4IO MANUAL OF BACTERIOLOGY. 



somes found in the stomachs of mosquitoes, tsetse flies, house 

 flies, etc., show forms like those met with in cuhures. 



From accumulating data it would appear likely that all 

 species of animals may show trypanosomes in the blood. 

 Novy and McNeal were the first to cultivate them in pure 

 cultures. Herbert U. Williams and Lewis were the first to 

 cultivate the frog trypanosome, Tr. rotatorium, and this 

 furnishes an excellent example for class demonstration. 



Tr. evansi is found in the blood of animals in India and the East, generally 

 suffering from a disease called surra. Horses, mules, camels, dogs and cattle 

 are particularly subject to the disease which is characterized by remittent fever 

 accompanied by anemia and wasting, edema of the legs, belly and other parts, 

 with a discharge from eyes and nose. The organism is transferred from sick 

 to healthy animals through the agency of flies. The disease is seldom fatal. 



Tr. brucei, almost indistinguishable from Tr. evavsi, causes the tsetse fly sick- 

 ness, nagana, of Africa, a most fatal disease of horses, donkeys, dogs, and 

 cattle. Nearly all mammals are susceptible to spontaneous or to artificial infec- 

 tion. Man appears to be immune. Tr. brucei was the first pathogenic try- 

 panosome which was cultivated artificially. Differs markedly in cultures from 

 Tr. lewisi and Tr. evansi. 



Tr. equiperdum causes the disease of horses, known as dourine. The disease 

 is not confined to tropical countries, but is found in many parts of Europe- as 

 well. It is said also to be met with in America. It is not spread as other 

 diseases which are caused by trypanosomes through the agency of flies; but 

 only by sexual contact, and hence is called "mal du coit," it is also called horse 

 syphilis owing to suggestive skin lesions. The diseases may be communi- 

 cated to asses, dogs and rabbits. Rats, mice and guinea-pigs are refractory. 



Tr. equinum causes the disease known as "mal de caderas," occurring almost 

 exclusively in horses. It is characterized by remittent fever, rapid loss in weight, 

 with eventually paralysis of the hind quarters. The organism has no blepharo- 

 plast which distinguishes it from all other trypanosomes. No definite success 

 has attended efforts at cultivation of Tr. equinum. 



Tr. dimorphon causes a disease of horses in Senegambia. No other domestic 

 animal than the horse suffers spontaneously, but most mammals can be arti- 

 ficially infected. 



Tr. theileri causes a disease of cattle in South Africa. 



Tr. gambiensis is the cause of the sleeping sickness of West Africa. The 

 disease is spread through the agency of the tsetse fly, though a different species 

 of this fly from that which spreads the nagana of South Africa. The disease 

 is characterized by two stages: A mild stage marked by mild symptoms 

 consisting of some fever, slight -edema and erythema; the second stage is the 

 sleeping stage always terminating fatally. Most animals may be infected 

 artificiaUy. 



Leishman-Donovan bodies are called with a question mark trypanosomes 

 by Novy who states that they resemble rounded forms of trypanosomes, showing 

 a nucleus and a micro-nucleus. They have no undulating membrane. They 

 are called piroplasma by Laveran. Rogers regards them as belonging to the 

 herpetomonas group and not to the trypanosomes. They are the cause of 

 Kala-Azar, a cachexia! fever of India. 



