A study of the records of 82 California hospitals, including 64.8% of hospital beds in the Central Valley and practically all of the state's referral beds, disclosed 69 cases of hydatid disease, 61 of them from the decade 1960–69. Among the 13 California-born patients, three new cases were found that were autochthonous to this state. Two modes of infection may be recognized among these patients. One involves principally native Californians plus immigrants from the Basque country of Spain and France and is associated with the sheep industry in the Central Valley of California. The second involves the more cosmopolitan urban populations of this state. The former mode includes infections acquired in California, while the latter represents mainly foreign-born patients from a number of countries in which infection with Echinococcus granulosus is endemic.
Present address: Veterinary Medical Officer, California State Department of Agriculture, 645 Aurora St., El Centro, California 92243.