SUPPLEMENT 621 



The course of the disease may be roughly divided into three 

 stages, the incubation, the febrile or glandular, and the cerebral stage. 



The exact incubation period is not known with certainty in man. 

 Probably, in most cases, it does not exceed two to three weeks, but 

 disease signs may not appear for months. The bite of the Glossina 

 gives rise to local irritation, which may be overlooked. The irrita- 

 tion usually subsides in the course of a few days. 



The febrile, or glandular stage, is marked by attacks of fever of an 

 intermittent type. An erythematous eruption is often found on Euro- 

 peans. This rash begins as irregularly shaped pinkish patches which 

 clear in the centre until a ring is produced. It may occur on any 

 part of the body but is more frequent on the trunk. A typical 

 symptom is the enlargement of one or more of the lymphatic glands, 

 especially those of the neck. A general, deep hyperaesthesia, known 

 as Kerandel's sign, may be present, and if the patient strikes a limb 

 against any hard object, a feeling of acute pain is felt, the sensation 

 being slightly delayed. As repeated attacks of fever increase, the 

 patient may become anaemic. The febrile stage may last for years, 

 and cure may be brought about at this phase, but frequently, after the 

 febrile stage has lasted some time, the cerebral stage is reached. 

 Tachycardia is also a symptom. Auto-agglutination of the red blood 

 corpuscles is another useful characteristic, as it is said to occur rarely 

 in other tropical diseases, but some workers doubt its value. 



The cerebral, or true sleeping sickness stage is marked by a great 

 change in the habits of the victim, who becomes apathetic and dull, 

 careless and dirty in habits, and begins to experience difficulty in 

 walking. Tremors of varying degrees of severity are common and 

 the gait is peculiar. There is usually fever with rise of temperature 

 from 100 F. to 104 F. in the evening, becoming subnormal in the 

 morning. For some days before death, it often becomes permanently 

 subnormal. Congestion and oedema of the lungs, with patches of 

 pneumonia, are not infrequently observed before death. The torpor 

 gradually deepens, and the patient loses flesh. Frequently the Jips 

 swell and saliva dribbles. The patient usually becomes comatose and 

 death ensues. Mania and delusions, and psychical and physical 

 symptoms resembling those found in general paralysis of the insane, 

 sometimes occur, and death may arise from secondary complications 

 such as pneumonia or dysentery. 



Pathologically, the disease seems to consist of a chronic inflam- 

 mation of the lymphatic system. The trypanosomes reach the 

 lymphatic glands w 7 hich become inflamed, and gradually invade the 

 blood and the cerebrospinal fluid. Sooner or later, as a result of 

 the lymphatic disease, changes occur in the membranes and 

 substances of the brain and spinal cord. There is round-celled 

 perivascular infiltration of the pia-arachnoid of the brain and spinal 



