96 



SriHOCH.ETOSIS OK SfHANESE FOWLS 



Significance 

 of the experi- 

 ments 



Ornithodoros 

 savignyi 



I jrainiln 

 infection, Imt 

 not spiro- 

 chiEtosis, 

 apparently 

 transmitted liy 

 O, iavignyi 



June 9 to 13. As above. Bodies persisted. 



June H. Died. Nothing to note post mortem. 



Chick. Clean bird. 



AWni/ 25. Inoculated with emulsion of washed and crushed oviduct tissue which showed ffranulcs only. 



Mill/ 29. Spirochirtes found for the tirst time. After a loiii; searcli a few very small bodies discovered. 



.1/(11/ 30. Marked increase Injth in spirochii'tes and IkkUcs, and ap|)earances certainly suK^estive t>f 

 invasion of the red cells by the former (Plate III., tig. 7). Some of the liodics are i|uitc lar^fc and 

 appro.xiinate to '"spore" forms. 



Miiy 31. Both present but not ipiite so numerous. 



Jiive 1. A few spiroeha>tes but a large number of bodies. Multiple infection of red cells observed. 



June 3. No spirochoetes. Bodies more numerous and an increase in multiple infection. 



June 5. A very heavy infection with bodies. No si)irochietes. 



June 6. Infection not so great. No spirochetes. 



June 7 to 10. As above. 



June 11. Died. 



These cases are highly interesting, not only from the point of view of the infectiveness 

 of tick tissues containing granules, hut because tliey appear to demonstrate, beyond all 

 doubt, a definite relationship between the spirochaetes and the erythrocyte inclusions. 

 One has several other records which need not be detailed. 



(iv) If batches of ticks, samples of wliich are found only to show granules in their 

 tissues, be fed on clean chicks, such chicks, after from two to four days, may exhibit, not 

 spirochaetes, but the corpuscular inclusions. It is scarcely necessary to give examples, 

 and in any case the observation requires confirmation, as only a few observations were 

 made in this direction. Its possible significance has already been discussed. 



The following furtlier points appear to me worthy of consideration and experimental 

 work, l)ut so far I have not been able to pay attention to them. It will be seen that, 

 in part, they are suggested by Leishman's able research. 



L The tracing of the development of the granules in eggs, larva? and nymphs. 



2. An investigation of the excretory fluid of .1. peisicns and inoculation experiments 

 with it. This tick, however, feeds best at niglit and does not excrete a copious discharge 

 like Ornithodoros. 



3. The feeding of uninfected ticks on chicks showing bodies only in their peripheral 

 blood. As noted it is not easy to obtain ticks wholly devoid of granule infection. 



(4) This brings us to the work with O. sariijinji, the human tick of the Sudan. 

 I do not intend here to enter into the question of the curious rod-shaped liodies 

 which I found in the organs of these ticks, and to which allusion has already l)een 

 made (ride pa(je 80). Captain Mackie, I. M.S., to whom I had the pleasure of showing 

 them, told me he had seen similar appearances in tsetse flies. 



One will only consider the relationship of (I. savignyi to onr fowl spirochictosis. 

 I have carried out work with this tick moie or less on the same lines as with A. prrfirua 

 and have decided tliat it is not a true host of the fowl spirocha'te. The parasites may 

 be found, either granular or tmaltered, for 4 or o days in their alimentary diverticula'', 

 hut the special granule infection does not occur as in the fowl tick, at least on a large 

 scale, nor have I found spirochaetes elsewhere in the ticks. Moreover, I have never 

 been able to give a chick spirochetosis by allowing O. snrignyi, which had jireviously 

 ingested blood from an infected bird, to feed on it, even when the ticks had. in the 

 interval, been kept at 37" C. I have, however, fed O. mriijnyi on chicks showing good 

 "after phase" infections, and by means of them apparently induced a i)ody infection 

 only in a clean chick, or a great increase in llic innnber of bodies in a chick which 

 was not clean hut harboui'c^l a few of the inclusions. Nothing was found in samples of 

 the tick batches examined, and, unless I mistook some other' corpuscular condition for 

 the supposed spirochaete inclusions, it seems difficult to explain these results, unless. 



