6i 
After leaving Old Fort Rosebery, I did not see any fly along the 
whole of the rest of the route. 
‘ I found two cases of trypanosomiasis on the road to Kazerabi's. 
Both these had decidedly enlarged glands and trypanosomes were 
present in the gland juice. Both men had worked at Kambove. 
The finding of these cases is a verification of my earlier opinion that 
cases would be found scattered over the country among the natives 
who had worked in the Congo Free State. 
‘ We have then, along the Luapula, all the factors which are 
necessary for an extension of the disease, i.e., cases of human 
trypanosomiasis and tsetse flies. Gl. falfalis is found chiefly along 
the borders of the river, but also e.vtends for a variable distance up 
some of the larger affluents. Gl. morsitans is found more or less 
plentifully over most of the country immediately behind the Luapula. 
‘ There is an impression here that Gl. palpalis is the only species 
of tsetse fly which is capable of transmitting human trypanosomiasis. 
As you are aware, this question has not been settled decisively; on 
the contrary, from the results of work done in Uganda it seems clear 
that species other than Gl. palpalis can carry the disease and also 
that mechanical transmission is possible. While I do not believe that 
mechanical transmission alone is sufficient to account for the spread 
of the disease, it must not be forgotten that it is a possible means, 
and in the light of this I am afraid I must criticise the action which 
is being taken here. 
‘ The Tanganyika Concessions, Limited, have here some six to 
eight thousand loads which have to be carried to Kambove. 
Permission has been given to recruit the labour for this in British 
territory. A strip along the Luapula, some ten miles in width, has 
been declared to be infected territory. If the natives required to 
carry these loads to Kambove are recruited in this “ infected strip,” 
they will leave here to proceed into uninfected territory on the Congo 
side of the river If they are recruited outside the infected area, 
they will have to come into this " infected strip ” for the loads. In 
either case natives will be moving from uninfected to infected 
country, or vice versd. This, of course, is the one thing which should 
not be allowed. 
It is said that there are no Gl. palpalis on the route which is 
to be followed from here to Kambove. While this is the 
case, 
