Creutzfeldt-Jakob disease (CJD) is a very rare, fatal disease that attacks the nervous system. There are two types of CJD: classical CJD and variant CJD.
Unlike other diseases that are caused by bacteria or viruses, this disease is caused by abnormal pieces of protein called prions. These abnormal prions damage cells of the nervous system, forming holes in the tissue and eventually leading to severe brain damage and death.
Classical CJD is very rare, affecting about 1 person in 1 million each year. About 30 people are diagnosed each year in Canada, most of them are between the ages of 45 and 75 years. The three types of classical CJD include:
- sporadic: this form of the condition occurs with no known cause and affects 85% to 90% of people with classical CJD
- familial: this form appears in families that seem to have a greater likelihood of developing this disease due to their genetics
- iatrogenic: affecting less than 1% of classical CJD cases, people with this form of the condition develop classical CJD from accidental contamination by the abnormal prions, often through contaminated medical equipment
Variant CJD (vCJD) typically affects younger people less than 30 years of age and is associated with eating meat from cows infected with bovine spongiform encephalopathy (BSE), popularly known as "mad cow disease."