808 Nagana. 



the Gl. lougipeimis, the Gl. palpalis and the Gl. Decorsei are also capable 

 of transmission. 



According to former vie^s the tsetse fly transmitted the infection 

 only mechanically, and as trypanosomes could be demonstrated in their 

 intestines 48 hours after sucking the blood, it was supposed that after 

 that time healthy animals could become infected only Avhen the flies 

 had in the meantime again alighted on infected animals. According to 

 the newer results of investigations on the generation changes of the 

 parasites (see p. 799), the possibility must be considered that the flies 

 may transmit the parasites for weeks. 



In accordance with the part played by the insects in the 

 transmission of the disease this usually rages in low-lying 

 localities with damp soil, especially during warm periods and 

 rainy seasons, the animals being exposed to the infection es- 

 l^ecially during the day, as long as they are in the vicinity of 

 marshes, lakes, water canals and rivers. The transmission of 

 the disease from animal to animal is also possible by contamina- 

 tion of fresh wounds on the skin or mucous membrane, with 

 blood containing parasites, while the possibility of natural in- 

 fection through the uninjured mucous membrane of the digestive 

 tract has not yet been proven. 



Anatomical Changes. The autopsy usually reveals pro- 

 nounced anemia and emaciation. The subcutaneous connective 

 tissue shows in many places gelatinous infiltration, and in the 

 serous cavities transudate is found in variable quantities. 

 Small hemorrhages may be present in the serous membranes, 

 in the mucous membrane of the stomach and intestines, as well 

 as in the kidneys. If the animal dies during a febrile attack 

 the spleen shows acute swelling, whereas otherwise a chronic 

 splenic tumor is usually present; sometimes however it may 

 have an entirely normal appearance. The lymph glands are 

 moderately sw^ollen. In some cases hemorrhages and catarrhal 

 pneumonic areas are present in the lungs. No trypanosomes 

 can be demonstrated in the blood or in the internal organs 24 

 hours after death. 



Symptoms. The manifestations of the disease are similar 

 in their nature in the different species of animals. 



In horses the temperature rises rapidly after an incubation 

 of 2 to 10 days, according to the severity of the infection, to 

 40° to 41° C, and at the same time other febrile s;s^nptoms, 

 such as languor, accelerated and weak pulse or diminished 

 appetite make their appearance. The mucous membranes are 

 reddened, there is profuse lachrymation, and at the same time 

 edematous swellings form on the extremities and lower abdo- 

 men, especially around the genital organs, also in the sub- 

 maxillary space, and on the eyelids. 



The febrile condition remains unchanged for 2 to 3 days, 

 sometimes for a week, then the temperature drops rapidly 



