Clinical disease

10. Immune response to non-structural protein
Group
Animal ID
0 dpc
1 dpc
2 dpc
3 dpc
4 dpc
5 dpc
6 dpc
7 dpc
10 dpc
14 dpc
21 dpc
28 dpc
35 dpc
1 (A22 IRQ, 21 dpv)
8092
32* 24 33 35 45 66 78 80 81
8093 39 38 34 37 36 59 79 73 84
8094 22 21 20 14 60 85 83
8095 30 25 28 62 76 86
8096 41 53 91 90 82 88
2 (A MAY97, 21 dpv)
8097 40 43 44 50 65 87
8098 27 31 55 69
8099 47 74
8100 26 32 70 71
8101
3 (A22 IRQ, 7 dpv)
8102 42 63
8103 68
 NS
8104 54
8105 49 67 93 94
8106 46 48 89
4 (A MAY97, 7 dpv)
8107 58
8108 9 12 13 16 17 23 64 75
8109 77
8110 19
8111 18 61 5
8112 72
8113 57 56 52
8114 NS
NS – No sample as the animals were euthanized or died; green = positive; blue = possible false positive; * values shown as percent inhibition

11. Virus detection in oro-pharyngeal fluid
Virus isolation indicates carrier
Group -7 7 10 14 21 28 30 35 V
A22
Iraq
21 dpv
A MAY
7 dpv UV
controls ND
ND 
RT-qPCR positive
V = virus isolated

12. Testing efficacy A MAY 97 and A22 IRQ monovalent vaccines against challenge with A/VIT/15/2012 in cattle
Summary
Both vaccines protected 100% of cattle, 21 dpv
High potency A22 Iraq vaccine protected 80% (4 of 5) of cattle, 7 dpv
High potency A MAY 97 vaccine protected 60% (3 of 5) of cattle, 7 dpv
Virus excretion in oral and nasal fluids in all groups
NSP antibody in all cattle in all groups
Virus persistence in all groups

13. Testing efficacy A22 IRQ monovalent vaccine against challenge with A/VIT/15/2012 in sheep
6 replicate rooms
3 donors, 1 vaccinated contact and 1 unvaccinated contact per room
Vaccine - A22 Iraq
Vaccination 4 days prior to challenge
High potency >6 PD50
Virus - A/VIT/15/2012
Donors inoculated by coronary band (CB) injection
Vaccinated/unvaccinated control sheep challenged by direct contact exposure
= natural route of infection
Vaccination
Day: -4
Contact 10 14 35
Sampling Weekly
Sampling Daily
Termination

14. Clinical Signs Donors Vaccinated Contacts 1/6 Diseased 18/18 Diseased
*diseased sheep euthanized day 9
Unvaccinated Contacts
5/6
Diseased
*donors euthanized on day 9
*UVs euthanized between day 9 and 14

15. Immune response to non-structural protein
Group
Sheep ID
NSP antibody ELISA
-4–5 dpc
6 dpc
7 dpc
8 dpc
9 dpc
10 dpc
12 dpc
14 dpc
21 dpc
28 dpc VC 7 - P 8 9 10 11 12 UC 13 14 15 16 17 18
Donor 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
(-) – Negative; P– Positive; VC – vaccinated contact; UI – unvaccinated infected; Grey = dead

16. Virus detection in oro-pharyngeal fluid
Vaccinated
Unvaccinated
Carrier
Carrier
DPC -4 1 2 3 4 5 6 7 9 12 14 21 28 35
Sheep 7 V
Sheep 8
Sheep 9
Sheep 10
Sheep 11
Sheep 12
DPC -4 1 2 3 4 5 6 7 9 12 14 21 28 35
Sheep 13 V
Sheep 14
Sheep 15
Sheep 16
Sheep 17
Sheep 18
2/6 vaccinated sheep became carriers
RT-qPCR positive
V = virus isolated

17. Testing efficacy A22 IRQ monovalent vaccine against challenge with A/VIT/15/2012 in sheep
Summary
The A/VIT/15/2012 virus was pathogenic in sheep
High potency A22 Iraq vaccine protected 83% (5 of 6) of sheep, 4 dpv
Vaccinated animals had
Virus excretion in oral and nasal fluids
NSP antibody
Virus persistence

18. Summary
A May 97
A22 Iraq
Species
Cattle
Sheep
Challenged at
21 dpv
7 dpv
4 dpv
Route
IDL
Direct Contact
Protection
100%
60%
80%
83%
NSP Ab
Yes
Carriers
Virus in nasal and oral swabs
High potency serotype A vaccines provide protection from clinical disease against heterologous challenge
Even at early time points - But is that good enough?
Vaccination does not prevent virus replication
However, the challenge route may be important
Vaccination does not prevent the development of carriers
What is the importance of these carriers?

19. Conclusions
Antigenic matching does not always accurately predict protection, especially with high potency vaccines
Other measures of control will be important during an outbreak, vaccination alone is not the golden bullet
Transmission studies would answer a lot of questions

20. Thank you Acknowledgements Soren Alexandersen Kurtis Swekla
Zhidong Zhang
Jaime Bernstein
Charles Nfon
Margaret Forbes
Kate Hole
Marlee Phair
Hilary Bittner
Cory Nakamura
Melissa Goolia
Tim Salo
FMD Risk Management Project
Jacquelyn Horsington (PhD, MSc, BSc) Research Scientist t e w
Aldo Dekker
Klaas Weerdmeester
Phaedra Eble
Meindert Bleijenberg
Froukje van Hemert-Kluitenberg
HEALTH AND BIOSECURITY