D5732.PDF

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Original: English
August/September 2004
REPORT OF THE MEETING OF THE
OIE AD HOC GROUP ON CLASSICAL SWINE FEVER
Paris, 27 – 29 September 2004
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The meeting of the OIE Ad hoc Group of the Scientific Commission for Animal Diseases (Scientific
Commission) on Classical Swine Fever was held at OIE Headquarters, Paris from 27 to 29 September 2004.
The Agenda and list of participants are presented as Appendices I and II respectively.
Dr Alejandro Schudel, Head of the Scientific and Technical Department, welcomed members of the Group and
explained the expectations of the OIE International Committee on the output of the Group particularly with
respect to the Appendix on ‘Guidelines for the surveillance required to support the establishment or regaining of
recognition for a classical swine fever free country or zone. He also stressed the importance of collaborative
work between various OIE Specialist Commissions and Ad hoc Groups to produce common and harmonized
documents for the OIE.
In accordance with standard practices whereby Ad hoc Groups functioning under the auspices of the Scientific
Commission are chaired by a member of that Commission, the meeting was chaired by Professor Vincenzo
Caporale, President of the OIE Scientific Commission for Animal Diseases. Dr Philippe Vannier replaced
Professor Caporale as chair for part of the meeting and Dr John Pasick was designated as rapporteur.
During the course of their deliberations, the Group incorporated information derived from a number of sources
that included but were not limited to:
• Chapter 2.1.13 of the Terrestrial Animal Health Code, on CSF
• Chapter 1.3.6 of the Terrestrial Animal Health Code, on Animal Health Surveillance
• Chapter 1.3.3 of the Terrestrial Animal Health Code, on the Evaluation of Veterinary Services
• The Manual of Diagnostic Test and Vaccines for Terrestrial Animals, 2004 Edition
• The report of the Ad hoc Group on Epidemiology, Paris, 28-30 June 2004
1. Terrestrial Animal Health Code: CSF Chapter 2.6.7
The group reviewed Chapter 2.6.7 and has several recommendations to the Scientific Committee.
A definition of CSFV infection should be included. One possible definition can be found in paragraph 5 of
the introduction in the draft Appendix on ‘Guidelines for the surveillance required to support the
establishment or regaining of recognition of freedom for a classical swine fever free country or zone’

2 Ad hoc Group on Classical Swine fever, September 2004
Article 2.6.7.2 (2) should be changed to “CSF should be notifiable in the whole country and all clinical
signs suggestive of CSF should be subjected to field and laboratory investigations”
In Article 2.6.7.4 (2e), the Group questions the efficacy of applying the absence of notified outbreaks as the
singular criterion on which to base CSF freedom following a stamping out process without vaccination.
Given the potential for CSF to circulate in a clinically inapparent form or one that is clinically
indistinguishable from a number of other conditions that are prevalent in other countries, the Group
advocates the application of active targeted or random serosurveillance as an adjunct to clinical surveillance
described.
The Group also questions the inconsistency in the recovery interval for CSF freedom post-eradication
versus post-outbreak. Article 2.6.7.4 (2e) states that “a country or zone may be considered free in domestic
and wild pigs where a stamping-out policy without vaccination has been practised for CSF, and when no
outbreak has been observed in domestic pigs for at least 6 months”. In contrast, the first paragraph of
Article 2.6.7.6 states that “should a CSF outbreak occur in an establishment of a free country or zone (free
in domestic and wild pigs, or free in domestic pigs only), the status of the country or zone may be restored
at least 30 days after completion of a stamping out policy”.
In Article 2.6.7.4 (2f and 2g) the Group questions the efficacy of applying serosurveillance only if
vaccination has occurred during the last five years. Given the potential for CSF to circulate in a clinically
inapparent form, or one clinically indistinguishable from a number of other conditions prevalent in many
countries, the Group advocates that serosurveillance be applied irrespective of the time which has elapsed
since cessation of vaccination.
Article 2.6.7.6 (4) should be extended to include serologic testing in clinically negative animals in addition
to laboratory tests on sick pigs.
The group proposes that consideration should also be given to the reciprocal of the situation described in
Article 2.6.7.5 i.e. freedom of CSF in wild pigs but present in the domestic pig population.
The group considers that the recognition of a free status where a vaccination strategy has been adopted will
depend on several factors, the most important ones being the quality of vaccines available and the
performance of companion diagnostic kits. Validated kits are specified but there are no official bodies with
the power of assessing the performance of such test kits at the international level. As a consequence, the
guarantees provided by a vaccination policy under such conditions cannot be the same as a stamping out
policy combined with a serological survey in the absence of vaccination. These points have to be
considered in the chapter and a validation procedure has to be implemented at the international level.
The proposed Guidelines is presented as Appendix III.
2. Discussion of the document submitted by Dr Domenico Rutilli on viral hazard
identification – classical swine fever virus
The Group recognized that the amount of information available regarding hazard identification was very
much dependent on the specific product. A significant amount of information is available for some products
while little or no information is available for others. Furthermore, previous reports regarding CSFV
inactivation times have been based on in vitro isolation assays. This approach is flawed since it has been
shown that product samples shown to be free of virus by in vitro isolation assays were still infectious to
pigs. Because of this, the Group’s recommendation to the Scientific Commission is that more research is
required before guidelines for curing/aging pork products to inactivate CSFV can be put forward.

Ad hoc Group on Classical Swine fever, September 2004 3
The Group is advocating the use of the “D” value, or time taken for the virus titre to drop by 1 log10, in
determining the safety of pork products with regards to CSFV. This would entail calculating the D value for
each product under various conditions of pH, temperature, etc.
3. Report on the epidemiological investigation of CSF cases in Japan during March, July, and
August of 2004 linked to the use of an unapproved vaccine
Dr Fukusho presented the Group with background information related to CSFV detection associated with
the use of an unapproved CSF vaccine in Japan. There was some question regarding the conclusion that the
virus was vaccine derived when virus was not actually isolated from the vaccine due to its (vaccine)
inavailability for analysis.
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…/Appendix

Ad hoc Group on Classical Swine fever, September 2004 5
Appendix I
REPORT OF THE MEETING OF THE
OIE AD HOC ON CLASSICAL SWINE FEVER
Paris, 27 – 29 September 2004
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Agenda
1. Terrestrial Animal Health Code: CSF Chapter 2.6.7
2. Discussion of the document submitted by Dr Domenico Rutilli on viral hazard identification – classical
swine fever virus
3. Report on the epidemiological investigation of CSF cases in Japan during March, July, and August of 2004
linked to the use of an unapproved vaccine
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