Leishmania tropica complex
(leesh-may-nee-uh / trop-i-kuh)
Basic Information
- There are three distinct organisms in this complex, each with its own geographical area:
- L. tropica - Mediterranean regions, Middle East, Armenia, Caspian region, Afghanistan, India and Kenya
- L. aethiopica - Highlands of Ethiopia, Kenya and Southern Yemen
- L. major - Desert regions of Turkmenistan, Uzbekistan and Kazakhstan, North Africa and the Sahara, Iran, Syria, Israel and Jordan
Transmission
Transmission of this complex occurs when an infected female sandfly (Phlebotomus spp.) bites a person, injecting promastigotes into the skin. Macrophages ingest the parasite, where the amastigotes multiply and eventually cause the cell to burst, releasing more parasites into the person's body. These parasites continue to infect other reticuloendothelial cells and lymphoid tissue.
Disease
Old World Cutaneous Leishmaniasis
- Also knows as Oriental sore.
- The incubation period for this infection can vary from several weeks to three years, depending on the specific organism causing it.
- L. major has a more rapid onset
- L. tropica and L. aethiopica are more prolonged
- L. major has a more rapid onset
- The first sign of infection is a red papule at the site of the fly bite.
- This progresses to a crateriform lesion, which can enlarge to 2 cm or more.
- can form secondary bacterial infections
- This progresses to a crateriform lesion, which can enlarge to 2 cm or more.
- They tend to heal spontaneously but leave serious scars.
Diagnostic
- Laboratory specimen
- aspiration of biopsy from active lesion
- whole blood
- Testing
- culture made on NNN media (amastigotes)
- permanent smears made with Giemsa or Wright's stain (promastigotes)
- Serological tests
- isoenzyme studies
- molecular diagnostic techniques (PCR)
- Montenegro skin test
- used to screen large populations that are at risk for infection
- it is a delayed hypersensitivity reaction from an injection that is administered intradermally
Treatment
The drug of choice for treatment is antimony sodium gluconate (Pentostam). Glucantime may be used as an alternated medication. In patients with long standing infections, Amphotericin B has been proven effective.