ir, 



MOSQl'ITO WORK IN KHARTOUM, ETC. 



F(n- all that, the presence of Culex fatigans Avas not felt to be very alamiing, 

 Imt it was a diiferent matter when Pyretophorus costalis was encountered. This 

 spi'cies i)f the Anoplielina has been proved to be both a tilaria and malaria 

 carrier, and though it did nut exist in great numbers had yet to be seriously 

 reckoned witli, even although Khartoum and its neighbourhood cannot be called 

 a malarious district. 'Phis is simply because the Anoi^helines cannot find many 

 suitable spots .wherein to breed — the result of a small and limited rainfall, the 

 compai'atix'e alisence of vegetation and the power of the sun's rays as an evaporating 

 Pyretophonis agi'iit. Still, as loug as Pi/retoplioi'us coatalis pei-sists in Khartoum there will bo a 

 malaria can ier rislv of malaria being spread from jierson to person. As already stated birds 

 of i)assage ai'e common in the town, and many of these come directly from the 

 malaria-ridden reaches of the Blue and White Niles, while a greater number hail 

 from Egypt, where malaria certainly occurs. In the bloods of diflerent patients in 

 Khartoum I have found all three forms of the malaria parasite, i.e., quartan, benign 

 tertian, and sub-tertian or malignant. The two latter forms are the most common, 

 and the small ringed form and crescent forms are frequent in patients coming fi-om 

 up the White Nile. Now Khartoum is a garrison town, and probalily the majority 

 of the Sudanese soldiers at least have served or lived in malarious districts and have 

 acquired the parasite. The same is true of their Egyptian comrades-in-arms, who 

 are exceedingly susceptible to infection and suffer severely. I believe that one reason 

 \\'\\x there has not been more malaria in Khartoum is to be found in the fact 

 that the military hospital is at present situated far fi'om the breeding grounds of the 

 .Vnopheline, Avhicli woidd have to cross a bare stretch of wind-swept desert, over a 

 quarter of a mile in breadth, to reach those who might transfer to it the protozoon. 

 Nor must it be forgotten that many members of the crews of the steamers 

 plving on both Niles harbour ci'escents in their bloods, and are constantly exposed to 

 infection during their journeys in the south. It is not infi'equent for several 

 membei-s of a steamer's company to an'ive in Khartoum prostrated by fever, and 

 such jjatients may well prove centres of distribution. 



Pyretophorus costalis is the only representative of the Anoplielina which has 

 been discovered in Khartoum, but a third genus of mosquito occui-s which in point 

 of numbers comes midway between ('iile.v fatirinns and Pyretophorus costalis, being 

 uothiug like so common as the former but considerably in excess of the latter. This 

 is a Stei/oniyia, species fasciata, Avhich in the western hemisphere has been proved 

 beyond all doubt to be the active agent in the dissemination of yellow fever. Here 

 the geiTn of that disease does not, so far, exist to be transferred by it, but the 

 Stegomyia is the most troublesome insect of the three, being exceedingly hvely and 

 biting viciously even in the heat of the day. As Avill be shewn Stegomyia also 

 breeds in Khartoum, though not to any great extent. Its prevalence is, I believe, to 

 be attributed to the presence of so many steamers on the Blue Nile for Stegomyia 

 fasciata, as has often been jiointed out, is an excellent traveller. Along "with Culex 

 fatigans it has been found breeding in large numbers in the bilge-water, tank-water, 

 and engine-room-water of the river steamers. 



Stegomyia 

 fasciata, the 

 yellow fever 

 mosquito 



