Leprosy

by G. Armauer Hansen; Carl Looft

Anyone who will maintain that these two forms of conveyance are the same, and both hereditary, must evidently sacrifice facts.

We hold then, that a specific disease may be conveyed to the children, but that it is never hereditary; the communication is by infection.

And since we regard leprosy as a specific disease we hold that it cannot be hereditary. There remains, however, the further question whether it can be conveyed to descendants by latent germinative infection. This cannot a priori be denied, although we have no right to assume it from our knowledge of the lepra bacillus and of the occurrence of the disease. We have indeed sought above to point out the possibility that the lepra bacillus is attenuated in the maculo-anæsthetic form of the disease; but we know of no phenomenon which would allow us to assume that the bacillus could occasionally become quite innocuous, and call forth no symptoms of disease.

All this, however, proves nothing against the hypothesis; and it is always a dangerous thing to use a simple absence of knowledge either to contradict or to found a hypothesis.

But we think we can supply an almost incontrovertible proof that Baumgarten’s hypothesis is wrong. It is well known that the Belgian Father Damien became a leper in the Sandwich islands. If the Father was of pure Belgian ancestry, and his disease was caused by latent hereditary bacilli, then these bacilli must have been at least several hundred years old, unless one assumes that one of his nearer ancestors had had connection with a leper, and that in this way the Father had acquired his bacilli. Against this is the explanation that the Father who tended the lepers on Molokai, with self-sacrificing love, was, through some want of care or caution, infected as he went in and out among the lepers. The choice between the two explanations does not appear to us a difficult one.

The view of the non-communication of leprosy by latent bacilli is further strengthened by the fact that there are places in Norway where many descendants of lepers live without one single one of them becoming leprous, as for example, in the town of Bergen where the descendants of lepers may certainly be numbered by thousands; and further, we have demonstrated by our investigations in North America, that of the numerous descendants of Norwegian lepers there, not one has developed the disease. But since about one hundred and seventy leprous Norwegians have emigrated to America, it may possibly be that the disease is spread by infection. There are indeed cases in America which have possibly arisen from infection, but they are not sufficiently definite to serve as arguments for its contagion. But even if leprosy be a contagious disease, one can easily understand how it should spread little, or not at all, in North America, when one compares the social condition and especially the cleanliness there with that in Norway, and probably especially with that of the districts in which leprosy is most prevalent. In North America the dwelling houses are roomy, so that the lepers whom we saw there had usually their own room, or at least their own bed; and everywhere, even among the Norwegians, great cleanliness is observed. And this is, according to our view, sufficient isolation in order, in most cases, to prevent the spread of the disease.

That leprosy is really contagious is primarily evident from its nature as a bacillary disease. No one has been able to demonstrate the presence of the bacillus outside the human body, so that we may abandon the idea of a miasmatic origin.

Unfortunately, all attempts to inoculate animals have failed. The now old experiments of Neisser and Damsch, as well as our own, we may pass over. We dealt with them in our Copenhagen communication. Since then Melcher and Ortmann believe that they have communicated the disease to rabbits. Dr. Ortmann has kindly sent us preparations from the infected rabbits, and on close examination of them we regret to say that we lost our faith in the leprous nature of this affection of rabbits. We found both caseous degeneration and myelo-plaques in the preparation, which, as we have noted, we have never found in leprosy. At the same time the affection does not look exactly like tubercle, and it is possible that in rabbits leprosy appears otherwise than in man. But we may note that Veterinary Surgeon Nielsen has, here in Bergen, observed a disease in mice, which shows a close resemblance to Ortmann’s rabbit leprosy. Inoculated on a rabbit, the disease appeared with new growths in the cœcum, just like Ortmann’s rabbit leprosy. These new growths had certainly more resemblance to tuberculosis; but there were in them, at many places around the vessels, cells, crammed full of bacilli. Nielsen’s investigations are not yet concluded, but it is possible that the disease is one of animals as yet unknown, which Melcher and Ortmann have by chance conveyed to their rabbits. All the inoculations of leprosy on rabbits which Dr. P. F. Holst made in the laboratory of the Lungegaards Hospital were unsuccessful; not one of the infected animals became leprous.

Although, as we have stated above, the lepra bacillus has never been found outside the human body, this might possibly be dependent on insufficient search, and it might be possible that the old view at present maintained by Hutchinson is the right one, viz., that leprosy is caused by the eating of putrifying fish, or that the contention of Holmsen that leprosy is a miasmatic disease, is correct.

Against Hutchinson’s hypothesis there is in the first place the fact that we have never succeeded in cultivating the bacillus, which, if the bacillus lived as a saprophyte on decaying fish, would be a very simple matter. And there are, secondly, places where the inhabitants certainly and frequently enjoy decaying fish without the disease appearing. And thirdly, there are many places authoritatively indicated where leprosy is present, and where no fish is ever eaten. For his hypothesis of the miasmatic origin, Holmsen can only bring forward the fact that the disease is often limited to certain districts. This is certainly correct, but this endemic appearance of leprosy may be as readily explained by infection, while the localities affected do not give the slightest support to the assumption of a miasma. Such areas are found here in Norway, both on the bare cliffs, on the coast, in the valleys, and on the mountains.