Alveolar hydatid disease (AHD) is a zoonotic disease of humans caused by the larval stage of the canine tapeworm Echinococcus multilocularis. E. multilocularis has been restricted to the upper latitudes of the northern hemisphere where transmission involves a sylvatic life-cycle involving wild canines and rodents. In the United States, E. multilocularis is endemic to northwest Alaska and has become endemic in the United States northern great plains since the early 1960's. Infection of humans is by inadvertent ingestion of eggs excreted by an infected canine. The long term objective of the proposed studies is to assess and monitor the potential risk of AND within the northern great plains. Difficulties arise when determination of the prevalence of E. multilocularis in dogs is necessary due to the morphological identity that the eggs share with other non-zoonotic dog tapeworms such as T. pisiformis. Therefore the central aim of this proposal is to develop a nonradioactive total genomic DNA probe that can be used to differentiate E. multilocularis in dog fecal flotations either using dot blot or microscope slide techniques.