THE TRYPANOSOMES OF MAN 



417 



Pathogenicity. — The symptoms in the horse begin with loss of vigour, 

 followed in two to three weeks by fever. During the next month the weakness 

 is more marked and the abdomen sv/ells, the testicles hang down and are 

 oedematous, the coat becomes staring, the animal looks apathetic, and death 

 ensues in about a year. 



The post-mortem shov/s oedema of the abdominal wall and a coloured fluid 

 in the pleura and pericardium, with hypertrophy of the lymphatic glands, 

 fatty liver, and congestion of the lungs. The spleen is normal. 



Trypanosoma frobeniusi Weissenborn, 191 1. 

 Allied to T. dimorphon and T. congolense, and found in horses in Togoland. 



Trypanosoma nanum Laveran, 1905. 

 Balfour in 1904 discovered this parasite in cattle, which appeared to be ill, 

 on the While Nile. The parasites are small (10 to 14 by 1-5 to 2 /^), with no 

 free fiagellum, and are non-pathogenic for dogs, rabbits, and monkeys. 

 Amoeboid forms were found in the cerebro-spinal fluid. Duke in 19 12 showed 

 that it was transmitted by Glossina palpalis, in which it developed in the hind- 

 gut, and from thenceforwards to the oesophagus, but did not infect the salivary 

 glands. Development, according to Miss Robertson, takes place in G. palpalis, 

 and is like Castelianella castellanii, but with crithidial phase in proboscis, not in 

 salivary glands. The parasite develops in. the hind intestine and reaches the 

 proventriculus on the twentieth day, and the proboscis on the twenty-fifth, 

 where they become crithidial forms, and finally trypanosomes, which, however, 

 may only be developed in the hypopharynx. 



Group 3 : Part of the Flagellum may or may not 

 BE Free. 



Trypanosoma pecaudi Laveran, 1907. 



In the French Sudan, in addition to m'bori and souma, there is a third 

 disease — baleri, in Equidse — caused by T. pecaudi, with two forms like 

 T. dimorphon — (i) long and slender (25 to 35 by 1*5 /a), (2) short and broad 

 (14 to 20 yu. by 3 to 4 fj). Carriers: Glossina longipalpis, rarely G. palpalis 

 and G. tachinoides. 



The incubation in G. longipalpis is about twenty-three days. The trjrpano- 

 somes multiply in the intestine, and in seven to nine days invade the whole 

 intestine and pharynx. The parasites now eiter the proboscis and pass 

 through crithidial and leptomonas stages. Finally, some reach the hypo- 

 pharynx, where they assume the ' salivary trypanosome form ' and become 

 infective. 



LITTLE-KNOWN TRYPANOSOMES. 



Trypanosoma elephantis Bruce, Hamerton, and Mackie, 1909, has been found 

 in the elephant in Uganda; it resembles T. soudanense. 



Trypanosoma ingens Bruce, Hamerton, and Mackie, 1909, has been found 

 the reed buck and ox in Uganda ; it is of large size (72 to 122 /a by 7 to 10 fi) . 

 Trypanosoma giganteum Lingard was found twice in cattle suffering from 

 mp.oms similar to those found in surra. 



Trypanosoma bovis Kleine was found in sick cattle near Tanganyika. 



THE TRYPANOSOMES OF MAN. 



There is evidence that man is infected with a variety of trypano- 

 somes, the number of which is likely to be increased in the near 

 future. Those described in man are ; — • 



27 



