Classical Swine Fever In Japan

JAPAN - This is a report via OIE on the detection of vaccine cases (follow-up report No. 2).

6 December 2004

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Classical Swine Fever In Japan - JAPAN - This is a report via OIE on the detection of vaccine cases (follow-up report No. 2).

Information received on 26 November 2004 from Dr Masako Kurimoto, Director of Animal Health and Animal Products Safety Division, Ministry of Agriculture, Forestry and Fisheries, Tokyo:

End of previous report period: 6 August 2004 (see Disease Information, 17 [32], 229, dated 6 August 2004).

End of this report period: 26 November 2004.

Two new events were reported in relation with the vaccine cases of classical swine fever (CSF) detected in March, July and August 2004 (see: Summary table of each event of classical swine fever in Japan in 2004).

The following information is on the final outcome produced by the control measures, such as epidemiological surveillance and inspections to confirm the classical swine fever free situation, that were actively carried out and were completed in November 2004.

Virus

Based on the result of genetic analysis of virus sequences, it was concluded that all the viruses isolated in the 2nd to the 5th events were identical with the one in the 1st event caused by the use of unapproved vaccine.

Control measures

In all cases, control movement was applied within a 3-km radius around the infected premises immediately after detection, and that restriction was lifted when the premises were confirmed to be free of infection by means of on-site inspection, serological tests and virus isolation tests. All pigs in the five premises where infected animals were detected were destroyed.

Epidemiological investigations

To investigate the situation regarding the use of unapproved vaccines, the Animal Hygiene Centre carried out on-site inspections in the five infected farms. However, apart from in the 1st event (in March 2004), it was not possible to verify evidence implying the illegal use of unapproved vaccine.

As for the investigation to determine the source of unapproved vaccines, in spite of strenuous efforts being made in cooperation with the appropriate Ministries and prefectural government and with relevant organisations, no useful information could finally be obtained on vaccine sales, analysis, marketing, etc.

Confirmatory tests for CSF free situation

On-site inspections, serological tests and disease investigations (including pathological diagnosis and virus isolation) have been implemented in all 1,008 pig farms located in Kagoshima prefecture. No evidence of any CSF outbreaks was found.

On-site inspections, serological tests and disease investigations in all pigs in 68 farms located in the area under movement restrictions in Kanoya have been carried out since 28 October 2004, with an interval of more than 40 days after confirmation of the 5th (last) case.

Since 12 August 2004, all pig farm owners in Kanoya have been required to report weekly on the number of dead animals and the existence of any clinically suspected cases, in accordance with Article 52 of “the Domestic Animal Infectious Diseases Control Law“.

In addition, prefectural veterinary officers have carried out further inspection on dead pigs if necessary.

To date, no cases have been detected despite these strict control measures.

Conclusion

Considering the fact that on-site inspection, serological tests and analysis of dead pigs have been implemented and that no suspected cases have been reported for a given period, as stated above, infection with CSF virus induced by application of unapproved vaccine has been eradicated.