Leishmaniasis Treatment: An Overview

Leishmaniasis is a parasitic disease caused by protozoa of the Leishmania genus. It is transmitted by the bite of infected sand flies. Over 1 million new cases are reported annually making it a major public health problem worldwide. In this article, we discuss the various treatment options available for leishmaniasis.

Classification and Types

There are three main clinical forms of leishmaniasis – cutaneous, mucocutaneous, and visceral leishmaniasis.

Cutaneous Leishmaniasis
Cutaneous leishmaniasis is the most common form which causes skin sores or lesions. It is widely distributed across parts of Africa, Asia, Europe, and South America. The lesions caused can vary from a few to thousands of nodules or bumps on exposed parts of the body.

Mucocutaneous Leishmaniasis
Mucocutaneous Leishmaniasis involves both skin and mucosal tissues of the nose, mouth, and throat. It is caused by Leishmania brasiliensis and spreads from an initial skin lesion. This form can lead to severe disfigurement if left untreated.

Visceral Leishmaniasis
Also known as Kala-azar, visceral leishmaniasis is the most severe form affecting internal organs like the liver, spleen, and bone marrow. It can be fatal if not treated properly. Visceral leishmaniasis is widespread in the Mediterranean region, East Africa, and the Indian subcontinent.

Conventional Treatments
The treatment options for leishmaniasis depend on the type and also involve factors like geographic location, parasite species, and the individual patient characteristics. Some of the conventional treatments include:

Pentavalent Antimonials
Pentavalent antimonials like Sodium Stibogluconate (SSG) and Meglumine Antimoniate have been the first-line drugs for many years. They require long parenteral administration for 15-30 days and can cause serious side effects in some patients.

Amphotericin B
Amphotericin B has been the treatment of choice for visceral leishmaniasis and unresponsive cases of cutaneous leishmaniasis. It has high cure rates but requires intravenous administration and closely monitoring due to potential renal toxicity and other side effects.

Paromomycin
Paromomycin is an effective oral drug used as a first-line or alternate treatment. The cure rates are over 90% for visceral leishmaniasis. However, it is not effective against all parasite species or clinical manifestations.

Pentamidine
Pentamidine has activity against some Leishmania species causing cutaneous and mucocutaneous infections. It is given as an intravenous or intramuscular injection but with risk of serious adverse effects.

Alternative Treatments
With the drawbacks of existing drugs, research efforts are being made to develop newer treatment options. Some promising alternatives include:

Miltefosine
Miltefosine is the first effective oral drug approved for use against visceral leishmaniasis. It has high cure rates of 94-95% and relatively fewer side effects. The drawback is the long treatment duration of 4 weeks.

Paromomycin Combinations
Combination of paromomycin with other antileishmanial drugs improves efficacy and reduces treatment period. The most effective combinations found are paromomycin with SSG or miltefosine.

Liposomal Formulations
Using liposomal formulations enables targeted delivery of antileishmanial medications and improves effectiveness. Liposomal amphotericin B has better safety profile compared to conventional amphotericin B with comparable therapeutic responses.

Local Therapies
Local therapies are primarily used for cutaneous leishmaniasis. Intralesional injections of antimonials, thermotherapy using heat application, and cryotherapy freezing nodules have shown promise as alternatives or additions to systemic therapies.

Phytomedicines
Plants with antileishmanial properties are being researched for new drug developments. Quercitin, artemisinin, and gallic acid isolated from various plant sources have displayed good in vitro activity against Leishmania parasites. Further studies are required for clinical use.

Conclusion
In summary, treatment of leishmaniasis involves a combination of drugs, their formulations, treatment duration, and other management techniques based on parasitic and host factors. While current options are effective against most cases, their limitations call for continuous research towards safer and shorter therapies. Alternative drugs, formulations, and therapeutic combinations hold promise in improving leishmaniasis treatment.

 

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