Emergence of antigenic variants of SAT2 FMDV at the ......other SAT2 isolates from topotype I (South Africa, Zimbabwe and Mozambique) The recent SAT2 outbreak viruses were genetically

1

Emergence of antigenic variants of SAT2

FMDV at the wildlife/livestock interface in South Africa

Blignaut, B.1, van Heerden, J.1, Reininghaus, B.2, Heath, L.1 & Fosgate, G.T.3

1Transboundary Animal Diseases Programme, Onderstepoort Veterinary Institute, Agricultural Research Council, Onderstepoort, 0110, South Africa, 2Mpumalanga Veterinary Services, Orpen, Mpumalanga, South Africa, 3Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, 0110, South Africa

2

Introduction

The South African Territories (SAT) type foot-and-mouth disease viruses (FMDV) are endemic to the greater Kruger National Park (KNP) area in South Africa, where it is maintained through persistent infections of African buffalo

The occurrence of FMDV within the KNP constitutes a continual threat to the livestock industry

FMD outbreaks are costly and require extensive logistical efforts

SAT types display high genomic and antigenic variation: implications for the control of the disease by vaccination

Several outbreaks have occurred in South Africa since the turn of the century emphasising the need for ongoing disease surveillance

To expand on knowledge of FMDV diversity, the genetic and antigenic relatedness of SAT2 type viruses isolated from cattle in 2013/2014 were investigated

3

Molecular epidemiological relationships of the viruses were determined by

sequencing and phylogenetic analysis

Genetically disparate viruses were chosen to determine neutralisation titres between

outbreak viruses using virus neutralisation tests (VNT) against four reference sera

Antigenic relatedness (r1-values) of the outbreak viruses and the most suitable vaccine

match was determined

Aims

4

Recent SAT2 FMD outbreaks

SADC South Africa

Zimbabwe

Zambia

Botswana

Namibia

Mozambique

Malawi

South Africa

2001

2003-2004

2011-2014

5

Geographic distribution of the SAT2 types

Topotype 1 South Africa Kruger National Park Mozambique

Topotype 3 Namibia Botswana Zimbabwe

Topotype 2 Namibia Botswana Zambia Zimbabwe Malawi

Neighbour joining tree depicting SAT2 viruses from topotypes 1, 2 and 3

KNP/16/93/Capricorn

KNP/5/06/2/Nwambi_block

KNP/3/10/Banyini_Pan

KNP/9/03/Ribye-Waterhole

MOZ/1/10/Gaza_Province

SAR/6/04/Poporoga-diptank

KNP/11/07/Bububu

KNP/6/96

KNP/1678/98/Bume

SAR/01/01/Mhala-district

KNP/12/08/Lower_Sabie

KNP/07/88

KNP/19/89

KNP/31/95

SAR/11/1919/Luphisi_DT

KNP/1/11/Impala

SAR/12/0050/Huntingdon_DT

SAR/15/13/2/Welverdiend A

SAR/5/13/2/Hlalakahle DT

SAR/11/13/2/Seville B





SAR/17/13/2/Welverdiend B



SAR/2/14/2/Athol

SAR/19/13/2/Eglington

SAR/4/14/2/Islington

SAR/1/14/2/Athol

SAR/3/14/2/Athol

KNP/5/91/Satara

SAR/1/03/Masisi

SAR/1/08/Maruleng/buffalo

KNP/04/03/Punda-Maria

SAR/1/10/Limpopo_Safaris/buffalo

ZIM/08/94

KNP/141/91

KNP/32/92/Boyela

ZAM/9/93

ZAM/7/96

BOT/31/98/Vumbura

NAM/4/07/Caprivi

ZIM/16/91/Matusadona

ZIM/267/98/Chizarira

ZIM/01/00

ZIM/14/90/DomaSafariarea

ZIM/34/91

BOT/13/02

ZIM/01/01/Bulawayo

ZIM/01/02/Beitbridge

ZIM/7/95/Sengwa

NAM/01/92

NAM/3/10/buffalo

NAM/286/98

ZIM/05/02/Lupane

BOT/18/98

BOT/1/98/Nxaraga

ZIM/07/83/Nyamandlovu

ZIM/1/97/Chiredzi

ZIM/1/88/Hwange

ZIM/4/88

ZIM/7/8975

97

99

36

99

80

75

99

50

99

47

99

21

24

38

36

66

75

87

99

98

98

99

95

99

99

89

52

87

60

95

27

50

42

25

22

29

61

21

26

35

95

50

11

4

37

68

64

45

53

99

29

40

63

0.02

6

SAT2 outbreak South Africa 2013/2014

Kruger National Park

7

KNP/16/93/Capricorn

KNP/5/06/2/Nwambi_block


KNP/9/03/Ribye-Waterhole

MOZ/1/10/Gaza_Province


KNP/11/07/Bububu

KNP/6/96

KNP/1678/98/Bume

SAR/01/01/Mhala-district

KNP/12/08/Lower_Sabie

KNP/07/88

KNP/19/89

KNP/31/95


KNP/1/11/Impala












SAR/2/14/2/Athol



SAR/1/14/2/Athol

SAR/3/14/2/Athol

KNP/5/91/Satara

SAR/1/03/Masisi


KNP/04/03/Punda-Maria


ZIM/08/94

KNP/141/91

KNP/32/92/Boyela

ZAM/9/93

ZAM/7/96

BOT/31/98/Vumbura

NAM/4/07/Caprivi

ZIM/16/91/Matusadona

ZIM/267/98/Chizarira

ZIM/01/00

ZIM/14/90/DomaSafariarea

ZIM/34/91

BOT/13/02

ZIM/01/01/Bulawayo

ZIM/01/02/Beitbridge

ZIM/7/95/Sengwa

NAM/01/92

NAM/3/10/buffalo

NAM/286/98

ZIM/05/02/Lupane

BOT/18/98

BOT/1/98/Nxaraga

ZIM/07/83/Nyamandlovu

ZIM/1/97/Chiredzi

ZIM/1/88/Hwange

ZIM/4/88

ZIM/7/8975

97

99

36

99

80

75

99

50

99

47

99

21

24

38

36

66

75

87

99

98

98

99

95

99

99

89

52

87

60

95

27

50

42

25

22

29

61

21

26

35

95

50

11

4

37

68

64

45

53

99

29

40

63

0.02

v

2013

2014

2012 2011

Genetic relatedness of SAT2 outbreak viruses

Neighbour joining tree depicting the SAT2 outbreak strains

characterised from cattle, Mpumalanga Province

Topotype 1 South Africa Kruger National Park Mozambique

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SAT2 antibody titres (ELISA)

0.0

0.5

1.0

1.5

2.0

2.5

4 7 8 9 12 13 14 16 17 18 23 24 26 27 28 29

* * * * * * * * Animal number

An

tib

od

y ti

tre

(lo

g 1

0)

9

SAT2 neutralising antibody titres

Neu

tral

isin

g an

tib

od

y ti

tre

SAR 2013 SAR 2014 SAR 2004 KNP 2010 BOT 2006

0

0.5

1

1.5

2

2.5

3

3.5

4

4 7 8 9 12 13 14 16 17 18 23 24 26 27 28 29

SAR 2014 SAR 2004 KNP 2010 BOT 2006Animal number










SAR/2/14/2/Athol



SAR/1/14/2/Athol

SAR/3/14/2/Athol


SAR/3/04/2


KNP/1/10/2


SAR/1/01/2

KNP/19/89/2


KNP/1/11/Impala



SAR/1/03/Masisi


ZIM/7/83/2

BOT/4/06/2

ZIM/14/90/2

ZIM/17/91/243

86

99

99

90

75

9864

51

69

68

44

37

78

46

5399

4228

30

57

0.05

10

SAR/3/04

KNP/19/89

ZIM/7/83

ZIM/14/90

SAR/1/13 SAR/15/13 SAR/4/14 SAR/13/13

Antigenic profiles of SAT2 outbreak viruses

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

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Vaccine match of SAT2 outbreak viruses

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.90

1.00

SAR/3/04 KNP/19/89 ZIM/7/83 ZIM/14/90

r 1-v

alu

es

SAR/1/13 SAR/15/13 SAR/4/14 SAR/13/13

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Summary

Phylogenetic analysis of the recent outbreak viruses revealed their genetic relatedness to other SAT2 isolates from topotype I (South Africa, Zimbabwe and Mozambique) The recent SAT2 outbreak viruses were genetically distinct from previously isolated viruses (2011 and 2012) and form an outgroup within the topotype I viruses Neutralising antibody responses were observed for samples from the outbreak when tested against viruses from South Africa, the KNP and Botswana High neutralisation titres were observed for all outbreak viruses tested against the reference sera representative of viruses from the endemic area in South Africa, as well as Zimbabwe Cross-neutralisation data for the SAT2 outbreak viruses yielded different antigenic profiles Comparison of the outbreak viruses with reference sera indicated a good vaccine match with 75% of r1-values > 0.4, 13% of r1-values between 0.3 and 0.4, and 13% of r1-values < 0.3

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Acknowledgements

Transboundary Animal Diseases Programme (ARC-OVI)

Department of Agriculture, Forestry and Fisheries

Mpumalanga Veterinary Services

National Research Foundation of South Africa (Grant Number 90578)

Documents

Emergence of antigenic variants of SAT2 FMDV at the ......other SAT2 isolates from topotype I (South Africa, Zimbabwe and Mozambique) The recent SAT2 outbreak viruses were genetically