About this Research Topic
Leishmaniasis is a neglected tropical disease (NTD) that is causing major health and economic burden globally. The infection is caused by protozoan parasites of the Leishmania genus (L. donovani, L. infantum, and L. major) and is transmitted by the bite of infectious female sand flies of the Phlebotomus and Lutzomyia species. Over 1 billion people, in 88 countries, are living in Leishmania endemic areas and are at risk of infection.
Leishmaniasis has three clinical forms. Cutaneous leishmaniasis (CL) is the most common form producing ulcers on the exposed parts of the body, such as the face, arms, and legs, invariably leaving permanent scars that lead to serious social prejudice. In mucocutaneous leishmaniasis (MCL), the lesions can lead to the partial or total destruction of the mucous membranes of the nose, mouth and throat cavities, and surrounding tissues. Visceral leishmaniasis (VL), also known as kala-azar, is characterized by irregular bouts of long-lasting fever, anemia, substantial weight loss, and enlarged liver and spleen, leading to death when left untreated. Post-kala-azar dermal leishmaniasis (PKDL) is a complication of VL, characterized by hypopigmented macular, maculopapular, and nodular lesions, usually in patients who have recovered from VL months to years earlier. PKDL is considered to have an important role in maintaining and contributing to the transmission of VL.
For many years, the public health impact of the leishmaniases has been grossly underestimated, mainly due to lack of funding and awareness. On January 2012, the London Declaration on NTDs endorsed the WHO control and elimination targets for leishmaniasis to be achieved by the year 2020. This is very welcome and laudable initiative triggered new research studies on leishmaniasis greatly influencing and improving sand fly control efforts, our understanding of the transmission dynamics, and the effectivity of diagnostics and treatments. However, to date, a number of important scientific questions, that are crucial for effective leishmania control and elimination, remain unsolved.
Vector control and prompt diagnosis and treatment are the main strategies of disease control. Important knowledge gaps include: sand fly susceptibility to insecticides; impact of insecticides on sand fly density and disease incidence; vector control management; challenges with PKDL diagnosis; challenges with safe and effective treatments of VL and PKDL; lack of sterile cure as parasites can persist in infected individuals after drug treatment; and lack of point of care diagnosis and treatment at the local level. Immunological research requires further studies on the long-term duration of immunity after infection, impact of a potential vaccine, relapse versus reinfection (need to uphold immunity persistent antigen), why do VL not generate cellular immunity (why no effective T-cell immunity responses in VL) and mechanism for long term dynamics of the evolution of immune response.
Regarding the transmission dynamics, the main knowledge gaps include: the reservoirs of infection and the geographical scale of transmission. Through this Research Topic we are inviting submissions of Original Research articles and Reviews on CL, MCL, and VL globally, focusing on the following areas, but not limited to:
1. Recent development in the field of diagnosis and treatment of leishmaniasis
2. Innovations in immunological aspects of leishmaniasis leading to novel vaccine development and immunotherapy
3. Intervention strategies and innovations in leishmania control and elimination
Keywords: Leishmaniasis, Vaccine development, Immunotherapy, Leishmania control
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