46 



great majority of cases of trypanosomiasis are persons of middle 

 age, almost none are elderly people. The percentage of individuals 

 with a considerable degree of glandular enlargement, which is 

 coincident with trypanosomiasis, is very much greater in younger 

 adults and children, and it is possible that the low incidence of 

 trypanosomiasis among elderly people may be due, in part at least, 

 to an immunity acquired by them. 



These conclusions are not strictly applicable to the disease as met 

 with in the Eket District of Nigeria [see this Review, Ser. B, iii., 

 p. 53]. It seems evident that human trypanosomiasis exists in the 

 hinterland and that there is more likelihood of its assuming epidemic 

 form there, in regions of localised fly, where a reservoir may exist 

 other than man, than in the thick forest regions of Ashanti in which 

 the fly is scattered and big game non-existent. It is probable that 

 the native of Ashanti owes his escape to the character of the country 

 he inhabits, and that, were he to travel and to adopt the same habits 

 as the north country native, the incidence of the disease would 

 show but little difference in the two races. In the more northerly 

 parts of the Western Province, where G. palpalis is more abundant 

 and w^here contact between the Ashanti and the northern trader 

 is closer and there are more infective flies, the incidence of trypano- 

 somiasis is greater. Todd's last conclusion is open to doubt, as both 

 old men and women do little work in the fields, remain for the most 

 part in the villages and are less exposed to the bites of tsetse-flies. 

 In the Nyasaland disease old people appear to be infected according 

 to the extent to which they are exposed to the attacks of Glossina. 

 It is therefore concluded that age, sex and race incidence in human 

 trypanosomiasis vary directly with the extent to which the individual 

 is exposed to the bite of infective flies. 



A bibhography of 19 references is given. 



Macfie (J. W. Scott). The Results of Dissections of Tsetse Flies at 

 Accra. — Rejpt. Accra Labor atory for the Year 1915, London [n. d.], 

 pp. 49-54, 4 figs., 2 tables. [Received 23rd January 1917.] 



The specimens of flies examined were collected a few miles outside 

 the town, as they do not breed in the immediate vicinity. The object 

 of the examination was to determine, if possible, the species of 

 parasites transmitted and what proportion of the flies was infected ; 

 75 G. paljjalis and 8 G. longipalis were dissected. Of the first 

 named, 63 gave negative results ; one showed spirochaetes in the gut ; 

 two had sporocysts in the abdomen, and one fungus infections ; 

 three showed trypanosome infection of gut and salivary glands, one 

 of proboscis and gut, three of proboscis only and four of the gut only. 

 Of the G. longi'pal'pis dissected, seven showed no infection, one only 

 showing trypanosome infection of the proboscis only. In five cases 

 various animals were inoculated with the infected parts of the flies, 

 but in no case was infection transmitted. Feeding experiments 

 conducted with the same flies before dissection were also without 

 positive results. Three flies showed flagellates of the Trypanosoma 

 grayi type in the gut. In the absence of positive results from feeding 

 and inoculation experiments it is difficult to decide what trypanosomes 



