Remarks on Trypanosome Diseases
Authors: R. Koch
Journal: BMJ (1904)

A NEw department for the investigation of infectious diseases has of late been opened up by bacteriology, that, namely, *relating to pathological protozoa.At first small and insigni-Scant, it became in a short time of great importance, and appears to be still increasing. HISTORY.The first discoyery in this new sphere was that of the alaria parasites, which we owe to Laveran.This was com- pleted and extended by the discoveries of R. Ross, who ,pursued the intricate course of development of malaria parasites in the body of mosquitos, and proved that malarial infection did not originate in decomposed organic matter nor Sin marshes, but is transmitted by infected mosquitos to healthy human beings.The etiology of Texas fever was then discovered by Th.Smith.This also was shown to be duie to a protozoon, which, like the malaria parasite, entered the red blood cor- puscles, and was transmitted by a blood-sucking insect, the wood-tick.The third important discovery was by Bruce, who found "the trypanosome of tsetse-fly disease in the blood, and showed that a stinging fly, belonging to the genus Glossina was the agent in transmitting this disease.In addition to these discoveries there have been numerous others of protozoal diseases in animals, but especially in man.Among these latter may bementioned: trypanosomiasis and sleeping sickness in Africa; the spotted fever in North America; tropical splenomegaly, in which protozoa have been proved to exist by Leishman, Donovan, and Marchand, and the Oriental boil (called also Delhi, Aleppo, or Biskra boil), the parasites of which were discovered by Wright.Scientifically and economically the protozoal diseases have nowadays acquired such importance that the practising physician must take notice of them.I have been asked by the directors of the Berlin Medical Society to tell you of my *bservations and experiences in Africa, to interest you in ,them, and to choose a subject from the region of pathological protozoa, and so I will give you some intormation about one *f the.most interesting groups-the trypanosomes.7GENERAL MORPHOLOGY AND SYMPTOMS.4]Before passing, however, to the principal subject of my discourse, it seems to me important for your enlightenment to give you a short description of the trypanosoma and trypanosome diseases which will come under your notice.Trypanosomes belong to the flagellata, the ciliated pro- tozoa.If blood containing trypanosomes be examined microscopically in a fresh state it is easy, under a moderate power, to recognize the relatively large and actively moving parasites.Their form, however, can only be distinguished when they are at rest.They then resemble a fish, are twice or three times as long as a red blood corpuscle, have a long Sagella, and on one side an undulating membrane.The ner structure can be made most distinctly visible by Romanowrsky's stain (Giemsa's modification).There is then seen a rather large red-stained nucleus, a granule stained very deeply red close to the hinder end, which looks like a centro- some, and, issuing from the latter, a red line extending to the edge of the undulating membrane which passes into the dagella, which is likewise stained red.The body of the trypanosome is shown by the blue staining of the plasma.Trypanosomes do not form pigments as do malaria parasites, from which we may conclude that they do not derive nutri- ment from the haemoglobin, but from the constituents of the blood plasma.They increase by longitudinal fission.All trypanosome diseases have this in common that, like malarial diseases, they may run a rather acute course, but as a rule drag on for a J^ng time, often for years.In their symptoms, too, they iewn resemble malaria.They give rise to irregular fever, often interrupted by longer or shorter intermissions, to anaemia, emaciation, weakness, localized oedema, and swelling *f the lymphatic glands and spleen.