630 THE ANIMAL PARASITES OF MAN 



due to S. dnttoni, the excitant of " tick " or " relapsing " fever in 

 Africa (see pp. 116-122). 



The incubation period of S. recurrently varies from two to 

 twelve days, during which time a very slight indisposition may be 

 noticed. The onset is usually sudden, with severe headache, pains 

 in the back, limbs and stomach and a feeling of weakness. There 

 is a rise of temperature to 103 F. or 104 F., and the temperature 

 continues high till about the sixth or seventh day. The skin is 

 yellowish, hot and damp ; a rash, disappearing on pressure, may occur 

 on the trunk and legs, nausea is always present and thirst is usual. 

 The liver and spleen both enlarge. The number of respirations and 

 pulse-rate become increased. On the sixth or seventh day a crisis 

 occurs. There is violent perspiration, with a rapid fall of tempera- 

 ture, pulse and respiration become normal and the patient sleeps and 

 awakes better. Improvement continues for some days, and recovery 

 may ensue, but usually about the fourteenth day relapse occurs, 

 lasting usually three or four days. A second relapse is unusual. 

 Numerous complications are known, e.g., bronchitis, pneumonia, 

 diarrhoea and dysentery. 



With regard to treatment, the specific appears to be salvarsan. 

 Caste) lani and Chalmers recommend salvarsan administered intra- 

 venously. Intramuscular inoculations (for example, into the buttock) 

 of a suspension of " 606 " in oil can also be given. The drug is very 

 efficacious, but large doses should not be given. An intravenous 

 injection of 4 or 5 gr. does not give rise to unpleasant symptoms 

 but is sufficient to effect a cure. 



The incubation period for the American form of the disease is at 

 least five to seven days, and the first attack lasts about five to six days. 

 The treatment is by salvarsan as detailed previously. 



As relapsing fever is spread by body lice and possibly by bugs, 

 preventive measures are directed against these insects. Strict 

 cleanliness of person, clothing, bedding and dwellings is essential. 

 Furniture, e.g., wooden bedsteads, liable to harbour such insects 

 should not be used. 



The principal and best-known relapsing fever of Africa is that 

 excited by Spirocliata dnttoni, and transmitted to man by ticks, chiefly 

 Ornithodonis nionbata. The incubation period is usually about 

 seven days but may be longer. The patient is dull and lethargic, 

 perspires freely and is often constipated. The temperature rises to 

 103 F. or 105 F., there is headache, pains in the back and limbs, 

 general chilliness and great pain in the region of the spleen, which 

 often enlarges. The symptoms become 'worse, there is a fall of 

 temperature with improvement in the morning, and a rise, with 

 increase of pain, in the evening. Spirochaetes are now found in 



