S4 



THE HEMOFLAGELLATES 



To treat dourine in horses, a single 

 subcutaneous dose of 5 mg/kg antrycide 

 methyl sulfate or two intravenous injec- 

 tions of 2 g suramin each 15 days apart 

 can be used. 



TRYPANOSOMA SUIS 

 OCHMANN, 1905 



This species, which was once thought 

 to be the same as T. siniiae, was redis- 

 covered in the Belgian Congo by Peel and 

 Chardome (1954). It is a member of the 

 brute i group, but differs from the others 

 in being monomorphic, having only stout 

 forms 14 to 19 ji long, with a short, free 

 flagellum. The kinetoplast is very small 

 and marginal. 



T. si</s occurs in pigs, causing a 

 chronic infection in adults and a more 

 acute disease with death in less than 2 

 months in young pigs. Peel and Chardome 

 attempted without success to transmit 

 T. suis to the goat, sheep, dog, white rat, 

 guinea pig, Cricetomys gambianus , Den- 

 drohyrax, chimpanzee, cat, rabbit, cattle, 

 monkey and ass. It is transmitted by the 

 tsetse fly, Glossina brevipalpis, in which 

 it develops first in the intestine and pro- 

 ventriculus and then in the salivary 

 glands. Metacyclic infectious trypano- 

 somes appear in the hypopharynx on the 

 28th day. 



TR YPANOSOMA 

 BRODEN, 1904 



CONGOLENSE 



Synonyms : Trypanosoma nanum, 

 T. confiisiun, T. pecorimi, T. somaliense, 

 T. cellu, T. frobeniusi, T. monlgomeryi, 

 T. ruandae. 



Disease : The South African disease 

 of cattle known as nagana is ordinarily 

 caused by T. cotigolense. Other names 

 which have been given to the disease are 

 paranagana, Gambia fever, ghindi and 

 gobial. 



Hosts : Cattle, equids, sheep, goats, 

 camels, dogs and, to a lesser extent, 

 swine. Antelopes, giraffes, zebras. 



elephants and wart hogs are also infected 

 and act as reservoirs. 



Location: This species develops 

 almost exclusively in the blood. It does 

 not invade the lymph or central nervous 

 system. 



Geographic Distribution : Widely 

 distributed in tropical Africa between 15° 

 N and 25" S latitude, coinciding with the 

 distribution of the tsetse flies which act 

 ad its vectors. 



Prevalence : T. co>igolense is the 

 commonest and most important trypano- 

 some of cattle in tropical Africa. 



Morphology : This species is small, 

 being 8 to 20|:i long; the mean lengths of 

 different populations range from 12.2 to 

 14.4|i (Hoare, 1959). It lacks a free 

 flagellum or has a short one, has an in- 

 conspicuous undulating membrane, and a 

 medium-sized kinetoplast which lies some 

 distance from the posterior end and is 

 typically marginal. 



Life Cycle : The vectors of T. con- 

 golense are various species of Glossina, 

 including G. morsitans, G. palpalis, G. 

 longipalpis, G. pallidipes and G. austeni. 

 After the trypanosomes have been ingested 

 by the tsetse flies, they develop in the 

 midgut as long trypanosomes without a 

 free flagellum. They then migrate to the 

 proventriculus and thence to the proboscis, 

 where they assume a crithidial form with- 

 out a free flagellum. These are attached 

 at first to the wall of the proboscis and 

 multiply for a time. Later they pass into 

 the hypopharynx, where they turn into 

 metacyclic, infective trypanosomes sim- 

 ilar in appearance to the blood forms. 

 These are injected into the blood stream 

 when the flies bite. 



T. congolense can also be transmitted 

 mechanically by other biting flies in tsetse- 

 free areas. 



Pathogenesis : Many strains which 

 differ markedly in virulence and also in 

 antigenic properties are united under T. 

 congolense (Fiennes, 1950). In cattle. 



