Creutzfeldt-Jakob disease cluster in an Australian rural city

Through the Australian National Creutzfeldt-Jakob Disease Registry, 6 pathologically confirmed sporadic cases were recognized over a 13-year period in persons who had been long-term residents of a moderate-sized rural city, whereas the expected number was 0.923. An extensive investigation could not find any point-source or case-to-case transmission links. This occurrence is highly statistically significant (p = 0.0027) when viewed in isolation and remains significant (p < 0.02) when only the cases that arose after the cluster was recognized were taken into account. However, a more conservative statistical analysis suggests that such a grouping could have arisen by chance in at least one population group of this size when the whole country is taken into consideration.