Human transmissible spongiform encephalopathies in eleven countries: diagnostic pattern across time, 1993-2002

Background: The objective of this study was to describe the
diagnostic panorama of human transmissible spongiform
encephalopathies across 11 countries. Methods: From data collected
for surveillance purposes, we describe annual proportions of deaths
due to different human transmissible spongiform encephalopathies in
eleven EUROCJD-consortium countries over the period 1993-2002, as
well as variations in the use of diagnostic tests. Using logistic
models we quantified international differences and changes across
time. Results: In general, pre-mortem use of diagnostic
investigations increased with time. International differences in
pathological confirmation of sporadic Creutzfeldt-Jakob disease,
stable over time, were evident. Compared to their counterparts,
some countries displayed remarkable patterns, such as: 1) the high
proportion, increasing with time, of variant Creutzfeldt-Jakob
disease in the United Kingdom, (OR 607.99 95% CI 84.72-4363.40),
and France (OR 18.35, 95% CI 2.20-152.83); 2) high, decreasing
proportions of iatrogenic Creutzfeldt-Jakob disease in France, (OR
5.81 95% CI 4.09-8.24), and the United Kingdom, (OR 1.54 95% CI
1.03-2.30); and, 3) high and stable ratios of genetic forms in
Slovakia (OR 21.82 95% CI 12.42-38.33) and Italy (OR 2.12 95% CI
1.69-2.68). Conclusion: Considerable international variation in
aetiological subtypes of human transmissible spongiform
encephalopathies was evident over the observation period. With the
exception of variant Creutzfeldt- Jakob disease and iatrogenic
Creutzfeldt- Jakob disease in France and the United Kingdom, these
differences persisted across time.