(Elsevier Ltd, 2000-02) Ward, Michael P; Carpenter, Tim E.
Techniques to describe and investigate clustering of disease in space Ð the nearest-neighbour
test, autocorrelation, Cuzick-and-Edwards' test and the spatial scan statistic Ð and in time Ð the
Ederer±Myers±Mantel test and the temporal scan statistic Ð are reviewed. The application of these
techniques in veterinary epidemiology is demonstrated by the analysis of a data set describing the
occurrence of blowfly strike Ð both body strike and breech strike Ð between August 1998 and
May 1999 in 33 commercial sheep flocks located within two local government areas of southeastern
Queensland, Australia. By applying a combination of these methods, the occurrence of blowfly
strike in the study area is well-characterised in both space and time. Guidelines for investigating
disease clusters in veterinary epidemiology are discussed. # 2000 Elsevier Science B.V. All rights
reserved.