120 THE ANIMAL PARASITES OF MAN 



illumination small, refractile spirochaetal granules may be seen to grow 

 into spirochaetes. The granule phase of spirochaetes has recently 

 been discussed by Fantham 1 (1914). 



Spirochaeta recurrentis, Lebert, 1874. 



Syn. : Spirochceta oberineieri, Cohn, 1875. 



This organism was discovered by Obermeier (1873) in cases of 

 relapsing fever in Berlin. Short forms 7 yit to 9 p long, and longer 

 (probably adult) forms, 16 //, to 19 //,, are found in the blood. The 

 width is 0-25 p. Parasites 12 //, or 13 //- long are often observed. 



The spirochaete is found in the blood during febrile attacks and 

 relapses, but not during intervening periods. It can be inoculated 

 into monkeys, rats and mice. It can live in the bed-bug, Cimex 

 lectnlarius, and Nuttall has succeeded in transmitting S. recurrentis 

 from mouse to mouse by the bites of the same bug. The French 

 investigators Sergent and Foley (1908-9) in Algeria, and Nicolle, 

 Blaizot and Conseil (1912) in Tunis, have shown experimentally that 

 S. recurrentis (var. berbera) is transmitted by lice. The latter workers 

 also demonstrated the method of infection that commonly occurs, 

 namely, by the scratching of the skin and crushing of lice containing 

 spirochaetes on the excoriated surface of the body. 



Lice as transmitting agents for relapsing fever were indicated by Mackie 2 in 

 1907. An epidemic among Indian school children furnished the materials. 3 It was 

 noted that out of 170 boys, 137 were infected, and the boys were very verminous. 

 Among the girls, 35 out of 114 suffered, and few lice were found on them. Twenty- 

 four per cent, of the lice taken from the boys contained spirochaetes as compared 

 with 3 per cent, of those from the girls. As the epidemic died out among the boys, 

 the lice also became fewer, and an increase in the number of cases among the girls 

 coincided with an increase in the number of lice. Spirochsetes were found in the 

 gut, Malpighian tubules and genital organs of the lice. Mackie thought that infec- 

 tion of the patients was brought about by the regurgitation of the spirochastes when 

 the lice fed, but proof of this was lacking. 



In 1912, Nicolle, Blaizot and Conseil, 4 working in Tunis and 

 using chiefly an Algerian strain of relapsing fever spirochaetes (some- 

 times called S. berbera), showed by direct experiments that infection 

 by means of the bites of Pediculus vcstiuienti and P. capitis was 

 untenable. As many as 4,707 infected lice were fed on one man, and 

 6,515 on another occasion were allowed to bite a man after they 

 had fed on a monkey heavily infected with spirochaetes, yet no 

 infection of the man followed. Examination of the lice showed 

 that the spirochaetes left the gut soon after they were ingested, and 



1 Annals Trop. Med. and Parasitol. , viii, p. 471. 



2 Brit. Med. Journ., Dec. 14, 1907, p. 1706. 



3 See also Nuttall, Herter Lecture on Spirochgetosis, Parasitology, v, p. 269. 



4 C.R. Acad. Set., cliv, p. 1636 ; civ, p. 481. 



