ABSTRACT
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.
ABSTRACT
OBJECTIVE@#To detect leishmanial antigens in pre and post treated urine of visceral leishmaniasis (VL) patients.@*METHODS@#Urine and serum sample from three VL patients were collected. Ammonium sulphate precipitation and purification of urine sample was done for proteins isolation. SDS PAGE of proteins was done followed by western blotting, with the patient's pre and post treatment serum.@*RESULTS@#Eight proteins of molecular weights 17 kDa, 25 kDa, 28 kDa, 42 kDa, 47 kDa, 54 kDa, 60 kDa and 85 kDa were detected in the urine of VL patients before treatment. After treatment with miltefosine, none of the above proteins was detected in urine samples. The western blot analysis with pre treatment serum confirmed the antigenicity of four urinary proteins of molecular weights 25 kDa, 28 kDa, 54 kDa and 60 kDa. The seropositivity with 25 kDa and 28 kDa antigens was negative with serum obtained after the completion of treatment.@*CONCLUSIONS@#In the context to unavailability of a prognostic tool, urinary leishmanial antigens may offer a better choice and may also be useful as immunoprophylactic candidates.