Leishmania: Types, Symptoms, Diagnosis and Treatment

Leishmania is caused by unicellular eukaryotic protozoan which produces different clinical syndromes ranging from cutaneous ulcers to fatal visceral diseases. The organisms are transmitted by sandflies (phlebotomus) which acts as a vector. The infective form is amastigote and the diagnostic form is promastigote. It mainly infects the reticuloendothelial system (Macrophages) and comes under the category of a hemoflagillate.  Transmission may be anthroponotic (from infected humans to healthy humans) and it can be zoonotic (from animal reservoir to humans). 

Leishmania Types and Symptoms

There are multiple types of leishmania depending upon the type of symptoms it produces.

Visceral Leishmaniasis

•  It is also called as Kala Azar or Black fever. The disease is named after the symptoms that is pigmentation of the skin ( Dark, blackened and scaly skin). 
• Patient will present with fever, chills and rigors during the intial stages of the disease. There will be protuberant abdomen due to hepatosplenomegaly.
• The spleen will be hugely enlarged. There will be weakness, weightloss and hypoalbuminemia as the disease progressed. There is risk of CHF due to anemia.

                                            Life cycle of leishmania

Cutaneous Leishmaniasis

• It is caused by L. Tropica. After getting bitten by the sandfly , an oriental sore develops also called as Baghdad Boil.
•  It has erythematous border with lot of yellow colour exudative discharge present in the center. 
• The lesions produced on the exposed body parts( Face and hands) can lead to permanent scar formation and can limits the social interaction of the person which can cause psychiatric problems like anxiety and depression. 
• It has a variant called as Diffuse Cutaneous Leishmaniasis which spreads from the face to rest of the body.

Mucocutaneous Leishmaniasis

• It is caused by L.Brasiliensis and it is associated with lesions on the buccal mucosa and skin. 
• The parasite enters via the lymphatics and reached the blood stream and can cause intense inflammation and destruction. 
• The lesions are mainly in the mouth or around the mouth or nose. Typically the mucosal leishmaniasis presents with nasal stuffiness and followed by bleeding due to perforation of the nasal septum. The more extensive the disease is the worst will be the prognosis.
• Other parts like soft palate, cheeks and lips can also get involved and there is risk of development of secondary bacterial infection. Aspiration pneumonia can develop which is fatal.

Leishmaniasis Recidivans

It is also called as Relapsing Leishmaniasis and it occurs due to inadequate treatment. There will be nodular lesions or rashes seen around a central healing.

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Leishmania Diagnosis

• The clinical history and physical examination plays an important role in the diagnosis. Spleen will be heavily enlarged.
• Amastigotes also known as LD bodies are diagnostic. These do not have any flagella. Amastigotes can be appreciated in the splenic smears (most sensitive) of the patients but bone marrow is preferred for sample.
• In HIV+ patients spleen and liver are not commonly involved, so lungs might be involved.

                                Amastigote and Promastigote of Leishmania

• Blood smear/Bone marrow analyis can detect the LD bodies being engulfed by Macrophages.
• On CBC there will be pancytopenia as the parasite destroys the reticuloendothelial system.
• There are two antibody tests that can be used for diagnosis and they will detect the Hypergammaglobulinemia. The tests are- Napier’s Aldehyde test and Chopra’s Antimony test.
• The medium used is Novy-McNeal-Nicolle medium and PCR technique can also be used for qualitative detection of leishmanial nucleic acid.
• Montenegro test is a skin test that can be used for the screening and diagnosis.

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Leishmania Treatment

• Severe anemia can be treated with the blood transfusion and manage the comorbid conditions carefully.
• Drug of choice for Visceral Leishmaniasis is Liposomal Amphotericin B. But there is a disease called as Post Kala Azar Dermal Leishmaniasis (PKDL) which happens in Kala azar patients getting treatment with Liposomal Amphotericin B. They develops hypopigmented nodules after 1-2 years. Treatment for PKDL is Oral Miltefosine.
• Multidrug therapy for leishmaniasis is likely to be preferred in the future.
• The treatment for Mucocutaneous and Cutaneous Lesihmaniasis is Sodium Stibogluconate and regular follow-up is required after the treatment.

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Leishmania Prevention

• There are no vaccines available for Leishmania therefore precautionary measures are important to avoid the spreading of the disease.
• Anthroponotic Leishmaniasis can be restricted by case finding, treatment and the use of insecticide-impregnated beds.

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