14

Mosquito Work in Khartoum and in the Anglo-Egyptian

Sudan generally

Prevalence of Mosquitoes in Khartoum

Before reaching Khartoum one had been informed by certain residents that

the town contained very few mosquitoes, that those of the malaria-carrying genera grouped under the sub-family Anophelina were unknown and that malaria did not occur. It was speedily apparent that such was not the case. Before any measures were taken against them, mosquitoes bred in their tens of thousands in Khartoum, the family Anophelina was represented by one genus and species to a considerable extent, though limited as to locality,^ and malaria was and is present, though whether it is frequently acquired in Khartoum itself is another

question and one more difficult to answer.

By far the commonest mosquito in the town and neighbourhood is the Culex fatigans (Wied.), so widely distributed throughout the tropics. The female of this insect has for some time been known to be capable of conveying the parasite of the disease, filariasis, from the sick to the sound. Of this disease elephantiasis is a form and elephantiasis occurs in the Sudan. Further, the recent laborious researches of Dr. Graham, of Beyrout,1 seem to have conclu¬

sively proved that this mosquito is the transgressor in the case of dengue 01

dandy fever, forming the intermediate host for the protozoon of that disease,

cuiex fatigans, One first encountered the Culex fatigans in the Grand Hotel, where this species

was very numerous and annoying, and the cause of many complaints by residents. The reason of its presence was not far to seek. The hotel possessed a well, the well water possessed egg-boats, larvas, and pupae in abundance and those in

charge possessed no knowledge of the life-history of the mosquito. This well was in no way peculiar, for subsequent researches showed that more than half

the wells throughout the length and breadth of Khartoum, and there are in the town over 600 wells, formed breeding places for the ubiquitous Culex.

This mosquito is voracious, nocturnal in its habits, and distinctly annoying, but in a place like Khartoum is unlikely to be the cause of much transference

of disease, save in the presence of an epidemic of dengue, which, if Dr. Graham be correct, it would spread wholesale. The dry climate of Khartoum is scarcely suited for filariasis, nor if Bastian’s hypothesis2 be correct, and the Filaria perstans be proved to be a Tylenchus and associated with the cultivation of the

banana, is that parasite likely to occur to any extent, for banana plants are few

and far between, and the fruit is not used in these parts. But, then again,

Khartoum is a centre, and natives are continually coming and going and passing through it, while steamers constantly reach it from the humid and typically tropical regions of the Southern Sudan. Herein lies a danger, and, as a matter

of fact, Dr. Christopherson has reported one case of elephantiasis from Omdurman and I have seen a second under the care of Major Bray in Khartoum.

a filaria carrier

Mosquitoes and disease

1 Jourr.al of Tropical Medicine, 1/2/03 2 Lancet, 30/1/04