Tsetse fly (Glossina)
Conservation status
Secure
Scientific classification
Kingdom: Animalia Phylum: Arthropoda Class: Insecta Order: Diptera Suborder: Brachycera Subsection: Calyptratae Superfamily: Hippoboscoidea Family: Glossinidae Theobald, 1903 Genus: Glossina Wiedemann, 1830
Species groups
morsitans ("savannah" species) fusca ("forest" species) palpalis ("riverine" species)

Tsetse (pronounced /ts/e-/ts/e, teet-SEE, or set-see) are large biting flies from Africa which live by feeding on the blood of vertebrate animals. Tsetse include all the species in the genus Glossina, which are generally placed in their own family, Glossinidae. Image File history File links No higher resolution available. ... The conservation status of a species is an indicator of the likelihood of that species continuing to survive either in the present day or the future. ... Scientific classification or biological classification is a method by which biologists group and categorize species of organisms. ... For other uses, see Animal (disambiguation). ... Subphyla and Classes Subphylum Trilobitomorpha Trilobita - trilobites (extinct) Subphylum Chelicerata Arachnida - spiders,scorpions, etc. ... Orders Subclass Apterygota Archaeognatha (bristletails) Thysanura (silverfish) Subclass Pterygota Infraclass Paleoptera (Probably paraphyletic) Ephemeroptera (mayflies) Odonata (dragonflies and damselflies) Infraclass Neoptera Superorder Exopterygota Grylloblattodea (ice-crawlers) Mantophasmatodea (gladiators) Plecoptera (stoneflies) Embioptera (webspinners) Zoraptera (angel insects) Dermaptera (earwigs) Orthoptera (grasshoppers, etc) Phasmatodea (stick insects) Blattodea (cockroaches) Isoptera (termites) Mantodea (mantids) Psocoptera... For other uses, see Fly (disambiguation) and Flies (disambiguation). ... Infraorder Orthorrhapha Cyclorrhapha Muscomorpha Brachycera is a suborder of Diptera. ... Superfamilies  Muscoidea  Oestroidea  Hippoboscoidea Calyptratae is a subsection (phenetics) of Schizophora. ... Families  Glossinidae  Hippoboscidae  Mormotomyiidae  Nycteribiidae  Streblidae Hippoboscoidea is a superfamily of Calyptratae. ... Christian Rudolph Wilhelm Wiedemann was a German , physician, historian, naturalist and entomologist born in Brunswick on 7th December 1770. ... Genera as listed in ITIS: Subfamily Chrysopsinae: Merycomyia Chrysops Neochrysops Silvius Subfamily Pangoniinae: Apatolestes Asaphomyia Brennania Esenbeckia Pangonia Pegasomyia Stonemyia Goniops Subfamily Tabaninae: Anacimas Bolbodimyia Catachlorops Chlorotabanus Diachlorus Dichelacera Holcopsis Lepiselaga Leucotabanus Microtabanus Stenotabanus Haematopota Agkistrocerus Atylotus Hamatabanus Hybomitra Poeciloderas Tabanus Whitneyomyia Not placed: Zophina Horse flies (family Tabanidae) are... A world map showing the continent of Africa Africa is the worlds second-largest and second most-populous continent, after Asia. ... Human blood smear: a - erythrocytes; b - neutrophil; c - eosinophil; d - lymphocyte. ... This article does not cite any references or sources. ... For other uses, see Genus (disambiguation). ...

Tsetse have been extensively studied because they are biological vectors of the African trypanosomiases, deadly diseases which include sleeping sickness in people and nagana in cattle. In epidemiology, a vector is an organism that does not cause disease itself but which spreads infection by conveying pathogens from one host to another. ... Trypanosomiasis is the name of the diseases caused by parasitic protozoan trypanosomes of the genus trypanosoma in vertebrates. ... This article is about the medical term. ... Sleeping sickness or African trypanosomiasis is a parasitic disease in people and animals, caused by protozoa of genus Trypanosoma and transmitted by the tsetse fly. ... Nagana, also called Animal African Trypanosomiasis, is a disease of vertebrate animals. ... For general information about the genus, including other species of cattle, see Bos. ...

Tsetse are crudely similar to other large flies, such as the housefly, but can be distinguished by four characteristics of their anatomy, two of which are easy to observe. Tsetse fold their wings completely when they are resting so that one wing rests directly on top of the other over their abdomen. Tsetse also have a long proboscis which extends directly forward and is attached by a distinct bulb to the bottom of their head. Binomial name Linnaeus, 1758 The housefly (also house fly or house-fly), Musca domestica, is the most common fly occurring in homes, the most familiar of all flies and indeed one of the most widely distributed animals; it is a pest that can carry and transmit serious diseases. ... Human heart and lungs, from an older edition of Grays Anatomy. ... The abdomen is a part of the body. ... In general, a proboscis (from Greek pro before and boskein to feed) is an elongated appendage from the head of an animal. ...

Tsetse have existed in the modern morphological form for at least 34 million years since fossil tsetse have been recovered from the Florissant Fossil Beds in Colorado^[1]. For other uses, see Fossil (disambiguation). ... Florissant Fossil Beds National Monument is located in a mountain valley just west of Pikes Peak and holds spectacular remnants of the earths prehistoric life. ... Official language(s) English Capital Denver Largest city Denver Largest metro area Denver-Aurora Metro Area Area  Ranked 8th  - Total 104,185 sq mi (269,837 km²)  - Width 280 miles (451 km)  - Length 380 miles (612 km)  - % water 0. ...

Biology

The biology of tsetse is relatively well understood. Tsetse have been extensively studied because of their medical, veterinary, and economic importance, because the flies can be raised in a laboratory, and because the flies are relatively large, facilitating their analysis. Entomologists have discovered a great deal about tsetse morphology, anatomy, development, and metabolism. Not to be confused with Etymology, the study of the origin of words. ... The term morphology in biology refers to the outward appearance (shape, structure, colour, pattern) of an organism or taxon and its component parts. ... Human heart and lungs, from an older edition of Grays Anatomy. ... Morphogenesis (from the Greek morphê shape and genesis creation) is one of three fundamental aspects of developmental biology along with the control of cell growth and cellular differentiation. ... A few of the metabolic pathways in a cell. ...

Morphology

Tsetse can be seen as independent individuals in two forms: as third instar larva, as adults.

Tsetse first become separate from their mothers during the third larval instar, during which they have the typical appearance of maggots. However, this life stage is short, lasting at most a few hours, and is almost never observed outside of the laboratory. For other uses, see Fly (disambiguation) and Flies (disambiguation). ...

Tsetse next become puparia—small, hard shelled, oblongs with two distinctive, small, dark lobes at one end. Tsetse puparia are under 1.0 cm long^[2]. Within the puparial shell, tsetse complete the last two larval instars and the pupal stage. A centimetre (American spelling centimeter, symbol cm) is a unit of length that is equal to one hundredth of a metre, the current SI base unit of length. ...

Tsetse then emerge as adult flies. Tsetse adults are relatively large flies, with lengths of ½–1½ cm ^[2], and have a recognizable shape or bauplan so they can usually be distinguished without trouble from other flies. Tsetse have large heads, distinctly separated eyes, and unusual antennae. The tsetse thorax is quite large, while the abdomen is wide rather than elongated and shorter than the wings. It has been suggested that this article or section be merged into body plan. ... Diagram of a tsetse fly, showing the head, thorax and abdomen The thorax is a division of an animals body that lies between the head and the abdomen. ...

Four characteristics definitively separate adult tsetse from other kinds of flies:

An photograph of the head of a tsetse clearly illustrating the forward pointing proboscis. ... Download high resolution version (900x300, 62 KB)A photograph of a tsetse fly showing the resting position of the wings folded one over the other above the abdomen. ... A photograph of the wing of a tsetse illustrating the central cell shaped in the form of a hatchet. ... A split photograph and diagram illustrating the antenna on the head of a tsetse showing the branched hairs of the arista. ...

Anatomy

Like all other insects, tsetse flies have an adult body comprising three, visibly distinct, parts: the head, the thorax, and the abdomen. Orders Subclass Apterygota Archaeognatha (bristletails) Thysanura (silverfish) Subclass Pterygota Infraclass Paleoptera (Probably paraphyletic) Ephemeroptera (mayflies) Odonata (dragonflies and damselflies) Infraclass Neoptera Superorder Exopterygota Grylloblattodea (ice-crawlers) Mantophasmatodea (gladiators) Plecoptera (stoneflies) Embioptera (webspinners) Zoraptera (angel insects) Dermaptera (earwigs) Orthoptera (grasshoppers, etc) Phasmatodea (stick insects) Blattodea (cockroaches) Isoptera (termites) Mantodea (mantids) Psocoptera...

The head has large eyes, distinctly separated on each side, and a distinct, forward-pointing proboscis attached underneath by a large bulb. The thorax is large, made of three fused segments. Three pairs of legs are attached to the thorax, as are two wings and two halteres. The abdomen is short but wide and changes dramatically in volume during feeding.

The internal anatomy of tsetse is fairly typical of the insects. The crop is large enough to accommodate a huge increase in size during the bloodmeal since tsetse can take a bloodmeal weighing as much as themselves. The reproductive tract of adult females includes a uterus which can become large enough to hold the third instar larva at the end of each pregnancy. Orders Subclass Apterygota Archaeognatha (bristletails) Thysanura (silverfish) Subclass Pterygota Infraclass Paleoptera (Probably paraphyletic) Ephemeroptera (mayflies) Odonata (dragonflies and damselflies) Infraclass Neoptera Superorder Exopterygota Grylloblattodea (ice-crawlers) Mantophasmatodea (gladiators) Plecoptera (stoneflies) Embioptera (webspinners) Zoraptera (angel insects) Dermaptera (earwigs) Orthoptera (grasshoppers, etc) Phasmatodea (stick insects) Blattodea (cockroaches) Isoptera (termites) Mantodea (mantids) Psocoptera... The crop is a thin-walled expanded portion of the alimentary tract used for the storage of food prior to digestion that is found in many animals, including earthworms, leeches, insects, and birds. ... This article is about female reproductive anatomy. ... A larval insect A larva (Latin; plural larvae) is a juvenile form of animal with indirect development, undergoing metamorphosis (for example, insects or amphibians). ... A pregnant woman near the end of her term Pregnancy is the carrying of one or more offspring in an embryonal or fetal stage of development by female mammals, including humans, inside their bodies, between the stages of conception and birth. ...

Most tsetse flies are physically very tough indeed. Houseflies are easily killed with a fly-swatter but it takes a great deal of effort to crush a tsetse fly.

Life cycle

Tsetse have an unusual life cycle which may be due to the richness of their food source. Female tsetse only fertilize one egg at a time and retain each egg within their uterus to have the offspring develop internally during the first larval stages, a strategy called adenotrophic viviparity. During this time, the female feeds the developing offspring with a milky substance which is secreted by a modified gland in the uterus. In the third larval stage, the tsetse larva finally leave the uterus and begin their independent life. However, the newly independent tsetse larva simply crawls into the ground, forms a hard outer shell called the puparial case in which it completes its morphological transformation into an adult fly. This lifestage has a variable duration, generally twenty to thirty days, and the larva must rely on stored resources during this time. The importance of the richness of blood to this development can be seen since all tsetse development prior to the emergence from the puparial case as a full adult occurs without feeding based only on nutritional resources provided by the female parent. The female must obtain enough energy for her needs, for the needs of her developing offspring, and to store the resources which her offspring will require until it emerges as an adult. Life cycle refers to: Biological life cycle New product development Honeybee life cycle This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ... Adenotrophic vivparity is a unusual stage in the life cycle of many insects such as the Tsetse Fly, gnats, moths, fleas, and mosquitos. ...

Technically these insects undergo the standard development process of insects which comprises oocyte formation, ovulation and fertilization, development of the egg, five larval stages, a pupal stage, and the emergence and maturation of the adult. Morphogenesis (from the Greek morphê shape and genesis creation) is one of three fundamental aspects of developmental biology along with the control of cell growth and cellular differentiation. ... An oocyte or ovocyte is a female gametocyte or germ cell involved in reproduction. ... A larval insect A larva (Latin; plural larvae) is a juvenile form of animal with indirect development, undergoing metamorphosis (for example, insects or amphibians). ... Cockchafer (Melolontha melolontha) pupa Chrysalis redirects here: for other meanings see Chrysalis (disambiguation). ...

Metabolism

Tsetse metabolism consists of ingesting vertebrate blood, which is called hematophagy, and digesting this blood to obtain energy and biomass. An Anopheles stephensi mosquito obtaining a blood meal from a human host through its pointed proboscis. ...

Tsetse have specialized cells that contain cells of Wigglesworthia glossinidia brevipalpis, the bacterial endosymbionts that it requires for survival^[3]. Binomial name Wigglesworthia glossinidia Wigglesworthia glossinidia brevipalpis is a gram negative bacterium in the enterobacteriaceae family, related to E. coli, which lives in the gut of the tsetse fly. ... An endosymbiont is any organism that lives within the body or cells of another organism, i. ...

An unusual aspect of tsetse metabolism is the particular pathway which tsetse use for flight which seems to be responsible for the extremely high energy output and elevated flying speeds which tsetse can achieve. Most insects, such as honey bees, consume sugar predominantly for metabolic energy. Tsetse, instead, use a pathway which involves the conversion of the amino acids proline and alanine. The result of this pathway is that tsetse can create large amounts of ATP but can only sustain this metabolic output for short durations. Tsetse therefore fly at very high speeds (they are known to be able to follow a car moving at thirty miles an hour) but can only sustain their flight for short durations of around thirty seconds. The honeybee is a colonial insect that is often maintained, fed, and transported by farmers. ... Phenylalanine is one of the standard amino acids. ... Proline is an α-amino acid with the chemical formula HO2CCH(NH[CH2)3]. L-Proline is one of the twenty DNA-encoded amino acids. ... Alanine (Ala, A) also 2-aminopropanoic acid is a non-essential α-amino acid. ... Adenosine 5-triphosphate (ATP) is a multifunctional nucleotide that is most important as a molecular currency of intracellular energy transfer. ...

General biology

Tsetse has three distinct symbionts. The primary symbiont is Wigglesworthia within bacteriocyte, the secondary symbiont is Sodalis intercellularly or intracellularly, and the third is some kind of Wolbachia. A bacteriocyte (Greek: bacteria cell), also called a mycetocyte, is a specialized adipocyte found in some insect groups such as aphids, german cockroaches, and many others. ... Wolbachia is a genus of inherited bacterium that infects arthropod species, including a high proportion of all insects. ...

The tsetse Glossina palpalis is also a vector and host of Hepatozoon petti, a parasitic Sporozoa of the nile crocodile. Classes & subclasses Class Conoidasida    Gregarinasina    Coccidiasina Class Aconoidasida    Haemosporasina    Piroplasmasina The Apicomplexa are a large group of protozoa, characterized by the presence of an apical complex at some point in their life-cycle. ... Binomial name (Laurenti, 1768) The Nile crocodile (Crocodylus niloticus) is one of the 3 species of crocodiles found in Africa, and the second largest species of crocodile. ...

Systematics

Glossina palpalis and G. morsitans from a 1920 lexicon

Tsetse include up to thirty four species and sub-species depending on the particular classification used. Image File history File links Download high resolution version (1024x755, 94 KB) deutsches kolonial lexikon 1920 - tafel tsetse fliegen File links The following pages link to this file: Tsetse fly ... Image File history File links Download high resolution version (1024x755, 94 KB) deutsches kolonial lexikon 1920 - tafel tsetse fliegen File links The following pages link to this file: Tsetse fly ...

Tsetse are sufficiently different in appearance and behavior to have been placed in their own distinct branch of the flies. This placement is controversial. The science of systematics is currently struggling to reconcile the traditional form of biological classification with the modern understanding of genomic evolution and speciation. The controversy surrounding the placement of tsetse is therefore likely to continue into the future. Biological systematics is the study of the diversity of life on the planet earth, both past and present, and the relationships among living things through time. ... Scientific classification or biological classification is a method by which biologists group and categorize species of organisms. ...

All current classifications place all the tsetse species in a single genus named Glossina. Most classifications place this genus as the sole member of the family Glossinidae. The Glossinidae are generally placed within the superfamily Hippoboscoidea, which contains other hematophagous families. This superfamily is in the subsection Calyptratae which includes the housefly and the blowfly due to the similarity of their developmental biology. This infraorder in turn, is part of the sub-order Brachycera, the stubby flies with reduced antenna. Glossina is a genus of flies from the African continent. ... Glossinidae is a monogeneric family comprising Glossina, the genus of the African tsetse fly. ... Families  Glossinidae  Hippoboscidae  Mormotomyiidae  Nycteribiidae  Streblidae Hippoboscoidea is a superfamily of Calyptratae. ... Which feed on blood, like mosquitoes, ticks, ... Categories: | ... Superfamilies  Muscoidea  Oestroidea  Hippoboscoidea Calyptratae is a subsection (phenetics) of Schizophora. ... Binomial name Linnaeus, 1758 The housefly (also house fly or house-fly), Musca domestica, is the most common fly occurring in homes, the most familiar of all flies and indeed one of the most widely distributed animals; it is a pest that can carry and transmit serious diseases. ... Subfamilies Calliphorinae Chrysomyiinae The Blowflies are members of the family Calliphoridae of flies (Diptera). ... Infraorder Orthorrhapha Cyclorrhapha Muscomorpha Brachycera is a suborder of Diptera. ...

Species

The tsetse genus is generally split into three different groups of species based on a combination of distributional, behavioral, and morphological characteristics. The genus includes ^[4][5]:

Trypanosomiasis

Tsetse are biological vectors of trypanosomes meaning that tsetse, in the process of feeding, acquire and then transmit small, single-celled organisms called trypanosomes from infected vertebrate hosts to uninfected animals. Some tsetse transmitted trypanosome species cause trypanosomiasis, an infectious disease. In humans, tsetse transmitted trypanosomiasis is called sleeping sickness. In animals, tsetse vectored trypanosomiases include nagana, souma, and surra according to the animal infected and the trypanosome species involved, although the usage is not strict and nagana is occasionally used for any form of animal trypanosomiasis. In epidemiology, a vector is an organism that does not cause disease itself but which spreads infection by conveying pathogens from one host to another. ... Genera Blastocrithidia Crithidia Endotrypanum Herpetomonas Leishmania Leptomonas Phytomonas Trypanosoma Wallaceina The trypanosomes are a group of kinetoplastid protozoa, which are exclusively parasitic. ... Genera Blastocrithidia Crithidia Endotrypanum Herpetomonas Leishmania Leptomonas Phytomonas Trypanosoma Wallaceina The trypanosomes are a group of kinetoplastid protozoa, which are exclusively parasitic. ... An infection is the detrimental colonization of a host organism by a foreign species. ... This article does not cite any references or sources. ... Trypanosomiasis is the name of the diseases caused by parasitic protozoan trypanosomes of the genus trypanosoma in vertebrates. ... Sleeping sickness or African trypanosomiasis is a parasitic disease in people and animals, caused by protozoa of genus Trypanosoma and transmitted by the tsetse fly. ... Nagana, also called Animal African Trypanosomiasis, is a disease of vertebrate animals. ... Sōma (相馬市; -shi) is a city located in Fukushima, Japan. ... Surra is a disease of vertebrate animals. ...

Trypanosomes are animal parasites, specifically protozoa of the genus Trypanosoma. These organisms are approximately the size of red blood cells. Different species of trypanosomes infect different hosts as can be seen in the table attached to this section. Trypanosomes range widely in their effects on the vertebrate hosts. Some species, such as Trypanosoma theileri, do not seem to cause any health problems except perhaps in animals which are already quite sick ^[7]. For other uses, see Animal (disambiguation). ... A parasite is an organism that spends a significant portion of its life in or on the living tissue of a host organism and which causes harm to the host without immediately killing it. ... Wikisource has an original article from the 1911 Encyclopædia Britannica about: Protozoa Protozoa (in Greek proto = first and zoa = animals) are single-celled eukaryotes (organisms whose cells have nuclei) that commonly show characteristics usually associated with animals, most notably mobility and heterotrophy. ... Genera Blastocrithidia Crithidia Endotrypanum Herpetomonas Leishmania Leptomonas Phytomonas Trypanosoma Wallaceina The trypanosomes are a group of kinetoplastid protozoa, which are exclusively parasitic. ...

Some strains are much more virulent. Tsetse seem to be unaffected by the infection of trypanosomes but it is entirely possible that the parasites alter tsetse behavior or have other effects which improve the chances of transmission and survival. These trypanosomes have become highly evolved and developed a life cycle which requires periods in both the vertebrate and tsetse hosts. In biology, Strain can be used two ways. ... Virulence refers to the degree of pathogenicity of a microbe, or in other words the relative ability of a microbe to cause disease. ...

Tsetse transmit trypanosomes in two ways, mechanical and biological transmission.

• Mechanical transmission involves the direct transmission of the same individual trypanosomes taken from an infected host into an uninfected host. The name mechanical reflects the similarity of this mode of transmission to the transmission which could be caused mechanically with a syringe. Mechanical transmission requires that tsetse feed on an infected host and acquire trypanosomes in the bloodmeal, and then, within in a relatively short period, for tsetse to feed on an uninfected host and regurgitate some of the infected blood from the first bloodmeal into the tissue of the uninfected animal. This type of transmission occurs most frequently when tsetse are interrupted during a bloodmeal and attempt to satiate themselves with another meal. Other flies, such as horse-flies, also can cause mechanical transmission of trypanosomes ^[8].
• Biological transmission requires a period of incubation of the trypanosomes within the tsetse host. The term biological is used because trypanosomes must reproduce through several generations inside the tsetse host during the period of incubation, which requires extreme adaptation of the trypanosomes to their tsetse host. In this mode of transmission, trypanosomes reproduce through several generations, changing in morphology at certain periods. This mode of transmission also includes the sexual phase of the trypanosomes. Tsetse are believed to be more likely to become infected by trypanosomes during their first few bloodmeals. Tsetse infected by trypanosomes are thought to remain infected for the remainder of their lives. Because of the adaptations required for biological transmission, trypanosomes which are transmitted biologically by tsetse cannot be transmitted in this manner by other insects.

The relative importance of these two modes of transmission for the propagation of tsetse-vectored trypanosomiases is not yet well understood. However, since the sexual phase of the trypanosome lifecycle occurs within the tsetse host, biological transmission is a required step in the life cycle of the tsetse vectored trypanosomes. A syringe nowadays nearly always means a medical syringe, but it can mean any of these: A simple hand-powered piston pump consisting of a plunger that can be pulled and pushed along inside a cylindrical tube (the barrel), which has a small hole on one end, so it can... For the American band, see The Horse Flies Genera as listed in ITIS: Subfamily Chrysopsinae: Merycomyia Chrysops Neochrysops Silvius Subfamily Pangoniinae: Apatolestes Asaphomyia Brennania Esenbeckia Pangonia Pegasomyia Stonemyia Goniops Subfamily Tabaninae: Anacimas Bolbodimyia Catachlorops Chlorotabanus Diachlorus Dichelacera Holcopsis Lepiselaga Leucotabanus Microtabanus Stenotabanus Haematopota Agkistrocerus Atylotus Hamatabanus Hybomitra Poeciloderas Tabanus Whitneyomyia... The eye is an adaptation. ...

The cycle of biological transmission of trypanosomiasis involves two phases, one inside the tsetse host and the other inside the vertebrate host. Trypanosomes are not passed between a pregnant tsetse and her offspring so all newly emerged tsetse adults are free of infection. An uninfected fly which feeds upon an infected vertebrate animal may acquire trypanosomes in its proboscis or gut. These trypanosomes, depending on the species, may remain in place, move to a different part of the digestive tract, or migrate through the tsetse body into the salivary glands. When an infected tsetse bites a susceptible host, the fly may regurgitate part of a previous bloodmeal which contains trypanosomes or may inject trypanosomes contained within its saliva. It is believed that the inoculation must contain a minimum of 300 to 450 individual trypanosomes to be successful, and may contain up to 40,000 individuals ^[7].

The trypanosomes are injected into vertebrate muscle tissue but make their way, first into the lymphatic system, then into the bloodstream, and eventually into the brain. The disease causes the swelling of the lymph glands, emaciation of the body, and eventually leads to death. Uninfected tsetse may bite the infected animal prior to its death and acquire the disease, thereby closing the transmission cycle. The human lymphatic system The lymphatic system is a complex network of lymphoid organs, lymph nodes, lymph ducts, lymphatic tissues, lymph capillaries and lymph vessels that produce and transport lymph fluid from tissues to the circulatory system. ...

The tsetse vectored trypanosomiases affect various vertebrate species including humans, antelopes, bovine cattle, camels, horses, sheep, goats, and pigs. These diseases are caused by several different trypanosome species which may also survive in wild animals such as crocodiles and monitor lizards. The diseases have different distributions across the African continent and are therefore transmitted by different species of tsetse. The following table summarizes this information ^[7][9]:

Sleeping sickness or African trypanosomiasis is a parasitic disease in people and animals, caused by protozoa of genus Trypanosoma and transmitted by the tsetse fly. ... Sleeping sickness or African trypanosomiasis is a parasitic disease in people and animals, caused by protozoa of genus Trypanosoma and transmitted by the tsetse fly. ... Nagana, also called Animal African Trypanosomiasis, is a disease of vertebrate animals. ... Nagana, also called Animal African Trypanosomiasis, is a disease of vertebrate animals. ... Nagana, also called Animal African Trypanosomiasis, is a disease of vertebrate animals. ... Nagana, also called Animal African Trypanosomiasis, is a disease of vertebrate animals. ... Surra is a disease of vertebrate animals. ... Binomial name (Pallas, 1766) This article is about the animal. ... Binomial name Thomas, 1904 The Giant Forest Hog (Hylochoerus meinertzhageni) is the largest wild member of the pig family Suidae. ...

Human trypanosomiasis

Main article: sleeping sickness

Human African trypanosomiasis, also called sleeping sickness, is caused by trypanosomes of the Trypanosoma brucei species. This disease is invariably fatal unless treated but can almost always be cured with current medicines, if the disease is diagnosed early enough. Sleeping sickness or African trypanosomiasis is a parasitic disease in people and animals, caused by protozoa of genus Trypanosoma and transmitted by the tsetse fly. ... Sleeping sickness or African trypanosomiasis is a parasitic disease in people and animals, caused by protozoa of genus Trypanosoma and transmitted by the tsetse fly. ...

Sleeping sickness begins with a tsetse bite leading to an inoculation in the sub-cutaneous tissue. The infection moves into the lymphatic system leading to a characteristic swelling of the lymph glands which is called Winterbottoms's sign. The infection progresses into the blood stream and eventually crosses into the central nervous system and invades the brain leading to extreme lethargy and eventually to death. The human lymphatic system The lymphatic system is a complex network of lymphoid organs, lymph nodes, lymph ducts, lymphatic tissues, lymph capillaries and lymph vessels that produce and transport lymph fluid from tissues to the circulatory system. ... A diagram showing the CNS: 1. ... In animals, the brain or encephalon (Greek for in the head), is the control center of the central nervous system, responsible for behaviour. ...

The Trypanosoma brucei species, which causes the disease, has often been subdivided into three sub-genera which were identified based either on the vertebrate hosts which the strain could infect or on the virulence of the disease in humans. The trypanosomes infectious to animals and not to humans were named Trypanosoma brucei brucei. The strains which infected humans were divided into two sub-species based on their different virulences: Trypanosoma brucei gambiense was thought to have a slower onset and Trypanosoma brucei rhodesiense refers to strains with a more rapid, virulent onset. This characterization has always been problematic but was the best that could be done given the knowledge of the time and the tools available for identification. A recent molecular study using restriction fragment length polymorphism analysis suggests that the three sub-genera are polyphyletic ^[10], so the elucidation of the strains of T. brucei infective to humans will require a more complex explanation. In molecular biology, the term restriction fragment length polymorphism (or RFLP, often pronounced rif-lip) is used in two related contexts: as a characteristic of DNA molecules (arising from their differing nucleotide sequences) by which they may be distinguished, as the laboratory technique which uses this characteristic to compare DNA... In biology, a taxon is polyphyletic if it is descended from more than one root form (in Greek poly = many and phyletic = racial). ...

Other forms of human trypanosomiasis also exist but are not transmitted by tsetse. The most notable is American trypanosomiasis, known as Chagas disease, which occurs in South America, caused by Trypanosoma cruzi, and transmitted by certain species of the Reduviidae, members of the Hemiptera. South America South America is a continent crossed by the equator, with most of its area in the Southern Hemisphere. ... Subfamilies Harpactorinae Reduviinae Stenopodainae Emesinae Apiomerinae Ectrichodiinae Peiratinae Tegeinae Triatominae etc. ... Suborders Archaeorrhyncha Clypeorrhyncha Prosorrhyncha Sternorrhyncha Hemiptera is a large, cosmopolitan order of insects, comprising some 67,500 known species in three suborders. ...

Animal trypanosomiasis

Animal trypanosomiasis, also called nagana when it occurs in bovine cattle or horses or sura when it occurs in domestic pigs, is caused by several trypanosome species. These diseases reduce the growth rate, milk productivity, and strength of farm animals, generally leading to the eventually death of the infected animals. Certain species of cattle are called trypanotolerant because they can survive and grow even when infected with trypanosomes although they also have lower productivity rates when infected. Trypanosomiasis is the name of the diseases caused by parasitic protozoan trypanosomes of the genus trypanosoma in vertebrates. ... Binomial name Bos taurus Linnaeus, 1758 Rainbow arching over a paddock of cattle Cattle are domesticated ungulates, a member of the subfamily Bovinae of the family Bovidae. ... horse, see Horse (disambiguation). ... This article needs additional references or sources to facilitate its verification. ... This article is about the medical term. ... See economic growth Growth rate (group theory) Population growth rate This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ... A glass of cows milk. ... For other uses, see Farm (disambiguation). ... This article or section does not adequately cite its references or sources. ...

The course of the disease in animals is similar to the course of sleeping sickness in humans. Sleeping sickness or African trypanosomiasis is a parasitic disease in people and animals, caused by protozoa of genus Trypanosoma and transmitted by the tsetse fly. ...

Trypanosoma congolense and Trypanosoma vivax are the two most important species infecting bovine cattle in sub-saharan Africa. Trypanosoma simiae causes a virulent disease in swine. A political map showing national divisions in relation to the ecological break (Sub-Saharan Africa in green) A geographical map of Africa, showing the ecological break that defines the sub-Saharan area Sub-Saharan Africa is the term used to describe the area of the African continent which lies south... Binomial name Sus scrofa Linnaeus, 1758 Synonyms The domestic pig is usually given the scientific name Sus scrofa, though some authors call it , reserving for the wild boar. ...

Other forms of animal trypanosomiasis are also known from other areas of the globe, caused by different species of trypanosomes and transmitted without the intervention of the tsetse fly.

Tsetse vector ranges mostly in the central part of Africa.

Control

Tsetse control has been undertaken in order to reduce the incidence of the diseases which the flies transmit. Two alternative strategies have been used in the attempts to reduce the African trypanosomiases. One tactic is primarily medical or veterinary and targets the disease directly using monitoring, prophylaxis, treatment, and surveillance to reduce the number of organisms which carry the disease. The second strategy is generally entomological and intends to disrupt the cycle of transmission by reducing the number of flies.

The idea of tsetse control implies a change in the relationship between people and these insects. Prior to the twentieth century, people in Africa had largely adapted to the presence of tsetse. Human settlement patterns and agricultural practices had adapted to the presence of the fly. For example, in Ethiopia draft powered farming was restricted to the highland areas where the flies were absent whereas lowland areas where tsetse are present were more sparsely populated by people living a nomadic, less agriculturally intensive lifestyle. Tsetse control is a response to changing conditions. Tsetse control has been proposed as a way of reducing the incidence of the disease in the populations living in tsetse regions, of allowing the expansion of human settlement and agriculture into new areas, and of helping people previously relocated either in forced transfers or due to migration.

Tsetse control efforts have been undertaken throughout the African continent but long-term, sustainable control has rarely been achieved. Tsetse control efforts invariably are tied to the complex problems of poverty, heath, politics, and violence which have proved such a disaster for the African people.

The reduction of fly numbers has generally been attempted with two different aims, either eradication which intends to completely eliminate tsetse from the area or control which aims simply to reduce the numbers. Eradication is an idea which has often been imagined, has repeatedly been attempted, and is still proposed but many reasons suggest that control is a safer, cheaper, more realistic, and sustainable approach. Eradication refers to the successful killing of every tsetse either in a region or, under more grandiose proposals, from the entire African continent. Local eradication efforts have repeatedly been undertaken and have achieved temporary success only to fail in the long term because tsetse were able to re-invade (Zanzibar).

All of the economic, ecological, political, and environmental justifications for eradication have been called into question. The economic justification for eradication offsets the immense costs of the eradication campaign against the medical and veterinary benefits which are considered to accrue in perpetuity.

However, eradication campaigns may have unintended social consequences, as a successful campaign may open up lands for agriculture which have previously been populated by nomadic hunters, resulting in the displacement of the original population with its attendant consequences.

Control techniques

Many techniques have been used to reduce tsetse populations with earlier crude methods being replaced in more recent times by methods which are cheaper, more directed, and ecologically better considered.

Slaughter of wild animals

One early technique involved the slaughter of all the wild animals on which tsetse fed. For example, the island of Principé off the west coast of Africa, was entirely cleared of feral pigs in the 1930s which led to the extirpation of the fly. While the fly eventually re-invaded in the 1950s, the new population of tsetse was free from the disease.

Land clearing

Another early technique involved the complete removal of any brush or woody vegetation from an area. Tsetse tend to rest on the trunks of trees so the removal of woody vegetation made the area inhospitable to the flies. However, the technique has not been widely used and has been abandoned in more recent times. Preventing the regrowth of woody vegetation requires continuous clearing efforts which is only practicable where large human populations are present. The clearing of woody vegetation has come to be seen as an environmental problem more than a benefit.

Pesticide campaigns

Pesticides have been used to control tsetse starting initially during the early part of the twentieth century in localized efforts using the inorganic metal based pesticides, expanding after the Second World war into massive aerial and ground based campaigns using the early organic pesticides such as DDT, and continuing with the targeted use of pour-ons in which advanced organic pesticides are applied directly to the backs of cattle. DDT or Dichloro-Diphenyl-Trichloroethane is the first modern pesticide and is one of the best known synthetic pesticides. ...

Trapping

Tsetse trap

Tsetse populations can be monitored and effectively controlled using simple, inexpensive traps. These often use electric blue cloth, since this colour attracts the flies. Early traps mimicked the form of cattle but this seems unnecessary and recent traps are simple sheets or have a biconical form. The traps can kill by channeling the flies into a collection chamber or by exposing the flies to insecticide sprayed on the cloth. Image File history File links TsetseTrap. ... Image File history File links TsetseTrap. ...

The use of chemicals as attractants to lure tsetse to the traps has been studied extensively in the late 20th century, but this has mostly been of interest to scientists rather than as an economically reasonable solution. The attractants studied have been those which might be used by tsetse to find their food, like carbon dioxide and acetone, which are given off in the animals' breath and distributed downwind to form an 'odour plume'. Synthetic versions of these chemicals can be used to create artificial odour plumes. A cheaper approach is to place some cattle urine in a half gourd near the trap. For large trapping efforts, the use of additional traps is generally cheaper than the use of expensive artificial attractants.

A special trapping method is applied in Ethiopia, where the BioFarm Consortium (ICIPE, BioVision Foundation, BEA, Helvetas, DLCO-EA, Praxis Ethiopia) applies the traps in a sustainable agriculture and rural development context (SARD). The traps are just the entry point, followed by improved farming, human health and marketing inputs. This method is in the final stage of testing (as per 2006).

Releases of irradiated males

The sterile insect technique has been used to reduce tsetse populations. This technique involves the rearing of large numbers of tsetse, separation of the males, irradiation of these flies with large doses of gamma rays to make them sterile and then release into to the wild. Since females only mate a few times in their life, generally only once, any mating with a sterile male will prevent that female from giving birth to any offspring. El Salvador successfully demonstrated the sterile insect technique by eliminating a malaria-causing mosquito from a region for a period of time. ... Irradiation is the process by which an item is exposed to radiation. ...

The Sterile Insect Technique has recently been used on Zanzibar, an island off the coast of East Africa. Like other eradication efforts, early indications are that the fly numbers have been decimated with the fly possibly extirpated (locally eradicated) from the island. A number of traps are in place to monitor the island and repress any resurgence. Map of Zanzibars main island Zanzibar is part of Tanzania Coordinates: , Country Tanzania Islands Unguja and Pemba Capital Zanzibar City Settled AD 1000 Government  - Type semi-autonomous part of Tanzania  - President Amani Abeid Karume Area  - Both Islands  637 sq mi (1,651 km²) Population (2004)  - Both Islands 1,070...  Eastern Africa (UN subregion)  East African Community  Central African Federation (defunct)  geographic, including above East Africa or Eastern Africa is the easternmost region of the African continent, variably defined by geography or geopolitics. ...

Additionally, using the parasite refractory strains is another method to control the tsetse, that means providing the blood meal containing the trypanocide before releasing the sterilised males. Also we can consider to use the cytoplasmic incompatibility (CI) strategy to control the population of tsetse. With the development of genetic engineering, the releasing of engineered parasite refractory counterparts is another strategy to control the population of tsetse.

Etymology

The word 'tsetse' comes from Tswana, a language of southern Africa, and, in that language, the word means fly^[11]. Recently 'tsetse' without the 'fly' has become more common in English, particularly in the scientific and development communities. Tswana (Motswana, plural Batswana) is the name of a Southern African people. ... The English language is a West Germanic language that originates in England. ...

The pronunuciation of the word differs in different regions. Many African languages have an ejective ts sound and so a common pronunciation of the word involves two identical syllables both having this ts sound and a shorter sound of the vowel, as ts-eh-ts-eh. The British pronunciation of the word uses two different sounds for the two different syllables, generally tee-tsee. In Zimbabwe, it is generally pronounced tseh-tsee. Map showing the distribution of African language families and some major African languages. ... Ejective consonants are a class of consonants which may contrast with aspirated or tenuis consonants in a language. ...

See also

• David Bruce (microbiologist)
• "Tsetse" was a nickname applied to the De Havilland Mosquito FB Mk XVIII aircraft

Sir David Bruce (Melbourne, May 29, 1855 - November 27, 1931) was an English pathologist and microbiologist who investigated the Malta-fever and trypanosomes, identifying the cause of sleeping sickness. ... The de Havilland Mosquito[1] was a British combat aircraft that excelled in a number of roles during the Second World War. ...

References

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Glossinidae

Image File history File links Commons-logo. ... Longman is a firm of English publishers. ... From Athenaeum Illustre to University In January 1632 two internationally acclaimed scientists, Caspar Barlaeus and Gerardus Vossius, held their inaugural speech in the Athenaeum Illustre - the illustrious school - which had its seat in the 14th-century Agnietenkapel. ... Chapman and Hall was a British publishing house, founded in the first half of the 19th century by Edward Chapman and William Hall. ... Allen & Unwin, formerly a major British publishing house, is now an independent, Australia-based book publisher and distributor. ... The University of South Carolina, Columbia (USC or Carolina) is a public, co-educational, research university located in Columbia, South Carolina, United States. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... is the 92nd day of the year (93rd in leap years) in the Gregorian calendar. ... Clinical Microbiology Reviews is an academic journal published by the American Society for Microbiology. ...

External links

• Programmes and information to assist in the planning and implementation of tsetse control operations
• Programme Against African Trypanosomiasis
• PAN AFRICAN TSETSE AND TRYPANOSOMIASIS ERADICATION CAMPAIGN (PATTEC)
• Leverhulme Trust Tsetse Research Network (LTTRN)

Resources

Fiction

• "Winged Death" by H. P. Lovecraft and Hazel Heald (1933). Gothic horror on the malevolent use of trypanosome
• Neil Gaiman's Sandman series started by using the sleeping sickness as a subplot(The Sandman #1, Sleep of the Just, Vertigo, 1988).

Scientific books on tsetse and trypanosomiasis

• Buxton, P. (1955) The Natural History of Tsetse Flies: An Account of the Biology of the Genus Glossina (Diptera). London, UK: H.K. Lewis & Co.
• Glascow, J. (1963) The Distribution and Abundance of Tsetse International Series of Monographs on Pure and Applied Biology, No. 20. Oxford, UK: Pergamon Press.
• Mulligan, H. & Potts, W. (1970) The Afrian Trypanosomiases London, UK: George Allen and Unwin, Ltd.
• Ford, J. (1971) The Role of the Trypanosomiases in African Ecology. Oxford, UK: Clarendon Press.
• Leak, S. (1998) Tsetse Biology and Ecology: Their role in the Epidemiology and Control of Trypanosomiasis. New York, NY, USA: CABI Publishing. book site
• McKelvey Jr., J. (1973) Man Against Tsetse: Struggle for Africa. Ithaca, NY, USA: Cornell University Press.