E. Hindle 
185 
From time to time other writers recorded the existence of “tick-fever” 
in various parts of Africa, and in 1903, Christy suggested that the 
disease was caused by a filaria carried by the tick. 
Nabarro in 1903 noticed the presence of spirochaetes in the blood 
of a boy from Uganda suffering fi’otn this fever, but as his results were 
not published until 1905 (Nabarro and Greig, 1905), he lost priority for 
his discovery. 
Cook (1904) was the first to definitely I'ecord the presence of a 
“spirillum” closely resembling S. recurrentis in the blood of patients 
suffering from the disease. Although this author gives a good descrip¬ 
tion of the symptoms of the fever, he failed to recognise its identity 
with “Tick-Fever,” but supposed it to be the same as European 
Relapsing Fever. The same year P. H. Ross and Milne (1904) found 
“ spirilla ” in the blood of eight natives of Uganda suffering from 
“Tick-Fever,” and recognised them as being the cause of the disease. 
Independently of these observers, Dutton and Todd (1905) at the same 
time had been carrying on observations on this fever in the Congo Free 
State and had discovered that it was caused by a spirochaete occurring 
in the blood, and that the infection was conveyed by the bite of the 
human tick, 0. mouhata. By a number of careful experiments they 
showed that when infected ticks were fed on healthy monkeys, the 
latter became infected with the disease and spirochaetes appeared in 
the blood. They also proved that the tick serves as a true intermediate 
host for this disease, and that infection is transmitted to their offspring. 
Koch (1905), at the same time, investigated the “Tick-Fever” of 
German East Africa, and made some observations on the life-history of 
the spirochaete after it had been taken into the gut of the tick. He 
confirmed Dutton and Todd’s observations on the hereditary nature of 
the infection in ticks, and observed the spirochaetes of an infected tick 
to make their way from the gut to the ovaries, and bore into the eggs. 
Distribution. The Relapsing Fever of Tropical Africa has been 
recorded from Uganda, the Soudan, British, German and Portuguese 
East Africa respectively, Nyasaland, Rhodesia, the Congo Free State, 
the Portuguese Congo and Angola. Recently, a relapsing fever trans¬ 
mitted by ticks and probably identical with the above, has been discovered 
in Zululand, as far south as the Umphalosi River*. Up to the present 
however, no attempt has been made to collect the records of its 
distribution and also very few observers have given the exact localities 
* Unpublished report. Dr C. Hill, Government Medical Officer for Natal, kindly 
supplied me with this information. 
