SEAC's recommendation was a consequence of the description of 10 cases of atypical Creutzfeldt-Jakob disease in persons of average age 27.5 years which were subsequently reported in an article in The Lancet of April 6.
SEAC's conclusion as to the origin of these unusual cases was as follows:
'On current evidence, and in the absence of any credible alternative, the most likely explanation at present is that these cases are linked to exposure to BSE before the introduction of the SBO ban (ie, the Specified Bovine Offals Order) in 1989.'
Most importantly, the 10 atypical cases have no discernible association with occupational exposure. Nevertheless, although no cases of the occupational transmission of BSE have been reported, vigilance needs to be maintained to ascertain any potential link.
The ACDP has re-examined , in the light of current evidence, the principles of the control measures recommended in the various guidance publications for abattoir workers, farmers, laboratory workers, vets, zoo-keepers and others published since 1990.
The ACDP advises that, subject to some adaptation to specific occupational settings, the prudent precautions incorporated in the current guidance remain valid.
The committee considers that there is no evidence of risk of transmission of BSE to humans from contact with live cattle in normal farming practices, or in dealing with their intact carcasses.
Furthermore in considering likely routes of transmission, it is the committee's opinion that the transmissible spongiform encephalopathies (TSEs), including BSE, are unlikely to be transmitted by the respiratory route.
Nevertheless, the committee strongly recommends that high standards of personal and occupational hygiene are maintained. Most importantly, there is a continuing need to protect persons in exposed occupations against splashing by specified bovine materials (SBM) especially those from the central nervous system.
If BSE is transmissible to humans in the occupational setting, then the most likely routes are from SBM contaminating wounds and skin lesions, splashing mucous membranes or ingestion.
On this basis, the ACDP advises that the most appropriate course of action, in the light of current knowledge, is to re-emphasise those principles already incorporated in the various guidance publications issued to date.
Attention should be paid to their consistent application by employers. The ACDP advises that all current guidance should be reviewed and revised where necessary to emphasise these points. The committee has agreed to establish a working group to examine, in detail, each item of guidance and determine where any specific changes are necessary.
This working group, which will include expertise from a spectrum of scientific disciplines, will meet shortly and will also be charged with identifying the need for any other targeted guidance.
The ACDP strongly endorses research already under way - for example: on the inactivation of the BSE agent; on the development of rapid diagnostic methods for detecting the disease; on the nature of the BSE agent; and on the molecular basis of the pathogenesis of BSE.
The ACDP working group has also been specifically delegated to identify any gaps in knowledge that impact on the derivation of the committee's recommendations such as: the routes of transmission of the BSE agent; the potential for aerosols and dusts to transmit BSE; the extent of generation of aerosols and dusts in working practices such as those in use in abattoirs and rendering plants.
The elements of the precautions advocated in the guidance issued to date are as follows:
- cover cuts and abrasions with waterproof dressings;
- wear protective clothing, including gloves of types appropriate to the work to be done;
- avoid cuts and puncture wounds;
- use face protection (chiefly for eyes and mouth) if there is a risk of splashing;
- avoid or minimise the use of equipment or tools likely to cause cuts, abrasions or puncture wounds wherever possible;
- wash hands and exposed skin before eating/drinking/smoking;
- wash down contaminated areas with detergent/disinfectant;
- wash and disinfect protective clothing after use.
Laboratories handling materials known or suspected to come from any source of TSE should continue to observe the precautions already recommended in the ACDP publication 'Precautions for Work with Human and Animal Transmissible Spongiform Encephalopathies'.