Transmitting prion diseases in milk

Scrapie can be transmitted to lambs through milk, according to new research published in the online open access journal BMC Veterinary Research. The study provides important information on the transmission of this prion-associated disease and the control of scrapie in affected flocks. Scrapie is a fatal neurodegenerative disease of sheep and goats. Clinical signs include itchiness, head tremor, wool loss and skin lesions as well as changes in behaviour and gait.

Timm Konold and colleagues from the Veterinary Laboratories Agency in Weybridge, UK, investigated the transmission of scrapie by feeding milk from scrapie-affected ewes to lambs that are genetically susceptible to contracting scrapie. The researchers were looking for the presence of the prion protein, PrPd, which is associated with the disease.

Eighteen lambs were fed milk from scrapie-affected ewes. Three of these lambs were culled and two were found to have PrPd in intestinal tissues. The prion protein was also detected in lymphoid tissue of the gut of the surviving lambs and in some control lambs mixed with the scrapie milk recipients after weaning. This suggested that scrapie milk recipients were able to shed the infectious agent and infect other lambs. There was no sign of PrPd in tissue samples from a control group of 10 lambs(one culled and the rest alive), which were housed in the same building but fed milk from healthy ewes. The research will continue, to see whether the lambs with PrPd develop the disease as they get older.

This work raises the possibility that other prion diseases could be transmitted in sheep via milk although it should have no direct implications for human health. Scrapie has been found in sheep and has not been shown to be transmissible to humans. BSE has not been found naturally in sheep and occurrence in sheep in the UK is considered to be unlikely. This research adds to our understanding of the transmission of prion diseases in sheep and would help to inform measures needed to protect human health if BSE were ever to be found in sheep.

Citation: Evidence of scrapie transmission via milk, Timm Konold, S. Jo Moore, Susan J. Bellworthy, and Hugh A. Simmons, BMC Veterinary Research (in press)

Source: BioMed Central

   

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4.7/5 after 3 votes

• googleplex - Apr 17, 2008
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  My hypothesis is that these "Nano diseases" such as BSE prions are the tip of an iceberg and endemic. It is only now that technology is able to detect them and with some difficulty. It is analagous to the discovery and early research of bacteria and viruses.
  It should be noted that nano disease cannot be disinfected like bacteria or viruses. The only effective way I have read is using a plasma autoclave. Incineration should not be used as it causes the pathogen to become airborne. They are very nasty indeed.
  I don't like the idea of shared surgical instruments.
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• bmcghie - Apr 17, 2008
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  Um... incineration works perfectly fine for destroying these particles. If you denature a protein, via heat for example, it ceases to function correctly, if at all. The mutated proteins in BSE act as catalysts for the formation of more of the same particles from a normal protein present in the cow's brain. Presumably, when you destroy their 3D shape, they will lose their enzymatic abilities, just like every other enzyme known to man. The trick is ensuring that you used high enough temperatures to denature any if not all of the proteins in question.
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