98 
SLEEPING SICKNESS 
Additional Notes by K. (t. Archibald, M.B., R.AAI.C., attached Egyptian Army 
Fellow of the Society of Tropical Medicine and Hygiene 
Pathologist and Assistant Bacteriologist, Wellcome Research Laboratories 
(ilossina 
palpalis 
in Uganda 
Clothing 
(rlossina 
palpalis 
only one factor 
Captain Ensor’s interesting and instructive paper contains valuable reconunendations 
as to the measures to be adopted in preventing and limiting the very possible spread of 
sleeping sickness into the Sudan. Many interesting points also are brought to notice as 
regards the distribution and haliits of the Glossma. At Dr. Balfour’s request, I am 
appending a few comparative notes with regard to the habits of the fTloasinif in Uganda, and 
a few notes on sleeping sickness in that Protectorate. 
My oliservations on the Glossind palpalis Hy, in nat.ura, have not been very extensive 
and are chiefly confined to this species as met with near Butiaba on Lake Albert, and at odd 
intervals while on trek from that place to Gondokoro. In Uganda, as in the Bahr-El-Ghazal, 
the essential conditions for a typical fly area are more or less open water with adjacent and 
overhanging shade, the fly having a selective preference for the shade of ambatch trees. 
The flies certainly were most active during bright sunlight, especially between the hours of 
10 and I, but no period of the day w'as entirely free from them. Tliey seemed entirely 
to disappear when a high wind arose, especially if it were accompanied by rain. The 
greatest distance the fly was found from w-ater was, roughly speaking, about 250 yards. 
Two of the swamp rivers examined for the presence of G. palpalis gave negative results. 
Examination of most of the flies that were caught revealed the fact that the male flies 
were far in excess of the female ones. Whether this was due to the fact that at some 
seasons of the year the male element predominates to a greater extent than the female, it is 
difficult to say. It is probable that the G. palpalis increases in number at certain times of 
the year wdiile it almost disappears at others ; this ma}' account for the discrepancies which 
sometimes occur in the mapping out of the fly areas. 
Clothing is not an absolute protection against the attacks of the fly, which seems to 
have a special peuchant for dark clothes and dark skin. It is a decided advantage, therefore, 
to have a native boy with one when studying the Glossina. When in the Nile districts of 
Uganda a search for G. palpalis on the shore gave negative results ; they were found 
in fair numbers w'hen shaping a course and paddling by the side of the trees on the river 
bank. Flies were not found where the river bank contained no trees or bush. 
It is well known that wherever sleeping sickness has been found, its area of 
distribution has closely followed that of the G. palpalis, and the inference to be drawn 
from this appears to be fairly conclusive, i.e. that this is the species of fly which 
transmits the parasite of sleeiiing sickness. Experimental evidence has shown that the 
Trijpanosonia yamhiease can also be transmitted by the Glossina fusca , but whether the latter 
is not simply an accidental carrier remains to be determined. It may not, however, be of 
much practical importance as regards the introduction of sleeping sickness into the Sudan, 
as up to the present G. fusca. has not been found in the Bahr-El-Ghazal. 
That there apiiears to be another factor concerned other than the G. palpalis in 
the transmission of T. yamldense receives some support from the fact that the Liverpool 
Expedition, in certain parts of the Congo Free State, found sleeping sickness widely 
prevalent while G. palpalis was only present in very small numbers. 
My experience in connection with the difficulty of finding the pupa of G. palpalis 
coincides with that of Captain Ensor, a search for this pupa in thickly infected fly areas 
always giving a negative result. As regards preventive precautionary methods. Captain 
Ensor lays great stress upon the clearing of trees, bushes and grass surrounding all places 
where drinking-water is obtained. This wholesale clearing will, however, require to be 
