Leprosy in California; danger of infection.

Reports on the prevalence of leprosy often do not disclose where the infection was acquired. This is important in connection with control measures if the case is found in an area in which transmission to the public is likely to occur. With new interest being taken in this disease by health authorities in the United States, it is desirable to know the danger of spread in different areas. This seemed especially important for California where many cases have been reported. Among 475 cases reported up to 1940, probably not more than 14 had been infected in the State (1) . The present investigation was undertaken to obtain more comprehensive and more recent data. California stands almost alone among the States in being geographically situated for receiving infection from two general sources. The proximity to Mexico, which has many cases, has resulted in the entrance of a very considerable number of cases; from that country. The State is the most convenient port of entry for Hawaii, Japan, and other Pacific islands, as well as China, which has resulted in the importation of a smaller but considerable number of cases. These undoubtedly included active cases and probably a larger number in the incubation stage. At the time California became a part of the United States (1850), the natives, excluding Indians, were designated as Hispano-Californians (Mexicans) and constituted a large part of the population. A number of native Hawaiians came to the State Soon after discovery of gold (1848), and at about the same time Chinese began to come in large numbers. Doubtlessly, both immigrations brought leprosy with them. The first readily available reference to the disease in California is a report by the jail physician of San Francisco in 1877, who mentioned treatment of 3 cases of "leprosis." A little later the State health officer of the day, Dr. H. S. Orme, in an annual report (2) included the following statistical data on lepers in San Francisco from 1871 to 1890, based on California State Board of Health reports from 1886 to 1894: