Trypanotolerance

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A trypanotolerant organism is one which is relatively less affected by trypanosome infestation.

Contents

By host

In livestock

Some breeds are known for their trypanotolerance. This is especially important in Africa where a few particular trypanosomes are major economic and agricultural pests. [1] [2] [3] [4]

Trypanotolerant livestock breeds

Trypanotolerance of the N'Dama Cattle and West African Dwarf Sheep and Goats

Certain domestic ruminant breeds in sub-saharan Africa show remarkable resistance to the effects of African trypanosomiasis: they can tolerate the parasites's presence while controlling parasitaemia levels and, most importantly, do not show the severe anemia and production loss that are typical of infection in susceptible breeds. [7]

The trypanotolerance trait is seen in N'Dama cattle, and it refers to the N'Dama cattle's ability to survive in areas with high tsetse fly endemicity, where other cattle breeds would frequently contract trypanosomiasis. [1] In areas or locations of low to moderate tsetse fly challenge, typanotolerant N'Dama cattle show lower numbers of parasites in their blood, develop less severe anemia and have also been shown to be more productive. [8]

An investigation to test the resistance of different small ruminant breeds (West African dwarf sheep and goats) to an artificial infection with T. congolense revealed that native sheep and goats had a higher natural resistance to the illness than exotic breeds, with exotic/indigenous crossbreeds falling somewhere in between. [9] Despite persistent parasitaemia, clinical signs in trypanotolerant West African dwarf sheep and goats revealed a milder illness with lower mortality. [9] The significance of these trypanotolerant traits is highlighted when choosing breeds of sheep and goats for selection programs. Some literature claims that trypanotolerance in small ruminants (sheep and goats) should be viewed as resilience rather than resistance because it is less apparent than in cattle. [10]

Trypanotolerance appears to include both non-immunological and immunological pathways and is most likely multifactorial. [11] However, physiological and nutritional factors, concurrent diseases, the presence and absence of tsetse, and inter-current diseases all have an impact on the level of resistance displayed by typanotolerant breeds of cattle, sheep, and goats. [7]

In addition to the above-listed criteria, studies have shown that the effective dose of the trypanosome parasite that these animals acquire following the bite of the tsetse fly is also a consideration. It only takes one fly bite to transmit the infection. [11] The quantity of trypanosomes injected into an animal's skin as a result of bites determines how severe the sickness will be; thus, trypanotolerance during natural exposure may be influenced by lower infective dosages. [7] The finding that some cattle that are highly resistant in the field don't always retain that level of resistance after being artificially infected with a specific dose of the parasite may be supportive of this hypothesis. [12]

History of genetic research

Trypanotolerance had previously been achieved through normal livestock breeding in cattle, but genetic analysis was becoming a serious option in the 1980s. The effort that would eventually bear fruit began with a conversation between Peter Brumby - then at the International Livestock Centre for Africa - and Morris Soller in 1985. This was followed by the opening of the shortlived International Trypanotolerance Center in the Gambia in 1987 with a seminar on the genome mapping project that would continue beyond the Center itself. The project was then actually completed by the ILRI - the successor to the ILCA - in 2003. [13]

Related Research Articles

<span class="mw-page-title-main">African trypanosomiasis</span> Parasitic disease also known as sleeping sickness

African trypanosomiasis is an insect-borne parasitic infection of humans and other animals.

<span class="mw-page-title-main">Tsetse fly</span> Genus of disease-spreading insects

Tsetse are large, biting flies that inhabit much of tropical Africa. Tsetse flies include all the species in the genus Glossina, which are placed in their own family, Glossinidae. The tsetse is an obligate parasite, which lives by feeding on the blood of vertebrate animals. Tsetse has been extensively studied because of their role in transmitting disease. They have a pronounced economic impact in sub-Saharan Africa as the biological vectors of trypanosomes, causing human and animal trypanosomiasis.

<span class="mw-page-title-main">Trypanosomiasis</span> Medical condition

Trypanosomiasis or trypanosomosis is the name of several diseases in vertebrates caused by parasitic protozoan trypanosomes of the genus Trypanosoma. In humans this includes African trypanosomiasis and Chagas disease. A number of other diseases occur in other animals.

<i>Trypanosoma</i> Genus of parasitic flagellate protist in the Kinetoplastea class

Trypanosoma is a genus of kinetoplastids, a monophyletic group of unicellular parasitic flagellate protozoa. Trypanosoma is part of the phylum Euglenozoa. The name is derived from the Greek trypano- (borer) and soma (body) because of their corkscrew-like motion. Most trypanosomes are heteroxenous and most are transmitted via a vector. The majority of species are transmitted by blood-feeding invertebrates, but there are different mechanisms among the varying species. Trypanosoma equiperdum is spread between horses and other equine species by sexual contact. They are generally found in the intestine of their invertebrate host, but normally occupy the bloodstream or an intracellular environment in the vertebrate host.

<i>Haemonchus contortus</i> Species of roundworm

Haemonchus contortus, also known as the barber's pole worm, is a very common parasite and one of the most pathogenic nematodes of ruminants. Adult worms attach to abomasal mucosa and feed on the blood. This parasite is responsible for anemia, oedema, and death of infected sheep and goats, mainly during summer in warm, humid climates.

<i>Trypanosoma brucei</i> Species of protozoan parasite

Trypanosoma brucei is a species of parasitic kinetoplastid belonging to the genus Trypanosoma that is present in sub-Saharan Africa. Unlike other protozoan parasites that normally infect blood and tissue cells, it is exclusively extracellular and inhabits the blood plasma and body fluids. It causes deadly vector-borne diseases: African trypanosomiasis or sleeping sickness in humans, and animal trypanosomiasis or nagana in cattle and horses. It is a species complex grouped into three subspecies: T. b. brucei, T. b. gambiense and T. b. rhodesiense. The first is a parasite of non-human mammals and causes nagana, while the latter two are zoonotic infecting both humans and animals and cause African trypanosomiasis.

<i>Trypanosoma evansi</i> Contagious protist

Trypanosoma evansi is a parasitic species of excavate trypanosome in the genus Trypanosoma that is one cause of surra in animals. Discovered by Griffith Evans in 1880 at Dera Ismail Khan, it is the first known trypanosome that causes infection. It is a common parasite in India and Iran and causes acute disease in camels and horses, and chronic disease in cattle and buffalo. In Pakistan, it has been found to be the most prevalent trypanosome species in donkeys. It is now established to infect other mammals, including humans.

Trypanosoma suis is a species of excavate trypanosome in the genus Trypanosoma that causes one form of the surra disease in animals. It infects pigs. It does not infect humans.

<span class="mw-page-title-main">Animal trypanosomiasis</span> Parasitic disease of vertebrates

Animal trypanosomiasis, also known as nagana and nagana pest, or sleeping sickness, is a disease of vertebrates. The disease is caused by trypanosomes of several species in the genus Trypanosoma such as T. brucei. T. vivax causes nagana mainly in West Africa, although it has spread to South America. The trypanosomes infect the blood of the vertebrate host, causing fever, weakness, and lethargy, which lead to weight loss and anemia; in some animals the disease is fatal unless treated. The trypanosomes are transmitted by tsetse flies.

<span class="mw-page-title-main">Sanga cattle</span> Breed of cattle

Sanga cattle is the collective name for indigenous cattle of some regions in Africa. They are sometimes identified as a subspecies with the scientific name Bos taurus africanus. Their history of domestication and their origins in relation to taurine cattle, zebu cattle (indicine), and native African varieties of the ancestral aurochs are a matter of debate. "African taurine", "sanga", "zenga", "sheko", "African indicine" are all sub-groups of Sanga cattle.

<i>Trypanosoma congolense</i> Protozoan parasite, cause of nagana

Trypanosoma congolense is a species of trypanosomes and is the major pathogen responsible for the disease nagana in cattle and other animals including sheep, pigs, goats, horses and camels, dogs, as well as laboratory mice. It is the most common cause of nagana in east Africa, but is also a major cause of nagana in west Africa. This parasite is spread by tsetse flies. In its mammalian host, Trypanosoma congolense only lives in blood vessels, and causes in particular anaemia.

<span class="mw-page-title-main">N'Dama</span> Breed of cattle

N'Dama is a breed of cattle from West Africa. Other names for them include Boenca or Boyenca (Guinea-Bissau), Fouta Jallon, Djallonké or Djallonké cattle, Fouta Longhorn, Fouta Malinke, Futa, Malinke, Mandingo (Liberia), and N'Dama Petite (Senegal). Originating in the Guinea highlands, they are also found in southern Senegal, Guinea-Bissau, the Gambia, Mali, Ivory Coast, Liberia, Nigeria, and Sierra Leone. They are trypanotolerant, allowing them to be kept in tsetse fly-infested areas. They also show superior resistance to ticks and the diseases they carry and to Haemonchus contortus stomach worms.

<span class="mw-page-title-main">West African dwarf goat</span> West African breed of goat

The West African Dwarf is a large and variable breed or group of breeds of domestic goat from coastal West and Central Africa, a range extending approximately from Senegal to Congo. It is characterised by achondroplasia or dwarfism, a trait that may have evolved in response to conditions in the humid forests of the area, and also by some degree of resistance to tsetse-borne trypanosomiasis or "sleeping-sickness".

A trypanocidal agent is an antiprotozoal agent that acts upon trypanosome parasites.

The West African Dwarf or Djallonké is an African breed or group of breeds of domestic sheep. It is the dominant breed of West and Central Africa. This breed is primarily raised for meat. The Cameroon or Cameroon Dwarf is a breed within this group.

<span class="mw-page-title-main">Agriculture in Sierra Leone</span>

Agriculture in Sierra Leone is a significant part of the economy of Sierra Leone, with it accounting for 58 percent national Gross Domestic Product (GDP) in 2007. Two-thirds of the population of Sierra Leone are involved in subsistence agriculture.

<i>Teladorsagia circumcincta</i> Species of roundworm

Teladorsagia circumcincta is a nematode that is one of the most important parasites of sheep and goats. It was previously known as Ostertagia circumcincta and is colloquially known as the brown stomach worm. It is common in cool, temperate areas, such as south-eastern and south-western Australia and the United Kingdom. There is considerable variation among lambs and kids in susceptibility to infection. Much of the variation is genetic and influences the immune response. The parasite induces a type I hypersensitivity response which is responsible for the relative protein deficiency which is characteristic of severely infected animals. There are mechanistic mathematical models which can predict the course of infection. There are a variety of ways to control the infection and a combination of control measures is likely to provide the most effective and sustainable control.

Glossina fuscipes is a riverine fly species in the genus Glossina, which are commonly known as tsetse flies. Typically found in sub-Saharan Africa but with a small Arabian range, G. fuscipes is a regional vector of African trypanosomiasis, commonly known as sleeping sickness, that causes significant rates of morbidity and mortality among humans and livestock. Consequently, the species is among several being targeted by researchers for population control as a method for controlling the disease.

The Sleeping Sickness Commission was a medical project established by the British Royal Society to investigate the outbreak of African sleeping sickness or African trypanosomiasis in Africa at the turn of the 20th century. The outbreak of the disease started in 1900 in Uganda, which was at the time a protectorate of the British Empire. The initial team in 1902 consisted of Aldo Castellani and George Carmichael Low, both from the London School of Hygiene and Tropical Medicine, and Cuthbert Christy, a medical officer on duty in Bombay, India. From 1903, David Bruce of the Royal Army Medical Corps and David Nunes Nabarro of the University College Hospital took over the leadership. The commission established that species of blood protozoan called Trypanosoma brucei, named after Bruce, was the causative parasite of sleeping sickness.

Morris Soller (1931–) is a research professor in the Department of Genetics of the Hebrew University of Jerusalem. He is especially interested in livestock- and crop- genetics including trypanotolerance in cattle.

References

  1. 1 2 d'Ieteren, G.; Authie, E.; Wissocq, N.; Murray, M. (1998). "Trypanotolerance, an option for sustainable livestock production in areas at risk from trypanosomosis". Revue Scientifique et Technique de l'OIE . 17 (1). O.I.E (World Organisation for Animal Health): 154–175. doi: 10.20506/rst.17.1.1088 . ISSN   0253-1933. PMID   9638808. S2CID   1188831.
  2. 1 2 Kim, Soo-Jin; Ka, Sojeong; Ha, Jung-Woo; Kim, Jaemin; Yoo, DongAhn; Kim, Kwondo; Lee, Hak-Kyo; Lim, Dajeong; Cho, Seoae; Hanotte, Olivier; Mwai, Okeyo Ally; Dessie, Tadelle; Kemp, Stephen; Oh, Sung Jong; Kim, Heebal (2017-05-12). "Cattle genome-wide analysis reveals genetic signatures in trypanotolerant N'Dama". BMC Genomics . 18 (1). BioMed Central: 371. doi: 10.1186/s12864-017-3742-2 . ISSN   1471-2164. PMC   5427609 . PMID   28499406.
  3. ↑ "Trypanotolerant livestock in the context of trypanosomiasis intervention strategies". Food and Agriculture Organization of the United Nations . Retrieved 2021-02-20.
  4. ↑ "Trypanotolerance in West African cattle". CIRAD (Centre de coopération internationale en recherche agronomique pour le développement). Retrieved 2021-02-20.
  5. ↑ R. T. Wilson (1991). Small Ruminant Production and the Small Ruminant Genetic Resource in Tropical Africa. Rome: United Nations Food and Agriculture Organization. ISBN   9789251029985.
  6. ↑ Mawuena, K. (1987). "Haut degré de tolérance à la trypanosomose des moutons et des chèvres de race naine Djallonké des régions Sud-guinéennes du Togo. Comparaison avec les bovins trypanotolérants" [High degree of tolerance to trypanosomiasis of dwarf Djallonké sheep and goats in the southern guinean area of Togo. Comparison with trypanosoma tolerant cattle]. Revue d'élevage et de médecine vétérinaire des pays tropicaux . 40 (1): 55–58. doi: 10.19182/REMVT.8696 . PMID   3444966. S2CID   86116225.
  7. 1 2 3 Authié, E. (1994). "Trypanosomiasis and trypanotolerance in cattle: A role for congopain?". Parasitology Today . 10 (9): 360–364. doi:10.1016/0169-4758(94)90252-6. ISSN   0169-4758. PMID   15275419. S2CID   42585897.
  8. ↑ Kemp, S.; Teale, A. (1998). "Genetic Basis of Trypanotolerance in Cattle and Mice". Parasitology Today . 14 (11). Elsevier: 450–454. doi:10.1016/s0169-4758(98)01334-9. ISSN   0169-4758. PMID   17040846. S2CID   3253779.
  9. 1 2
  10. ↑ Geerts, Stanny; Osaer, Sabine; Goossens, Bart; Faye, Déthié (2009). "Trypanotolerance in small ruminants of sub-Saharan Africa". Trends in Parasitology . 25 (3). Cell Press: 132–138. doi:10.1016/j.pt.2008.12.004. PMID   19200783.
  11. 1 2 Duvallet, Gérard (2017). "Chapitre 1. Arthropodologie générale". Entomologie médicale et vétérinaire[Medical and Veterinary Entomology]. IRD Éditions. pp. 19–35. doi:10.4000/books.irdeditions.21962. ISBN   9782709923767.
  12. ↑ Chow, Y. W.; Pietranico, R.; Mukerji, A. (1975-10-27). "Studies of oxygen binding energy to hemoglobin molecule". Biochemical and Biophysical Research Communications. 66 (4): 1424–1431. doi:10.1016/0006-291x(75)90518-5. ISSN   0006-291X. PMID   6.
  13. ↑ Soller, Morris (2015-02-16). "If a Bull Were a Cow, How Much Milk Would He Give?". Annual Review of Animal Biosciences . 3 (1). Annual Reviews: 1–17. doi: 10.1146/annurev-animal-022114-110751 . ISSN   2165-8102. PMID   25493539. S2CID   46733451.
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