CHAPTER LIII. 

 THE BLOOD INHABITING SPIROCH^TES. 1 



A. Human spirochaetosis. 

 Introduction. 



Section I. Experimental inoculation, p. 713. 

 Section II. Morphology and methods of detection, p. 714. 



1. Microscopical appearance and staining reactions, p. 714. 2. Cultivation of the 

 parasites, p. 715. 

 Section III. Serum therapy, p. 716. 



The differentiation of the various human spirochaetes, p. 717. 



B. Spirochaetosis in the lower animals. 



1. Spirochceta anserina, p. 717. 2. Spirochceta marchouxi, p. 718. 3. Spirochceta 

 theikri, p. 719. 



A. HUMAN SPIROCHAETOSIS. 



It is a matter of historical interest that the parasite of human relapsing 

 fever, a spirochaete discovered by Obermeyer in 1868, was the first micro- 

 organism to be found in a strictly human disease. 



Under natural conditions relapsing fever only affects man. The parasite is present 

 in the blood during the attacks of fever but can only be found occasionally and in 

 small numbers during the apyrexial intervals : about the time of the crisis the 

 spirochsetes generally disappear from the blood of the peripheral circulation and can 

 then only be found in the spleen where they are taken up by the leucocytes. The 

 disease can be readily reproduced in man by the inoculation of blood containing the 

 parasites. The spirochsete has been found to remain alive for more than a month 

 in the intestines of leeches which have been fed upon infected blood, and the disease 

 seems to be transmitted naturally by certain blood-sucking insects. 



Relapsing fever was first observed in certain parts of Europe : Russia, 

 Turkey., Northern Germany. The disease is most common among the dirtier 

 members of the population and in Europe bugs (Aoanthia lectularia) and lice 

 (Pediculus corporis) would seem to be the agents of transmission. 



[Nicolle, Blaizot and Conseille have shown that in Algeria relapsing fever 

 is transmitted by lice (Pediculus vestimenti and P. capitis). The bite of the 

 insect is innocuous and infection takes place by the " contaminative " method, 

 the spirocheetes being rubbed into the wound caused by the bite of the insect 

 by the scratching induced as the result of the bite. The method of infection 



1 The Spirochsstse were formerly grouped with the Vibrios among the Bacteria but 

 since Schaudinn's investigations they have been regarded as Protozoa and have been 

 classified with the Trypanosomata (Flagellata). The point is however still sub judice. 

 Caullery and Mesnil, Doflein and also Borrel consider that these parasites occupy an 

 intermediate position between the Bacteria and the Protozoa. 



