^14 THE SPIROGHMTES 



Antigenic Structure. — Little exact information. Some evidence that " relapse " strams 

 differ from the parent strain. 



Pathogenicity. — Causes European relapsing fever in human beings. Infection can be 

 transmitted to monkeys, rats, and mice, but not to rabbits or guinea-pigs. In monkeys 

 the disease runs much the same course as in man. Two or three days after subcutaneous 

 inoculation with the patient's blood a pyrexial attack occurs, lasting for 3 or 4 days ; two, 

 three, or four relapses may occur at intervals of 2 to 8 days, each relapse lasting from 

 1 to 4 days (Norris et al. 1906). After intraperitoneal inoculation of mice the organisms 

 appear in the blood within 24 hours, and persist for 3 to 4 days ; they then disappear 

 for several days, after which a relapse may occur ; three or four relapses may follow each 

 other, separated by an interval of about 7 days (Novy and Knapp 1906). As many as 

 10 to 50 organisms may be present per field during the first infection, but in the relapses 

 only 1 or 2 organisms are seen as a rule. Intraperitoneal inoculation of white rats is 

 followed by the appearance of spirochaetes in the blood in about 40 hours ; they disappear 

 about 2 days later. The spirochsetes are found not only in the blood, but in all the organs of 

 the body. Infection is never fatal. Novy and Kjiapp ( 1906) state that rats never relapse. 



Numerous strains of relapsing fever spirochaetes have been isolated in different 

 parts of the world. As these exhibit certain antigenic differences from Trep. 

 recurrentis, they have been regarded as different species and named accordingly. 

 Thus we have Trep. cluttoni of Central Africa, Trep. novyi of America, Trep. kochi 

 of East Africa, Trep. carteri of India, and several others (see p. 1804). 



Treponema anserinum 



Described by Sakharoff (1891), who observed it in the blood of infected geese. Mor- 

 phologically it closely resembles Trep. recurrentis. In blood its mean length is about 14 //, 

 and the mean number of coils about five (Knowles et al. 1932). The organism was cultivated 

 by Noguchi (1912gr), using his ascitic-fluid rabbit kidney medium. Growth reaches its 

 maximum about the 5th day, after which degeneration sets in ; death is usually complete 

 in 3 weeks. Growth occurs best at 30° C. Subcultures should be made every 4 days. 

 In culture the organism is said to be 8-16 fj, long, 0-3 /n wide, and to show rounded spirals, 

 each of which is about 1-8 /i long and 1 ^ in amphtude. According to Landauer (1931) 

 and to Knowles and his colleagues (1932), one of the best media for its cultivation is that 

 devised by Galloway (1925) ; this consists of coagulated egg white to which dilute in- 

 activated serum is added. In early cultures blood is advantageous. No growth occurs 

 anaerobically. Trep. anserinum is pathogenic for birds, but not for rodents. Intra- 

 muscular inoculation of fowls with 0-5 ml. of infected blood gives rise to acute spirochsetosis 

 in 24 hours. A high mortaUty results. Spirochsetes are numerous in the blood (Knowles 

 et al. 1932). Cross -spirochaeticidal and cross-protection tests in chickens suggest that 

 fowl spirochsetes may be subdivided into different antigenic groups (Khgler et al. 1938). 



Treponema vincenti 



Described by Vincent (1896, 1899), who observed it in the throat of patients suffering 

 from Vincent's angma. This organism is very dehcate, about 5-10 // long, and has 3 to 8 

 irregular spirals. In cultures filamentous forms are common. It stains poorly but 

 unfformly, is Gram-negative, and is actively motile. It can be cultivated under anaerobic 

 conditions in serum agar or in serum broth. Growth occurs most readily at 37° C. ; there 

 is no growth at room temperature. In serum agar, colonies appear in 3 days, and are very 

 tiny and tenacious (Ellermann 1904). Injected subcutaneously into guinea-pigs, the 

 organisms are generally without effect (Tminicliff 1906). It is not clear whether Trep. 

 vincenti is responsible for the necrotic lesions in human beings in which it is found, or 

 whether it is a mere secondary invader. Since the organism may sometimes be demon- 

 strated in the depths of the infected tissues, it is possible that it may possess actual 



