354 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 foimd in dogs in Zimgeru, 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 ofl^ 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 is 

 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 difl['erent 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 efi:brt 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 traflSc this would be impracticable, and the only solution of the 

 problem is extensive clearing. 



The case of river transport is very diflferent, as certain factors, such as 

 "bilge-water," which cannot be avoided, have to be taken into account. 

 There is no doubt that mosquitos, and amongst them Steyomyia 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 i-ecord 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. Ees., II., pt. 3, pp. 210 and 226. 



