Regional differences in leprosy; leprosy among Chinese in Malaya.

Regional differences in leprosy constitute major difficulties in our common understanding of the disease. The incidence of lepra fever, tuberculoid reaction, .ulcerative tuberculoid leprosy, leprotic affections of the eye, peripheral nerve involvement and leprotic alopecia varies so markedly as to make the commonplaces of one area the rarities of another. Again the relative proportion of tuberculoid and lepromatous leprosy in different countries, and even districts, is often in marked contrast. It seems probable too that the incidence of "uncharacteristic " cases shows the same variety in distribution. Lastly the disease seems to vary in virulence in different places even within the same types. The three factors which appear to influence variations in the course of the disease are race, climate and social conditions .