OIE Reference Laboratory Reports
Activities in 2011
Name of disease (or topic) for
which you are a designated OIE
Reference Laboratory:
Lumpy skin disease
and
Sheep pox and goat pox
Address of laboratory:
100 Old Soutpan Road
Onderstepoort 0110
Tshwane
SOUTH AFRICA
Tel.:
Tel.: (+27 12) 529 9117
Fax:
Fax: (+2712) 529 9418
e-mail address:
LubisiA@arc.agric.za
website:
http://www.arc.agric.za
Name (including Title and
Position) of Head of Laboratory
(Responsible Official):
Dr Baratang Alison Lubisi
Name(including Title and
Position) of OIE Reference
Expert:
Dr Baratang Alison Lubisi
Name (including Title and
Position) of writer of this report
(if different from above):
Dr Baratang Alison Lubisi
Annual reports of OIE Reference Centres, 2011
1
Lumpy skin disease and Sheep pox and goat pox
Part I: Summary of general activities related to the disease
The OIE Lumpy Skin Disease (LSD) reference laboratory at Onderstepoort Veterinary Institute (OVI) aligns its
activities with the Agricultural Research Council’s (ARC) strategic objective related to enhancing the ability of the
agricultural sector to manage and mitigate agricultural risks. Activities for the report period included the provision of
diagnostic services; disease certification of ruminants for breeders and exporters of susceptible live animals; conducting
serological tests for studies aimed at understanding the prevalence of the disease in certain geographical areas and
vaccine quality assurance (Table 1); and performance of research aimed at improving the currently utilised diagnostic
tests and vaccines. Among the animal species tested were eland, gemsbok, springbok, buffalo, giraffe, kudu, oryx,
caprine and bovine.
Table 1 Results for tests conducted on South African samples
Province
No. of specimens
Positives/Test
PCR
SNT
VI
EM
Gauteng
235
2/26
69/209
N/A
N/A
Limpopo
31
0/10
5/21
N/A
N/A
North West
362
1/3
28/359
N/A
2/2
Northern Cape
29
0/2
5/27
N/A
N/A
Kwa-Zulu Natal
14
0/0
0/14
N/A
N/A
Free State
239
14/86
14/150
0/3
5/5
Eastern Cape
18
0/0
0/16
0/2
1/1
Mpumalanga
4
1/1
0/2
1/1
N/A
Western Cape
8
0/1
1/7
N/A
N/A
N/A – not applicable; Orf virus was identified by electron microscopy in 8 samples submitted from Free State (4/4);
Limpopo (1/1); Eastern Cape (2/2); and Mpumalanga (1/1).
1.
Test(s) in use/or available for the specified disease/topic at your laboratory
Test
For
Specificity
Total
Serum Neutralisation (SN)
Antibody
Group
805
Electron Microscopy (EM)
Virus
Group
16
PCR
Genomic material
Group
129
MDBK/CFT cell culture
Virus isolation
Group
Six submissions with varying
numbers of specimens
Diagnostics project leaders: Drs BA Lubisi – BVMCh.MSc (classical virological methods) and Marco Romito –
BVSc.MSc (molecular based diagnostic tests).Mr John Putterill (MSc) is the activity leader for EM imaging using
negative contrasting techniques (2-3% phosphor-tungstic acid (pH 6.2) or 1% aqueous uranyl acetate).
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Annual reports of OIE Reference Centres, 2011
Lumpy skin disease and Sheep pox and goat pox
2.
Production and distribution of diagnostic reagents
Type of reagent
Amount supplied nationally
(including for own use)
Amount supplied to other
countries
LSDV positive antiserum
None
5ml
LSDV antisera (5 ml) was prepared for Dr Joseph Hyera of Botswana National Veterinary Laboratory, Private Bag
0035, Gaborone, in December 2011.
Part II: Activities specifically related to the mandate
of OIE Reference Laboratories
3.
International harmonisation and standardisation of methods for diagnostic testing or the
production and testing of vaccines
I. Participation in an International Proficiency Test Scheme
a)
Establishment and maintenance of a network with other OIE Reference Laboratories
designated for the same pathogen or disease and organisation of regular inter-laboratory
proficiency testing to ensure comparability of results
ARC-OVI embarked on an inter-laboratory exercise with the Institute for Animal Health (IAH), Pirbright
Laboratory, Ash Road, Pirbright, Woking, Surrey GU24 ONF, UK, in 2011. The exercise was aimed at
comparing the performance of our LSD serum neutralisation test (SNT) with that of another reference
laboratory for quality control purposes. Table 2 indicates the results obtained.
Table 2 Results of the LSD inter-laboratory test between ARC-OVI and IAH, Pirbright conducted in October
2011
LSD sera samples
SNT results
Sample ID
Sample Details
IAH
ARC - OVI
A1
VN83, 21DPI, 070306
1:60
1:64
A2
VN84,34 DPI, 200306
1:120
1:64
A3
VN83, 15 DPI, 010306
Negative
Negative
A4
VN83, 34 DPI, 200306
1:120
1:8
A5
VN83, 0 DPI, 140206
Negative
Negative
A6
VN84, 21DPI, 070306
1:30
1:32
A7
VN83, 37 DPI, 230306
1:160
1:28
A8
VN84, 15 DPI, 010306
Negative
Serum
depleted
Positive control
LSD + cattle serum 2006, VN84, 37 DPI
!:160
1:128
Negative control
Cattle serum UK, VN84, prior to inoculation
Negative
Negative
The tests results were in good agreement. In general, similar levels of antibody titres were detected by both
institutions, despite the cells used by the IAH being lamb testis or bovine dermis, while OVI utilised Madin
Darby Bovine Kidney cell lines. In addition, the first serum dilution at IAH was 1:5, while that at OVI was
1:4.
Annual reports of OIE Reference Centres, 2011
3
Lumpy skin disease and Sheep pox and goat pox
Nonetheless sample A4 which tested strongly positive at the IAH (1:120), tested weakly positive at OVI
(1:8). The sample was collected from an experimentally infected animal, VN83, which showed severe
clinical disease at 34 days post inoculation (DPI).
Root cause analysis (RCA) at OVI has since revealed that protection was actually seen up to 1:64, but since
one duplicate showed what seemed like cytopathic effect (CPE) at 1:16, but was clear (no CPE) at two
consecutive dilutions, the analyst decided to report the titre as 1:8. The other duplicate clearly showed the
titre to be 1:64, which compared well with the IAH results, given that one titre lower or higher is permissible
in such tests. The serum was depleted and re-testing could not be done.
b)
Organisation of inter-laboratory proficiency testing with laboratories other than OIE
Reference Laboratories for the same pathogens and diseases to ensure equivalence of
results
Not done.
4.
Preparation and supply of international reference standards for diagnostic tests or vaccines
Not done
5.
Research and development of new procedures for diagnosis and control
I. Improvement of lumpy skin disease virus (LSDV), both as a vaccine and a vector, by using recombinant
knockout (KO) technology to remove putative immuno-modulatory genes.
The four knockout recombinant viruses that were generated previously have been grown to high titre stocks for
use in an upcoming animal trial (2012).
Project leader: Dr David Wallace (PhD); co-worker: Mr Pravesh Kara(MSc)
II. Determination of the binding in an invitro system (e.g. ELISA, dot blot) of the putative LSDV interferon
gamma receptor-like protein (IFNγR) to bovine interferon gamma (IFN γ).
To understand the effects of the putative immuno-modulatory genes encoded by LSDV on the host’s immune
responses, a number of these genes have been selected for expression and functional assays. Open reading frame
008 (ORF008) has domains homologous to the receptor of IFN γ, an important cytokine in the defense against
viral infection. Thus the binding capability of the putative LSDV IFNγR to bovine IFN γ is being studied.
Vaccinia virus, other orthopoxviruses, capripoxvirus, myxomavirus and swinepox encode related proteins. The
poxvirus receptor-like protein binds interferon γ thereby preventing the cytokine from binding to its cellular
receptor, leading to moderated host immune responses. The putative LSDV IFNγR protein has been expressed in a
bacterial system and purified. The protein is soluble and is now available for further evaluation.
Project leader: Dr Arshad Mather (PhD); co-worker: Mr Pravesh Kara (MSc).
III. Evaluation of a marker-free recombinant LSDV-vectored RVF vaccine
The project on this construct is on-going. A single animal (sheep) trial was conducted late in 2011 using a primeboost regime. Results of sample testing and analysis are pending.
Project leader: Dr David Wallace (PhD); co-worker: Busisiwe Khoza (NDiP)
6.
Collection, analysis and dissemination of epizootiological data relevant to international disease
control
Not done.
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Annual reports of OIE Reference Centres, 2011
Lumpy skin disease and Sheep pox and goat pox
7.
Maintenance of a system of quality assurance, biosafety and biosecurity relevant to the
pathogen and the disease concerned
All diagnostic tests are performed by competent personnel; the laboratories engage in inter-laboratory tests, and
verified control reagents are employed. Tests are performed in BSL2 laboratories in biohazard cabinets, and
personnel wear protective clothing in addition to exercising good laboratory practice. Biological waste is
autoclaved and incinerated.
8.
Provision of consultant expertise to OIE or to OIE Member Countries
Not done.
9.
Provision of scientific and technical training to personnel from other OIE Member Countries
Not done.
10. Provision of diagnostic testing facilities to other OIE Member Countries
Country
Namibia
No. of
specimens
24
Test
Tentative
Confirmatory
Yes
No
No. Positive
4
Positive results
reported to OIE
N/A
N/A - not applicable because the test conducted was not confirmatory, or if confirmatory, the results were negative
11. Organisation of international scientific meetings on behalf of OIE or other international bodies
Not done.
12. Participation in international scientific collaborative studies
Not done.
13. Publication and dissemination of information relevant to the work of OIE (including list of
scientific publications, internet publishing activities, presentations at international conferences)

Presentations at international conferences and meetings
Not done.

Scientific publications in peer-reviewed journals
Not done.

Other communications
N/A
_______________
Annual reports of OIE Reference Centres, 2011
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