Prophylaxis of Leprosy*

The discussion which followed my last communication and the statement itself were so hurried that I failed to insist on certain aspects which I thought were already known. Then and later, I also realized that for some colleagues the idea of transmission of leprosy by mosquitoes was totally new, although it first came up thirty years ago. I do not claim to have opened a new avenue, nor to have been the very first to bring up this idea, though it is now over a quarter of century that I first thought of this possibility while observing the facts. Being unable to provide positive proof, I did not publish especially on the subject, but mentioned that leprosy as probably belonging to the diseases transmitted by mosquitoes, and requested Prof. Unna to call the attention of leprosy specialists also to this possibility, on my behalf, at an international congress. At that time, unfortunately, the question was completely disregarded by the persons who were most favorably placed for its investigation, and in some places this continues to be so. Besides historicgeographical and statistical studies of interest, but devoid of vital information, the first volumes of Lepra bring only unimportant case-histories. Beginners voice their views on problems which require years of observation and very often conclude in favor of great contagiosity of leprosy because they found two cases in the same family or in the same place, without giving a thought to the numerous and well-known facts which speak against direct contagion. It was only in the last years that experimental pieces of work were undertaken, but their authors generally gave up as soon as they encountered the first difficulties regarding the role of the mosquitoes, without grasping that they are the only insects that can explain the form of propagation of leprosy. For this reason they were led to suggest preferably flies and bedbugs without stopping to ponder that these could not explain the capricious way of propagation. These difficulties were already encountered by Arning and by me, but gradually I found the very probable explanations. The arguments that follow are my own and for this reason my statement was considered subjective. I did not want to repeat arguments and facts which were already known. You cannot acquire knowledge of leprosy and become able to diagnose incipient cases merely by reading the information contained in the French, English, German and Portuguese literature, although it is now much larger than when I began my studies. When one has Prophylaxis of Leprosy*