Leishmania braziliensis, Leishmania mexicana - History, Habitat, Culture, Morphology

Introduction of Leishmania braziliensis, Leishmania mexicana

Leishmania braziliensis Complex and Leishmania mexicana Complex cause New World cutaneous and mucocutaneous leishmaniasis. The lesions may vary from a single localized ulcer in the skin to spreading lesions such as espundia.

Depending upon their geographical location, mucocutaneous leishmaniasis has several names- espundia, pian bois, bubas braziliana, uta, chiclero ulcer, etc.

History of Leishmania braziliensis, Leishmania mexicana

Historically, in 1909, Lindenberg and Paranhos were the first ones to describe amastigotes in ulcers of skin from a man in Brazil. Carini in 1911 reported observing amastigotes in ulcers and nasopharyngeal mucous membranes. The same year, in 1911, Vianna named the species Leishmania braziliensis.

Habitat of Leishmania braziliensis, Leishmania mexicana

Leishmania braziliensis are intracellular parasites and habitats inside the macrophages of the skin as well as the mucous membranes of the nose and buccal cavity.

Unlike Leishmania donovani, they are absent from peripheral blood and internal organs.

Morphology of Leishmania braziliensis, Leishmania mexicana

The morphology of Leishmania braziliensis Complex and Leishmania mexicana Complex is similar to that of Leishmania donovani. The protozoa parasites exist in two forms- amastigote and promastigote form.

Amastigote form

• Amastigote form is found in humans and other mammal hosts

• small, round to oval bodies

• each amastigote form measures 2-3μm in length

• resides inside monocytes, endothelial cells, polymorphonuclear leucocytes of the host

• the nucleus is large and lies at a right angle to the kinetoplast which is slender, rod-shaped

• axoneme arises from the kinetoplast and extends to the margin of the amastigote

• vacuole, which is not stained lies alongside the axoneme

• stained well in Giemsa and Wright stain

• in Giemsa-stained preparations, the nucleus, and kinetoplast, are stained red

Promastigote

• promastigote occur naturally in the digestive tract of sand fly (vector)

• mature promastigotes are long, slender, and spindle-shaped

• measures 15 μm to 25 μm in length and 1,5 μm to 3.5 μm in breadth

• a single nucleus is centrally located

• kinetoplast located transversally near the anterior end

• the presence of a single flagellum measuring 15μm -28 μm

• Leishman stain stains the cytoplasm blue, the nucleus pink, and the kinetoplast bright red

Culture of Leishmania braziliensis, Leishmania mexicana

Leishmania braziliensis, Leishmania mexicana can be cultured in artificial media as well as in laboratory animals.

In media

The Leishmania braziliensis Complex and Leishmania mexicana Complex can be cultured in biphasic media, liquid media, or laboratory animals. They are slow growers and require more incubation time.

Biphasic media

• consists of two parts of salt agar and one part defibrinated rabbit blood

• Novy and McNeal (1904) and Nicolle (1908) (NNN) medium was the first biphasic medium for the culture of Leishmania braziliensis Complex and Leishmania mexicana Complex

Liquid media

• includes Schneider’s, Grace’s, and Mituhasi-Maramorosh media- which are insect cell culture media

• liquid media do not contain any blood

• usually used for the preparation of a large volume of promastigotes

• Schneider’s medium which contains 20% fetal calf serum (FCS) is more sensitive to culture than the NNN biphasic medium

Laboratory animals

Chinese hamsters and golden hamsters are routinely used in the culture and diagnosis of Leishmania braziliensis Complex and Leishmania mexicana Complex.