EFSA evaluates TSE risk from small ruminants’ milk

In an opinion published today, EFSA’s Panel on Biological Hazards (BIOHAZ) assessed the human and animal exposure to Transmissible Spongiform Encephalopathy (TSEs) agents from milk and milk products derived from sheep and goats. The Panel concluded that milk and milk products from flocks affected by classical scrapie, and to a lesser extent from sheep and goats in general (due to the presence of infected animals showing no clinical signs), could expose animals and humans to the causal agents of this TSE. As classical scrapie is an animal disease and has not been found to affect humans, these findings have implications for animal rather than human health.

EFSA’s study follows a request of the European Commission to deliver an opinion on a recent scientific article from Konold et al.[1], published on 8 April, 2008 in BMC Veterinary Research, which concluded that classical scrapie can be transmitted to genetically susceptible lambs through milk. The Commission also asked EFSA to update, if considered necessary, the current risk assessments on human and animal exposure related to TSEs from milk and milk products derived from sheep and goats.

The opinion updates EFSA’s previous statement[2], which had concluded that milk from small ruminants was unlikely to present a TSE exposure risk, provided it was sourced from clinically healthy animals. “These new findings have implications for animal health. With respect to possible human exposure, we should keep in mind that, with the exception of BSE, TSEs in animals have not been found to affect human health,” Professor Dan Collins, chair of the BIOHAZ Panel, said. EFSA has previously addressed in detail whether TSE agents found in sheep and goats could affect humans[3].

EFSA’s BIOHAZ Panel noted that milk from ewes incubating classical scrapie could contain the causal agents of this TSE, even when the ewes show no symptoms and appear healthy. The Panel pointed out that as both the prevalence of classical scrapie and the production of milk from sheep and goats vary greatly between Member States, so will the potential risk of exposure.

EFSA’s BIOHAZ Panel also analysed data on the exposure risk to atypical scrapie and BSE. The Panel noted that in sheep and goats no information was available on whether or not these TSE agents are present in the milk of infected animals. To date, only one single case of naturally occurring BSE has been identified in goats and none in sheep.

The Panel recommended that more research should be carried out to assess the exposure risk from milk, in particular in the case of atypical scrapie and BSE, and to evaluate what would happen to these TSE agents if and when milk from affected sheep flocks or goat herds is processed for consumption as milk or other dairy products.

The French Food Safety Agency, Afssa, is also publishing an opinion on the possible implications for animal and human health of newly available scientific data regarding the transmission of the classical scrapie agent via milk. EFSA and Afssa have kept each other informed of their respective ongoing work and of the conclusions of their independent risk assessments.

Human and animal exposure risk related to Transmissible Spongiform Encephalopathies (TSEs) from milk and milk products derived from small ruminants Scientific opinion of the Panel on Biological Hazards

Notes to editors

The issue of the risk to humans by TSEs in sheep and goats has been previously assessed by EFSA in detail. The BIOHAZ Panel concluded in March 2007 that there is no evidence for an epidemiological or molecular link between classical and/or atypical scrapie and TSEs in humans. The BSE agent is the only TSE agent identified as zoonotic, ie that can be transmitted from infected animals to humans.

For more information see:

[1] Konold, T., Moore, S. J., Bellworthy, S. J. and Simmons, H. A. 2008. Evidence of classical scrapie transmission via milk. BMC Vet Res 4. 1, 14.
[2] EFSA provides preliminary advice on health risks of goat milk and derived products with regards to BSE/TSE
[3] See notes for editors and links to previous EFSA’s statements and opinions, for further information.

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