188 Relapsing Fever 
in which the disease occurs. The following list contains all the places 
which I have been able to collect, from which the disease has been 
definitely recorded. In addition these localities are shown in the 
accompanying Map (Map A) of the distribution of the Relapsing Fever 
of Tropical Africa. It is hoped that investigators in Africa will give 
records of the exact localities in which they observe this disease so that 
it will be possible to see how rapidly it is spreading. There is no doubt 
that during the last 50 years the disease has spread very rapidly. In 
1854 it could not have been common in Angola or else Livingstone 
(1857) would have noticed it, but although he distinctly mentions the 
occurrence of 0. moiibata and the effects of its bite, the fever is only 
mentioned as occurring in Portuguese East Africa, at Tete. At present 
this disease is common in Angola (Wellman, 1906), probably having 
been introduced by travellers from the Zambesi. Livingstone (1871) 
was also annoyed by ticks at Nyangwe but does not mention the 
occurrence of the fever, whereas in 1904 (Dutton and Todd, 1905) 
the same locality had a particularly bad reputation for this disease. 
These and other cases all tend to , show that the distribution of this 
fever has widely extended during recent times, probably as a result of 
the increased facilities of communication. 
The distribution of 0. mouhata is shown in Map B, for com¬ 
parison with that of the spirochaetosis which it carries. It will be 
noticed that its distribution is much wider than that of the disease and 
accordingly there is plenty of opportunity for the latter to spread. It 
is jirobable that in a few more years it will occur in most if not all of 
the regions where 0. mouhata is found, for at present there is so much 
communication between one state and another that the possibilities of 
infected ticks being carried from one place to another are very great. 
Dutton and Todd note that the ticks occur mostly along the Arab 
trade routes and have been introduced into the Oriental Province of 
the Congo Free State from the East Coast. The main centre of the 
Relapsing Fever of Tropical Africa is probably German East Africa, 
where Koch (1905) found that a large percentage of ticks from outlying 
districts were infected, as well as those along the trade routes. The 
disease is also very prevalent in Uganda, as a result of the communi¬ 
cations which have existed between these two countries. The next 
centre of infection seems to have been the banks of the river Zambesi, 
which was infected in Livingstone’s time (1857). From these two 
centres the disease has spread along the East Coast of Africa from 
British East Africa and possibly Somaliland in the north, to Zululand 
