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MEMORANDUM BY DR. WATSON, ACTING PRINCIPAL MEdical OfficeR,

NORTHERN Provinces, dated 24TH JUNE, 1920.

We know very little about sleeping sickness in the Northern Provinces, especially where it is most prevalent. As far as I know no recent investigations have been undertaken for the last four or five years.

2. Sleeping sickness, from the little I have seen, probably causes a considerable mortality amongst natives of Northern Provinces, and is likely to increase, due to the easier and more rapid means of transport that prevails now; one finds imported cases in Kano township and Zaria native town.

3. The number of cases returned and the death rate, as far as my experience goes, is very misleading. Acute cases, those that die within four days of the first symptoms of illness, must be frequently missed, the more chronic cases are very frequently wrongly diagnosed. No reliance can be placed on native diagnosis.

4. The number of fly varies greatly according to season, but I do not think this applies so much to the palpalis group which live mostly in so-called kurumis.

5. I understand that the fly in Uganda was far more numerous than on the Niger in 1911, but this might not always remain so.

No one appears yet to have discovered the breeding grounds in the Northern Provinces.

6. There is no doubt that many fertile areas have been abandoned and will have to be given up, even now, unless extensive clearing operations can be carried out, as that appears at present the only means of ridding the country of these deadly flies.

7. The number of horses and cattle that die annually of trypanosomiasis must be enormous.

8. I should certainly recommend further investigations to be undertaken.

C. E. S. WATSON, Acting Principal Medical Officer,

Northern Provinces,

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5. Personally, I consider that the most important question in Nigeria is that of tsetse in connexion with stock. Sleeping sickness exists, but is comparatively infrequent, and human infection has invariably been of the T. gambiense type, presumably carried by G. palpalis. In great tracts of country in the east and north the cattle problem is one of G. sub-morsitans. However, the rôle of G. tachinoides in carrying infection (especially the T. vivax group) requires further investigation, as G. tachinoides is very plentiful and widespread in certain areas.

6. I would suggest that :---

(a) A detailed tsetse survey be made of the Northern Provinces. (b) Special attention be paid to finding suitably isolated G. sub-morsitans areas for experimental work upon the bionomics of that fly.

(c) Suitable G. tachinoides areas be found for work upon the bionomics of this fly also.

7. I would further suggest that the interest of the Veterinary Department be engaged, so that the work this department has already done upon stock may be placed at the disposal of the investigators before they commence work.

8. The assistance of the Forestry and Agricultural Departments is needed for experimental work in clearing and farming, and I would suggest that officers from these departments be seconded from time to time to visit the investigators' camps.

9. The early survey work could be done by a Medical Officer, who could send specimens for confirmation of identification to a headquarters laboratory or to England. Later a trained entomologist would be essential for experimental work.

10. A travelling laboratory, under a pathologist, is essential, and much useful work could be done by a pathologist during the early survey of the country.

11. Suitable areas for experimental work cannot be settled until the survey has been made, but I attach notes on a few areas which I tentatively suggest as being suitable.

Kaduna, 23rd June, 1920.

I have, &c.,

W. B. JOHNSON,

Medical Officer.

PUBLIC RECORD OFFICE

Reference :-

CO.885/25

PUBLIC RECORD OFFICE, LONDON

ALLY WITHOUT PERMISSION OF THE BE REPRODUCED PHOTOGRAPHIC-

COPYRIGHT PHOTOGRAPH-NOT TO

SIR,

24th June, 1920.

MEMORANDUM BY DR. W. B. JOHNSON, PRincipal Medical Officer, NORTHERN PROVINCES, DATED 23rd June, 1920.

As requested by the Director of Medical and Sanitary Service, I have the honour to forward some suggestions as to investigation of tsetse fly areas in Nigeria, Northern Provinces.

1. It appears to me that Nigeria, Northern Provinces, is most suitable for experimental work on Glossina. Tsetse areas are numerous and fairly well defined, and I believe it will be possible to find G. sub-morsitans areas sufficiently isolated for valuable experimental work. Wild game is fairly numerous, and trypanosomes have been found frequently in their blood (I have found 5-7 per cent. of wild mammals infected of eighty-eight examined). A great part of the country is good cattle country, and the suitable areas for stock would be enormously increased with control of tsetse, especially of G. sub-morsitans.

2. We have a great part of the country already roughly mapped for tsetse, but obviously the first important duty of investigators would be to make a detailed tsetse survey.

This could be done comparatively quickly if a large staff of native collectors are trained and employed under supervision; Hausa boys from the Government schools could be trained quite easily to collect and label specimens. The whole country, except certain unsettled areas, can be mapped out in detail, as has already been done in Ilorin Province (Dr. J. W. Scott Macfie, Bull. Ent. Res. vol. LV, Part 1).

3. An officer seconded from the Survey Department would materially assist this work.

4. The survey should be made at the height of the rains, and again during the dry season. In selected areas the survey could be made in detail (1) at the height of the rains, (2) during the hot, dry season before the cold harmattan wind com- mences, (3) during the harmattan season, first before bush fires have started, and secondly after the grass has been burnt, (4) at the end of the dry season or during early rains.

River.

SUGGESTED POSSIBLE AREAS FOR EXPERIMENTAL WORK.

1. In the angle made by the emergence of the Donga River into the Benue

[*Indicated by a rough sketch, which has not been reproduced.]

Access by river in wet season and by a journey of about ten days from the rail- way in the dry season.

In this area I have found no over-lapping of G. sub-morsitans area with belts of G. palpalis and G. tachinoides. Game is fairly plentiful (roan, hartebeest, water- buck, kob, warthog, buffalo, baboons, monkeys). I have found wild game infected with trypanosomes in this area, and cases of sleeping sickness occur on the Benue and Donga Rivers.

The area is sparsely populated, but labour could be obtained from the fair- sized towns of Wukari and Donga. Fulani cattle are available just outside the area, and pagan (immune) cattle can easily be obtained.

In addition to work on G. sub-morsitans, work could also be done upon G. palpalis and G. tachinoides in this area, and work on immunity amongst river- side canoemen also suggests itself.

2. The area [indicated by a sketch, which has not been reproduced] between the railway line and the River Kaduna, between Zungeru and Minna, a sparsely populated area infested with G. sub-morsitans, and containing roan, hartebeest, buffalo, warthog, monkeys, etc. The country is open orchard bush, hilly in parts, and intersected with kurimis. I have found trypanosomes in wild game in this area, and it has the advantage of being easily accessible by the railway.

3. Any part of the extensive fadama and thorn bush country between the Kata- gun and Hadeija Rivers on the border of Kano and Bornu Provinces. These fadamas are heavily infested with G. sub-morsitans, but good areas of high, sandy ground, free of fly, can be found comparatively close to infected country. The game consists of roan, hartebeest, kob, waterbuck, warthog, monkey, etc. I have found trypano- somes in wild game here. Distance about ten days' journey from the railway (Kano). 4. Following the tsetse survey good areas are likely to be found in the Ruma bush (Katsina-Sokoto), which consists of grass, thorn bush, and kurimi, and also in the Ningi bush in Bauchi Province.