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PicturesTop of page
OverviewTop of page
Tsetse flies are of economic and biological importance because they act as cyclical vectors of protozoan parasites belonging to the genus Trypanosoma. Species of this genus transmitted by tsetse flies cause diseases of economic importance in humans and domestic animals in sub-Saharan Africa. Tsetse flies are not found outside Africa. Trypanosomiasis is a major limiting factor of livestock production in Africa. Tsetse flies belong to the genus Glossina of the family Glossinidae. Twenty-three species and eight subspecies have been identified in this genus and, of these, the most important are Glossina morsitans, G. pallidipes, G. swynnertoni, G. austeni, G. tachinoides, G. palpalis, G. fuscipes, G. brevipalpis and G. longipennis (Leak, 1999).
IdentityTop of page
Preferred Scientific Name
International Common Names
- English: flies, tsetse; tsetse; tsetse flies
- tsetse bites
Taxonomic TreeTop of page
- Domain: Eukaryota
- Kingdom: Metazoa
- Phylum: Arthropoda
- Subphylum: Uniramia
- Class: Insecta
- Order: Diptera
- Family: Glossinidae
- Genus: Glossina
Hosts/Species AffectedTop of page
Host selection by tsetse flies is determined by three main factors: host availability; host tolerance; and digestion of blood of various animals. Natural hosts of the G. morsitans group include: wild pigs, particularly warthog (Potamochoerus larvatus) andbovids such as buffalo and bushbuck. Domestic livestock attacked by this group include donkeys and cattle. Species of the G. palpalis group feed on reptiles (crocodiles and lizards) and Bovidae. This group also frequently attacks pigs and humans. Forest pigs are an important host of many species of the G. fusca group. Species of this group rarely feed on humans and are not commonly vectors of cattle trypanosomes. These species are confined to densely shaded bush and so do not come in close contact with cattle (Leak, 1999). In a study in rain forest and derived savanna areas in Nigeria, sedentary management of cattle was associated with a reduced trypanosome infection rate as compared to semi-sedentary management. The lower infection rates in the rain forest were attributed to increasing human activity reducing the habitat for the vector. The high infection rate in the derived savanna was influenced by proximity to the Glossina morsitans belt as well as to an increasing density of animals and grazing activities. The infection rate of the N'Dama was lower than those of Muturu, Keteku and Zebu breeds (Ogunsanmi et al., 2000).
DistributionTop of page
Tsetse flies occur only in Africa south of the Sahara desert and north of the temperate climes in southern Africa. The northern limit of the genus extends across Africa from Senegal to southern Somalia, at about 10-14°N (4°N in Somalia), following the southern edges of the Sahara and Somali deserts. The southern limit varies from 10 to 20°S, following the northern border of the Kalahari and Namibian deserts, extending to 29°S at the eastern coast. The tsetse-infested tropical and subtropical zones of Africa comprise two climax vegetation types, lowland rain forest and savanna woodland (Jordan, 1993). A fairly discrete infestation of tsetse, covering about 322,000 km2 in Malawi, Mozambique, Zambia and Zimbabwe, is known as the ‘common fly belt’. Within this area, G. morsitans morsitans and G. pallidipes are the most abundant species, with G. brevipalpis occurring in low numbers in localized areas and G. m. centralis being found in the north and west (Robinson et al., 1997). The general distribution of Glossina spp. is defined mainly by climate and influenced by altitude, vegetation and the presence of host animals. The limit of distribution is closely correlated with the tropical savanna climate, which follows the 508 mm annual isohyet. Each tsetse species has relatively narrow ecological requirements within the range of habitats of sub-Saharan Africa. Generally, the tropical rain forest climate limits the habitats of the G. fusca and G. palpalis groups, whereas the G. morsitans group is found in the surrounding woodlands. The cumulative effects of a series of long rainy seasons or long dry seasons are thought to be of importance in influencing the advances and recessions of tsetse populations. Human population density also affects distribution, due to destruction of vegetation and removal of hosts (Leak, 1999).
ReferencesTop of page
Brightwell R; Dransfield RD, 1997. Odour attractants for tsetse: Glossina austeni, G. brevipalpis and G. swynnertoni. Medical and Veterinary Entomology, 11(3):297-299.
Brightwell R; Dransfield RD; Williams BG, 1992. Factors affecting seasonal dispersal of the tsetse flies Glossina pallidipes and G. longipennis (Diptera: Glossinidae) at Nguruman, south-west Kenya. Bulletin of Entomological Research, 82(2):167-182.
Hendrickx G; Napala A; Dao B; Batawui K; Bastiaensen P; Deken Rde; Vermeilen A; Vercruysse J; Slingenbergh JHW, 1999. The area-wide epidemiology of bovine trypanosomosis and its impact on mixed farming in subhumid West Africa; a case study in Togo. Veterinary Parasitology, 84(1/2):13-31; 28 ref.
Jordan AM, 1993. Tsetse-flies (Glossinidae). In: Lane RP, Crosskey RW, 1993. Medical Insects and Arachnids. UK: Chapman & Hall.
Kamau SW et al., 2000. Financial analysis of animal Trypanosomosis control using cypermethrin pour-on in Kenya. Preventive Veterinary Medicine, 44(3-4):231-246.
Kappmeier K, 2000. A newly developed odour-baited "H trap" for the live collection of Glossina brevipalpis and Glossina austeni (Diptera: Glossinidae) in South Africa. Onderstepoort Journal of Veterinary Research, 67(1):15-26.
Lako GT, 1998. Cost of tsetse trapping using the NG2G trap: a case study in Kenya. Insect Science and its Application, 18(4):319-324.
Leak SGA, 1998. Tsetse biology and ecology: their role in the epidemiology and control of trypanosomosis. Tsetse biology and ecology: their role in the epidemiology and control of trypanosomosis., xxiii + 568 pp.; 115 pp. of ref.
Masake RA; Majiwa PAO; Moloo SK; Makau JM; Njuguna JT; Maina M; Kabata J; ole-MoiYoi OK; Nantulya VM, 1997. Sensitive and specific detection of Trypanosoma vivax using the polymerase chain reaction. Experimental Parasitology, 85(2):193-205; 35 ref.
Ogunsanmi AO; Ikeda BO; Akpavie SO, 2000. Effects of management, season, vegetation zone and breed on the prevalence of bovine trypanosomiasis in southwestern Nigeria. Israel Journal of Veterinary Medicine, 55(2):69-73; 28 ref.
Omoogun GA; Dipeolu OO; Akinboade OA, 1988. Population estimate of Glossina species in Egbe area of the derived savanna zone of Nigeria. OAU-STRC, Nineteenth Meeting, Lome, Togo, 1987. Publication International Scientific Council for Trypanosomiasis Research and Control, 114:351-359.
Reifenberg JM; Solano P; Bauer B; Kabore I; Cuny G; Duvallet G; Cuisance D, 1997. Advantage of the PCR technique in assessing the epidemiology of bovine trypanosomiasis: example of the agropastoral development area of Yalé, Burkina Faso. Revue d'élevage et de Médecine Vétérinaire des Pays Tropicaux, 50(1):14-22; 50 ref.
Robinson T; Rogers R; Williams B, 1997. Mapping tsetse habitat suitability in the common fly belt of Southern Africa using multivariate analysis of climate and remotely sensed vegetation data. Medical and Veterinary Entomology, 11(3):235-245.
Rogers DJ; Hendrickx G; Slingenbergh JHW, 1994. Tsetse flies and their control. Revue scientifique et technique Office International des Epizooties, 13(4):1075-1124.