།།།།
PUBLIC RECORD OFFICE
Reference :-
C.O.885
ALLY WITHOUT PERMISSION OF THE BE REPRODUCED PHOTOGRAPHIC- COPYRIGHT PHOTOGRAPH-NOT TO
18 PUBLIC RECORD OFFICE, LONDON
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accurately known. In some places and at some seasons, at any rate, it does not begin to attack till the sun is well up, it is rarely seen after 5 p.m., and it is met with in greater numbers on bright sunny days, whereas G. morsitans may attack fiercely before daybreak, is often most voracious about sundown, and has been said to prefer dull weather.
6. Investigations should be made as to the natural food of G. palpalis— whether vegetable juices form a part of it and what animals besides man it habitually attacks, especially water or water-side mammals, birds and reptiles, of which blood-smears should be obtained whenever possible. Some of these should be examined fresh and others dried and sent in for examination. Observations as to feeding (e.g. on crocodiles or hippopotami) could sometimes be made with the aid of binoculars.
7. Special efforts should be made to discover breeding-places and where larva and pupæ are deposited and concealed. Medical officers are recommended to search cracks and crevices in rocks, dry earth, dead wood and the bark of trees. Sand and loose earth and grass or other vegetation should also be examined. Pupæ are perhaps more likely to be found somewhere above the high-water mark of rivers, &c.
8. Little is known as to the seasonal absence or variations in numbers of the tly in a given locality. This should be studied. In some cases information on this head may possibly be gained from natives, but very often the fly is barely known to them. Where there is a local name for it this should be recorded. Among the Baganda it is called ki'vu (plural bi'vu) and among the Bachopi in N. Unyoro it is known as malingwa, these names probably including all tsetse-flies. Others, such as the Banyoro and the Nile tribes, have names which include all biting flies, varying only with the size of the insect.
9. Specimens from each fly-area, male and female, should be collected and sent in as soon as possible after capture for identification. Males may be distin- guished by the oval protuberance on the ventral aspect of the hinder end of the abdomen, which is placed longitudinally. Each fly or set of flies must be clearly labelled with the date and locality of capture and the approximate distance from water (e.g. close, 50 yards, 200 yards, &c.). In the case of flies caught in the early morning or late evening the hour of capture should be added.
10. The surest method of capture is to wait quietly near the water's edge (or wherever the fly has been seen or heard) either in the shade or in a small open space. It is well to have one or more natives waiting in front of the observer. It may be necessary to wait for half an hour to an hour or even a little longer before one is caught, though with a little practice its presence may be detected long before this by its buzz or its peculiar manner of settling. It will more readily settle on the lee side of its victim and on the shaded parts such as under the chin in man or behind the knee in the sitting posture, and on the under parts of animals. It would be well to determine whether it can bite through clothes, for it certainly attempts it.
11. The greatest care should be taken in drying and packing flies, as, if they cannot be identified, this may entail in some cases serious waste of time and labour in going over the same ground a second time.
Specimens should be packed in glass tubes, but, if the supply of these should fail, pill boxes may be used. In either case sufficient tissue paper should be inserted to prevent damage to the flies by shaking. To prevent mould it is a good plan before packing to dip them in 1/40 Carbolic and then to dry them quickly in the sun on blotting-paper, taking care that they are not carried off meanwhile by ants, &c. The tube, also, should be sterile and thoroughly dry, and gorged flies should not be packed with others, as they would probably putrify and spoil the whole consignment.
12. Other biting insects should also be collected. Flies may be packed as above but not in the same tubes or boxes with tsetses. Ticks, &c., should be placed in 2 per cent. formalin or weak spirit. Any observations on biting insects which may bear on the present investigations should be embodied in the reports.
13. Fresh ungorged flies should be examined microscopically to determine whether they carry trypanosomes and, if so, in what percentage of captures. This should be done both in infected and in apparently non-infected fly-areas, and the nethod recently employed by Dr. Koch of squeezing out the contents of the pro- boscis on to a slide should be adopted, as well as examination of the abdominal contents.
Should trypanosomes be found in this way dry preparations should be made,
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not only from the proboscis but also from the alimentary tract, and sent in for examination, to determine if possible the nature of the trypanosomes present.
14. Freshly gorged flies should be captured and examined to determine the kind of blood (mammal, bird or reptile) on which they have fed, and from these also dried films should be sent in.
15. Two of the most important questions at the present stage of the investiga- tion of sleeping sickness are, that of the occurrence of a cycle of development of the trypanosome in G. palpalis and that relating to whether the trypanosome of sleeping sickness can be carried by other species of tsetse flies. Any observations or experiments which medical officers may be able to make, or any material they may be able to send in which might assist enquiry on these heads may prove to be of the greatest value.
Another question which may prove to be of importance is that of the relative infectivity of male and female flies. On this point it will be more difficult to carry out any research, but any information bearing on it will be of great interest.
16. Maps will be supplied which should be amplified, and corrected where necessary, with the aid of local officials of the administration, who will be able to assist in fixing the location and in the naming of villages, streams, &c. On these maps the extent and position of the various fly-areas and of sleeping sickness epidemics will be indicated as exactly as possible, the former by red and the latter by black dots.
17. Local epidemics of sleeping sickness are to be enquired into, mapped and reported on with respect to origin, imported and local infection, number and propor- tion of persons attacked, the relation to fly-areas, the nature and frequency of communication with neighbouring fly-areas, the occupations of the natives, the probabilities of the spread of infection as regards direction and the possibilities of large or small outbreaks resulting in various districts.
Recent epidemics or recently infected villages will demand most careful study, especially as regards origin and the transmission of infection to or from surrounding fly-areas.
A numerical record should be kept of the sick in epidemic areas, distinction being made between imported and locally infected cases and between the stages of the disease in which cases are found at the time of investigation.
18. Cases of sleeping sickness occurring in persons (especially children) alleged or supposed never to have visited an epidemic or infected fly-area should be examined and enquired into with the utmost care and reported fully by name.
19. Special investigations should be made as to how far it might be practic- able, in each epidemic area, by removing huts or villages for a short distance (e.g. from a river-bank to the next hill-side) to place them outside the fly-area, and also, by supplying the sick with water and perhaps other necessaries obtained within the fly-area, to keep them from contact with the fly.
Such measures would greatly reduce the risk of infection wherever they could be carried out, for, although the apparently sick form only a proportion of those actually infected, they a ford immensely greater opportunities to the fly and, further. it has been suggested recently by Koch that probably only advanced cases are able to infect the fly.
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20. Examination of the lymphatic glands should be systematically carried out both in populations living in connection with infected fly-areas and in those living entirely outside such areas. It should be remembered that in sleeping sickness the enlarged glands are soft to the feel, somewhat like a ripe damson, and are not hard and shotty.
Examination for trypanosomes by gland puncture should be made where feasible but medical officers should proceed with caution in this matter till they have gained the confidence of the natives (see paragraph 23). One dozen spare needles will be supplied with each hypodermic syringe so that a separate one can be used for each puncture, the needles used being afterwards sterilized by boiling.
A good method of procedure for the operation is as follows:-Draw into the syringe a little 1 per cent. citrate of potash solution and eject it again, leaving the inside of the syringe and needle moist; then puncture the gland, move the needle about slightly in the gland, draw out the piston, disconnect the syringe from the needle, withdraw the needle, attach the syringe again and blow out the contents of the needle on to a slide. A thoroughly clean slide and coverslip arc essential.
22. It is most important to enlist the sympathy and interest of chiefs and