Visceral leishmaniasis: An immunological viewpoint on asymptomatic infections and post kala azar dermal leishmaniasis

• Published in: Asian Pacific Journal of Tropical Medicine
• Main Authors: Neeraj Tiwari, Dhiraj Kishore, Surabhi Bajpai, Rakesh K Singh
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wolters Kluwer Medknow Publications 2018
• Subjects: visceral leishmaniasis; immune response; asymptomatic infection; sterile cure; post kala-azar dermal leishmaniasis; Arctic medicine. Tropical medicine; RC955-962; Arctic; Indian; Azar
• Online Access: https://doi.org/10.4103/1995-7645.225016; https://doaj.org/article/66413425b00e4b9686c532bf4e4b06d1

Elimination of visceral leishmaniasis is a priority programme in Indian subcontinent. The World Health Organization has set a new target to eliminate kala-azar by the year 2020 as previous target elimination year (2015) has passed. The elimination programme has successfully curbed the rate of infection in endemic regions; however, there are still few challenges in its route. The current drug control regime is extremely limited and comprises only two (amphotericin B and miltefosine) drugs, which are also susceptible for parasites resistance. Moreover, these drugs do not produce sterile cure, and cured patients may develop post kala-azar dermal leishmaniasis even after a decade of cure leaving behind a potent source of parasitic reservoirs for further disease transmission. A significant proportion of endemic population remain seropositive but aymptomatic for many years without any clinical symptom that serve as latent parasitic reservoirs. The lack of tools to identify live parasites in asymptomatic infections and there association in disease transmission, parameters of sterile cure along with post kala-azar dermal leishmaniasis progression remain a major threat in its elimination. In this review, we discuss the potential of host immune inhibitory mechanisms to identify immune correlates of protective immunity to understand the mystery of asymptomatic infections, sterile cure and post kala azar dermal leishmaniasis.