MICROBIAL DISEASES OF MAN AND DOMESTIC ANIMALS 845 



the cells. In preparations stained by Romanowsky's method they are colored like 

 chromatin. 



Ultramicroscopic Viruses (See page 116) 



SpiROCaiETA (Ehrenberg, 1833) ^ 



Many spirochaetes are, apparently, harmless parasites in shell fish, in the ali- 

 mentary canals of various animals and in the blood of fish, birds, and many mammals; 

 other spirochetes produce disease in men and in lower animals. 



Several spirochsetes are parasitic in man. Spirochata dentium and Spira- 

 chcBta buccalis are harmless organisms which are found in tartar, about the 

 teeth. 



Spirochteta vincenti occurs in great numbers in a certain form of sore throat. 

 Other spirochaetes have been found in foul ulcers, and others have been found in 

 association with bronchitis and enteritis. All these are comparatively unimportant 

 parasites. Spirochceta duitoni, Spirochata obermeieri and Spirochmla pMidula are 

 more important ones. 



African Tick Fever 



Spirochceta duttoni — Novy and Knapp, 1906 



African tick fever is a disease caused by Spirochata duttoni and 

 transmitted by the bites of a tick Ornitkodoros moubata (Fig. 181). 



Via. 181.— Ornilhodoros moubata. {Murray from Doflein.) 



This disease exists in Central and Eastern Africa, wherever Ornitk- 

 odoros moubata occurs. A disease, which is probably caused by 

 a spirochete, is transmitted by another tick, Argas persicus,m Persia. 



