888 MICROBIOLOGY OF DISEASES OF MAN AND DOMESTIC ANIMALS 



horses, cattle, and other domestic animals in many parts of Africa; 

 they are probably all transmitted by the bites of flies. 



One of the commonest trypanosomes is Trypanosoma lewisi (Kent). 

 It is usually a harmless parasite and it is found in rats in all parts of 

 the world. It is transmitted through the rat flea. Trypanosomes 

 ingested by fleas develop and are excreted in a resting stage with the 

 fleas' droppings. Rats, swallowing the infected droppings, or fleas, 

 become infected. It is not transmissible to other mammals. 



Dourine or maladie de coit, is a serious disease of equines; it is 

 caused by Trypanosoma equiperdum (Doflein). This disease was 

 brought to North America by an imported Percheron stallion. It is 

 now endemic in some of the western states and in part of southern 

 Alberta, in Canada. It is transmitted by coitus and, perhaps, rarely 

 by the bites of fleas. 



A very large trypanosome, Trypanosoma theileri (Bruce), occurs in 

 cattle in southern Europe and in Africa. A similar large trypanosome, 

 Trypanosoma aniericanum, has been found in cattle in the United 

 States. These trypanosomes seem to do no harm to their hosts. 



Although there are slight differences, the symptoms are much the 

 same in all the trypanosomiases of animals, and they much resemble 

 those which occur in the diseases produced in men by trypanosomes. 

 Occasionally, as in nagana, an animal trypanosomiasis may run an acute 

 course, and kill the host in two or three weeks, but usually, they are 

 diseases of long duration, characterized by irregular fever, cedemas and 

 progressive loss of strength, weight, and energy. Localized areas of 

 oedema beneath the skin and about the genitals are especially seen in 

 dourine; Trypanosoma equiperdum is most easily found by examining 

 serum obtained by puncturing these cedemas. 



The remaining flagellates, mentioned in the classification on page 

 14, are unimportant. They are usually parasites of the urinary or 

 intestinal tracts and they may be associated with inflammation of 

 these parts. 



SPOROZOA (Leuckart, 1879) 

 This class contains many very important pathogenic parasites. 



COCCIDIA (Leuckart) 



Coccidia of various species are parasitic in the epithelial cells lining 

 the intestines of mice, horses, cattle, pigs, goats, and other animals. 



