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Leishmania

Leishmania is a genus of parasitic flagellate, belonging to the trypanosomes and responsible for diseases such as leishmaniasis. Leishmania is spread through sand flies, with two different vectors: Phlebotomus[?] in the Old World, and Lutzomyiasis[?] in the New World. The parasite havetwo morphological[?] states: promastigote[?] (leptimonad), which lives in the digestive tract of the fly, and amastigote[?], which is found in the lysosomes in the macrophages of vertebrates. Common vertebrates that are infected include hyraxes, canids[?], rodents, and humans. Infections are represented as cutaneous (localized and diffuse), mucocutaneous and visceral.

Cutaneous[?] infections shown with obvious skin reactions. Most common is the Oriental Sore (l. major. l. tropica and l. aethiopica; all are Old World). The common New World cutaneous culprits are l. mexicana and l. viannia braziliensis.

Mucocutaneous[?] (espundia) infections will start off as a reaction at the bite, and can go metastasis in to the mucus membranes and be fatal.

Visceral[?] infections (a l. donovani exclusive)are often recognized with with fever, weight loss, swelling of the liver and spleen and anaemia. An important aspect to the life of the Leishamania protozoan is its glyconjugate[?] layer of lipophosphoglycan (LPG). Held together with a phopshoinosite membrane anchor; tripartite structure, it consists of a lipid domain, a neutral hexasaccharide core and a phosphorylated galactose-mannose, with a termination in a neutral cap. Not only do the little unfriendlies not develop post-phlebotmus digestion but, it is thought to be essential to oxidative bursts, thus allowing passage for infection. Along with oxidative bursts, the parasites destroy macrophages through acidification and digestion. Chararacteristics of digestion include an endosome[?] fusing with a lysosome, releasing acid hydrolases[?] which degrade DNA, RNA, proteins and carbohydrates.

The origins of leishmania is a well thought out subject. One scientist suggested a palaearctic migration of leishmania into the New World. This is much like the palaearctic migration of human across the Bering Strait land bridge. Most of both theories concur. In the theory, the reservoirs are humans and rats. The humans migrate in North America and South America and leishmania picks up it's current New World vectors in their respective ecologies. This is the cause of the epidemics now evident. One recent New World epidemic (an area being studied by Auburn University's Laboratory of Animal Health, including the author's mother) concerns foxhounds of Tennessee. The study is being done as these words are written.

Leishmania currently effects 12 million people in 88 countries. Visceral infections are most common in Bangladesh, Brazil, India, Nepal and Sudan. Mucocutaneous infections are most common in Bolivia, Brazil and Peru. Cutaneous infections are most common in Afghanistan, Brazil, Iran, Peru, Saudi Arabia and Syria. Treatments of the disease generally involve a solution containing antimony. A solution which breaks down the LPG is also a form of treatment being looked at. Those who feel they are infected should seek immediate attention. Transmission is intravenous, with the aid of sand flies and needle-sharing drugs users. Most at risk are humans infected with HIV, canines and rodents.

There are 37 different species, including:

  • L. aethiopica
  • L. amazonenis
  • L. arabica
  • L. archibaldi
  • L. aristedes
  • L. viannia braziliensis
  • L. chagasi
  • L. viannia colombiensis
  • L. deanei
  • L. donovani
  • L. enriettii
  • L. viannia equatorensis
  • L. forattinii
  • L. garnhami
  • L. gerbili
  • L. viannia guyanensis
  • L. herreri
  • L. hertigi
  • L. infantum
  • L. killicki
  • L. viannia lainsoni
  • L. major
  • L. mexicana
  • L. naiffi
  • L. viannia panamensis
  • L. viannia peruviana
  • L. viannia pifanoi
  • L. viannia shawi
  • L. turanica
  • L. tropica
  • L. venezuelenis sauroleishmania adler



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