444 



TR YPA NO SOMIDM 



Spiroschaudinnia duttoni Novy and Knapp, 1906. 



Synonyms. — ■Spirillum dtittoni Novy and Knapp, 1906; Spiro- 



cJicBta duttoni Todd, 1906. 



This spirochaete is the cause of the West African and the Colombian 

 tick fever. 



Morphology.— Its length is variously described; thus Novy and 

 Knapp say that the young forms are 16 in length, while Breinl 

 and Kinghorn make them 24 // in length and 0-45 fj. in width when 

 fully grown. The number of spirals varies from two to three to 

 eight to ten, with a width of 2-2 The parasite is ribbon-shaped 

 on transverse section, and though it is often in spirals, may be 

 simply waved. The two ends are pointed {vide Fig. 125). 



The central core is seen to consist of lighter and darker portions, 

 which correspond to the chromatic and the achromatic portions of 

 the nucleus. The chromatic portion can break up into granules, 

 when the parasites begin to disappear from the circulation. 



The periplast is well marked, but there is great doubt as to the 

 presence of an undulating membrane. Breinl, who has studied 

 the subject carefully, could not definitely define one, but Dutton 

 and Todd have seen it in blood taken directly from the circulation 

 in man, or animals, or from the gut of Ornithodoros moubata. A 

 small uncoloured transverse band is often to be seen in specimens 

 stained by Giemsa lying across the parasite, about one-third its 

 length from one end. 



Life-History. — Reproduction can take place by longitudinal and 

 transverse division. In the former the parasite thickens and then 

 divides from one end, while in the latter the parasite increases in 

 length and divides in the middle. Some authors deny the occur- 

 rence of transverse division, but this is untenable after Fantham 

 and Porter's experiments. 



There is, however, another and but little known method of repro- 

 duction, which appears to be analogous to spore-formation. 



Just before the crisis, when the blood is swarming with parasites, 

 they can be seen, according to Breinl, in the spleen and bone-marrow, 

 and more rarely in the liver, coiling themselves up, and either show- 

 ing a swollen appearance, or becoming thinner and rolling themselves 

 into more and more complicated skein-like forms, which may be 

 engulfed by phagocytes in the spleen, but in other organs become 

 more regular and surrounded by a thin cyst-wall, the interior of 

 which is filled with faintly blue-staining plasma. 



In this cyst the parasite becomes more and more indistinct, and 

 at a later stage small red granules are to be seen, which are thought 

 to be the cause of the infection in the blood When filtered through 

 a Pasteur-Chamberland filter. Therefore, according to the investiga- 

 tions by Breinl, the life-history of the parasite has two Well-defined 

 stages in the vertebrate. In the first it is found free in the liquor 

 sanguinis in its typical form; in the second it enters a cell, and, 

 becoming coiled, its chromatin breaks up into a number of granules, 

 each of which is believed to become a new spirochsete. 



