SPJROCH^TA DUTTONI 



117 



from Congo native huts in which infected persons lived, on monkeys 

 and the latter became infected. Button and Todd also found the 

 offspring of infected ticks to be capable of transmitting the infection 

 to experimental animals. They concluded that 0. moubata was a 

 true intermediate host. 



A little later in 1905, Koch stated that spirochaetes from the gut 

 of the tick penetrated the gut wall and tissues and found their 

 way into the eggs in the ovary. Koch figured tangled masses of 

 spirochaetes as occurring in the tick eggs. He found ticks infective 

 to the third generation. He thought that the infection was spread 

 by the salivary fluid of the tick, in the act of biting. (This is now 

 known to be incorrect.) Markham Carter (1907) corroborated Koch's 

 work on the spirochaetes in the 

 tick eggs, and they have been 

 seen since by Kleine and Eckard 



Sir William Leishman, 1 in 

 1909-10, found that at ordinary 

 temperatures the salivary glands 

 of infected ticks (0. moiibatd) 

 were not themselves infective, 

 and that the infection occurred 

 by way of the ticks' excretion. 

 The spirochaetes (contained in 

 the ticks' excrement) found their 

 way into the vertebrate host 

 through the wound made by 

 biting. While feeding, ticks 

 pass large quantities of clear 

 fluid from the coxal glands ; 

 in this fluid an anticoagulin 

 occurs. Some of the ticks also 

 pass thick, white Malpighian 

 secretion, that is, excrement, 

 towards the end of the feed. 

 Leishman, using experimental 



monkeys, showed that if infected ticks were interrupted while 

 feeding, then no infection resulted in the monkeys. If, however, the 

 ticks were allowed to finish their feed, and the Malpighian secre- 

 tions were passed, then the experimental monkeys became infected. 

 Fantham 2 and Hindle 3 (1911), independently, have repeated the 

 experiments with mice. 



FIG. 54. Spirochixta duitoni. a, blood 

 form showing slight membrane ; b, granules or 

 coccoid bodies clearly formed within the organism ; 

 c, beginning of extrusion of coccoid bodies in the 

 tick. (After Fantham.) 



1 Journ. Roy. Army RIed. Corps, xii, p. 123 ; Lancet (1910), clxxviii, p. II. 



a Annals Trop. Med. and Parasitol. , v, p. 479. 3 Parasitology, iv, p. 133. 



