304 JAS. J. SIMPSON 
ENTOMOLOGICAL 
to find the reservoir. Consequently a fruitful line of research lies open and 
would well repay investigation, namely, the discovery of the animal or animals 
which act as reservoirs of the trypanosomes which are responsible for the 
mortality amongst horses, and the insect or insects which convey the infection. 
Piroplasmosis. 
Piroplasmosis has been found in dogs in Zungeru, and it possibly also occurs 
in the Katagum district. No definite case of this disease in cattle has been 
recorded, but it must be remembered that practically nothing has been done to 
investigate the disease or diseases which kill off the cattle in Northern Nigeria, 
and although it is almost certain that trypanosomiasis is the chief factor, it is 
not improbable that some of the deaths are due to piroplasmosis. 
IX. REMEDIAL MEASURES AND RECOMMENDATIONS. 
At various points in the report, when discussing individual localities, I have 
indicated certain lines of action which might profitably be adopted, so that it 1s 
unnecessary again to enter into these in any detail. At the same time it might 
be advisable to recapitulate the more important items, as some are applicable to 
widely different localities. 
Although recognising the immense advantages accruing from the extension of 
railway systems in opening up such a Protectorate as Northern Nigeria, one 
must not overlook potential dangers, and not the least of these is the possibility 
of extending the range of noxious insects and the introduction of insect-borne 
diseases to areas previously free. The same applies, though probably to a 
greater extent, in the case of river transport on launches and steamers. 
Consequently every effort should be made to minimise such risks, in the case 
of railways, by clearing large spaces in close proximity to the permanent way in 
areas known to harbour such insects as are proved to carry, or suspected of 
carrying, pathogenic organisms. Until this is done the transport of cattle and 
horses in open railway vehicles is attended by grave risks, and it is certainly 
desirable that the trucks used for conveying these animals should be rendered 
mosquito-proof. By this means horses and cattle might be taken from one free 
area to another without infection, a procedure at present impossible. In the 
case of passenger traffic this would be impracticable, and the only solution of the 
problem is extensive clearing. 
The case of river transport is very different, as certain factors, such as 
“ bilee-water,” which cannot be avoided, have to be taken into account. 
There is no doubt that mosquitos, and amongst them Stegomyia fasciata, do 
breed in such water. Only by careful supervision and the free use of oil can 
this be checked, and it is pleasing to record that this has commanded con- 
siderable attention from Dr. E. A. Chartres, the Senior Medical Officer at 
Lokoja. The co-operation of the Marine Department has also been enlisted 
in this work. 
Certain other factors, however, present themselves, but these are more 
intimately connected with the construction of the vessels. In another report* 
I entered in some detail into the question of the mosquito-proofing of cabins, 
* Bull. Ent. Res., IL, pt. 3, pp. 210 and 226, 
