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PATHOGENIC PROTOZOA 



in the lake region of Central Africa, and in the Congo basin. It 

 was early introduced into Martinique in the West Indies, but did not 

 spread and has now died out. 



Dutton and Todd found the parasite in 1901 in the blood of an 

 Englishman in Gambia, who died after a febrile illness of two years' 



FIG. 174. TRYPANOSOMA GAMBIENSE. Calkin, "Protozoology." 



duration ; Castellani in 1903 found the parasite in the cerebro-spinal 

 fluid of well-marked cases of sleeping sickness occurring among 

 natives of Uganda. 



Clinical Signs. The disease begins with slight febrile attacks, 

 headache and increasing weakness, emaciation, swelling of the eyelids 

 and enlargement of the lymph nodes'. The temperature increases, 

 edema of the extremities appears and the spleen enlarges. During 

 the last stages nervous symptoms predominate and the patient sleeps 

 day and night, but may have periods of excitement or convulsions, 

 yet finally sinks into deep coma and dies of exhaustion. 



Etiology. The disease is transmitted by the bite of the tsetse fly, 

 Glossina palpalis, which is apparently able to transmit the infection 

 mechanically immediately after biting an infected host, yet in most 

 flies the trypanosomes disintegrate and disappear from the intestinal 

 tract within four or five days. Jn from fiye to ; ten per cent of the 



