The control of tsetse
Inoculation of cattle is mainly an interim measure before fly has been completely eliminated, but it is no easy matter to persuade the average African to bring in his animals regularly for treatment. If it is done too late the effect is negligible and it is almost impossible to convince the owner of cattle which have succumbed to the disease that had his animals been dealt with earlier they would have been saved.
As tsetse live on blood alone, theoretically if the supply is removed the fly will die. With this in mind, in many parts of Africa a huge tsetse area has been selected and thousands of head of game slaughtered in the hope of exterminating the fly. In Zululand alone within the space of eight years over 100,000 head of game were shot. Glossina morsitans, often known as the ‘game fly’, finds its chief source of food in the larger ungulates, although when pressed it will feed on almost any bird or mammal. Glossina palpalis, another species, takes much reptilian blood and is scarcely affected by lack of ungulates, so that the eradication of tsetse in this manner is not only well nigh impossible, but ethically indefensible.
To wipe out the game has never been the policy in Northern Rhodesia and the methods employed there include the erection of over 135 miles of game-control fencing. The first of these experiments, completed in 1958, stretches for about 65 miles, and by 1963 will run for over 250 miles from the Kafue River to the Zambesi. On one side game can live and breed under natural conditions (here it is the Kafue National Park) while away from the danger zone the farming area begins. Men stationed in four hunting camps along the fence-line control the game and service the fence, but today a break-out is a rare occurrence indeed.
Up in the Chinyunyu area east of Lusaka I saw yet another fence-line under preparation, a wide swathe of green straight as an arrow, 200 yards wide and hand-cleared through the bush, where one day the Chongwe game-control fence will run from the Changali Hills to within a short distance of the Zambesi, to prevent game crossing from the Luano Valley to the farming area.
Later we crawled down the southern end of the valley, pitching and tossing along a tiny track hewn out of the hillside, little more than the bed of a dried-up mountain torrent, over smooth boulders between banks of matete grass. We emerged into the heart of the valley, where a small village lay in a cleared area, a tiny oasis of cultivation in thousands of square miles of tsetse country and visible testimony to the success of yet another operation.
One of the major problems in the control of tsetse is how to prevent a re-infestation of a cleared area. This is done by gazetting infected areas and confining movement from fly-belt into fly-free country to authorized routes, and pickets are set up at strategic points on all roads. The simplest of these road blocks consists of a spring-bar gate or white pole bearing the notice `TSETSE BARRIER-STOP’. The pickets are trained uniformed Africans, who stop cars, cyclists or pedestrians, examine them for fly, note any that are found, spray with insecticide and write down the number of the vehicle and the date. There are over 135 fly pickets in the territory, of which twenty have ‘smudge houses’: you drive into these, the doors are shut and the vehicle is thoroughly sprayed. Most of the others have smaller chambers for cyclists and pedestrians. The sides of all roads leading up to the picket are regularly sprayed to trap any fly that may have left the vehicle before it reaches the picket. In addition, large areas of farm and ranching country have been declared quarantine areas and movement in and out of them has been prohibited except under veterinary permit. In all there are at the moment twenty-one districts in Northern Rhodesia, representing 4,741,760 acres, where fly is being eradicated near existing settlements, cattle ranches and areas where land will be suitable for grazing once the fly has gone.
A considerable amount of success has been achieved in control of the tsetse fly in Northern Rhodesia and the ultimate prospects are bright, but I am still surprised that, with all the international organizations in existence for malaria control and locust control, each area in Africa subject to the scourge of the tsetse must battle on alone, finding money to finance an unremitting campaign over years to come. There is little glamour attached to the work and small recognition; but, without the constant vigilance of the authorities and the tireless efforts of tsetse supervisors everywhere, nothing could live in the miles of territory inhabited by the fly. On these few men depend the lives and livelihoods of millions of Africans.