"Clusters" of CJD in Slovakia: the first statistically significant temporo-spatial accumulations of rural cases.

A space-time analysis of clustering among 78 definite CJD cases who died in Slovakia (75) and an adjacent part of Hungary (3) during 1972-1991 is presented. Two geographical rural accumulations of sporadic and familial CJD patients in the north and south of Central Slovakia were found. There was evidence of two significant clusters when spatial and temporal neighborhoods were defined by distances of 2,4,5 and 7 km within 1.5 and 2 years. Involvement of genetic mechanisms in the clusters was demonstrated, and the possible role of environmental (zoonotic) risk factors are considered.