138 
REPORT OF TRAVELLING PATHOLOGIST AND PEOTOZOOLOGIST 
T. nanum 
probably not 
a form of 
T. di?norpJion 
T. nanum 
a distinct 
species 
these became infected in twelve days and the other in fifteen days. These two dogs were left 
at the Wellcome Laboratories when I returned to England. One died later from the infection, 
while the other perished in the fire which broke out at the Laboratories. From one of the 
infected dogs a gerbil was inoculated by Dr. Balfour, with a positive result. It will thus be 
seen that positive results have been obtained in gerbils by Dr. Balfour by inoculation from 
the mule and also from the dog which had been infected with trypanosomes from a cow. It 
would appear that rats are resistent to inoculations with Trypanosoma nanum, while dogs and 
gerbils are susceptible. From the evidence brought forward, I think it is clear that the small 
trypanosome found in mules and donkeys in the Bahr-El-Ghazal Province is no other than 
Trypanosoma nanum. 
In their paper entitled “ Cattle Trypanosomiasis in the Congo Free State,” Dutton, Todd, and 
Kinghorn, in discussing T. nammi, say: “ Is it not possible that further work on this parasite 
may show that it is merely the tadpole form of T. dimorphonl" I do not think this likely, 
for T. nan am in the Sudan is found along the Sobat, where Glossiiia does not occur, while 
T. pacaudi is only found in Glossina-mfeoted areas. {T. pecaudi is the Sudan representative 
of T. diniorphon. The two may be merely variations of one trypanosome.) The symptoms 
produced in animals by T. nanum differ from those produced by T. pecaudi. Animals 
artificially infected with T. nanum (one rat and two dogs) show characteristic small trypanosomes 
in their blood. There is no tendency for the trypanosomes to assume the T. pecaudi form and 
vice versa. T. pecaudi, easily inoculable into rats, retains its characteristic form throughout all 
passages. It must be remembered that T. 7ianum does occur in districts where T. piecaudi is 
found, so that one must not lose sight of the possibility of a double infection ; but in Wau 
donkeys and mules remaining in or near the town became infected with T. namim alone, but 
the same animals (uninfected with T. nanum) taken to a Glossina morsitans district at once 
contracted typical T. pecaudi, from which they rapidly died. It is possible for an animal to 
be infected with T. pecaudi and have in its blood the tadpole forms of this trypanosome while 
at the same time it is infected with T. nanum. In such a case the tadpole forms of T. pecaudi 
would be indistinguishable from T. nanum. I do not think it probable that T. nanum is the 
tadpole form of T. dimorphon, though the reverse might be true that the tadpole form of 
T. dimorphon is really T. nanum. In a district in which both these trypanosomes are found 
confusion of the two must occur, at least sometimes. From my observations in the Sudan I 
feel convinced that T. nanum is a definite entity distinct from T. pecaudi or T. dimorphon. 
On the Sobat I conducted some experiments to determine the mode of transmission of 
this trypanosome, but owing to the fact that I did not discover that dogs were susceptible 
till after I left I obtained no definite results. The Sobat cattle are not liable to liites from 
Glossina, as this fly is not found here. Various Tahanidce, Stomoxys, Hippoboscidce and 
ticks {Tihipicephalus sanguineus, B. evertsi, Boophilus australis, Amblyomma sp.) attack the 
animals. Numbers of ticks were made to feed on rats with no result, but this is hardly to 
be wondered at when one considers the resistance of these animals to T. nanum inoculation. 
Experiments with gerbils or young dogs would be more likely to give results. In the intestine 
of ticks and Hippoboscidce taken from infected animals trypanosomes of the T. nanum type 
were found, but these only in small numbers. The Tabanida, chiefly Tabanus socius, in and 
around this district are infected with Ilerpetomonas. liut there is no evidence to show that has 
any bearing on the trypanosome question. 
At the Mission Station on the Sobat, as far as I could discover, about twenty-five per cent, 
of the cattle had died. Many of the cattle were suffering from Piroplasmosis (P. mutans and 
P. bicjeminum), but the cause of death seemed to be the trypanosome. Asked as to whence the 
disease had come the natives gave very contradictory reports. Some said the ejiidemie first 
commenced on the Khor Filus, others that it had come with cattle from El Oheid, while some 
