Other trypanosomes, more or less allied to T. brucei, and possibly representing only varieties of the same parasite, have been observed in German East Africa and Togoland among cattle, horses, and other animals. Again, the disease known as "aino," which occurs in Somaliland among dromedaries, and which Brumpt believes to be transmitted by G. longipennis, locally termed the "aino," is probably a variety of nagana.
T. equiperdlim (T. rougeti) (Dofl., 1901); length, 25-28 μ; breadth, 1½-2 μ; differs from T. brucei in not having prominent granules in the cytoplasm. It is the cause of a peculiar disease in stallions, brood mares, and donkeys, occurring in South Europe, North Africa, Chile, and probably in the United States, and known as dourine or mal du co'it. The latter name it has received from the fact that, as a rule, the infection is communicated through coitus. It is not yet certain whether the parasites have any alternate insect host into which they must pass at intervals in order to complete the life-cycle. Fleas have been suggested as possible intermediaries.
Symptoms appear in from ten to twenty days after infection. They begin in the case of the stallion with oedema of the sheath and some inflammation of the end of the penis and discharge from the urethra; in the mare there is a similar oedema of one or both labia and a muco-purulent vaginitis. Concurrently with increase of these symptoms oedema of the limbs and of the abdominal walls sets in, together with pro- gressive anaemia, wasting, muscular weakness, flexion of the fetlocks, and skin eruptions. The appetite is preserved. Fever, except at the outset (40° C.), rarely exceeds 39° C. The disease continues for many months four to ten. Before death weakness increases, the cornea may ulcerate, and there may be complete paraplegia from softening of the spinal cord.
The trypanosome of dourine occurs in the blood, but in numbers so scanty that to communicate the infection with certainty by this medium it may be necessary to inject from 10 to 15 c.c. Hence the improbability of infection by biting insects. On the other hand, it occurs in great abundance in the oedematous tissues, in the skin lesions, in the lymph, and in the discharge from the genitals.
In marked contrast with T. brucei, T. equiperdum is but feebly pathogenic to rats and mice, some of the former being quite refractory. In the rabbit and dog the disease resembles that in the horse, and is communicable by coitus. Monkeys, goats, sheep, and bovines are said to be insusceptible.
Although in many respects the parasites of dourine and nagana resemble each other, the differences in susceptibility of various animals as regards the two parasites indicate specific difference.
T. equinum (Voges, 1902); length, 22-55 μ; breadth, l.5-2 μ. This parasite is clearly distinguished from the above-mentioned species by the very minute size of its blepharoplast. The cytoplasm contains granules, but not so numerous as in T. brucei. Its normal vertebrate host is probably the capy-
