THE NATURE OF HUMAN 
TICK-FEVER IN THE EASTERN PART 
OF THE CONGO FREE STATE 
BY THE I. ATE 
J. EVERETT DUTTON, M.B., Vict. 
( WALTER MYERS FELLOW OF THE LIVERPOOL SCHOOL OF TROPICAL MEDICINE) 
AND 
JOHN L. TODD, B.A., M.D M< Gill. 
On the twenty-sixth of November, 1904, we sent a message to the 
Committee of our School saying that a spirochaete was the pathogenic agent 
of the human tick-fever which occurs in the Oriental province of the Congo 
Free State, and that we had been able to infect monkeys with spirochaetes 
through the bites of ticks. 
In the countries of Africa where it occurs the human tick is generally 
found to have an evil reputation among the natives. To its bite is attributed 
a sickness of longer or shorter duration, which may end in death. Accounts 
of the sickness are mainly derived from the writings of travellers. 
Livingstone was the first (4, 5) to describe a "human tick disease" in 
Portuguese South Africa. In the beginning of 1903 Manson, in his work on 
Tropical Diseases, (1) was able to sum up in two short pages the known 
facts of the African disease. 
Since our arrival in the Congo our attention has often been called to the 
human tick and to its evil properties. We found that natives who knew the 
arachnid had, as usual, a decided dread of it ; but it was not until we had 
left Stanleyville, on our way up the Congo to Kasongo, that we constantly 
encountered the tick, and saw, for the first time, cases of the disease. 
We were at Nyangwe, an infective centre, from November 13 to 22, 1904. 
Here we collected a large number of ticks for experimental purposes, and 
were fortunate enough to obtain an autopsy on the only fatal case of " tick- 
fever " that we have seen. We reached Kasongo on November 23, and have 
here seen further cases, and have been ourselves attacked by the disease. 
From this clinical material, from transmission experiments with ticks, 
and from information and reports received from residents in the Congo, we 
have been able to show that " tick-fever " in the Oriental province is a 
relapsing fever, produced by a spirochaete, probably identical with Spiro- 
chaete Obermeicri, and that this organism can be transmitted by the bite of the 
tick.* 
In addition, we have in one experiment been successful in transmitting 
the spirillum by the bites of young ticks newly hatched in the laboratory 
from eggs laid by infected parents. 
* We are not in a position to identify the species of ticks which we found in the Congo. All that we 
have seem to be the same as those we found in the Lower Congo, and judged to be Ornithodorns moubata. 
Some of our specimens have been taken home by Dr. Christy, and have been identified by Mr. R. 1. Pocock, 
of the British Museum as Ornithodoros moubata. 
