23. Variant Creutzfeldt-Jakob Disease (vCJD), 1996-2001
VCJD emerged in 1996, with the majority of cases since reported in Great Britain, though it has also been reported in Canada, Asia, the United States, Western Europe, Japan, and Saudi Arabia. Researchers in the United Kingdom identified its primary cause as the consumption of beef with bovine spongiform encephalopathy (BSE), commonly referred to as mad cow disease. The first symptoms include vague sensations of pain in limbs and extremities and psychiatric disorders leading to behavioral changes, including delusions. The time between exposure to the disease and its early symptoms presenting is unknown, though British researchers speculated that it is many years. Once the symptoms present average life expectancy is a little more than one year.
Speculation that the disease is transmitted through blood transfusions changed blood donor policies of several governments during the early 21st century. The United Kingdom, United States, New Zealand, Canada, Poland, the Czech Republic, Finland, and other countries instituted restrictions on blood donors based on their travel histories and other factors. Work to develop a screen for blood supplies was ongoing as of 2018. In the United Kingdom researchers claimed that one person in 2,000 is a carrier of the disease, which continued to make sporadic appearances around the globe in the second decade of the 21st century.