CJD: it hasn’t gone away

The science of the variant form of the disease is still exercising scientific minds around the world, and more practical guidance for healthcare is regularly updated by the Advisory Committee on Dangerous Pathogens (ACDP) Transmissible Spongiform Encephalopathy (TSE) Working Group. Much of their guidance has been recently updated, changing some instructions to healthcare staff working in many different fields of healthcare. The author will highlight where it is believed that practice should change to reflect the new guidance. Creutzfeldt Jacob Disease (CJD) is a group of rare diseases known as transmissible spongiform encephalopathies, which affect the structure of brain causing neurological symptoms and dementias. The diseases are caused by an abnormal folding of a protein, called a prion. All forms of the disease are incurable. Although the majority of the UK population is thought to have been exposed until 1996, via beef products, the precise prevalence of preclinical infection of vCJD is unknown. The most reliable evidence comes from analysis of anonymised appendix and tonsil tissue taken from UK patients between 1995-1999. In this study,1 three positive samples from 12,674 samples tested, equates to a prevalence of approximately 1:4,000 cases. Although the infectious risk of these cases is uncertain, there is obvious potential for iatrogenic transmission in a significant number of patients. Figure 1 demonstrates the number of patients who have definitely or probably died from all forms of CJD since 1990.

Sporadic CJD (sCJD)

This is the most common of the CJDs, affecting older people and is known to affect around one in a million people in the world, thus giving an incidence of around 60 new cases per year in UK. Early symptoms are usually behavioural disturbance or mental deterioration. Within weeks the patient may become unsteady on their feet and show rapid onset dementia. Death is usually a few months after the first symptoms appear.