Leprosy. The terminology of this disease is somewhat confused; it was called by the ancients elephantiasis and lepra, but the latter term at least was also used of other forms of disease (of psoriasis, for example). In modern times, too, both these names have been applied to other diseases as well; Elephantiasis Arabum (q.v.) is distinct from leprosy, which is distinguished as Elephantiasis Græcorum, or Lepra Arabum. It is also sometimes called Leontiasis.
History and Distribution.—It is highly probable that what is now known as leprosy was one of the diseases, though certainly not the only one, spoken of by that name in the English Bible; Leviticus xiii. deals specially with the rules for the detection and isolation of cases of leprosy. It is not mentioned there prior to the sojourn of the Israelites in Egypt. It is worthy of note that it was regarded by the earlier Greek and Roman writers as an Egyptian disease. But it certainly existed in India and China at very early periods. Regarding its first appearance in Europe nothing is known. It has been supposed that it was brought from the East by the Crusaders; but there is evidence that it was prevalent long before the first crusade. During the middle ages it was extremely common; lazar-houses, dedicated to St Lazarus (from whom lepers were called also lazars), existed throughout Europe, including the British Islands, for the reception of lepers, though in all likelihood not for them exclusively. Efforts were made to secure stringent isolation. The old Jewish leper with his rent garments and melancholy cry, 'Unclean! unclean!' was reproduced in the medieval leper, with a gray gown and a clapper to announce his approach. Since about the 14th century leprosy has been steadily declining in Europe. From Shetland where (as also in Cornwall) it lingered long, leper, of a leprosy stock, was sent to Edinburgh Infirmary in 1798, and a few cases occurred in the beginning of the 19th century. Liberton, near Edinburgh, is believed to take its name from the leper-house established there.
At the present day the only part of Europe where it is common is Norway; but it also occurs in Iceland, on the Russian coasts of the Baltic and Gulf of Finland, in south Russia, in Portugal, Spain, Italy, Turkey, Greece, and many of the Mediterranean islands. Everywhere in Europe, however, it is found only in limited districts. In Africa it is met with almost all round the coast and in the adjacent islands. In Asia it occurs in all the countries and most of the islands on the south, from Arabia and Persia to China and Japan. In America it occurs in New Brunswick, in Central America, the West Indies, and the northern and eastern parts of South America. In the United States and in Australia cases have occurred, but almost all among the Chinese immigrants; in New Zealand it is much more common among the natives. In the Sandwich Islands it seems to have first appeared about 1850, but has spread with alarming rapidity; it is also met with in some others of the Pacific islands (for the leper island of Molokai and its institution, see HAWAII). The seclusion of lepers is in most places carefully aimed at. Larger or smaller leper-hospitals are found in all countries where lepers are numerous; notable ones being at Bergen, Tracadie (in New Brunswick; administered by devoted religious sisters), Robben Island (near Cape Town); there are upwards of a dozen in India.
Cause and Mode of Spreading.—The above list of localities is enough to show that the disease is not dependent upon climate. There has been a general belief from time immemorial in countries where it occurs that it is contagious; but, though numerous cases are met with of persons temporarily residing in districts where the disease is prevalent who have become affected by it, instances are extremely rare in which they have communicated the disease to others in countries where it is not endemic; and if it is contagious, it must be under very rare and exceptional conditions. Almost all qualified observers, however, believe that the disease, or a constitutional tendency to it, is strongly hereditary. Evidence has recently been adduced which seems to show that it may be communicated by vaccination from a leprosy child. Insanitary conditions, filthy habits, and unwholesome food are generally believed to favour its occurrence; though persons in comfortable circumstances are by no means exempt. Some authorities, among whom Mr Jonathan Hutchinson is prominent, think that 'in some way fish-food, and especially when either salted or decomposed,' is the main cause of its origin. In 1874 Hansen of Bergen found a bacillus, extremely like the bacillus of tubercle, afterwards discovered, in the affected tissues; and his observations have been confirmed by many other observers, so that there is no doubt that this organism is a constant feature of the disease.
Symptoms and Course.—The disease is usually very slow and insidious in its appearance and progress. The earliest symptoms are debility, depression, loss of appetite, and general constitutional disturbance. Two forms of the disease are recognised, tubercular and anaesthetic leprosy, according to the tissues first and chiefly involved. In the tubercular form the earliest recognisable change consists in the appearance of reddish-brown spots on the skin, usually of the limbs, tender to the touch, and somewhat swollen. They may disappear, leaving the skin only slightly thickened; but repeated attacks occur and affect wider areas; ultimately the skin of the face becomes thickened, puckered, and nodulated, giving a 'peculiar, heavy, morose expression'; the hands and feet become similarly affected; some of the nodulated spots form into deep intractable ulcers; owing to changes in the cornea the sight is dimmed or lost; the tubercular membrane of the mouth and throat becomes thickened, and the voice reduced to a hoarse whisper. In the anaesthetic form certain of the nerves are chiefly affected, and before any visible changes occur sensation is lost in the areas of skin supplied by them. Mutilation of the fingers and toes often occurs, the bones being destroyed, or the whole parts dropping off, often without pain. This form is generally slower in its progress than the tubercular form, but frequently leads to the development of the latter. In whatever way the disease begins, the constitution is slowly enfeebled, and the sufferer falls a ready victim to some intercurrent malady; for leprosy is seldom itself the direct cause of death.
Treatment.—The disease may under favourable conditions remain quiescent for long periods. In the Tracadie lazaretto there have been patients who have suffered from leprosy for fifty years. Cases have even been reported of complete recovery. Improvement has sometimes followed the use of Gurjun (q.v.) and Chaulmoogra oils. But in the vast majority of cases no treatment has proved of any use in arresting the progress of the disease.
See a monograph on True Leprosy by Liveing (1873); and the works on Skin Diseases by Wilson, Hutchinson, and others. For medieval leprosy, see Sir J. Y. Simpson in Edin. Med. and Surg. Jour. (1846-47); for leprosy in India (where in 1888 there were 135,000 lepers, or, according to other estimates, 250,000), see Vandyke Carter's work (1873); for leprosy on Robben Island, see Blackwood's Magazine for 1889.