] 



SLEEPING SICKNESS 88i 



3. Laveran's cross immunity experiments mentioned in Chapter 

 XIX. show that T. brucei and T. rhodesiense are quite different from 

 an immunity point of view. 



4. Taute has injected himself with 2 c.c. of blood from a dog 

 infected with T. brucei. He did not become infected, and suffered 

 no bad effects. 



5. Taute fed Glossina morsitans upon animals infected with 

 T. brucei, and after waiting the necessary time these flies were 

 allowed to feed upon two men, with negative results, although 

 control animals became infected and died. 



Thus the chain of evidence is strengthening which tends to show 

 that T. brucei is not T. rhodesiense, and if this is so, then we do not 

 know the intermediate reservoir of this trypanosome, and its chart 

 becomes: — 



Stephens and Fantham Type of Sleeping Sickness. 



Parasite. 



Definitive 

 Host. 



Definitive 

 Reser- 

 voir. 



Infection. 



Inter- 

 mediate 

 Host. 



Inter- 

 mediate 

 Reser- 

 voir. 



Trans- 

 mission. 



Trypano- 

 soma 

 rhodesiense. 



Glossina 

 morsitans. 



Hereditary 

 infection 

 of tsetse- 

 fiies{?). 



Short 

 salivary 

 trypano- 



somes. 



Inocula- 

 tive. 



Man. 



Game 

 ani- 

 mals (?). 



Short 

 blood 

 trypano- 

 somes. 



Ingestive. 



With regard to the other forms of sleeping sickness due to trypano- 

 somes allied to T. vivax, etc. [vide p. 1280), too little is known about 

 them and their carriers, and therefore it is impossible for us to 

 discuss the means of infection and transmission. G. tachinoides is 

 suggested as a possible carrier. 



Chagas' Disease. — Chagas has shown that Trypanosoma cruzi 

 in the vertebrate intermediate host finally enters the lungs, where 

 it loses its flagellum, while its two extremities join, and it becomes 

 a sphere, inside which eight daughter spheres arise, which, elongating 

 and entering red blood cells, become male and female trypano- 

 somes. These are the transmission agents which carry on the life- 

 cycle of the parasite in Lamtts megistus (Triatoma megista) when 

 it sucks infected blood. 



In this insect the trypanosome lives and multiplies in the gut of 

 the insect, and gives rise to crithidial forms in the mid-gut. These 

 eventually develop into small trypanosomes, which pass into the 

 salivary glands, and from there are injected into the intermediate 

 host when the insect bites. 



He considers that the armadillo, Dasypus novemcinctus, may be 

 the intermediate reservoir, and that Lamus geniculatus, which lives 



56 



