Trypanosoma vivax

Trypanosoma vivax is a parasite species in the genus Trypanosoma. It causes the disease nagana, also known as animal trypanosomiasis, affecting cattle or wild mammals such as the nyala. It is mainly occurring in West Africa, although it has spread to South America.[3][1]

Trypanosoma vivax
Scientific classification
Domain: Eukaryota
Phylum: Euglenozoa
Class: Kinetoplastea
Order: Trypanosomatida
Family: Trypanosomatidae
Genus: Trypanosoma
Species:
T. vivax
Binomial name
Trypanosoma vivax
Ziemann, 1905
Synonyms
  • Trypanosoma caprae
  • Trypanosoma angolense
  • Trypanosoma (subg. Duttonella) vivax[1][2]

Range

Historically restricted to sub-Saharan Africa especially West Africa, it has spread to 13 countries of South America. This has been made easier by its mechanical transmission route, see §Life cycle below.[1]

Hosts

Cattle, horses, sheep, and camels.[2][1] As of 2016 in South America it is an emerging pathogen of cattle, and sometimes horses and other ruminants.[1]

Life cycle

Unusual for a trypanosome, T. vivax does not infect the Glossina vector midgut. Instead it infects and completes an abbreviated life cycle only in the vector's proboscis. Thus it is entirely mechanically transmitted. For this reason it has had a relatively easy time jumping vectors, and thereby jumping geographic ranges which do not have its customary vector.[1]

Symptoms

Symptoms of T. vivax include "rapid weight loss, lethargy, weakness, clumsiness, pale mucosa, swelling of superficial lymph nodes, anemia, and fluctuating pyrexia, causing[...]a drop in animal productivity."[4]

Enzymes

A novel proline racemase of medical and veterinary importance has been described in T. vivax (B8LFE4).[5]

It also produces vivapain, a cysteine peptidase.[6]

Host immunity

The smallest variable surface glycoprotein (40 kDa in size) to date has been found in T. vivax, which bears little carbohydrate.[7]

Economic impact

Trypanosoma vivax is a significant drag on Africa's cattle production every year, and increasingly is a concern in South America: One outbreak in 1995 in the Pantanal in Brazil and Bolivia cost the industry over US$160 million.[1]

Trypanocide resistance

Some resistance to trypanocides has been observed: Some African countries have isometamidium-resistant populations, with some of these also being resistant to diminazene. (This has been ascribed variously to cross-resistance or to two separate events of acquisition of separate resistance genetics. Isometamidium and diminazene are not thought to be in the same trypanocide class.) Resistance to both is widespread in both West and East Africa. Diminazene resistance has been observed in South America.[1]

Mechanisms of resistance are not necessarily shared across the genus, and this is especially true for this, the most genetically divergent species.[1]

References
  1. Giordani, Federica; Morrison, Liam J.; Rowan, Timothy G.; De Koning, Harry P.; Barrett, Michael P. (2016-10-10). "The animal trypanosomiases and their chemotherapy: a review". Parasitology. Cambridge University Press (CUP). 143 (14): 1862–1889. doi:10.1017/s0031182016001268. ISSN 0031-1820.
  2. Osório, Ana Luiza Alves Rosa; Madruga, Claudio Roberto; Desquesnes, Marc; Soares, Cleber Oliveira; Ribeiro, Laura Raquel Rios; Costa, Sylvio Celso Gonçalves da (2008). "Trypanosoma (Duttonella) vivax: its biology, epidemiology, pathogenesis, and introduction in the New World - A Review". Memórias do Instituto Oswaldo Cruz. FapUNIFESP (SciELO). 103 (1): 1–13. doi:10.1590/s0074-02762008000100001. ISSN 0074-0276. S2CID 27672643.
  3. Batista JS, Rodrigues CM, García HA, Bezerra FS, Olinda RG, Teixeira MM, Soto-Blanco B (2011). "Association of Trypanosoma vivax in extracellular sites with central nervous system lesions and changes in cerebrospinal fluid in experimentally infected goats". Veterinary Research. 42 (63): 1–7. doi:10.1186/1297-9716-42-63. PMC 3105954. PMID 21569364.
  4. Camejo, María; Spencer, Lilian; Núñez, Armando (15 December 2014). "TNF-alpha in bulls experimentally infected with Trypanosoma vivax: A pilot study". Veterinary Immunology and Immunopathology. 162 (3–4): 192–197. doi:10.1016/j.vetimm.2014.10.010. PMID 25464824.
  5. Chamond N, Cosson A, Coatnoan N, Minoprio P (June 2009). "Proline racemases are conserved mitogens: characterization of a Trypanosoma vivax proline racemase". Mol. Biochem. Parasitol. 165 (2): 170–9. doi:10.1016/j.molbiopara.2009.02.002. PMID 19428664.
  6. Vather, Perina (2012-01-06). Vivapain : a cysteine peptidase from Trypanosoma vivax (Thesis). hdl:10413/4775.
  7. Gardiner, Peter R.; Nene, Vishvanath; Barry, Michele M.; Thatthi, Ravi; Burleigh, Barbara; Clarke, Michael W. (1996). "Characterization of a small variable surface glycoprotein from Trypanosoma vivax". Molecular and Biochemical Parasitology. 82 (1): 1–11. doi:10.1016/0166-6851(96)02687-4. PMID 8943146.

Further reading
  • Camejo, Maria; Nunez, Armando; Spencer, Lilian (December 2014). "TNF-alpha in bulls experimentally infected with Trypanosoma vivax: A pilot study". Veterinary Immunology and Immunopathology (Thesis). 162 (3–4): 197. doi:10.1016/j.vetimm.2014.10.010. PMID 25464824.

"Trypanosoma vivax". National Center for Biotechnology Information (NCBI).

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