Tsetse fly control (1988) Pt. 1 of 2

[Music] setti flies are a serious threat to the peoples of Africa and their domestic animals they transmit the trypanosomes that cause sleeping sickness in man and debilitating killing diseases of cattle horses and camels trypanosomes are microscopic blood parasites transmitted from one host to another by etsi flies when they feed on the blood of infected animals including man ever since the diseases caused by trpn were recognized at the turn of this Century many methods have been tried to control the spread of the disease until a few years ago large areas of vegetation that formed the habitat of the tsti fly were cleared fences were built to keep cattle away from the wild animals that act as Reservoir hosts of trypanosomes and sometimes the wild animals were just [Music] killed for many years it's been possible to protect cattle by chemotherapy but frequent underdosing has resulted in a serious increase inrease in drug [Music] resistance fixed Wing aircraft and helicopters were used to spray residual insecticides over at setti Bush but the standard crop spraying methods were ineffective and caused serious contamination of the environment but light aircraft are now being used very successfully in several parts of Africa very fine droplets of Pyro or endos sulfan are distributed by Micron near rotary atomizers attached to the fuselage spraying takes place at night and early morning when there's temperature inversion and when the Flies are resting all the operations are carefully planned and monitored so that the whole area is covered spraying from the ground of the fly's resting places on Tree Trunks and branches is also used spraying is effective if carefully managed but it must be done regularly and it costs foreign currency that Africa can't afford so what are the Alternatives setti flies breed very slowly the female produces a single lava every 9 days or so unlike most flies which lay large numbers of eggs because setti breede so slowly it's possible to control them by removing only a small proportion of the the population each day this was realized as long ago as the early years of this Century by a Portuguese estate manager on the island of pipe off the west coast of Africa he noticed that his field workers were being bitten on their backs by the tsti so he provided his workers with dark colored jackets the backs of which were smeared with a sticky resin these sticky patches trapped large numbers of tsti and great reduced their biting nuisance and combined with other methods setti were eventually eradicated from the island the sticky cloth was possibly the very first setti trap in later years many different types of traps were designed and used most of them were cumbersome and as we now know not very efficient at catching tsti flies nevertheless some successes were achieved particular for the control of tsti populations living in the vegetation fringing rivers and streams the invention of the light and easily transported biconical trap in the 1970s resulted in A Renewed interest in the use of traps for control purposes rather than for just population sampling researchers indicated the best colors and shapes of traps for all tsti species of major economic importance and improvements AR regularly being made tsti are attracted to a simple black cloth Target especially if it moves in the wind and if the target is impregnated with insecticide it kills the tetsi which land on it experiments have been conducted on small Islands in Lake kba Zimbabwe Islands formed from hilltops when the Kuba dam was built this one pimp island is 6 km from the shore and setti flies from the mainland cannot reach it unless they hitch a ride on a boat likewise flies released there can't reach the mainland so it's an ideal place for studying them clean uninfected flies are bred at the setti research laboratory at Langford near Bristol in England they're kept in mesh cages and are fed through a membrane on Pig's blood from the slaughter house the cages are stored on trays on sloping racks where they produce their lari which wriggle through the mesh they roll down the sloping tray into sand where they soon pupate and are collected daily the pupy are packed for dispatched to Africa by air mail in Africa the Flies are hatched and in some experiments before they're released each one is colorcoded with spots of colored paint using nine colors in pairs at 14 positions on the thorax of the fly upwards of 25,000 individuals can be coded and identified this method was published in 1953 the four Central positions represent hundreds and the 10 peripheral positions T and units on any date two colors are used of which two spots of the first color and one of the second are applied the two spots of the same color indicate hundreds and tens and the second color indicates units in this way every individual fly released in Africa can be identified on pimple Island there are three oxen to provide food for the Flies plus a small team to look after the animals and to help the scientist set up and run his experiments three times a day an ox is taken on its fly round stopping at a series of locations for 5 minutes the flies that come to feed on the animal can be observed and identified 1 3 2 setti locate their hosts by scent as well as by sight and the effectiveness of targets and traps is dramatically increased by placing an attractive scent in their vicinity