Tsetse flies

Dieldrin [60-57-1] or l,2,3,4,10,10-hexachloro-l,4,4t ,5,8,8t -hexahydro-6,7-epoxy-l,4- <7o, Aro-5,8-dimethanonaphthalene (34) (mp 176°C, vp 0.4 mPa at 20°C) is formed from aldrin by epoxidation with peracetic or perben2oic acids. It is soluble in water to 27 / g/L. Aldrin and dieldrin have had extensive use as soil insecticides and for seed treatments. Dieldrin, which is very persistent, has had wide use to control migratory locusts, as a residual spray to control the Anopheles vectors of malaria, and to control tsetse flies. Because of environmental persistence and propensity for bio accumulation, registrations in the United States were canceled in 1974. 

Vector Control and Plagues rodents, mosquitoes, tsetse flies, grasshoppers, locusts... 

African sleeping sickness is a parasitic disease of increasing importance, with an estimated 300,000-500,000 cases annually. The etiological agents, T. brucei gambiense and T. brucei rhodesiense, are transmitted to humans by the bite of Tsetse flies. 

African trypanosomiasis (sleeping sickness) and American trypanosomiasis (Chagas disease) are caused by Trypanosoma brucei and Trypanosoma cruzi, respectively. Sleeping sickness results from being bitten by the insect vector, the tsetse fly. At first there is only local lymphadenitis but about a month later generalized malaise, fever, and systemic disease involving skeletal muscle is seen. 

In field trials following multiple aerial applications of endosulfan for tsetse fly control in Africa over a 3-month period, residues of the compound in fish tissues decreased to low concentrations within 3 months after spraying. The fish tissue residues were still detectable after 12 months. Residue concentrations in fish-eating birds and crocodiles were similar to fish tissue residue levels endosulfan did not biomagnify in the food chain (HSDB 1999). 

The cyclodiene insecticides aldrin, dieldrin, endrin, heptachlor, endosulfan, and others were introduced in the early 1950s. They were used to control a variety of pests, parasites, and, in developing countries, certain vectors of disease such as the tsetse fly. However, some of them (e.g., dieldrin) combined high toxicity to vertebrates with marked persistence and were soon found to have serious side effects in the field, notably in Western European countries where they were extensively used. During the 1960s, severe restrictions were placed on cyclodienes so that few uses remained by the 1980s. 

Heeds indirectly affect the health of man and animals by harboring animals or insects. Control of aquatic weeds is effective for mosquito (Anopheles quadrimaculatus Say) control by eliminating breeding habitats. In control of the tsetse fly (Glossian spp.) (vector of sleeping sickness in Africa), herbicides are involved to reduce growth of the brush so essential to the survival of the fly. 

Welburn, S.C., Arnold, K., Maudlin, I. and Gooday, G.W. (1993) Rickettsia-like organisms and chitinase production in relation to transmission of trypanosomes by tsetse flies. Parasitology 107,141-145. 

Both male and female tsetse live solely on vertebrate blood, and the various species that carry sleeping sickness typically feed not only on humans but also on both domestic and wild animals. Infected flies pass on trypanosomes whenever they take a blood meal, so that the parasites not only move between flies and humans, but also infect a number of other hosts. Infected domestic animals develop nagana, but wild animals may show no sign of illness. They serve instead as healthy animal reservoirs of trypanosomes, permitting tsetse flies to pick up the parasites at any time without necessarily feeding on infected humans or domestic animals. For this reason and also because available drug therapies have proved no more practical here than for leishmaniasis, control of trypanosomiasis has long emphasized eradication of tsetse flies. 

These discoveries led to the simple traps that are now used to monitor tsetse flies and to control them. A test operation in Zimbabwe in the late 1980s gave dramatic evidence of how potent such traps can be. Insecticide-impregnated screens, baited with acetone and octenol, were distributed at a density of four screens per square kilometer. These traps reduced tsetse populations by more than 99.99 percent over an area of 600 square kilometers (230 square miles). The screens are even more effective when the urine-derived phenols are added to the attractants employed. Their effectiveness having been clearly demonstrated, traps and screens have become important complements to insecticide-based measures for controlling tsetse flies. 

A third ICIPE study focuses on identifying tsetse repellents. Field biologists recognized long ago that tsetse flies bite some wild animals but not others. We now know that flies shun such animals as waterbucks, elands, and zebras, because the odors of these mammals contain fly repellents. This discovery precipitated a search for odor components that deter tsetse and led eventually... 

The tsetse flies are viviparous. The egg is retained and hatched in the body of the female fly, where it is nourished until full grown, then it is deposited on loose or sandy soil in a shaded place. The larva pupates within a few hours and after several weeks an adult fly emerges. The gestation period in the fly is about 10 days, and the flies may reproduce over a period of several months. Most of the species are limited to fly belts within their respective ranges. Shade and abundant ground cover characterize typical fly belts. 

Prior to the advent of DDT, no highly successful chemical control of tsetse flies had been accomplished. In 1945 duToit, Graf, and Theiler of the Onderstepoorte Staff began their investigations on aircraft-distributed DDT for the control of adult tsetses. The site selected was a belt 30 square miles, comprising the Mkuzi Reserve in Northern Zululand, an area well populated with G. pallidipes. In the preliminary tests a 5% solution of DDT in furnace oil was applied as a spray at the... 

Figure B2(i) The pathway for conversion of proline and alanine in the flight muscle of the tsetse fly the major ATP-generating pathway. Alanine aminotransferase is essential for the proline oxidation pathway in order for glutamate to enter the Krebs cycle as oxoglutarate and pyruvate to be converted to alanine, the end of the pathway. It is assumed that the pathway is the same for the Colorado beetle, but no studies have been reported.

A recent study in Ethiopia found the most effective attractant for tsetse flies was acetone, octenol, and cow urine (Belete etal, 2004). An American company markets Mosquito Magnet, a device that purportedly attracts mosquitoes with l-octen-3-ol, heat, carbon dioxide, and water vapor (Enserink, 2002). Simpler traps are being used in East Africa. A black-and-blue cloth, impregnated with insecticide, attracts mosquitoes with acetone and octenol, or alternatively, buffalo urine (Enserink, 2002). 

Urine of a wild host bovid, the African buffalo, Syncerus coffer, also attracts tsetse flies. Up to eight phenols are active (Hassanali etal, 1986). The phenols are the... 

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