Regional Workshop on BSE Diagnosis and Surveillance Bangkok, Thailand, 19-22 November 2001
The OIE/FAO-APHCA/DLD* Regional Workshop on Bovine Spongiform Encephalopathy (BSE) Diagnosis and Surveillance was held in Bangkok, Thailand on 19-22 November 2001. The opening ceremony and subsequent lectures were attended by about 250 people including participants and observers from eight countries/territories: Hong Kong, China, Taipei China, Republic of Korea, the Philippines, Thailand, Malaysia and Vietnam, and Switzerland (three speakers) and two international organisations: OIE and FAO (including one speaker).
The presentation on the Overall Aspects on BSE Diagnosis and Surveillance included Transmissible Spongiform Encephalopathy (TSE) in general, current situation of BSE worldwide, quoting BSE in UK, Switzerland and other countries, epidemiological aspects including age of the BSE cases, cases per herd, surveillance both in passive and active ways, diagnosis of BSE, targeted surveillance, organisation and initial problems of the targeted surveillance in Switzerland, measures taken for animal health and public health, processing of animal waste, effect of the measures concerning feed, elimination of BSE cases, risk assessment of BSE, and problems and lessons to be learned.
The lecture on Bovine Spongiform Encephalopathy, Risk Management Under Different Livestock Production Systems - Veterinary Services' Capacity and Structures covered: how to identify BSE or TSE cases in a country, effective communication and incentive-based reporting from livestock industry, risk-based, clinical syndrome-based surveillance to identify TSE cases and collaboration with human health authorities.
A paper on Sample Collection and Biosafety, Pathogenesis and Diagnosis of TSE was presented which included characteristics of TSE, causes of Spongiform Encephalopathy, prion protein, support of the prion theory, BSE pathogenesis, vertical transmission of BSE, species barrier, BSE in transgenic mice, genetic code, neuropathology of TSE (neuropil and intraneuronal vacuolation, neuronal degeneration, gliosis, PrP accumulation) and differential diagnosis for BSE.
The lecture on Laboratory Diagnosis of TSE covered methods of TSE diagnosis, clinical symptoms including typical and atypical clinical presentation of BSE, factors influencing the number of reported clinical BSE cases, some anti-PrP antibodies, EU-validated BSE rapid tests, required conditions, new attempts to demonstrate PrP, and further tests for TSE, particularly BSE.
After the lectures, a demonstration of sample collection of medulla oblongata was given, and the participants practiced preparing samples for histopathology and immunohistochemistry (IHC) using cattle heads provided.
The participants were also engaged in microscopic observations on histopathological slides. The slide collection included different types of diseases, which provided the participants with interesting experiences to observe histopathological changes in the brain caused by different diseases including listeriosis, sepsis, brain abscess, lymphosarcoma, ependymoma and brain edema as well as BSE and Scrapie.
The important and critical points of brain changes caused by BSE and scrapie on the HE stained and IHC sections were explained by the lecturers, and discussions followed on the pathological changes characterised by these diseases.
All the participants participated in IHC practices, including bovine PrP staining on paraffin sections. During the ongoing process of preparatory stage of section staining, the lecture using audiovisual aids helped the participants discuss and understand the whole process of preparation for the IHC test. In addition, the participants had a chance to observe negative, positive and false positive sections provided by the lecturers, as well as the sections stained during the workshop.
The participants were also given instructions for preparing samples for rapid tests. They gained theoretical and practical experiences on BSE diagnosis using the ELISA technique. The practices on ELISA test using negative and positive samples were made in line with the protocol. The theory of Western blot was given intensively by the lecturer as well.
- OIE = Office International des Epizooties
- FAO-APHCA = FAO Animal Production and Health Commission for Asia and the Pacific
- DLD = Department of Livestock Development, Thai Ministry of Agriculture and Cooperatives